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The Soil Health-Human Health Nexus
Critical Reviews In Environmental Science and Technology
Abstract
Soils can beneficially or adversely affect human health, and likewise human activity can improve or destroy soil health. In the new anthropogenic era, it is worth examining the soil health–human health nexus. To do this, the author evaluates soil from the perspective of what infects us, what heals us, what contaminates us, what nourishes us, and what we breathe. Likewise, the author examines the impact of humans on soil using a similar matrix and suggests strategies to improve human health by maintaining or improving soil health.
... Some metals or metalloids (e.g., As, Cd, Cr, Ni) can be carcinogens (Morgan 2012). Most metals or metalloids can also cause a wide range of chronic health effects if humans are exposed to contaminated soil (Morgan 2012;Pepper 2013). Historically, considerable concern has been raised about lead contamination in soils, since lead exposure in children can cause a range of neurological disorders, and children have a greater risk of direct or indirect soil ingestion than do adults (e.g., Aelion et al. 2009;Oliver and Gregory 2015;Li et al. 2018). ...
... Chronic (long-term) exposure to non-asbestos silicate minerals can also lead to human health effects. Inhalation of quartz particles less than about 4 μm in size can lead eventually to silicosis, a non-cancer lung disease similar to asbestosis (Derbyshire 2007;Pepper 2013). ...
... Permeable urban soils can act as physical/chemical/biological filters for groundwater (Pepper 2013). The filtration ability of soils is partly physical; the transport of particulates and microorganisms (including pathogens) can be suppressed by soil pores which are too fine to allow passage of solid particles or microbial cells (Voisin Table 10.2 ...
In cities, human health and well-being, socioeconomic status, food security, education, gender equity, employment, climate change, and biodiversity are interlinked, and one perhaps surprising common factor is urban soils. In this chapter we explore how a unifying framework for these interrelationships is presented by the United Nations’ Sustainable Development Goals (SGDs). The analysis in this chapter suggests that soils have a role to play in the first fifteen of the seventeen Sustainable Development Goals. We suggest ways in which the knowledge and use of soils by urban inhabitants can help to address poverty, maintain a stable food supply, sustain physical, emotional, and social health, provide opportunities for education, promote gender equality and empowerment of women and girls, generate employment, maintain water quality, moderate climate change, and slow biodiversity and habitat loss. The chapter also addresses other soil-related effects on human health such as soil remediation and acid sulfate soils and has a particular focus on environmental justice issues related to urban soil contamination.
... The links between soil and human health have received increasing attention since the beginning of the 21st century (Brevik & Sauer, 2015), and a wide range of authors have recently published in this area (e.g. Oliver & Gregory, 2015;Pepper, 2013;Stockamp & Thompson, 2016;von Lindern, Spalinger, Stifelman, Stanek & Bartrem, 2016;Wall, Nielsen & Six, 2015). We know that soil can affect human health both directly and indirectly. ...
... Note that promotion of human health is explicit in the definition provided by Doran & Safley (1997). This relationship between soil health and human health has been documented (Kemper & Lal, 2017;Pepper, 2013;Wrench, 1939), and human management can make a considerable difference to the soil properties that influence soil health (Parras-Alcántara, Lozano-García, Keesstra, Cerdà & Brevik, 2016). For example, it has been reported that (a) soil managed in a way that produced higher soil health indicators can produce better quality strawberries, with greater nutritional value to support human health, than soil with lower health indicators (Reganold et al., 2010), (b) using cover crops to enhance microbial activity increases zinc uptake in wheat (Aghili et al., 2014) and (c) organic compost can reduce the uptake of cadmium in rice (Liu, Chen, Cai, Liang & Huang, 2009). ...
... Subsidies help connect farmers to soil by giving them economic incentives to manage their soils more effectively (Galati, Gristina, Crescimanno, Barone & Novara, 2015;Martínez-Casasnovas, Ramos & Cots-Folch, 2010). As indicated previously, management decisions can affect the condition of the soil and thus the quality of the food produced (Reganold et al., 2010) and the overall soil health-human health relationship (Kemper & Lal, 2017;Pepper, 2013;Wrench, 1939). ...
Despite the definite links between soil and human health, it is likely that most people do not think about soil when considering human health. There is a disconnect between most people in our modern society and soil, and when people notice soil it is often in a negative context. People care for things that matter to them, and creating a more positive public image of soil could improve human health by leading to better treatment and understanding of the soil resource. There are a number of concepts that may be able to connect people to the soil, including terroir, soil health and soil security. While terroir originally established a connection between those who appreciate wine and the soils that produce those wines, the concept has been expanded to many additional products. It might be possible to provide a terroir link to human health benefits if they can be shown to be characteristic of a given soil environment. The concept of soil health has caught on with many farmers, policymakers, scientists and the general public, thus providing another possible approach to improve peoples’ connection with soil. Soil security is a recent concept that has been advanced as a way to take advantage of the connection that concepts such as energy, food and water security have made with policymakers. Therefore, we advocate a concerted effort to investigate terroir, soil health and soil security as concepts to improve overall human health. Soil health and soil security might have the most promise, and some social marketing campaigns that include soil health are ongoing.
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... The water-mirror approach underlying aquaphotomics research can be effectively applied especially when examining herbaceous plants (Tsenkova 2009). The soil embraces a significant part of the abiotic (inorganic particles) and biotic (e.g., soil organisms, humus) factors essential for the evolution of plants, therefore, consideration is ineluctable (Pepper 2013). In this chapter section, we will briefly present some of the recent studies on plant health, with special emphasis on stress tolerance and quality of crops. ...
... The biotic stress factors include microbial pathogens-the prokaryotic (bacteria), eukaryotic (fungi and protozoa) organisms and viruses-vermin, insects, and herbivorous animals. The pathogens may originate and live in soils (geo-indigenous) or be introduced allogenic and become inactivated (geo-treatable) (Pepper 2013). In the last years, a trend can be observed in detection of infections in plants-instead of conventionally used destructive and expensive ELISA and PCR assays, non-invasive and real-time spectroscopy methods are becoming more widely spread. ...
... Healthy soils constitute the foundation of thriving ecosystems and societies and are directly tied to food and nutritional security, water quality, human health, climate change mitigation/adaptation, and biodiversity (Manter et al., 2017;National Academies of Sciences, 2017). It is imperative to prevent land degradation that occurs via soil erosion, nutrient losses, and losses of ecological integrity (Doran & Jones, 1996;Doran & Parkin, 1994; fundamental role of SH in food production, nutrition, and food security (Brevik & Sauer, 2015;Oliver & Gregory, 2015;Pepper, 2013;Steffan, Brevik, Burgess, & Cerdà, 2018;Wall, Nielsen, & Six, 2015). Concerningly, statements in the published literature also suggest that SH improvements lead to increased crop productivity and/or nutritional quality (Brevik & Burgess, 2012;Brevik & Sauer, 2015;Bünemann et al., 2018;Pepper, 2013;Wall et al., 2015). ...
... It is imperative to prevent land degradation that occurs via soil erosion, nutrient losses, and losses of ecological integrity (Doran & Jones, 1996;Doran & Parkin, 1994; fundamental role of SH in food production, nutrition, and food security (Brevik & Sauer, 2015;Oliver & Gregory, 2015;Pepper, 2013;Steffan, Brevik, Burgess, & Cerdà, 2018;Wall, Nielsen, & Six, 2015). Concerningly, statements in the published literature also suggest that SH improvements lead to increased crop productivity and/or nutritional quality (Brevik & Burgess, 2012;Brevik & Sauer, 2015;Bünemann et al., 2018;Pepper, 2013;Wall et al., 2015). Recent media headlines state that "Healthy soils lead to healthy food," suggesting that SH practices will "produce crops that contain more nutrients for humans to consume" (Latzke, 2020). ...
... Healthy soils constitute the foundation of thriving ecosystems and societies and are directly tied to food and nutritional security, water quality, human health, climate change mitigation/adaptation, and biodiversity (Manter et al., 2017;National Academies of Sciences, 2017). It is imperative to prevent land degradation that occurs via soil erosion, nutrient losses, and losses of ecological integrity (Doran & Jones, 1996;Doran & Parkin, 1994; fundamental role of SH in food production, nutrition, and food security (Brevik & Sauer, 2015;Oliver & Gregory, 2015;Pepper, 2013;Steffan, Brevik, Burgess, & Cerdà, 2018;Wall, Nielsen, & Six, 2015). Concerningly, statements in the published literature also suggest that SH improvements lead to increased crop productivity and/or nutritional quality (Brevik & Burgess, 2012;Brevik & Sauer, 2015;Bünemann et al., 2018;Pepper, 2013;Wall et al., 2015). ...
... It is imperative to prevent land degradation that occurs via soil erosion, nutrient losses, and losses of ecological integrity (Doran & Jones, 1996;Doran & Parkin, 1994; fundamental role of SH in food production, nutrition, and food security (Brevik & Sauer, 2015;Oliver & Gregory, 2015;Pepper, 2013;Steffan, Brevik, Burgess, & Cerdà, 2018;Wall, Nielsen, & Six, 2015). Concerningly, statements in the published literature also suggest that SH improvements lead to increased crop productivity and/or nutritional quality (Brevik & Burgess, 2012;Brevik & Sauer, 2015;Bünemann et al., 2018;Pepper, 2013;Wall et al., 2015). Recent media headlines state that "Healthy soils lead to healthy food," suggesting that SH practices will "produce crops that contain more nutrients for humans to consume" (Latzke, 2020). ...
Globally, food systems face multiple challenges, including minimizing environmental impacts, adapting to a changing climate, increasing yields, and maintaining and/or increasing crop nutritional quality. Management techniques that focus on soil health (SH) are promising solutions to mitigate some environmental impacts and may increase economic returns. However, claims that SH increases will concurrently increase crop quality and productivity merit careful examination. Factors beyond SH metrics determine crop nutritional quality. Yield outcomes of SH management are of significance, as there are concerns that yield increases are insufficient to meet future food demands. While SH frameworks are comparatively recent initiatives, there are thousands of published conservation agriculture studies that examine yield outcomes with cover crops, no‐till, and rotation. This literature indicates that SH practices can also have neutral or negative yield impacts—only in select systems have consistent yield increases been realized, highlighting the need for language clarification and improvements in mechanistic understanding of regional‐scale yield impacts.
... Biological diversity of soil ecosystems is fundamentally important for soil and human health. Soil macroorganisms are important in establishing soil health, and soil health has direct ties to human health 19,204 ; therefore, soil macroorganisms are important to human health at least to the extent they are important to soil health. However, the complexities and associated quantification of that diversity provide many challenges. ...
... One is that the idea of human health is already implicit in widely accepted definitions of soil health, 277 and the connection between soil health and human health is already documented. 19,204 Commonly used soil health definitions also incorporate the concepts of improving air and water quality, and these are goals that already enjoy widespread public support. 278,279 Soil health already has international acceptance by agricultural interests [280][281][282] and policy makers. ...
Soil influences human health in a variety of ways, with human health being linked to the health of the soil. Historically, emphasis has been placed on the negative impacts that soils have on human health, including exposures to toxins and pathogenic organisms or the problems created by growing crops in nutrient-deficient soils. However, there are a number of positive ways that soils enhance human health, from food production and nutrient supply to the supply of medications and enhancement of the immune system. It is increasingly recognized that the soil is an ecosystem with a myriad of interconnected parts, each influencing the other, and when all necessary parts are present and functioning (ie, the soil is healthy), human health also benefits. Despite the advances that have been made, there are still many areas that need additional investigation. We do not have a good understanding of how chemical mixtures in the environment influence human health, and chemical mixtures in soil are the rule, not the exception. We also have sparse information on how most chemicals react within the chemically and biologically active soil ecosystem, and what those reactions mean for human health. There is a need to better integrate soil ecology and agronomic crop production with human health, food/nutrition science, and genetics to enhance bacterial and fungal sequencing capabilities, metagenomics, and the subsequent analysis and interpretation. While considerable work has focused on soil microbiology, the macroorganisms have received much less attention regarding links to human health and need considerable attention. Finally, there is a pressing need to effectively communicate soil and human health connections to our broader society, as people cannot act on information they do not have. Multidisciplinary teams of researchers, including scientists, social scientists, and others, will be essential to move all these issues forward.
... On the one hand, natural microbial communities are a source of ARGs for all antibiotics of natural origin that have already been used in clinical and veterinary medicine, as well as those that are promising or not even discovered yet. On the other hand, various taxa of microorganisms, including soil bacteria and fungi, serve as reservoirs of natural antibiotics [2]. ...
... As an example, due to the gradual historical disenfranchisement of mankind from soil, the collective imagination lost the connection between food and soil. The root of our livelihood derives directly from soil but humans have lost this perception (Pepper, 2013). This last author, in fact, stress the soil health-human health nexus which is no more perceived making it difficult to conceive that threats to soil may ultimately affect human well-being (Brevik et al., 2017). ...
