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Worldwide pesticide usage and its impacts on ecosystem

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Pesticides are extensively used in modern agriculture and are an effective and economical way to enhance the yield quality and quantity, thus ensuring food security for the ever-growing population around the globe. Approximately, 2 million tonnes of pesticides are utilized annually worldwide, where China is the major contributing country, followed by the USA and Argentina, which is increasing rapidly. However, by the year 2020, the global pesticide usage has been estimated to increase up to 3.5 million tonnes. lthough pesticides are beneficial for crop production point of view, extensive use of esticides can possess serious consequences because of their bio-magnification and persistent nature. Diverse pesticides directly or indirectly polluted air, water, soil and verall ecosystem which cause serious health hazard for living being. In the present manuscript, an attempt has been made to critically review the global usage of different pesticides and their major adverse impacts on ecosystem, which will provide guidance for a wide range of researchers in this area.
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SN Applied Sciences (2019) 1:1446 |
Review Paper
Worldwide pesticide usage andits impacts onecosystem
AnketSharma1,2 · VinodKumar3· BabarShahzad4· MohsinTanveer4· GaganPreetSinghSidhu5· NehaHanda2,6·
SukhmeenKaurKohli2· PoonamYadav2· AditiShreeyaBali7· RipuDamanParihar8· OwiasIqbalDar9·
KirpalSingh9· ShivamJasrotia9· PalakBakshi2· M.Ramakrishnan10· SandeepKumar11· RenuBhardwaj2·
© Springer Nature Switzerland AG 2019
Pesticides are extensively used in modern agriculture and are an eective and economical way to enhance the yield qual-
ity and quantity, thus ensuring food security for the ever-growing population around the globe. Approximately, 2 million
tonnes of pesticides are utilized annually worldwide, where China is the major contributing country, followed by the USA
and Argentina, whichis increasing rapidly. However, by the year 2020, the global pesticide usage has been estimated
to increase up to 3.5 million tonnes. Although pesticides are benecial for crop production point of view, extensive use
of pesticides can possess serious consequences because of their bio-magnication and persistent nature. Diverse pes-
ticides directly or indirectly polluted air, water, soil and overall ecosystem which cause serious health hazard for living
being. In the present manuscript, an attempt has been made to critically review the global usage of dierent pesticides
and their major adverse impacts on ecosystem, which will provide guidance for a wide range of researchers in this area.
Keywords Global pesticide usage· Pesticide application· Pesticide bio-magnication· Pesticide ecotoxicology
1 Introduction
Pesticides are the chemicals (natural or synthetic)
employed in various agricultural practices to control pests,
weeds and diseases in plants. Pesticides include a wide
range of herbicides, insecticides, fungicides, rodenticides,
nematicides, etc. In the process of agricultural develop-
ment, pesticides became a vital tool for plant protection
and for enhancing crop yield. Approximately, 45% of the
annual food production is lost due to pest infestation;
therefore, eective pest management by using wide range
of pesticides is required to confront pests and to increase
the crop production [1]. However, in the last half of the
nineteenth century, robust growth in the world economy
including both industrial and agricultural sectors has led
to the progressive mount in the generation and utiliza-
tion of agriculture-based chemicals which often induce
calamitous eects on the environment. Injudicious use of
pesticides and other persistent organic pollutants in agri-
cultural soils have devastated future repercussions. The
Received: 31 May 2019 / Accepted: 11 October 2019 / Published online: 21 October 2019
Anket Sharma, Vinod Kumar and Babar Shahzad have contributed equally to this work.
* Anket Sharma, | 1State Key Laboratory ofSubtropical Silviculture, Zhejiang A&F University, Hangzhou311300,
China. 2Plant Stress Physiology Lab, Department ofBotanical andEnvironmental Sciences, Guru Nanak Dev University, Amritsar,
Punjab143005, India. 3Department ofBotany, DAV University, Sarmastpur,Jalandhar, Punjab144012, India. 4School ofLand andFood,
University ofTasmania, Hobart, TAS, Australia. 5Department ofApplied Sciences, UIET, Chandigarh160014, India. 6Department
ofBotany, School ofBioengineering andBiosciences, Lovely Professional University, Phagwara, Punjab144411, India. 7Department
ofBotany, M.C.M. DAV College forWomen, Chandigarh160036, India. 8Department ofZoology, DAV University, Sarmastpur,Jalandhar,
Punjab144012, India. 9Department ofZoology, Guru Nanak Dev University, Amritsar143005, India. 10Division ofPlant Biotechnology,
Entomology Research Institute, Loyola College, Chennai, India. 11Department ofEnvironmental Sciences, DAV University,
Sarmastpur,Jalandhar, Punjab144012, India.