... Heavy metals can be added to the environment through a variety of sources, which includes air that contains mining, smelting, and refining of fossil fuels; water having domestic sewage and industrial effluents; and soil like agricultural and animal wastes, municipal and industrial sewage, coal ashes, fertilizers, and pesticides. Heavy metal pollution often results in the degradation of soil health (Kools et al. 2005, Abdu et al. 2017, the contamination of surface and groundwater (Hashim et al. 2011, Mohankumar et al. 2016) and food chain pollution (Hapke 1996, Notten et al. 2005, Tchounwou et al. 2012, and consequently is a threat to human health (Pepper 2013, Jovanović et al. 2015, Oliver & Gregory 2015, Sarwar et al. 2017, Yang et al. 2017. Contrary to the pollution brought on by excessive levels of heavy metals in the soil, it has been documented in numerous regions of the world that agricultural lands are deficient in one or more micronutrients, including heavy metals/metalloids. ...
Regional geochemical mapping was carried out in Bilaspur and Korba Districts of Chhattisgarh, and stream sediments/slope wash, soil, and water samples were analyzed for concentration of heavy metals. The study contributes to understanding heavy metals contamination of sediments, soils, and water due to anthropogenic activity, mainly in agriculture-based rural areas. The study reveals that high geochemical anomalies observed for heavy metals like Ni, Cr, As, and Zn in sediments and soil samples are due to the extensive uses of phosphatic fertilizer and soil amendments in the form of poultry and swine manure. Water quality assessment of major streams in the study areas shows that the water is suitable for domestic and agricultural uses. Correlation analysis reveals that the chemical weathering of rock-forming minerals doesn’t control the surface water chemistry of the study area and is also an anthropogenic source of sodium in water. This study also shows the importance of the country’s geochemical mapping database, which will have much broader applications than conventional mineral exploration and geological mapping.
... Soil is the most complicated biomaterial on the planet other than perhaps humans themselves. [8] This complexity lies not only in its various properties and different constituents but starts from its many definitions. Soil definition has changed over time and mainly among the different disciplines whose interests converge on this natural resource. ...
The present paper introduces soil as a complex system, so a multidisciplinary approach is needed to study not only the composition, abundance, and transport of microplastics (MPs) in terrestrial ecosystems but also soil properties and processes involved in their degradation and/or interaction with soil polyphasic matrix. Despite many researchers focusing their studies on the impact of MPs on the terrestrial ecosystem over the past years, little has been done about the use of biochemical indicators to study their effect on soil functionality.
... Literature at the onset of the 21st century has outlined the vital role of soil health conservation in farm production, productivity, nutrition, and food security (Pepper, 2013;Grassini et al., 2013;Luis et al., 2020). Furthermore, it points out that soil health management is essential for augmenting production and productivity to meet future global demand for food (Grassini et al., 2013). ...
Purpose
This paper finds the returns from soil conservation practices and examines whether the welfare implications of adopting the conservation practices are heterogeneous across the farming groups in Indian agriculture.
Design/methodology/approach
The study uses an endogenous switching regression (ESR) method on the data collected from the 77th round of National Sample Survey (2019–21) to quantify the returns from adopting soil conservation practices.
Findings
It finds that farmers adopting soil health conservation practices would have reduced their crop yield by 13% if they did not implement them. Similarly, smallholders who have not adopted soil health management practices would have increased crop yield by 16% if they had adopted the practices. The authors also observed that the returns from adopting soil health management practices vary across farming groups, where marginal and large farms tend to gain higher yields. Finally, the authors find that regardless of farm size, smallholders who did not adopt soil health management practices would benefit from adopting these with increased crop yields of 29%–31%.
Research limitations/implications
More data could have been better for drawing policy implications, since the number of soil card users are relatively less.
Originality/value
This research work uses nationally representative data, which is first in nature on this very aspect.
... In recent decades, anthropogenic impacts have led to more severe soil pollution with hydrocarbon substances, becoming one of the world's environmental problems (Cachada et al., 2018;Dallas Khamehchiyan et al., 2007). If pollution with rocket fuel is mainly characteristic only for areas of rocket impact, then pollution with oil products such as kerosene and diesel fuel is widespread (Pepper, 2013;Shein et al., 2007). ...
Studies of the influence of hydrocarbon rocket fuel kerosene T-1 on the physical and geochemical properties were carried out in laboratory circumstances on different types of soils: brown semi-desert soil designated as zone (U-25) located in Central Kazakhstan, mountainous brown desert soil zone (U-30) located in East Kazakhstan, and a model soil standard (control soil). The soil was treated with various concentrations (0.002–150.0 g/kg) of hydrocarbon rocket fuel kerosene T-1, while the contact time was 3, 10, and 30 days. Pollution with kerosene T-1 in concentrations 5.0–15.0 g/kg affects the hydraulic characteristics of soils from the U-25 zone, and the filtration rate decreases by 4–5 times. For the mountainous brown desert soil from the U-30 zone, the concentration of kerosene up to 15.0 g/kg does not affect the mechanical composition of the soil, as well as the availability of the main nutrients (potassium, phosphorus, nitrogen). According to the mechanical composition, both soils belong to medium loamy soils. It has been established that when soil is contaminated from the U-25 zone in concentrations 15.0–150.0 g/kg, the fraction from 1.0 to 0.05 mm increases by 4–5%, and the silty and clay fractions in the soil decrease.
... This is because of the profound effect soil has on the health and well-being of humans and depending on the condition of the given soil and the interactions of interest, this effect can be either positive or negative and direct or indirect (Steffan et al. 2018). Soils that affect human health include natural soil, which usually has little anthropogenic contamination, and soils in agroecosystems, urban areas, mines, oil and gas extraction areas, landfill sites and other locations where anthropogenic contamination is more likely (Pepper, 2013;Brevik and Burgess, 2015;Oliver and Gregory, 2015;Steffan et al. 2018). Although soils can be polluted by multiple means, pollution through waste discharges, particularly hazardous wastes has become a worldwide phenomenon due to heavy metals presence that is transferrable to plants (Akinbile 2012. ...
Akure town has over the years witnessed increasing human activities as a result of urban expansion. One of the indictors of this expansion is solid waste generation and associated land pollution arising from open dump waste disposal method. Leachate from these dump sites are known to be major source of heavy metal contaminations in soil. The study investigated the levels of heavy metals in soil around open dumpsites in Akure, Nigeria. Four dumpsites namely Igbatoro, Edema and Ado were selected with one control at relatively undisturbed vegetation at the Federal College of Agriculture, Akure. Lead, copper, cadmium, chromium and nickel were investigated. A total of twenty four (24) samples were collected at 0-15cm and 15-30cm depths, from the base of dumpsite, 20m and 50m away from the dumpsites for the purpose of comparison. Mean Cu 2+ levels at 0cm-15cm were 7.71mg/kg, 4.42mg/kg, 3.59mg/kg and 3.17mg/kg, for Igbatoro, Edema, Orire and Ado respectively. At 15cm-30cm there was a general decline in mean Cu 2+ to 5.034 mg/kg, 3.65 mg/kg, 5.3 mg/kg and 4.54 mg/kg in Igbatoro, Edema, Orire and Ado respectively. Mean Ni 2+ levels were generally high and exceed FEPA standard. At 0.15cm depth, Ni 2+ levels were 10.02 mg/kg, 5.74 mg/kg, 4.67mg/kg, 4.12 mg/kg and 3.22 mg/kg in Igbatoro, Edema, Orire and Ado respectively. At 15cm-30cm depth, Ni 2+ levels were 6.54 mg/kg, 4.75 mg/kg, 6.91 mg/kg, 5.9 mg/kg and 3.01 mg/kg. Cd 2+ levels, at 0cm-15cm depth were 1.54 mg/kg, 0.88 mg/kg, 0.72 mg/kg, 0.63 mg/kg and 0.5 mg/kg, in Igbatoro, Edema, Orire and Ado respectively, while at 15cm-30cm depth, concentration levels were 1.01 mg/kg, 0.73 mg/kg, 1.06 mg/kg, 0.90 mg/kg and 0.46 mg/kg in Igbatoro, Edema, Orire and Ado respectively. Cr 6+ levels were generally high in all the sample site and above permissible limit. At 0cm-15cm depth, concentration levels were 12.34 mg/kg, 4.69 mg/kg, 3.96 mg/kg, 2.53 mg/kg and 1.98 mg/kg in Igbatoro, Edema, Orire and Ado respectively, while at 15cm-30cm depth, Cr 6+ levels were 8.05 mg/kg, 3.78 mg/kg, 6.72 mg/kg, 4.79 mg/kg and 1.85 mg/kg. Concentration of Pb2 + were 7.25 mg/kg, 1.66 mg/kg, 1.51 mg/kg and 0.32 mg/kg at 0cm-15cm, while 4.73 mg/kg, 1.27 mg/kg, 2.13 mg/kg and 0.45 mg/kg at 15cm-30cm in Igbatoro, Edema, Orire and Ado respectively. Result of ANOVA shows significant difference in metal levels at different sampling points. Elevated levels were found at the base of the dumpsites compared to levels at 20m and 50m. Test result for statistical difference in concentration levels between depths using student t test shows significant difference at P>0.05. Contamination levels were generally high at 0-15cm sample depth.
... Human health is connected to soil in many ways (Table 1; Fig. 1), and the soil-human health nexus has long been known (Oliver and Gregory, 2015;Reeve et al., 2016;Pepper, 2013). Soil can have positive and negative impacts on human health, as recently summarized by Brevik et al. (2020). ...
Soils have recently received attention in the policy area due to their various connections to climate change, human health and their key role in sustaining human societies in general. In this context, agricultural production and healthy nutritious food are linked to soil health and the diversity of their (micro-)biome, which depend on organic carbon materials as an energy and nutrient source. In this paper, we review the evidence showing that carbon-rich soils improve the resilience of human societies to pandemics and other crises. We indicate pathways for how the loss of soil carbon due to farming could be reversed by transformations within our food systems. Moreover, we argue that soil carbon has a strong role to play in enhancing environmental and human health in addition to mitigating and adapting to climate change. This multifaceted role requires a transdisciplinary dialogue and multi-stakeholder collaboration.
... Aerosols and other particulate substances derived from geogenic dust are produced as a result of various geological processes that endanger human health (Pepper, 2013). The wind, which carries dust particles from volcanoes, arid regions (deserts, marine aerosols, and forest fires) has a negative impact on health and environment (Table 2). ...
All living organisms on the earth require elements (major, minor, and trace) for their survival, and excessive or insufficient consumption of such elements cause serious health problems. These elements usually reside in earth material of the geosphere from where they enter into biosphere through various continuously operating geological processes such as weathering, erosion, transportation, or volcanic eruptions. Medical geology is a new and emerging branch of geosciences that studies material derived from geological processes and its effects on the health of animals and plants. The relationship between elements derived from the geological processes and their impacts on human beings had been recognized from ancient times. Keeping the importance of medical geology to the society, various organizations had been working to popularize medical geology and to bring its benefits to the society by organizing various activities and offering courses in medical geology. Currently, medical geology is being developed as an interdisciplinary science with the coordination of geoscientists and health researchers to unfold the health issues associated with the use of material derived from the natural geo-environment. This paper presents a historical overview of medical geology from the very beginning to the present and highlights areas where future research attention is required.
... According to the Food and Agriculture Organization of the United Nations, only 12.6% of the world's land is available for agricultural activities (FAO and ITPS, 2015). While agricultural production and food safety are seriously threatened after various pollutants (e.g., heavy metals, polycyclic aromatic hydrocarbons, and pesticides) enter the soil (Pepper, 2013). The above processes may affect human health, leading to various diseases and immunocompromise. ...
Soil pollution has become an important environmental issue worldwide. Various pollutants in soils may harm human health through the food chain. At present, the commonly used remediated methods mainly include thermal treatment, electrokinetic remediation, stabilization/solidification, soil washing, and bioremediation. Among them, ball milling is a non-combustion technology with simple operation, green, and mild reaction conditions as well as wide applicability, and it is promising in the decontamination of soil pollutants. Ball milling techniques have been gradually used for the detoxification of persistent organic pollutants and heavy metals in contaminated soils, while related reviews focusing on ball milling for soil remediation are limited. It is necessary to fully understand the potential and applied value of ball milling for remediation of contaminated soils. Ball milling has different effects and mechanisms for different pollutants and soil types. Therefore, there is a need to systematically review and digest the relevant knowledge on ball milling remediation of contaminated soils. In this review, the main types of ball milling and influencing factors are summarized, and the mechanisms of ball milling for soil remediation are analyzed. Finally, the problems which need to be solved are briefly described and the future research direction and trend are pointed out. This review is expected to promote the application and its in-depth research of ball milling technology on soil remediation.
... An increased risk of death from COVID-19 was observed in counties with the lowest concentration of Zn in surface soils, and this observation was consistent over time during our assessment period (first sampling time point October 8, 2020, and last point March 25, 2021). The concentrations of trace elements in human body are fundamentally influenced by geochemical distribution via the food chain, and this has been evident to impact the health of the local population (Johnson et al., 2010;Pepper, 2013;Steffan et al., 2018). Particularly, it has been shown that low concentration of Zn in soil is one of the major factors associated with Zn deficiency in crops and humans (Alloway, 2009;Gashu et al., 2021). ...
Severe outcome particularly death is the largest burden of COVID-19. Clinical observations showed preliminary data that deficiency in certain trace elements, essential for the normal activity of immune system, may be associated with worse COVID-19 outcome. Relevant study of environmental epidemiology has yet to be explored. We investigated the geographical association between concentrations of Se, Zn, Fe and Cu in surface soils and case fatality rate of COVID-19 in USA. Two sets of database, including epidemiological data of COVID-19 (including case fatality rate, from the University of John Hopkinson) and geochemical concentration data of Se, Zn, Fe and Cu in surface soils (from the National Geochemical Survey), were mapped according to geographical location at the county level across conterminous USA. Characteristics of population, socio-demographics and residential environment by county were also collected. Seven cross-sectional sampling dates, with a 4-week interval between adjacent dates, constructed an observational investigation over 24 weeks from October 8, 2020, to March 25, 2021. Multivariable fractional (logit) outcome regression analyses were used to assess the association with adjustment for potential confounding factors. In USA counties with the lowest concentration of Zn, the case fatality rate of COVID-19 was the highest, after adjustment for other influencing factors. Associations of Se, Fe and Cu with case fatality rate of COVID-19 were either inconsistent over time or disappeared after adjustment for Zn. Our large study provides epidemiological evidence suggesting an association of Zn with COVID-19 severity, suggesting Zn deficiency should be avoided.
... In the last decades, vehicular traffic has been one of the main causes of air and soil pollution in urban and rural areas. According to epidemiological studies, there is an association between exposure to soil pollutants and adverse health effects [1][2][3]. Many cars and trucks run on highways and county roads, spreading pollution across several countries. ...
The objective of the present study was to investigate metal(loid)s in soils, in the trunk xylem sap and in the leaves of the Dipteryx alata plant located near the highway with high vehicle traffic in agricultural regions and near landfills, and to assess the transfer of metal(loid)s from soil to plant and possible health risk assessment. Trunk xylem sap, leaves and soil samples were collected at three sites near the highway. The analysis of trace elements was carried out using inductively coupled plasma optical emission spectroscopy (ICP OES). In the three soil sampling sites far from the highway edge, 15 elements were quantified. The concentrations of elements in the soil presented in greater proportions in the distance of 5 m in relation to 20 and 35 m. The metal(loid)s content in the study soil was higher than in other countries. The concentrations of Al, Cu, Fe, Mg, Mn, P, Se and Zn in the xylem sap were much higher than the leaves. The values of transfer factor of P, Mg and Mn from soil to the xylem sap and transfer factor of P from soil to leaf were greater than 1, indicating that the specie have a significant phytoremediation and phytoextraction potential. This plant has a tendency to accumulate As, Cd and Cr in its leaf tissues. The chronic hazard index (HI) values recorded in this study were above 1 for adults and adolescents. It is concluded that the soil, the trunk xylem sap and leaves of this plant are contaminated by heavy metals. Ingestion of the trunk xylem sap of this plant can cause toxicity in humans if ingested in large quantities and in the long term; therefore, its consumption should be avoided.
... The importance of the soil-human health nexus has also been recognized ever since the dawn of civilization (Howard 1947;Magdoff 2001;Sherwood and Uphoff 2000;Brevik 2014;Brevik and Sauer 2015;Pepper 2013;Oliver and Gregory 2015;Wall et al. 2015;Kemper and Lal 2017;Lehmann et al. 2020). Viewing soil as a living ecosystem transforms the way we think about soil and how to improve and manage it to advance our agricultural production without degrading environmental quality. ...
... The importance of the soil-human health nexus has also been recognized ever since the dawn of civilization (Howard 1947;Magdoff 2001;Sherwood and Uphoff 2000;Brevik 2014;Brevik and Sauer 2015;Pepper 2013;Oliver and Gregory 2015;Wall et al. 2015;Kemper and Lal 2017;Lehmann et al. 2020). Viewing soil as a living ecosystem transforms the way we think about soil and how to improve and manage it to advance our agricultural production without degrading environmental quality. ...
... This provisioning function of soils depends on and can be further improved by intelligent and sustainable agricultural land-use management; it cannot work without the natural soil fertility (with the exception of hydroponic systems), quality and health status [8,153]. The soil health-human health nexus goes even beyond that, e.g. it involves healthy food with high nutritional value that depends on the soil nutrient status, or the provision of a more balanced climate in urban areas [13,154,155]. It also includes the supply of medicinal resources (see § §4b-e). ...
Intact, ‘healthy’ soils provide indispensable ecosystem services that largely depend on the biotic activity. Soil health is connected with human health, yet, knowledge of the underlying soil functioning remains incomplete. This review highlights selected services, i.e. (i) soil as a genetic resource and hotspot of biodiversity, forming the basis for providing (ii) biochemical resources and (iii) medicinal services and goods. Soils harbour an unrivalled biodiversity of organisms, especially microorganisms. Some of the abilities of autochthonous microorganisms and their relevant enzymes serve (i) to improve natural soil functions and in particular plant growth, e.g. through beneficial plant growth-promoting, symbiotic and mycorrhizal microorganisms, (ii) to act as biopesticides, (iii) to facilitate biodegradation of pollutants for soil bioremediation and (iv) to yield enzymes or chemicals for industrial use. Soils also exert direct effects on human health. Contact with soil enriches the human microbiome, affords protection against allergies and promotes emotional well-being. Medicinally relevant are soil substrates such as loams, clays and various minerals with curative effects as well as pharmaceutically active organic chemicals like antibiotics that are formed by soil microorganisms. By contrast, irritating minerals, soil dust inhalation and misguided soil ingestion may adversely affect humans.
This article is part of the theme issue ‘The role of soils in delivering Nature’s Contributions to People.
... This knowledge brings about the question, what can we do to maximize the health benefits and minimize the risks associated with soil? Previous work has established links between the concepts of soil health (Kemper and Lal 2017;Pepper 2013) and soil security ) with human health. Within soil security, there are close connections between the condition dimension and soil health Field 2017). ...
Soils influence human health in many ways, both positive and negative. These include the supply of nutrients; exposure to heavy metals, organic chemicals, and pathogens; the supply of antibiotics and other medicines; and soils may even support mental health. Soils can impact all aspects of the human system, from the skin to the respiratory tract, digestive and nervous systems, and beyond. Human management of the soil system can have a major impact on these influences. In particular, any management that supports soil health also supports human health. Establishing the health of a soil involves the measurement of soil biological, chemical, and physical properties. Future needs in the area of soil and human health include well-designed scientific studies that investigate the links between soil abiotic and biotic properties and human health as well as soil science links to soils and human health.
... Medzi faktory, ktoré ovplyvňujú proces kontaminácie pôdy zaraďujeme najmä ľudskú činnosť (Navarrete et al., 2017). Kontaminácia pôdy potenciálne rizikovými prvkami môže priamo alebo nepriamo vplývať aj na ľudské zdravie (Pepper, 2013;Oliver, Gregory, 2015). Príčinou ich nepriaznivého vplyvu je vysoká toxicita, nebiologická odbúrateľnosť, správanie a bioakumulácia rizikových prvkov v potravovom reťazci (Li et al., 2014). ...
... В последние годы в связи с увеличением распространения бактерий с множественной лекарственной устойчивостью и сокращением числа АБ, эффективных против патогенных бактерий, возрос интерес к резистому микробных сообществ окружающей среды как потенциальному резервуару новых генов устойчивости [4]. Необходимо отметить, что природный резистом изначально содержит гены антибиотикорезистентности (Antibiotic Resistance Gene, ARG, АРГ) ко всем уже применявшимся, вновь открытым и даже еще не известным АБ природного происхождения, так как они вырабатываются различными популяциями почвенных микроорганизмов, включая бактерии, грибы и актиномицеты [5]. ...
Antibiotics are widely used in animal husbandry at present. Due to their excessive and incorrect use, they have led to the rapid spread of antibiotic resistance genes (ARGs), as well as antibiotic-resistant bacteria (ARB) in microbial communities of the environment. The review examines works on the use of antibiotics in animal husbandry, the transmission of ARGs and ARB from animals to humans, their spread in the environment with wastewater from livestock enterprises and water and air flows. The role of manure as a reservoir of ARGs and the effect of the processing and storage of manure on the abundance and diversity of ARB and ARGs have been also analyzed. We have also touched on issues related to the presence of ARGs and ARB in animal and plant products and their introduction into the human microbiome with food.
... Heavily contaminated soils may pose long-term risks to ecosystems and human health [11] [12] [13] via the increased uptake and accumulation of heavy metals in plant tissues [14] [15] [16]. Risk assessment has emerged in recent [17] [18]. ...
... Numerous researchers have suggested that improvements in SH also lead to increases in crop productivity and nutritional quality (Pepper 2013;Wall et al. 2015;Warkentin 1995). Although improvements in SH can potentially promote crop yields in some systems via increased nutrient cycling and water capture, these linkages are only beginning to be quantitatively explored (Roper et al. 2017). ...
... Soil 'health' is a metaphor that captures an important parallel between soils and human health; soils that are poorly cared for will have shorter lifespans and require increasing levels of intervention to deliver the functions required. This metaphor serves as a teaching tool that captures an essential parallel between soils and our human health (Shaxson et al., 2008;Pepper, 2013;Oliver and Gregory, 2015). The concept of health as it relates to human health is slowly developing into a movement that helps improve, understand and manage the complex soil system. ...
... Heavily contaminated soils may pose long-term risks to ecosystems and human health [11] [12] [13] via the increased uptake and accumulation of heavy metals in plant tissues [14] [15] [16]. Risk assessment has emerged in recent [17] [18]. ...
... Soil is a dynamic living system whose condition underpins agricultural productivity and ecosystem function (Doran et al., 1996). While healthy soils promote the provision of ecological services, soil degradation can lead to environmental strain and loss of productivity (Bennett et al., 2010;Pepper, 2013). Broadly, soil health is understood to be the combination of physical, chemical and biological properties that promote the ability of a soil to support human, plant and animal needs while maintaining or enhancing environmental quality (Doran et al., 1996;Moebius-Clune et al., 2016). ...
More meaningful and useful soil health tests are needed to enable better on-farm soil management. Our objective was to assess the relationship between field management, soil health, and soil microbial abundance and composition (phospholipid fatty acid analysis (PLFA)) in soil collected from two fields (farmer-designated ‘good’ versus ‘poor’) across 34 diverse (livestock, grain or vegetable cropping) farms in Maritime Canada. Soil health was measured using soil texture, surface hardness, available water capacity, water stable aggregates, organic matter, soil protein, soil respiration, active carbon, and standard nutrient analysis. All soils were medium to coarse textured (<8% clay). Mixed models analysis showed that both CSHA and PLFA were able to resolve statistical differences between cropping systems, however conventional soil chemical analysis was the only testing method to resolve statistical differences between farmer designated ‘good’ and ‘poor’ fields. Principle component analyses determined management history (rotation over previous three years), but not ‘good’ or ‘poor’ field designation, to be an important determinant of soil health. Water-stable aggregates and soil respiration were positively correlated with all PLFA microbial groups, and negatively correlated with sand, P, Cu and Al. Lower-intensity management (perennial forage, mixed annual-perennial cropping), manure application and low tillage were linked to higher soil respiration, water-stable aggregates, fungi, mycorrhizae, Gram negative bacteria, and lower soil available P. Correlations between CSHA and PLFA shows promise for integrating these two tests for improved soil health assessment.
... Few studies addressed the importance of the soil quality on human health [2,[6][7][8][9][10][11]; however, these researches did not focus on urban soils. A study by Li et al. [2] is the only review with a focus on urban soils. ...
Based on the hypothesis that urban activities can deposit chemical contaminants in soil and consequently have an impact on the vitality of key organisms of the ecosystem, the aim of the present study was to analyse genotoxicity in earthworm's coelomocytes in urban soil samples in comparison to soil samples from protected areas. Earthworms (Eisenia andrei) were exposed to soil samples for 14 days, subsequently the coelomocytes were extracted with an 10% ethanol solution and used in single cell gel electrophoresis (SCGE) assay and the micronucleus (MN) assay. The levels of copper, cadmium, lead, zinc, and arsenic were measured in monitored soil samples. Earthworms exposed to urban soils had higher levels of DNA damage, according to the results of the SCGE assay, than earthworms exposed to protected area soils. The frequency of micronuclei did not differ between the studied soil samples. There was an association between % DNA (SCGE assay) and arsenic and zinc levels. Copper, lead and zinc levels in urban soil samples exceeded the limits of legal values in Brazil. Our findings show that the genotoxicity markers we tested are sensitive to contamination and this association should be taken into account by regulatory agencies.
... While consistent quantitative SH assessment systems are only slowly developing, largely because of their complexity, practitioners of soil management, including many farmers and consultants, are enthusiastic about SH improvement, and there is a growing understanding of the connection between human, environmental and soil health (Oliver, 1997;Pepper, 2013;Brevik, 2014). ...
... Even though soil ES-human health connections have not received much study, the links between soils and human health have received a large amount of attention (Baumgardner, 2012;Brevik and Burgess, 2013;Pepper, 2013;Oliver and Gregory, 2015;Zornoza et al., 2015;Steffan et al., 2018). Many of the soil-human health connections identified fall under the category of provisioning services. ...
There are clear connections between ecosystem services (ES) and human health, as well as between soils and human health. However, studies to date have not investigated links between soil ES and human health. Viewing the relationship between soils and human health through the ES lens reveals that soil ES such as the provisioning of shelter, clothing, and fuel have been overlooked in the soil and human health literature. Shelter is important to human health because it provides protection against inclement weather, temperature extremes, and other potential threats. Clothing provides a more consistent micro-environment around the skin and also provides protection from ultraviolet radiation and some parasites. Fuel allows us to warm shelters, providing refuge from cold temperatures, and cook food, which reduces disease. The materials supplied by soils in support of these functions are often done so in a more environmentally responsible way than is the case with many modern building and clothing materials or with fossil fuels. However, it is important to realize that sustainable management practices are critical in order to achieve environmentally responsible production of these products. Future studies need to investigate the links between these overlooked soil ES and human health.