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... Additionally, from 2 lac tonnes in the 1950s to nearly 50 lac tonnes in 2000, pesticides worldwide climbed by 11% annually. Only 1% of all pesticides are utilized effectively to control insect pests on target plants, despite the three billion kg of pesticides used annually worldwide (Özkara et al., 2016;Sharma et al., 2019). Pesticides that are still present in large amounts seep into or reach environmental media and nontarget plants. ...
... The soil's pH is also essential. As soil pH decreases, additional ionizable pesticides (Morillo and Villaverde, 2017;Sharma et al., 2019). ...
... What scenario will be if the rest of the countries start similar agricultural practices to increase crop production? Apparently, pesticides are beneficial for crop production; however, extensive use of pesticides can possess serious consequences because of their biomagnification and persistent nature (Nicolopoulou-Stamati et al., 2016;Sharma et al., 2019). The toxicity of chemicals severely impacts plants, insects, humans, animals, soil, water, air, and eventually the ecosystem (M. ...
... Crops constantly interact with a wide range of bacteria in their environment, and these plant-associated bacteria colonize predominantly in plant tissues, rhizosphere, and phyllosphere, which are commonly mentioned as endophytic-bacteria, rhizobacteria, and epiphytic-bacteria, respectively (Sharma et al., 2019). The endophytic bacteria live in the tissues of various plant species without causing any disease or damage to their host plants (Mengoni et al., 2003). ...
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The exploration of knowledge for crop improvement has been a continuous practice to address the food insecurity of the growing human population, and the necessity of the new knowledge is extremely important due to decreasing arable land and climate change. The proper use of technology and knowledgebase has the potential to narrow down poverty in the world, more specifically in developing countries. This review aimed to assess the role of the endophytic and rhizospheric bacteria as a potential crop improvement tool in climate-smart agriculture. Endophytic and rhizospheric were found to be efficient alternatives to the chemical-based solution to develop crops. Endophytic and rhizospheric bacteria have improved many agronomic traits such as yield, quality, disease resistance, and stress tolerance. Besides, we discussed the recent development of the field-level application of endophytic and rhizospheric bacteria. These bacteria have potential since they are efficient in developing crops significantly without affecting the environment in a deleterious way. In terms of biodiversity, natural resources such as endophytic and rhizospheric bacterial application to crops are unlikely to affect the non-target species. Hence, endophytic and rhizospheric bacteria application in crop improvement is applicable for agricultural development, thereby ensuring food sustainability worldwide without affecting the environment, eventually leading us to climate-smart agriculture. This review aims to recapitulate the current knowledge and prospective of endophytic and rhizospheric bacteria to achieve the goal of climate-smart agriculture.
... However, the adoption of integrated pest management which advocates the use of host plant resistance, biological control, and cultural controls along with pesticides was not widely adopted and did not significantly affect the number of pesticides used worldwide [5]. In Europe there is a clear decrease in the use of synthetic agrochemicals due to consumer pressure and restrictive regulations, while in the USA and South America, especially in Brazil, this market keeps increasing [6]. ...