... Thus, there are several complicated soil variables which makes the investigations of soils and human health difficult and also means that the complete study of soils and human health should involve many different specialties such as soil scientists, medical professionals, toxicologists, anthropologists, etc. These specialty groups traditionally do not work together on research projects and do not always effectively communicate with one another (Pepper et al. 2009;Brevik and Hartemink 2010;Brevik 2013a, b;Pepper 2013;Shishkov and Kolev 2014;Brevik and Burgess 2014;Brevik and Sauer 2015;El-Ramady et al. 2015;Brevik et al. 2017). ...
Soil has a great and holy position worldwide. This position has been acquired from the importance of soil in saving food, feed, fuel, and fibre for animals and humans. Egypt was and still one of the most important countries, which soils played a crucial role in the Egyptian civilization. Therefore, very strong link between soils and humans has been reported based on the great roles of soils in plant and human nutrition. On the other hand, there are several anthropogenic activities, which cause many problems for soils such as pollution, degradation, and erosion. There are direct and/or indirect effects of soils on human health as well as plants. Therefore, this chapter is an attempt to emphasize the great roles of soils in plant and human health as well as the security of soils under pollution conditions.
... heavy metals) and organic pollutants (e.g. polycyclic aromatic hydrocarbons (PAHs) and halogenated compounds such as pesticides, polychlorinated biphenyls (PCBs), etc.) produces several negative effects on food safety and crop production (Pepper, 2013). For example, extensive use of pesticides has determined a notable depletion of soil microbial biodiversity, determining a reduction in nitrogen fixation processes with a consequent loss of soil productivity (Das & Mukherjee, 2000;Jacobsen & Hjelmsø, 2014). ...
In recent years, the destruction of (persistent) organic pollutants and the immobilization of heavy metals and radioactive nuclides in contaminated matrices by mechanochemical treatment have been proved. Several studies demonstrate a remarkable versatility of the high energy ball milling technology in the detoxification of contaminated soil, a primary issue that demand rapid and adequate solutions. In the present mini-review, scientific and technological aspects of polluted soil mechanochemical treatment are discussed. In addition, an economic feasibility study is performed, employing technical and cost data obtained by constructors. It corroborates the competitiveness of the mechanochemical treatment as potential cleaning technology.
... Nitrate-N becomes a water quality problem when it reaches and contaminates groundwater, causing health hazards if this water is used for drinking purposes (Mullen, 2011). Leached nitrates in groundwater can cause blue baby syndrome, methemoglobinemia, which can be fatal to humans (Pepper, 2013). Factors affecting nitrate leaching losses from soil have been reviewed recently by Cameron et al. (2013). ...
Integrated nutrient management systems that use a holistic approach, using inorganic fertilizers as well as management practices aimed to increase soil organic matter, are needed to improve soil health. Management practices need to take into account differences in soil properties, climate and available local resources. In this chapter, we discuss the chemistry of nutrients focusing mostly on nitrogen and phosphorus. The impact of chemical composition of soils (nutrients, pH and salinity) on soil health is discussed. We review factors influencing the solubility of nutrients and discuss management practices to improve nutrient availability and reduce the reliance on inorganic fertilizers. We illustrate a case study from India that shows how integrated nutrient management, using both inorganic fertilizers, including sulphur and micronutrients, and practices to improve and increase soil organic carbon, can be done successfully and used on a large scale using site-specific research and available resources.
... Heavy metal pollution often results in the degradation of soil health ( Abdu et al., 2017;Kools et al., 2005), the contamination of surface and groundwater (Hashim et al., 2011;Mohankumar et al., 2016;Wuana and Okieimen, 2011) and food chain pollution (Hapke, 1996;Notten et al., 2005;Tchounwou et al., 2012), and consequently is a threat to human health ( Jovanovi? et al., 2015;Oliver and Gregory, 2015;Pepper, 2013;Sarwar et al., 2017;Weil and Magdoff, 2004;Yang et al., 2017). ...
Heavy metal pollution often results in the degradation of soil health. The term ‘soil health’ or ‘soil quality’ is used to express the status of the soil’s functional ability in the ecosystem, as indicated by its physical, chemical and biological properties. Contamination of heavy metals above threshold values can destroy the soil’s natural ability to perform ecosystem services, a change which can be irreversible. Heavy metal contamination of soils is a global challenge that needs to be resolved by the joint efforts of governments and scientific communities. The purpose of this chapter is to summarize the available literature regarding sources, impacts, indicators, risk assessment, remediation and the future problems of heavy metals in relation to soil and human health, and to provide directions for the improvement of soil management and the development of effective pollution control strategies.
Soil underpins the functioning of all terrestrial ecosystems. Sustainable soil management is crucial to preventing further degradation of the non-renewable soil resources and achieving sustainability. The soil health concept has gained popularity as a means to this end and has been integrated into the policies of many countries and supranational organisations. We need an accurate definition and scientifically robust assessment framework for effectively measuring, monitoring and managing soil health, a framework that can effectively be communicated to the policy arena and to stakeholders. Linking soil health to the provision of ecosystem services in line with selected UN Sustainable Development Goals (SDGs) provides an effective link with the policy arena focusing on sustainable development. This is needed because lack of operational procedures to measure soil health leads to policies that ignore soils and focus on management measures. We review the literature on soil health, its conceptualisation, the current criteria for selecting indicators and thresholds, as well as the implementation of different soil health assessment frameworks. Most published studies on soil health focus on agriculture; however, a broader perspective that includes various terrestrial ecosystems is needed. Soil health assessments should not be limited to agricultural contexts. We highlight the significant potential of advanced sensing technologies to improve current soil health evaluations, which often rely on traditional methods that are time-consuming and costly. We propose a soil health assessment framework that prioritises ecological considerations and is free from anthropogenic bias. The proposed approach leverages modern technological advancements, including proximal sensing, remote sensing, machine learning, and sensor data fusion. This combined use of technologies enables objective, quantitative, reliable, rapid, cost-effective, scalable, and integrative soil health assessments.
This chapter covers the time from the ancient history period to the present. It also includes some of the needs to expand the topic of soil and human health as a means to improve peoples’ health in several ways. The therapeutic uses of soil to heal wounds and to detoxify have been known since prehistorical times. Ancient civilizations from 3000 BCE had an empirical understanding of the relations between soil, the environment, and human health. The soil is an important resource for the provision of adequate food, materials for building and clothing, and as a source of medicines such as antibiotics. The latter offers huge possibilities for the future. Trace elements are involved in plant, animal, and human nutrition; knowledge of these depended on growing expertise in chemistry in the twentieth century and medicine to understand the causes of diseases such as anemia, goiter, and cretinism. Toward the end of the 20th century new tools such as omics and the use of DNA started the great explosion in understanding of soil microbiology. This will be at the root of much improvement in management of the soil and our understanding of the soil–human nexus, such as the gut microbiome. Soil pollution is a major problem related to past industry, waste disposal, and agricultural practices. The use of organic chemicals and metal-based pesticides that persist in the soil and environment has caused human illnesses. Modern challenges such as microplastics create challenges for soil and human health that are not well understood at present. The use of data collection, statistical analyses, spatial analyses, machine learning and graphical tools have provided insight into links between soil and health and this area will continue to flourish with future needs and developments. A major drawback to the future exploration of soil and human health is the general lack of interdisciplinary engagement between soil scientists, clinicians, medical scientists, and others who have interests and expertise in soil, human health, and related subjects. Future research would benefit tremendously from scientists in these areas forming collaborations and from funding agents and governments promoting the benefits of such collaboration with interdisciplinary and transdisciplinary grant opportunities.
The presence and reproduction of pathogens in soil environment have significant negative impacts on soil security and human health in urban-rural ecosystem. Rapid urbanization has dramatically changed the land use, soil ecosystems, and the presence of pathogens in soil environment, however, the risk associated with soil pathogens remains unknown. Identifying the potential risk of pathogens in soils in urban-rural ecosystem has become an urgent issue. In this study, we established a risk evaluation method for soil pathogens based on analytic hierarchy process and entropy methods to quantitatively estimate the potential risk of soil pathogens to children and adults in urban-rural ecosystem. The abundance and species number of soil pathogens, network structure of soil microbial community, and human exposure factors were considered with 12 indicators to establish the risk evaluation system. The results revealed that 19 potential pathogenic bacteria were detected in soils within a typical urban-rural ecosystem. Substantial differences were observed in both abundance and species of soil pathogens as well as network structure of soil microbial community from urban to rural areas. Urban areas exhibited relatively lower levels of soil pathogenic abundance, but the microbial network was considerably unstable. Rural areas supported relatively higher levels of soil pathogenic abundance and stable microbial networks. Notably, peri-urban areas showed relatively unstable microbial networks alongside higher levels of soil pathogenic abundance compared to other areas. The risk evaluation of soil pathogens for both adults and children showed that peri-urban areas presented the highest potential risk, with children being more susceptible than adults to threats posed by soil pathogens in both urban and peri-urban areas. The established evaluation system provides an innovative approach for quantifying risk of soil pathogens at regional scale and can be used as a reference for preventing soil pathogens contamination and enhancing soil health in areas with intense human activities.
In this study, the efficiency of energy consumption and the amount of greenhouse gas emissions from the cultivation of sauceboat pepper were determined. The experiments and research data are based on the 2020 growing season and were conducted in the Karaisali district of Adana province, Turkey. The primary data used in this study, such as the financial system, labor efficiency, fuel consumption levels, weights of tools and machinery used in sauceboat pepper production, fertilizer, and seedling quantities, were obtained from existing calculations, previous studies, and various sources. The energy ratio, specific energy, energy productivity, and net energy in sauceboat pepper were calculated as 0.82, 0.98 MJ kg-1, 1.02 kg MJ-1, and -6845.51 MJ ha-1, respectively. In the case of the sauceboat peppers, the energy of the fuel oil had the highest share of the total energy input, 31.65%. It was followed by energy for planting seedlings, energy for fertilizer, water energy for irrigation, energy for human labour, energy for spraying, and energy for machinery, with 21.55%, 19.64%, 12.55%, 8.59%, 4.45%, and 1.87%, respectively. Total GHG emissions were estimated as 3703.54 kgCO2-eq ha-1 for sauceboat pepper highest-quality production portion in human labour (31.18%). Human labour was followed by diesel fuel consumption (25.79%), machine (0.08%), seedling planting (15.90%), nitrogen fertilizer (15.88%), phosphate fertilizer (4.09%), herbicides (3.68%), fungicides (1.93%), calcium consumption (0.09%), magnesium application (0.08%) and iron (0.52%). In addition, the GHG value for the production of sauceboat peppers was calculated to be 0.096 kgCO2-eq kg-1.
Although in Latin America there is the presence of many developing countries, the chemical industry is highly competitive in today's globalized world, due to its availability of natural resources and raw materials. The production of highly profitable chemicals, high value-added metals, petroleum and its derivatives, cosmetics, perfumes and pharmaceutical products have placed Latin America as an interesting option for the global chemical industry in the 21st century. However, given the inefficiency of various processes and the growing production of various industrial areas, the daily production of 430,000 tons of waste materials is recorded in the region. In recent years, in Latin America there has been a growing interest in increasing energy efficiency and reducing waste. An example of such a situation is the development in relevant research areas that are reflected in energy, environmental, economic and inherent security aspects; in short, applications of chemical engineering. In a context of growing population, Latin America's chemical and petrochemical industries are well positioned for significant growth, if the logistical and political challenges characteristic of the geographic area can be addressed. The upcoming challenges associated with achieving sustainable operations in conjunction with the dynamics of global trade are key issues that the industry must face, in addition to the particularities of each country in this diverse, multicultural and dynamic part of the world. Consolidation through increased merger and acquisition activity and an increasingly blurred line between logistics service providers and distributors are notable trends across the value chain that suggest competition is intensifying in Latin America. The purpose of this document is to provide a summary of the current status of the application of sustainability tools in chemical processes in research in Latin America and to forecast what additional beneficial contributions might be on the horizon. We present here a brief literature review of the actions that are already being carried out, in Latin America, in the pertinent topics in sustainability where Chemical Engineering is involved, in the last 25 years.
Soils, as a crucial component of the critical zone of the Earth’s surface that sustains life on land, are as essential in cities and peri-urban areas as they are in natural or agricultural environments. In this chapter we explore the idea that the properties and geographical location of soils have influenced the historical and present location of urban environments. The importance of cities to human survival and well-being is established by analysing global trends in urbanisation and urban migration and by noting that urban areas will become increasingly important for food production. The remainder of this introductory chapter presents the main topics which are covered in this textbook. Human impacts on urban soils are described in several ways, through an investigation of soil-forming factors in urban environments (Chap. 2), soil variability and data analysis (Chap. 3), ecosystem functions provided by soils (Chap. 4), changes in soil physical properties (Chap. 5), chemical pollution of soils (Chaps. 6 and 7), and soil biological phenomena in urban soil (Chap. 8). We start to consider the management of soils in urban environments in Chap. 9, which covers urban soils as a source and sink for material and some basics of risk analysis. The management theme is continued in Chap. 10 which analyses the role of soils in sustaining human health within the framework of the United Nations’ Sustainable Development Goals and in Chap. 11 which presents remediation options for degraded urban soils. Finally, Chap. 12 looks to the future of soil science in an urban context.
This study assisted in identifying and preventing the increase in heavy metals in soil and winter wheat. Its accumulation can affect cultivated crops, quality and crop yields, and consumers’ health. Selected heavy metals were analyzed using the GTAAS method. They were undertaken on selected heavy metals content (Cd, Cu, Pb, and Zn) in arable soils at three sites in Slovakia and their accumulation in parts of cultivated winter wheat. Our study showed that the limit value of Cd in soil samples was exceeded in the monitored arable soils from 2017–2019. The average content values of Cu and Zn did not exceed the limit values, even in Pb values (except for the spring period). The analyses also showed that the heavy metals content for plants bioavailable in soil did not exceed the statutory critical values for Cd, Cu, and Zn’s average content values. However, Pb content exceeded permitted critical values. Heavy metals bioaccumulation (Zn, Cu) was within the limit values in wheat. Analyzed Cd content in wheat roots and Pb content were determined in all parts of wheat except grain. The study showed that grain from cultivated winter wheat in monitored arable soils is not a risk for consumers.
The concept of “One Health” links environmental health to human health through interactions with soil, plants, and animals. This chapter emphasizes the importance of the soil microbiome in these complex interactions and how soil microbes can impact all aspects of our everyday lives, including: what infects us; what heals us; what we eat, drink, and breathe; and even the composition of our gut microbiome. Given the quantity and speed of new technological advances, it remains to be seen the extent to which we can manipulate soil microbial communities to improve environmental and human health. Possibilities include: genetic manipulation of plant chromosomes; “designer” rhizospheres with specific root border cells; and engineered microbial inoculants with desirable traits for rhizobial and mycorrhizal root/microbial interactions. Finally, note that development of new soil-based probiotics could improve human health by directly introducing soil microorganisms into the gut.
Soil fulfills a wide-range of ecological services such as a platform towards biomass generation, a filter/buffer for water, main store of carbon, important source of nutrients in our foodstuff as well as medicines like antibiotic and so on. However, currently, soil pollution has become one of the alarming issues in most of the developed/developing countries that is mainly contributed by anthropogenic activities like mining, smelting, manufacturing, pesticides, herbicides, etc. The rapid urbanization as well as industrialization led to enormous release of pollutants that adversely affects the characteristics of soil. Further, the nutrient inequities of soil together with the pathogenic biotic community result in undesirable impacts on human health including plants, wildlife and animals. In this context, conceptions like soil security could offer a solution by involving multidisciplinary approaches. The amalgamation of diverse scientific and non-scientific approaches could contribute significantly towards addressing issues between soil pollution and its effect on human health including other living organisms. Overall, this chapter is an attempt to deliver elaborated and comprehensive information on interaction between urban soil pollution and human health issues.
Keywords: Human health; industrialization; soil pollution; urbanization; xenobiotic.
In the U.S. approximately 60% of all biosolids are currently land applied. Although it is known that bacteria in biosolids normally decrease to low or non-detectable levels following treatment, a major concern is that regrowth of pathogens may occur. Specifically the question arises: "Does regrowth occur following reintroduction or recolonization of pathogens after land application or during storage under favorable conditions?" The following paper reviews available information on survival and potential regrowth of pathogenic and indicator bacteria in biosolids, compost, soil, and land applied biosolids. Based on the literature, a conceptual framework is provided to explain the phenomenon of "regrowth."
Endophytes are microorganisms that live within host plants for at least part of their life and do not cause apparent symptoms of diseases. In general, beneficial endophytes promote host plant growth, increase plant nutrient uptake, inhibit plant pathogen growth, reduce disease severity, and enhance tolerance to environmental stresses. As sustainable and renewable agricultural production (including current biofuel and bioenergy crops) increases in prominence, endophytic microorganisms will play important roles and offer environmentally-friendly methods to increase productivity while reducing chemical inputs. This review discusses various aspects of beneficial fungal and bacterial endophyte interactions with plants, including the physiological and molecular mechansims by which they benefit plant performance. We also discuss the potential for genetic modification of endophytes with useful genes, which could be used to impart additional traits following inoculation with the genetically engineered endophytes. Finally, we review US-issued patents over the past decade which relate to the use of fungal and bacterial endophytes for plant growth and stress tolerance improvement.
The common corrosion inhibitor, 1H-benzotriazole (Bz), found as a component of glycol-based aircraft deicers, and its derivatives, such as 5-chloro-1H-benzotriazole (CBz), 1-hydroxybenzotriazole (HBz), and 5- methyl-1H-benzotriazole (MBz), are all potential nitrification inhibitors (McCarty and Bremner, 1989). The inhibitory effect of benzotriazoles on the nitrification of urea-N fertilizer in agricultural soils was examined over a four-week period. At 10 mg/kg, all compounds tested, except HBz, have the ability to inhibit the nitrification of urea-N fertilizer effectively. Their inhibitory capabilities depend on the structural components of the soil, particularly organic matter (O.M.). In the soil with the largest percent of O.M. (2.3%), inhibition by all the benzotriazole derivatives was considerably decreased. In the soil with least O.M. (0.3%), even HBz, the poorest of the inhibitors, showed signs of inhibition. For Bz, MBz, and CBz in the range of 90%, inhibition was observed in the soil with the lowest O.M. content during a four-week treatment period. On a mass basis Bz had the greatest inhibitory effect followed by MBz and CBz, whereas HBz showed little inhibition of the nitrification of urea-N in soils with >0.5% O.M. On a molar concentration basis, there would be little variation in inhibitory potency for MBz, CBz, and Bz. It was concluded that all three are effective nitrification inhibitors with urea-N fertilizer. Incorporation of benzotriazoles as inhibitors could help economize N fertilizers by helping prevent nitrate leaching and denitrification. However, the environmental fate of these compounds has not been determined, and they are toxic to plants and other organisms at higher concentrations (10-100 mg/L). Inhibition of nitrification is undesirable when high levels of ammonia are to be removed by combined nitrification and denitrification, as occurs in some sewage treatment processes.
Long-term data from the Hubbard Brook Experimental Forest, New Hampshire, suggest that although changes in stream pH have
been relatively small, large quantities of calcium and magnesium have been lost from the soil complex and exported by drainage
water because of inputs of acid rain and declines in atmospheric deposition of base cations. As a result, the recovery of
soil and streamwater chemistry in response to any decreases in acid deposition will be delayed significantly.
Water for irrigation is a major limitation to agricultural production in many parts of the world. Use of waters with elevated levels of salinity is one likely option to meet the supply of increased demands. The sources of these waters include drainage water generated by irrigated agriculture, municipal wastewater, and poor quality groundwater. Soil salinity leaching requirements that were established several decades ago were based on steady-state conditions. Recently transient-state models have been developed that potentially can more correctly predict the dynamics of the chemical-physical-biological interactions in an agricultural system. The University of California Center for Water Resources appointed a workgroup to review the development of steady-state analyses and transient-state models, and to determine whether the current recommended guidelines for leaching requirement based on steady-state analyses need to be revised. The workgroup concludes that the present guidelines overestimate the leaching requirement and the negative consequences of irrigating with saline waters. This error is particularly large at low leaching fractions. This is a fortuitous finding because irrigating to achieve low leaching fractions provides a more efficient use of limited water supplies.
Volcanic ash, generated in the long-lived eruption of the Soufrière Hills volcano, Montserrat, is shown to contain respirable
(sub-4 μm) particles and cristobalite, a crystalline silica polymorph. Respirable particles of cristobalite can cause silicosis, raising
the possibility that volcanic ash is a respiratory health hazard. This study considers some of the main factors which affect
human exposure to respirable volcanic ash, namely, the composition and proportions of respirable ash, and the composition
and concentrations of airborne suspended particulates. The composition, size distribution and proportion (by weight) of respirable
particles in representative samples of the Soufrière Hills tephra (dome-collapse ash-fall deposits, dome-collapse pyroclastic-flow
matrix, Vulcanian explosion ash and mixed ash) have been characterized. Dome-collapse ash-fall deposits are significantly
richer in respirable particles (12 wt%) than the other tephra samples, in particular the matrices of dome-collapse pyroclastic-flow
deposits (3 wt%). Within the respirable fraction, dome-collapse ash contains the highest proportion of crystalline silica
particles (20–27 number%, of which 97 wt% is cristobalite), compared with other primary tephra types (0.4–5.6 number%). This
enrichment of crystalline silica in the dome-collapse ash is most pronounced in the very fine particle fraction (sub-2 μm). The results are explained as being due to significant size fractionation during fragmentation of pyroclastic flows, resulting
in a fines-depleted dome-collapse matrix and a fines-rich dome-collapse ash deposit. For all sample types, the sub-4 μm fraction comprises 45–55 wt% of the sub-10 μm fraction. Aeolian deposit, lahar deposit and airborne samples of suspended ash, collected on filters, were characterized.
These samples show enrichment of crystalline silica in the respirable fraction (10–18 number%). The results are consistent
with ash in the environment having a mixed origin but originating predominantly from dome-collapse eruptions. The reworked
ash, however, contains low proportions of respirable ash (∼3 wt%) compared to primary ash samples. The concentration of ash
particles re-suspended by road vehicles on Montserrat is found to decrease exponentially with height above the ground, indicating
higher exposure for children compared with adults: PM4 concentration at 0.9 m (height of two-year-old child) is 3 times that at 1.8 m (adult height). The composition of the re-suspended
road particles is similar to that re-suspended by the wind.
KeywordsCristobalite–Montserrat–Ash–Respirable–Health–Soufrière Hills volcano–Pyroclastic flows
Land application of Class B biosolids is routinely undertaken in the United States. However, due to public concern over potential hazards, the long-term sustainability of land application has been questioned. Thus, the objective of this review article was to evaluate the sustainability of land application of Class B biosolids. To do this we evaluated (i) the fate and transport of potential biological and chemical hazards within biosolids, and (ii) the influence of long-term land application on the microbial and chemical properties of the soil. Direct risks to human health posed by pathogens in biosolids have been shown to be low. Risks from indirect exposure such as aerosolized pathogens or microbially contaminated ground water are also low. A long-term land application study showed enhanced microbial activity and no adverse toxicity effects on the soil microbial community. Long-term land application also increased soil macronutrients including C, N, and, in particular, P. In fact, care should be taken to avoid contamination of surface waters with high phosphate soils. Available soil metal concentrations remained low over the 20-yr land application period due to the low metal content of the biosolids and a high soil pH. Soil salinity increases were not detected due to the low salt content of biosolids and irrigation rates in excess of consumptive use rates for cotton. Our conclusion, based on these studies, is that long-term land application of Class B biosolids is sustainable.
Coccidioidomycosis is an endemic infectious disease in western North American deserts caused by the dimorphic ascomycete Coccidioides spp. Even though there has been an increase in the number of reported cases in the last years, few positive isolations have been obtained from soil samples in endemic areas for the disease. This low correlation between epidemiological and environmental data prompted us to better characterize the fundamental ecological niche of this important fungal pathogen. By using a combination of environmental variables and geospatially referenced points, where positive isolations had been obtained in southern California and Arizona (USA) and Sonora (Mexico), we have applied Genetic Algorithm for Rule Set Production (GARP) and Geographical Information Systems (GIS) to characterize the most likely ecological conditions favorable for the presence of the fungus. This model, based on environmental variables, allowed us to identify hotspots for the presence of the fungus in areas of southern California, Arizona, Texas, Baja California, and northern Mexico, whereas an alternative model based on bioclimatic variables gave us much broader probable distribution areas. We have overlapped the hotspots obtained with the environmental model with the available epidemiological information and have found a high match. Our model suggests that the most probable fundamental ecological niche for Coccidioides spp. is found in the arid lands of the North American deserts and provides the methodological basis to further characterize the realized ecological niche of Coccidioides spp., which would ultimately contribute to design smart field-sampling strategies.
Soil degradation affects human nutrition and health through its adverse impacts on quantity and quality of food production. Decline in crops' yields and agronomic production exacerbate food-insecurity that currently affects 854 million people globally, and low concentration of protein and micronutrients (e. g., Zn, Fe, Se, B, I) aggravate malnutrition and hidden hunger that affects 3.7 billion people, especially children. Soil degradation reduces crop yields by increasing susceptibility to drought stress and elemental imbalance. Strategies include: improving water productivity, enhancing soil fertility and micronutrient availability, adopting no-till farming and conservation agriculture and adapting to climate change. There are also new innovations such as using remote sensing of plant nutritional stresses for targeted interventions, applying zeolites and nanoenhanced fertilizers and delivery systems, improving biological nitrogen fixation and mycorrhizal inoculation, conserving and recycling (e. g., waste water) water using drip/sub-drip irrigation etc. Judiciously managed and properly restored, world soils have the capacity to grow adequate and nutritious food for present and future populations.
There is uncertainty over the nutrition-related benefits to health of consuming organic foods.
We sought to assess the strength of evidence that nutrition-related health benefits could be attributed to the consumption of foods produced under organic farming methods.
We systematically searched PubMed, ISI Web of Science, CAB Abstracts, and Embase between 1 January 1958 and 15 September 2008 (and updated until 10 March 2010); contacted subject experts; and hand-searched bibliographies. We included peer-reviewed articles with English abstracts if they reported a comparison of health outcomes that resulted from consumption of or exposure to organic compared with conventionally produced foodstuffs.