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Background Pesticides have become a central public health problem and a source of environmental contamination. The use of organic matter is an important strategy to reduce synthetic agrochemicals, improve soil conditions, and increase nutrient uptake by plants. Organic matter can also induce plant resistance against biotic stress in some circumstances. However, the results reported for different types of organic matter applications are often very different form each other, thus making difficult their interpretation and hindering and discouraging their use as valuable alternative. Identifying the main factors involved in the efficacy of these sustainable methodologies and the associated research gaps is important to increase the efficiency of organic matter and reduce the use of pesticides. Materials and methods We performed a comprehensive meta-analysis of the current recent scientific literature on the use of organic matter as control method for pest and disease, using data reduction techniques, such as principal component analysis. We found 695 articles listing the keywords in the databases between 2010 and 2021 and selected 42 that met inclusion criteria. Results In general, all organic matter reported showed a high inhibition of pests and diseases. Control effectiveness was close to 75% for fungal diseases and 67% for the pest control. The source of organic matter most frequently reported was the vermicompost. However, humic substances showed the greatest effectiveness of 74% when compared to both fungal and bacterial disease control. The concentration of humic substances ranged from 1 to 500 mg L ⁻¹ , with the highest concentrations used in case of soil application. Conclusions The study demonstrated the potential role of organic matter as a resistance elicitor in plants, thus allowing a partial/total reduction of pesticides in crops. Despite the efficiency reported in the works, the mechanisms of induction of pest and disease control remains poorly studied. Graphical Abstract
... Moreover, excessive use of pesticides has an impact on the entire population, especially on children who can suffer from skin irritation and immune system deficiency. The EPA study from 2012 showed that the most commonly used conventional pesticides such as Glyphosate, Atrazine and Metolachlor-S might be associated with health problems such as cancer, abortion and human hormone disorders [14]. Some pesticides are characterized by being excessively persistent in the environment and belong to the class of persistent organic pollutants (POPs), including organochlorine and organophosphates (OC and OP). ...
Lack of clean water requires the use of new wastewater treatment technologies. Adsorption is a simple and effective method for removing contaminants from contaminated water. Graphene composites with hydrogels have found application in wastewater treatment because they have unique properties such as porous structure, unique morphology, good rheological properties, non-toxicity, etc. The paper presents a literature overview of potential solutions to wastewater treatment using composite graphene and graphene oxide with hydrogel-like adsorbents. The mentioned composite compounds have been used in the treatment or elimination of various hazardous substances. In this work, we have investigated the possible adsorption of different classes of colored pollutants (paints) and pesticides (both organic and inorganic).
... Oysters need Zn as a micronutrient, since it is incorporated into a range of metalloenzymes (Coombs, 1972). Furthermore, the accumulation of Zn and Cu in oyster C. angulata has been shown to play a role in protecting against bacterial pathogens (Sharma et al., 2019). In this study, the maximum Zn concentration detected in SRO flesh was much lower at 561 mg/kg ww. ...
This study investigated relationships between Sydney Rock Oyster (SRO) health and element concentrations in sediments and oysters from the Richmond River estuary. Six sites were sampled between November 2019 and May 2020. Multivariate permutational analysis of variance was used to compare oyster health parameters and element concentrations between sites, wet and dry conditions, and in oyster and sediment samples. Statistical analysis revealed significant spatial differences in oyster mortality, condition index, and size. Metal concentrations in oyster flesh significantly differed from metals in sediments. Most metals in sediments were below guideline values, except for Ni at some sites. Mortality, condition index, and weight correlated negatively with individual elements in oyster flesh (P, Zn, Mg, Al, Ni). BEST statistical models included various combinations of metals in sediment and flesh. This study highlights that spatial differences in SRO health tend to be related to site-specific metal compositions in sediment and oysters.
... Persistent nature and irrational use of insecticides to enhance crop yields by controlling insect or other pests has raised health concerns due to considerable damage caused by these pesticides to non-target organisms. When enter food chains, insecticide residues can easily transfer to human and animal bodies where they can cause serious health related issues (Sharma et al. 2019; Al-Ahmadi 2019). Use of traditional insecticides, like organophosphates, pyrethroids and carbamates, has either been banned or curtailed to minimum due to environmental poisoning effects and insect resistance (Rajmohan et al. 2020). ...
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Purpose Buprofezin is a type-1 chitin synthesis inhibitor insecticide used to control a variety of insect pests at immature stages but potential adverse effects on non-target organisms and humans have been raised. The present study determined buprofezin toxicity after 4 weeks exposure to Balb/c mice and investigated the role of vitamin C and curcumin as possible protective agents. Methods Mice were exposed orally for 28 days to low, medium and high buprofezin doses (50, 100 and 250 bw respectively). Only high dose animals were co-treated with vitamin C and curcumin (100 dose each), alone or in combination. Data were analyzed statistically; P<0.05. Results Results demonstrated that medium and high buprofezin doses were toxic to mammalian tissues. Supplementation with vitamin C and curcumin alleviated toxicity by significant (P<0.001) lowering of ROS and TBARS whilst increasing the levels of antioxidant enzymes SOD, POD and CAT. Similarly, serum ALT, AST, ALP, triglycerides, total cholesterol, LDH, creatinine and urea levels that were significantly elevated (P<0.05) and decreased tissue proteins upon exposure to buprofezin were restored to near normal values with vitamin C and curcumin. Similar protective effect was obtained (P<0.001) for hematological parameters. Histology and comet assay of liver and kidney further confirmed reduction in buprofezin-induced cellular and DNA damage and preservation of tissue integrity with vitamin C and curcumin. Conclusion Both vitamin C and curcumin are therefore effective remedial measures against buprofezin-induced toxicity but in combination, they are more effective.
... Agrochemicals such as pesticides are widely used in agriculture, with about half of them were herbicides applied in 2010 (Sharma et al. 2019). Herbicides show detrimental effects on non-target organisms, such gut microbiota of honey bees (Motta et al. 2018), however, how this affects the soil microbial community structure and functions is still unclear. ...
Microbes are essential for life on earth. The recently proposed “one health” concept emphasizes the importance of the microbiome and its diversity on ecosystem and human health. In this chapter, losses in microbial diversity including both soils and human (intestine) and potential consequences on the functioning of the respective systems and interlinkages are depicted. In particular, the use of plant protection agents and antimicrobials in human medicine as well as resistance in soils is discussed in the prospect of the declining biodiversity. The development of the human microbiome and how environmental microbes can proliferate over large distances and impact human health and diseases are outlined. Sustainable agricultural management is of crucial importance for terrestrial ecosystem functioning in the face of changing climate. We discuss potential steps for the latter, in combination with a human lifestyle that is re-connecting to a microbial rich and diverse nature and show how essential this is to maintain and retrieve human health.
Over the past century, rapid economic development and population explosion across the globe have caused environmental concerns such as severe pollution and climate change. In the last decade, recent advancements in nanotechnology and specifically related to organic inorganic nanohybrids have created tremendous opportunities to provide technological solutions in the fields of environmental pollution control and remediation. Several investigations were conducted recently to develop versatile, highly efficient, low-cost, and environmental friendly organic–inorganic nanohybrids. The main specialty of an organic–inorganic nanohybrid is its development with desired composition, physical, and chemical properties in accordance with its utilization in various applications. In this chapter initially, organic–inorganic nanohybrids have been briefly introduced. Then, sources and detrimental health effects of various environmental pollutants are discussed. After that, the chapter focused on the latest progressions in the development methods, surface morphologies, multicomponent composition, surface properties (i.e., surface, functional groups), and synergistic physicochemical properties (i.e., adsorptive, catalytic) of organic–inorganic nanohybrids. Additionally, their respective applications in treating various environmental pollutants such as industrial dyes (i.e., Rhodamine B, methylene blue), harmful volatile organic compounds (i.e., benzene, toluene), and gases (i.e., CO2) with the emphasis on their roles in adsorptive and photocatalytic removal of the pollutants are analyzed and compared. Despite all the progress to date, futuristic approaches, challenges, and specific directions for further research relevant to organic–inorganic nanohybrids are also highlighted.