From a total of 98,727 articles, we identified 12 relevant studies. A variety of different study designs were used; there were 8 reports (67%) of human studies, including 6 clinical trials, 1 cohort study, and 1 cross-sectional study, and 4 reports (33%) of studies in animals or human cell lines or serum. The results of the largest study suggested an association of reported consumption of strictly organic dairy products with a reduced risk of eczema in infants, but the majority of the remaining studies showed no evidence of differences in nutrition-related health outcomes that result from exposure to organic or conventionally produced foodstuffs. Given the paucity of available data, the heterogeneity of study designs used, exposures tested, and health outcomes investigated, no quantitative meta-analysis was justified.
From a systematic review of the currently available published literature, evidence is lacking for nutrition-related health effects that result from the consumption of organically produced foodstuffs.
A study of the quality of reclaimed water in treated effluent, after storage, and at three points in the distribution system
of four plants in California, Florida, Massachusetts, and New York was conducted for 1 year. The plants had different treatment
processes (conventional versus membrane bioreactor), production capacities, and methods for storage of the water, and the
intended end uses of the water were different. The analysis focused on the occurrence of indicator bacteria (heterotrophic
bacteria, coliforms, Escherichia coli, and enterococci) and opportunistic pathogens (Aeromonas spp., enteropathogenic E. coli O157:H7, Legionella spp., Mycobacterium spp., and Pseudomonas spp.), as well as algae. Using immunological methods, E. coli O157:H7 was detected in the effluent of only one system, but it was not detected at the sampling points, suggesting that
its survival in the system was poor. Although all of the treatment systems effectively reduced the levels of bacteria in the
effluent, bacteria regrew in the reservoir and distribution systems because of the loss of residual disinfectant and high
assimilable organic carbon levels. In the systems with open reservoirs, algal growth reduced the water quality by increasing
the turbidity and accumulating at the end of the distribution system. Opportunistic pathogens, notably Aeromonas, Legionella, Mycobacterium, and Pseudomonas, occurred more frequently than indicator bacteria (enterococci, coliforms, and E. coli). The Mycobacterium spp. were very diverse and occurred most frequently in membrane bioreactor systems, and Mycobacterium cookii was identified more often than the other species. The public health risk associated with these opportunistic pathogens in
reclaimed water is unknown. Collectively, our results show the need to develop best management practices for reclaimed water
to control bacterial regrowth and degradation of water before it is utilized at the point of use.
Endophytes are microorganisms that live within host plants for at least part of their life and do not cause apparent symptoms of diseases. In general, beneficial endophytes promote host plant growth, increase plant nutrient uptake, inhibit plant pathogen growth, reduce disease severity, and enhance tolerance to environmental stresses. As sustainable and renewable agricultural production (including current biofuel and bioenergy crops) increases in prominence, endophytic microorganisms will play important roles and offer environmentally-friendly methods to increase productivity while reducing chemical inputs. This review discusses various aspects of beneficial fungal and bacterial endophyte interactions with plants, including the physiological and molecular mechanisms by which they benefit plant performance. We also discuss the potential for genetic modification of endophytes with useful genes, which could be used to impart additional traits following inoculation with the genetically engineered endophytes. Finally, we review US-issued patents over the past decade which relate to the use of fungal and bacterial endophytes for plant growth and stress tolerance improvement.
The long-term stabilization of soil organic matter (SOM) in tropical and temperate regions is mediated by soil biota (e.g. fungi, bacteria, roots and earthworms), soil structure (e.g. aggregation) and their interactions. On average, soil C turnover was twice as fast in tropical compared with temperate regions, but no major differences were observed in SOM quality between the two regions. Probably due to the soil mineralogy dominated by 1:1 clay minerals and oxides in tropical regions, we found a higher aggregate stability, but a lower correlation between C contents and aggregate stability in tropical soils. In addition, a smaller amount of C associated with clay and silt particles was observed in tropical versus temperate soils. In both tropical and temperate soils, a general increase in C levels (≈ 325 ± 113 kg C·ha-1·yr-1) was observed under no-tillage compared with conventional tillage. On average, in temperate soils under no-tillage, compared with conventional tillage, CH4 uptake (≈ 0.42 ± 0.10 kg C-CH4·ha-1·yr-1) increased and N2O emissions increased (≈ 1.95 ± 0.45 kg N-N2O·ha-1·yr-1). These increased N20 emissions lead to a negative global warming potential when expressed on a CO2 equivalent basis.
This study describes the effects of garden-based education on children's vegetable consumption. As part of a pre-post panel study, 236 students complete the Garden Vegetable Frequency Questionnaire and 161 complete a taste test. Results indicate that school gardening may affect children's vegetable consumption, including improved recognition of, attitudes toward, preferences for, and willingness to taste vegetables. Gardening also increases the variety of vegetables eaten. Future research should explore whether effects persist over time and if and how changes in children's behavior affect the behavior of their caregivers. Implications of study findings for policy and practice are discussed. Suggestions for applying results to future health promotions are provided.
The Critical Zone (CZ) is a holistic framework for integrated studies of water with soil, rock, air, and biotic resources in terrestrial environments. This is consistent with the recognition of water as a unifying theme for research on complex environmental systems. The CZ ranges from the top of the vegetation down to the bottom of the aquifer, with a highly variable thickness (from 10 km). The pedosphere is the foundation of the CZ, which represents a geomembrance across which water and solutes, as well as energy, gases, solids, and organisms are actively exchanged with the atmosphere, biosphere, hydrosphere, and lithosphere to create a life-sustaining environment. Hydropedology – the science of the behaviour and distribution of soil-water interactions in contact with mineral and biological materials in the CZ – is an important contributor to CZ research. This article reviews and discusses the basic ideas and fundamental features of the CZ and hydropedology, and suggests ways for their advances. An "outward" growth model, instead of an "inward" contraction, is suggested for propelling soil science forward. The CZ is the right platform for synergistic collaborations across disciplines. The reconciliation of the geological (or "big") cycle and the biological (or "small") cycle that are orders of magnitude different in space and time is a key to understanding and predicting complex CZ processes. Because of the layered nature of the CZ and the general trend of increasing density with depth, response and feedback to climate change take longer from the above-ground zone down to the soil zone and further to the groundwater zone. Interfaces between layers and cycles are critical controls of the landscape-soil-water-ecosystem dynamics, which present fertile grounds for interdisciplinary research. Ubiquitous heterogeneity in the CZ can be addressed by environmental gradients and landscape patterns, where hierarchical structures control the landscape complex of flow networks embedded in mosaics of matrices. Fundamental issues of hydropedology are linked to the general characteristics of the CZ, including (1) soil structure and horizonation as the foundation of flow and transport characteristics in field soils; (2) soil catena and distribution pattern as a first control of water movement over the landscape; (3) soil morphology and pedogenesis as signatures of soil hydrology and soil change; and (4) soil functional classification and mapping as carriers of soil hydrologic properties and soil-landscape heterogeneity. Monitoring changes in the crucible of terrestrial life (soil) is an excellent (albeit complex) environmental assessment, as every soil is a "block of memory" of past and present biosphere-geosphere dynamics. Our capability to predict the behaviour and evolution of the CZ in response to changing environment can be improved significantly if a global alliance for monitoring, mapping, and modeling of the CZ can be fostered.
Industrial computing manufacturers need to consider several factors in order to deliver an efficient thermal design for industrial-grade computers. Engineers need to apply efficient thermal design in order to create a computer that is both small and fast-cooling. A successful component-level thermal design must include a sophisticated analysis of each individual component's thermal characteristics to determine the parameters and requirements of the heat sink. Engineers also need to strategically organize the system components in order to achieve optimum system-wide thermal characteristics. Components should not simply be put wherever they fit on the motherboard. Each heat source and heat spot will be placed on the motherboard as part of a broader overall thermal design strategy that dissipates heat through a specific transfer route.
Interest in anthrax has increased recently due to its use in bioterrorism attacks. Bacillus anthracis, the causative agent of anthrax, is genetically similar to other Bacillus spp. that occur in the environment, and is known to persist in soil for years in the form of spores. In many soils, naturally occurring anthrax infections tend to occur during dry periods following a wet period. The "incubator theory" suggests that spores are concentrated in low-lying areas during rainfall events and animals are subsequently exposed to contaminated soil during foraging in dry periods. It is currently believed that B. anthracis spores require a host for germination, and thus do not undergo proliferation cycles in the soil. There is a potential for B. anthracis spores to be transported as an aerosol, but human infection due to inhalation of spores is unlikely given the high minimum infectious dose required to cause disease. Historically, naturally occurring anthrax infections in humans have most commonly occurred due to contact with diseased animals or animal products. However, B. anthracis has been developed as a biological weapon with accidental and intentional releases resulting in human death. With the development of an anthrax vaccine, anthrax outbreaks have generally been controlled in developed countries; however, anthrax is still a major problem in many parts of the world. The advent of molecular techniques has enhanced the detection of B. anthracis spores, which is now possible in less than 1 h. However, due to the persistence of spores, it is difficult to eliminate B. anthracis contamination from the environment. There remains a need for additional research on anthrax in several areas including evaluation of the conditions that favor B. anthracis survival in soil, determination of whether B. anthracis undergoes a growth cycle in soil, and determination of the potential for transfer of B. anthracis virulence genes to other soil microorganisms.
This chapter discusses the biogeochemical cycles pertaining to carbon, nitrogen, sulfur, and iron. The carbon cycle involves circulation of carbon between reservoir and sink, through various processes such as photosynthesis, respiration, degradation of organic compounds, and burning of fossil fuels. While photosynthesis is the primary means of carbon fixation and conversion into organic compounds, respiration by the organisms results in the release of carbon dioxide back into the reservoir. Nitrogen cycle is the best studied and most complex of the mineral cycles and includes the microbially catalyzed processes of nitrogen fixation, ammonium oxidation, assimilatory and dissimilatory nitrate reduction, ammonification, and ammonium assimilation. Several bacteria including Azotobacter, Beijerinckia, Azospirillum, and Clostridium can fix N2. Sulfur cycle involves assimilatory sulfate reduction and sulfur mineralization. Two recent practices that have caused a disturbance in the global sulfur reservoirs are strip mining and burning of fossil fuels, resulting in the emission of sulfur dioxide into the atmosphere and subsequent formation of acid rain.
Through interactions with other competing organisms in soil, microbes may acquire traits that lead to virulence when they encounter animal hosts. Each soil-dwelling microbe possesses a unique combination of characteristics, including some held widely in common such as the ability to form biofilms, acquire iron, or produce proteolytic enzymes, that can contribute to virulence. Not only can soil-dwelling microbial pathogens acquire fitness traits when passing through animal hosts, these sojourns provide opportunities to change rapidly and to move between particular soil environments. The virulome for humans consists of an enormous set of traits for configuring both established and emerging pathogenic microbes.
Radon is a natural radioactive gas that you cannot see, smell, or taste and that can only be detected with special equipment. It is produced by the radioactive decay of radium, which in turn is derived from the radioactive decay of uranium. Uranium is found in small quantities in all soils and rocks, although the amount varies from place to place. Radon decays to form radioactive particles that can enter the body by inhalation. Inhalation of the short-lived decay products of radon has been linked to an increase in the risk of developing cancers of the respiratory tract, especially of the lungs. Breathing radon in the indoor air of homes contributes to about 15,000 lung cancer deaths each year in the United States and 1,100 in the UK (HPA 2009). Only smoking causes more lung cancer deaths.
In a field study, the fate of estrogenic activity, nonylphenol, and PBDEs in soil was determined following 20 years of land application of Class B biosolids. The study was conducted under highly controlled conditions at a university research site in southern Arizona, USA. Four replicates of plots containing biosolids land applied at two rates, and control plots were utilized in this study.
Following twenty years of annual biosolid application, four sets of soil cores were collected from each treatment (one core sample from each replicated plot using a soil auger core 7.5cm in diameter to a depth of 150 cm in 30 cm intervals) in December 2005, nine months after the final land application in March 2005. Soil samples were taken from each of the treatment plots across a transect line down the length of the plot to determine the soil chemical properties as a function of depth. Measurements of selected endocrine disruptors (EDCs) within soil were used to assess their long term fate and their potential for adverse human health effects via risk assessment.
Estrogenic activity, nonylphenol and polybrominated diphenyl ethers (PBDEs) were all assayed following accelerated solvent extraction of soil samples. Estrogenic activity was determined via a yeast estrogen screen bioassay. Nonylphenol was measured via HPLC. PBDEs were assayed via GC-ECD analysis of the hexane extracts. Risk assessments, where appropriate, were made based on intake of compounds via inhalation, dermal sorption or ingestion. Data show that low levels of nonylphenol were detected in the soil samples. However, nonylphenol has a much lower estrogenic response than estrogen steroidal hormones, and assuming a potency ratio of 8,500:1 (nonylphenol:ethinylestradiol) a nonylphenol concentration of 1271 ng per g soil would be needed to elicit on estrogenic response. The highest measured nonylphenol concentration was 1,253 ng per g soil, consistent with the nondetection of estrogenic activity in any soil sample. However, significant PBDE concentrations were detected, primarily in the surface 30 cm depth sample. Surface accumulation of PBDEs occurs due to their hydrophobic nature which results in sorption to colloids. The maximum amount of PBDE detected was 80ng/g soil as congener BDE- 209. A risk evaluation of PBDEs based on ?Hazard Indices? indicated that the health risk to humans of PBDEs was negligible even when all three routes of exposure were considered. Based on data for these selected endocrine disruptors found in soil following long term land application of Class B biosolids, it would appear they do not pose a significant risk to human health.
All rights reserved. No part of this publication may be reproduced without written consent of the California Geological Survey. The Department of Conservation makes no warranties as to the suitability of this product for any particular purpose. SPECIAL PUBLICATION 124
The world population of 6.8 billion people all produce sewage. In the developed world most of this is treated by the activated sludge process, which results in large volumes of sludge or biosolids being produced (NRC, 2002). This results in millions of tons of biosolids produced each year in the United States, which must either be disposed of or recycled in some manner. Land application has been seen as the most economical and beneficial way of handling biosolids. Biosolids that result from municipal wastewater treatment processes contain organic matter and nutrients that, when properly treated and applied to farmland, can improve the productivity of soils or enhance revegetation of disturbed ecosystems. However, besides the documented benefits of land application, there are also potential hazards, which have caused the public response to the practice to be mixed. Here we review one of the potential hazards associated with biosolids and its land application, namely human pathogens associated with biosolids.
Soil is the most complicated biomaterial on the planet due to complex soil architecture and billions of soil microbes with extreme biotic diversity. Soil is potentially a source of human pathogens, which can be defined as geo-indigenous, geo-transportable, or geo-treatable. Such pathogens cumulatively can and do result in multiple human fatalities annually. A striking example is Helminths, with current infections worldwide estimated to be around two billion. However, soil can also be a source of antibiotics and other natural products that enhance human health. Soilborne antibiotics are used to treat human infections, but can also result in antibiotic-resistant bacteria. Natural products isolated from soil resulted in 60% of new cancer drugs between the period 1983–1994. Soils are also crucial to human health through their impact on human nutrition. Finally, from a global perspective, soils are vital to the future well-being of nations through their impact on climate change and global warming. A critical review of soil with respect to public health leads to the conclusion that overall soil is a public health savior. The value of soil using a systems approach is estimated to be $20 trillion, and is by far the most valuable ecosystem in the world.
Compaction by 8 and 12.5 Mg farm equipment caused significant subsoil compaction that persisted after 4 years in a silty clay and a silt loam soil in Wisconsin, USA. Hydraulic conductivity of saturated soil cores showed a general trend of decreasing with increasing levels of compaction. Bulk density values increased with increasing levels of compaction. Penetration resistance dramatically increased with increasing levels of compaction. Corn growth (plant height) was also a good indicator of compaction. Plant height was smaller in the compacted plots in all years. Corn grain yields were reduced in the compaction treatments the first year after compaction at both sites and the second and fourth years at the silt loam site and silty clay site, respectively.
Objective:
To examine how life-course experiences and events are associated with current fruit and vegetable consumption in 3 ethnic groups.
Design:
A theoretic model developed from previous qualitative research guided the development of a telephone survey. Data were collected on fruit and vegetable consumption, sociodemographic characteristics, ethnic identity, and life-course events and experiences, including food upbringing, social roles, food skills, dietary changes for health, and practice of food traditions.
Subjects/setting:
Low- to moderate-income adults living in a northeastern US city were selected randomly from 3 ethnic groups: black (n = 201), Hispanic (n = 191), and white (n = 200).
Statistical analyses:
Bivariate and multiple linear regression analysis of associations between life-course variables and fruit and vegetable consumption.
Results:
Black, Hispanic, and white respondents differed significantly in life-course experiences, family roles, socio-demographic characteristics, and place of birth. Explanatory models for fruit and vegetable consumption differed among ethnic groups and between fruits and vegetables. Among black respondents, a college education was positively associated with fruit consumption; education and family roles contributed most to differences in fruit (R2 = .16) and vegetable (R2 = .09) consumption. Among Hispanic respondents, life-course experiences such as liking fruits and vegetables in youth, making dietary changes for health, and food skills were positively associated with fruit (R2 = .25) and vegetable (R2 = .35) consumption. Among white respondents, socio-demographic characteristics, such as being married with a young child or single with no child and having a garden as an adult, were positively associated with fruit (R2 = .20) and vegetable (R2 = .22) consumption.
Applications/conclusions:
An understanding of the determinants of food choice in different subcultural groups can be used to design effective nutrition interventions to increase fruit and vegetable consumption. Experiences such as eating fresh-picked fruits and vegetables while growing up or vegetable gardening as an adult may enhance fruit and vegetable consumption among members of some ethnic groups.
Land application is a practical use of municipal Class B biosolids and manure that also promotes soil fertility and productivity. To date, no study exists comparing biosolids to manure microbial risks. This study used quantitative microbial risk assessment to estimate pathogen risks from occupational and public exposures during scenarios involving fomite, soil, crop, and aerosol exposures. Greatest one-time risks were from direct consumption of contaminated soil or exposure to fomites, with one-time risks greater than 10. Recent contamination and high exposures doses increased most risks. and enteric viruses provided the greatest single risks for most scenarios, particularly in the short term. All pathogen risks were decreased with time, 1 d to14 mo between land application and exposure; decreases in risk were typically over six orders of magnitude beyond 30 d. Nearly all risks were reduced to below 10 when using a 4-mo harvest delay for crop consumption. Occupational, more direct risks were greater than indirect public risks, which often occur after time and dilution have reduced pathogen loads to tolerable levels. Comparison of risks by pathogen group confirmed greater bacterial risks from manure, whereas viral risks were exclusive to biosolids. A direct comparison of the two residual types showed that biosolids use had greater risk because of the high infectivity of viruses, whereas the presence of environmentally recalcitrant pathogens such as and maintained manure risk. Direct comparisons of shared pathogens resulted in greater manure risks. Overall, it appears that in the short term, risks were high for both types of residuals, but given treatment, attenuation, and dilution, risks can be reduced to near-insignificant levels. That being said, limited data sets, dose exposures, site-specific inactivation rates, pathogen spikes, environmental change, regrowth, and wildlife will increase risk and uncertainty and remain areas poorly understood.
Interest in anthrax has increased recently due to its use in bioterrorism attacks. Bacillus anthracis, the causative agent of anthrax, is genetically similar to other Bacillus spp. that occur in the environment, and is known to persist in soil for years in the form of spores. In many soils, naturally occurring anthrax infections tend to occur during dry periods following a wet period. The incubator theory suggests that spores are concentrated in low-lying areas during rainfall events and animals are subsequently exposed to contaminated soil during foraging in dry periods. It is currently believed that B. anthracis spores require a host for germination, and thus do not undergo proliferation cycles in the soil. There is a potential for B. anthracis spores to be transported as an aerosol, but human infection due to inhalation of spores is unlikely given the high minimum infectious dose required to cause disease. Historically, naturally occurring anthrax infections in humans have most commonly occurred due to contact with diseased animals or animal products. However, B. anthracis has been developed as a biological weapon with accidental and intentional releases resulting in human death. With the development of an anthrax vaccine, anthrax outbreaks have generally been controlled in developed countries; however, anthrax is still a major problem in many parts of the world. The advent of molecular techniques has enhanced the detection of B. anthracis spores, which is now possible in less than 1 h. However, due to the persistence of spores, it is difficult to eliminate B. anthracis contamination from the environment. There remains a need for additional research on anthrax in several areas including evaluation of the conditions that favor B. anthracis survival in soil, determination of whether B. anthracis undergoes a growth cycle in soil, and determination of the potential for transfer of B. anthracis virulence genes to other soil microorganisms.
Relationships between carbon (C) production and nitrogen (N) mineralization were investigated in two alpine wetland soils of the Tibetan Plateau using laboratory incubation under different temperatures (5, 15, 25, and 35°C) and water saturation (noninundation and inundation). A significant positive relationship was found between CO2 production and N mineralization under increasing temperatures from 5 to 35°C with the same water saturation condition in the marsh soil (r2 > 0.49, P <0.0001) and the peat soil (r2 > 0.38, P < 0.002), and a negative relationship with water saturation increasing at the same temperature, especially 25 and 35°C, in the marsh soil (r2 > 0.70, P < 0.009) and the peat soil (r2 > 0.61, P < 0.013). In conclusion, temperatures and water saturation could regulate the relationship between CO2 production and net N mineralization in the Tibetan alpine marsh and peat soils.
This study evaluates the effect of surface application of dried Class A biosolids on microbial populations within copper mine tailings.
Mine tailing sites were established at ASARCO Mission Mine close to Sahuarita Arizona. Site 1 (December 1998) was amended with 248 tons ha(-1) of Class A biosolids. Sites 2 (December 2000) and 3 (April 2006) were amended with 371 and 270 tons ha(-1), respectively. Site D, a neighbouring native desert soil, acted as a control for the evaluation of soil microbial characteristics. Surface amendment of Class A biosolids showed a 4 log(10) increase in heterotrophic plate counts (HPCs) compared to unamended tailings, with the increase being maintained for 10-year period. Microbial activities such as nitrification, sulphur oxidation and dehydrogenase activity were also sustained throughout the study period. 16S rRNA clone libraries obtained from community DNA suggest that mine tailings amended with biosolids achieve diversity and bacterial populations similar to native soil bacterial phyla, 10 years postapplication.
Addition of Class A biosolids to copper mine tailings in the desert south-west increased soil microbial numbers, activity and diversity relative to unamended mine tailings.
The amended tailings resulted in a functional soil with respect to microbial characteristics, which were sustainable over a 10-year period enabling the development of appropriate vegetation.
This review examines the interactions between soil physical factors and the biological processes responsible for the production and consumption in soils of greenhouse gases. The release of CO2 by aerobic respiration is a non-linear function of temperature over a wide range of soil water contents, but becomes a function of water content as a soil dries out. Some of the reported variation in the temperature response may be attributable simply to measurement procedures. Lowering the water table in organic soils by drainage increases the release of soil carbon as CO2 in some but not all environments, and reduces the quantity of CH4 emitted to the atmosphere. Ebullition and diffusion through the aerenchyma of rice and plants in natural wetlands both contribute substantially to the emission of CH4; the proportion of the emissions taking place by each pathway varies seasonally. Aerated soils are a sink for atmospheric CH4, through microbial oxidation. The main control on oxidation rate is gas diffusivity, and the temperature response is small. Nitrous oxide is the third greenhouse gas produced in soils, together with NO, a precursor of tropospheric ozone (a short-lived greenhouse gas). Emission of N2O increases markedly with increasing temperature, and this is attributed to increases in the anaerobic volume fraction, brought about by an increased respiratory sink for O2. Increases in water-filled pore space also result in increased anaerobic volume; again, the outcome is an exponential increase in N2O emission. The review draws substantially on sources from beyond the normal range of soil science literature, and is intended to promote integration of ideas, not only between soil biology and soil physics, but also over a wider range of interacting disciplines.
Biological dinitrogen (N2) fixation is a natural process of significant importance in world agriculture. The demand for accurate determinations of
global inputs of biologically-fixed nitrogen (N) is strong and will continue to be fuelled by the need to understand and effectively
manage the global N cycle. In this paper we review and update long-standing and more recent estimates of biological N2 fixation for the different agricultural systems, including the extensive, uncultivated tropical savannas used for grazing.
Our methodology was to combine data on the areas and yields of legumes and cereals from the Food and Agriculture Organization
(FAO) database on world agricultural production (FAOSTAT) with published and unpublished data on N2 fixation. As the FAO lists grain legumes only, and not forage, fodder and green manure legumes, other literature was accessed
to obtain approximate estimates in these cases. Below-ground plant N was factored into the estimations. The most important
N2-fixing agents in agricultural systems are the symbiotic associations between crop and forage/fodder legumes and rhizobia.
Annual inputs of fixed N are calculated to be 2.95Tg for the pulses and 18.5Tg for the oilseed legumes. Soybean (Glycine max) is the dominant crop legume, representing 50% of the global crop legume area and 68% of global production. We calculate
soybean to fix 16.4Tg N annually, representing 77% of the N fixed by the crop legumes. Annual N2 fixation by soybean in the U.S., Brazil and Argentina is calculated at 5.7, 4.6 and 3.4Tg, respectively. Accurately estimating
global N2 fixation for the symbioses of the forage and fodder legumes is challenging because statistics on the areas and productivity
of these legumes are almost impossible to obtain. The uncertainty increases as we move to the other agricultural-production
systems—rice (Oryza sativa), sugar cane (Saccharum spp.), cereal and oilseed (non-legume) crop lands and extensive, grazed savannas. Nonetheless, the estimates of annual N2 fixation inputs are 12–25Tg (pasture and fodder legumes), 5Tg (rice), 0.5Tg (sugar cane), <4Tg (non-legume crop lands)
and <14Tg (extensive savannas). Aggregating these individual estimates provides an overall estimate of 50–70Tg N fixed biologically
in agricultural systems. The uncertainty of this range would be reduced with the publication of more accurate statistics on
areas and productivity of forage and fodder legumes and the publication of many more estimates of N2 fixation, particularly in the cereal, oilseed and non-legume crop lands and extensive tropical savannas used for grazing.
Soil structure exerts important influences on the edaphic conditions and the environment. It is often expressed as the degree of stability of aggregates. Aggregation results from the rearrangement, flocculation and cementation of particles. It is mediated by soil organic carbon (SOC), biota, ionic bridging, clay and carbonates. The complex interactions of these aggregants can be synergistic or disruptive to aggregation. Clay-sized particles are commonly associated with aggregation by rearrangement and flocculation, although swelling clay can disrupt aggregates. Organo-metallic compounds and cations form bridges between particles. The SOC originates from plants, animals and microorganisms, and their exudates. It enhances aggregation through the bonding of primary soil particles. The effectiveness of SOC in forming stable aggregates is related to its decomposition rate, which in turn is influenced by its physical and chemical protection from microbial action. Soil inorganic carbon (SIC) increases aggregation in arid and semi-arid environments, and the formation of secondary carbonates is influenced by the presence of SOC and Ca2+ and Mg2+. Soil biota release CO2 and form SOC which increase dissolution of primary carbonates while cations increase precipitation of secondary carbonates. The precipitation of (hydr)oxides, phosphates and carbonates enhances aggregation. Cations such as Si4+, Fe3+, Al3+ and Ca2+ stimulate the precipitation of compounds that act as bonding agents for primary particles. Roots and hyphae can enmesh particles together while realigning them and releasing organic compounds that hold particles together, a process with a positive impact on soil C sequestration. Soil structure can be significantly modified through management practices and environmental changes. Practices that increase productivity and decrease soil disruption enhance aggregation and structural development.
Interest in the quality and health of soil has been stimulated by recent awareness that soil is vital to both production of food and fiber and global ecosystems function. Soil health, or quality, can be broadly defined as the capacity of a living soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and promote plant and animal health. Soil quality and health change over time due to natural events or human impacts. They are enhanced by management and land-use decisions that weigh the multiple functions of soil and are impaired by decisions which focus only on single functions, such as crop productivity. Criteria for indicators of soil quality and health relate mainly to their utility in defining ecosystem processes and in integrating physical, chemical, and biological properties; their sensitivity to management and climatic variations; and their accessibility and utility to agricultural specialists, producers, conservationists, and policy makers. Although soils have an inherent quality as related to their physical, chemical, and biological properties within the constraints set by climate and ecosystems, the ultimate determinant of soil quality and health is the land manager. As such, the assessment of soil quality or health, and direction of change with time, is the primary indicator of sustainable management. Scientists can make a significant contribution to sustainable land management by translating scientific knowledge and information on soil function into practical tools and approaches by which land managers can assess the sustainability of their management practices. The first steps, however, in our communal journey towards sustainable land management must be the identification of our final destination (sustainability goals), the strategies or course by which we will get there, and the indicators (benchmarks) that we are proceeding in the right direction. We too often rush to raise the sails of our ‘technological’ ship to catch the wind, before knowing from where it comes or in properly defining our destination, charting our course, and setting the rudder of our ship. Examples are given of approaches for assessing soil quality and health to define the sustainability of land management practices and to ‘translate our science into practice’.
In a handful of fertile soil there are billions of microorganisms and yet, even with a conservative estimate, the surface area covered by these organisms is considerably less than 1%. What does this tell us about the function of the physical structure in which soil organisms reside and function, collecting, and separating micropopulations from each other and from resources? It would seem that most of the soil is akin to desert regions with little life been supported on its terrains, yet with vast communities of individuals, from an amazing array of species, supported in small-scale habitats, connected or disconnected by saturated or unsaturated pore space over relatively short time-scales. The biodiversity of these communities remains impressive yet overall functionally illusive, bar some considerations of inbuilt redundancy. What is far more impressive is the range of habitats on offer to populations with short-term evolutionary time frames. The availability of spatially and temporally diverse habitats probably gives rise to the biodiversity that we see in soil.It is not too far fetched to state that the majority of habitats on Earth (and indeed extraterrestrial) are revealed in that handful of soil. The key question is what is the functional consequence of such habitat heterogeneity? To answer this it is clear that we need to bring together a new discipline that combines the biology and physics of the soil ecosystem. This biophysical approach, combined, where required, with important mineral-microbe knowledge is needed to help us understand the mechanisms by which soils remain productive, and to identify the tipping-points at which there may be no return to sustainability.This review aims to highlight the importance of addressing the soil ecosystem as a dynamic heterogeneous system focusing on microbiota–habitat interactions.
A method for the detection of the effects of antibiotics on soil microbial communities was optimised in the present study. We investigated the influence of measurement time and nutrient status on the pollution-induced community tolerance (PICT), using the sulfonamide sulfachloropyridazine (SCP) as model compound. The tolerance development in soil microcosms that were exposed to SCP under different conditions was compared with the background tolerance in SCP-unexposed microcosms. The tolerance of bacterial extracts from the soil microcosms was determined in Biolog® multiwell plates as the SCP sensitivity of a range of physiological processes. The background tolerance was not affected by soil nutrient amendments, but an influence of the inoculum density in the microtiter plates was observed. Still, the variance of the background tolerance was low, which is in favour of the usage of community tolerance measurements for a selective detection of a toxicant impact. In line with the assumptions of the PICT concept, soil amendment with SCP led to an increase in community tolerance. This tolerance development was enhanced upon additional soil amendment with fresh pig slurry, and less by alfalfa meal addition. Tolerance increases were observed after a soil exposure to SCP of only 7 days, possibly because nutrient input facilitates the fast adaptation of the soil microbial community. However, a further increase in exposure time led to variable changes in the observed tolerance. Prolonged tolerance detection in the microtiter plates (11 days) enabled a clearer differentiation between different soil treatments, as it better resolved the EC50 values of processes with a high tolerance to bacteriostatic antimicrobial compounds. For the detection of antibiotic effects on soil microbial communities, it is therefore recommended to use nutrient amendments (possibly fresh pig slurry), to standardize the soil exposure time, and to extend the period of Biolog plate measurement beyond 7 days.
Various cultural practices, including the use of cover and rotational crops, composts, tillage systems, and others have been promoted as management options for enhancing soil quality and health. All cultural practices are known to directly or indirectly affect populations of soilborne pathogens and the severity of their resultant root diseases. Soil biology is a major component and contributes significantly to soil quality and productivity. The major activities of soil microbes include the decomposition of organic materials, mineralization of nutrients, nitrogen fixation, suppression of crop pests and protection of roots, but also parasitism and injury to plants. Thus, there is a great need to assure that the introduced soil management practices to improve soil quality will also result and maintain a healthy soil. The latter include the abundance and diversity of total soil microbes, high population of beneficial organisms and low population and/or activities of crop pests. Production of vegetables and other food crops is often significantly affected by several soilborne pathogens that require control. The incidence and severity of root diseases is an indirect assessment of soil health for specific commodity/soil use. In addition, understanding and selecting the appropriate cultural practices that limit or prevent damage of root diseases is essential for the long-term and sustainable management of soil quality and health. Case-study examples are presented to illustrate the impact of cover crops and their green manures on the density and damage of root-knot and lesion nematodes to vegetables; and also tillage, soil amendments, crop rotation, and cover crops on bean yield and root rot severity.
This study is the first report assessing the effect of soil inoculation on the signalling interaction of Bradyrhizobium japonicum, arbuscular mycorrhizal fungi (AMF) and soybean plants throughout the early stages of colonisation that lead to the tripartite symbiosis. In a study using soil disturbance to produce contrasting indigenous AMF treatments, the flavonoids daidzein, genistein and coumestrol were identified as possible signals for regulating the establishment of the tripartite symbiosis. However, it was unclear whether soil disturbance induced changes in flavonoid root accumulation other than through changing the potential for AMF colonization. In this study, soil treatments comprising all possible combinations of AMF and B. japonicum were established to test whether (1) modifications in root flavonoid accumulation depend on the potential for AMF colonization, and (2) synthesis and accumulation of flavonoids in the roots change over time as a function of the early plant–microbial interactions that lead to the tripartite symbiosis. The study was comprised of two phases. First, maize was grown over 3-week periods to promote the development of the AM fungus Glomus clarum. Second, the interaction between soybean, G. clarum and B. japonicum was evaluated at 6, 10, 14 and 40 days after plant emergence. Root colonization by G. clarum had a positive effect on nodulation 14 days after emergence, producing, 30% more nodules which were 40% heavier than those on roots solely inoculated with B. japonicum. The tripartite symbiosis resulted in 23% more N2 being fixed than did the simpler symbiosis between soybean and B. japonicum. The presence of both symbionts changed accumulation of flavonoids in roots. Daidzein and coumestrol increased with plant growth. However, development of the tripartite symbiosis caused a decrease in coumestrol; accumulation of daidzein, the most abundant flavonoid, was reduced in the presence of AMF.
Stress-relieving effects of gardening were hypothesized and tested in a field experiment. Thirty allotment gardeners performed a stressful Stroop task and were then randomly assigned to 30 minutes of outdoor gardening or indoor reading on their own allotment plot. Salivary cortisol levels and self-reported mood were repeatedly measured. Gardening and reading each led to decreases in cortisol during the recovery period, but decreases were significantly stronger in the gardening group. Positive mood was fully restored after gardening, but further deteriorated during reading. These findings provide the first experimental evidence that gardening can promote relief from acute stress.
Despite the rapid, widespread accumulation of polybrominated diphenylethers (PBDEs) in our surroundings, their environmental fate has been largely unknown. In the present study, most common congeners (BDE 47, 99, 100, 138, 153, 154, 183 and 209) were investigated for their dynamics in municipal sewage sludge under mesophilic condition (37 degrees C). In anaerobic batch cultures, the concentrations of BDE 47, 99, 100 and 209, exhibited significant decreases (by 22-40% from their initial concentration), whereas the levels of the other congeners, BDE 138, 153, 154 and 183, remained stable during a 238-d incubation. However, in a parallel study conducted in a pilot-scale anaerobic sludge digester, loss of all eight congeners was observed. The present study indicates that certain PBDE congeners undergo a significant mass decrease under anaerobic conditions.
Soil is a basic natural resource for food production, the vast majority of food we consume is either directly or indirectly derived from soil. Soil quality determines the quantity (calories) and quality (nutritional value and safety) of the foods grown. Protecting the soil's physical, chemical and biological integrity is therefore of vital importance in safeguarding global food security. Soil science, as a discipline, will contribute to new knowledge related to soil quality and its sustainable management. However, soil scientists are not alone in securing the global food production system, instead they shall work with environmental engineers, agronomists, nutritionists, animal scientists and social scientists in developing integrative approaches to soil conservation, material cycling and environmental protection.
We have developed a modeling and measurement framework for assessing transport of contaminated soils and airborne particulates into a residence, their subsequent distribution indoors via resuspension and deposition processes, and removal by cleaning and building exhalation of suspended particles. The model explicitly accounts for the formation of house dust as a mixture of organic matter (OM) such as shed skin cells and organic fibers, soil tracked-in on footwear, and particulate matter (PM) derived from the infiltration of outdoor air. We derived formulas for use with measurements of inorganic contaminants, crustal tracers, OM, and PM to quantify selected transport parameters. Application of the model to residences in the U.S. Midwest indicates that As in ambient air can account for nearly 60% of the As input to floor dust, with soil track-in representing the remainder. Historic data on Pb contamination in Sacramento, CA, were used to reconstruct sources of Pb in indoor dust, showing that airborne Pb was likely the dominant source in the early 1980s. However, as airborne Pb levels declined due to the phase-out of leaded gasoline, soil resuspension and track-in eventually became the primary sources of Pb in house dust.
This authoritative reference volume emphasizes the importance and interrelationships of geological processes to the health and diseases of humans and animals. Its accessible format fosters better communication between the health and geoscience communities by elucidating the geologic origins and flow of toxic elements in the environment that lead to human exposure through the consumption of food and water. For example, problems of excess intake from drinking water have been encountered for several inorganic compounds, including fluoride in Africa and India; arsenic in certain areas of Argentina, Chile, and Taiwan; selenium in seleniferous areas in the U.S., Venezuela, and China; and nitrate in agricultural areas with heavy use of fertilizers. Environmental influences on vector borne diseases and stormflow water quality influences are also featured. Numerous examples of the environmental influences on human health from across the globe are also presented and discussed in this volume.
In some areas of Bangladesh and West Bengal, concentrations of As in groundwater exceed guide concentrations, set internationally and nationally at 10 to 50 μg l−1 and may reach levels in the mg l−1 range. The As derives from reductive dissolution of Fe oxyhydroxide and release of its sorbed As. The Fe oxyhydroxide exists in the aquifer as dispersed phases, such as coatings on sedimentary grains. Recalculated to pure FeOOH, As concentrations in this phase reach 517 ppm. Reduction of the Fe is driven by microbial metabolism of sedimentary organic matter, which is present in concentrations as high as 6% C. Arsenic released by oxidation of pyrite, as water levels are drawn down and air enters the aquifer, contributes negligibly to the problem of As pollution. Identification of the mechanism of As release to groundwater helps to provide a framework to guide the placement of new water wells so that they will have acceptable concentrations of As.
Analyses of plant and microbial genome sequences have revealed many genes and gene clusters encoding proteins similar to those known to be involved in the biosynthesis of structurally-complex natural products. Many of these genes and gene clusters do not direct the production of known metabolites of the organism in which they are found. Others represent novel gene clusters that direct the biosynthesis of known natural products. This article highlights several examples of new biosynthetic chemistry discovered in the course of investigating such gene clusters.