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Background: Multiple epidemiological studies have shown that exposure to pesticides is associated with adverse health outcomes. However, the literature on pesticide-related health effects in the Latin American and the Caribbean (LAC) region, an area of intensive agricultural and residential pesticide use, is sparse. We conducted a scoping review to describe the current state of research on the health effects of pesticide exposure in LAC populations with the goal of identifying knowledge gaps and research capacity building needs. Methods: We searched PubMed and SciELO for epidemiological studies on pesticide exposure and human health in LAC populations published between January 2007 and December 2021. We identified 233 publications from 16 countries that met our inclusion criteria and grouped them by health outcome (genotoxicity, neurobehavioral outcomes, placental outcomes and teratogenicity, cancer, thyroid function, reproductive outcomes, birth outcomes and child growth, and others). Results: Most published studies were conducted in Brazil (37%, n=88) and Mexico (20%, n=46), were cross-sectional in design (72%, n=167), and focused on farmworkers (45%, n=105) or children (21%, n=48). The most frequently studied health effects included genotoxicity (24%, n=62) and neurobehavioral outcomes (21%, n=54), and organophosphate (OP) pesticides were the most frequently examined (26%, n=81). Forty-seven percent (n=112) of the studies relied only on indirect pesticide exposure assessment methods. Exposure to OP pesticides, carbamates, or to multiple pesticide classes was consistently associated with markers of genotoxicity and adverse neurobehavioral outcomes, particularly among children and farmworkers. Discussion: Our scoping review provides some evidence that exposure to pesticides may adversely impact the health of LAC populations, but methodological limitations and inconsistencies undermine the strength of the conclusions. It is critical to increase capacity building, integrate research initiatives, and conduct more rigorous epidemiological studies in the region to address these limitations, better inform public health surveillance systems, and maximize the impact of research on public policies.
Pesticides play a key-role in the development of the agrifood sector allowing controlling pest growth and, thus, improving the production rates. Pesticides chemical stability is responsible of their persistency in environmental matrices leading to bioaccumulation in animal tissues and hazardous several effects on living organisms. The studies regarding long-term effects of pesticides exposure and their toxicity are still limited to few studies focusing on over-exposed populations, but no extensive dataset is currently available. Pesticides biomonitoring relies mainly on chromatographic techniques coupled with mass spectrometry, whose large-scale application is often limited by feasibility constraints (costs, time, etc.). On the contrary, chemical sensors allow rapid, in-situ screening. Several sensors were designed for the detection of pesticides in environmental matrices, but their application in biological fluids needs to be further explored. Aiming at contributing to the implementation of pesticides biomonitoring methods, we mapped the main gaps between screening and chromatographic methods. Our overview focuses on the recent advances (2016–2021) in analytical methods for the determination of commercial pesticides in human biological fluids and provides guidelines for their application.
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Pesticides are applied all over the world to protect plants from pests. However, their application also causes toxicity to plants, which negatively affects the growth and development of plants. Pesticide toxicity results in reduction of chlorophyll and protein contents, accompanied by decreased photosynthetic efficiency of plants. Pesticide stress also generates reactive oxygen species which causes oxidative stress to plants. To attenuate the negative effects of oxidative stress, the antioxidative defense system of plants gets activated, and it includes enzymatic antioxidants as well as non-enzymatic antioxidants. The present review gives an overview of various physiological responses of plants under pesticide toxicity in tabulated form.
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In present study, the data of pesticide use, crop (the total of cereals, pulses, roots and tubers, oil crops, fibre crops, fruits, vegetables, and melons, etc.) production and the area harvested of the world and major countries for the period between 1990 and 2014 were collected, organized and summarized from FAOSTAT. First I proposed an index to measure the productive efficiency of pesticide use, cost / benefit, which refers to the amount of pesticide use to produce a certain amount of crop in a year. Theoretical relationship between crop yield and cost / benefit of pesticide use is a model with the sigmoid curve: y = a + b / (1 + e^(c-rx)), where y is crop yield, x is cost / benefit of pesticide use. The results showed that global cost / benefit of pesticide use (total) increased with time during 1990 to 2007, and declined since 2007. Pesticide use (total) (kg / ha) had the similar trend. Global insecticides, herbicides, and fungicides & bactericides use and cost / benefit declined with time since 2007. During 2010 and 2014, mean pesticide cost / benefit was 0.645 g pesticide use (total) / kg crop production, and mean annual pesticide use (total) was 2.784 kg /ha. Mean cost / benefit of insecticides, herbicides and fungicides & bactericides use between 2010 and 2014 were 0.051, 0.16 and 0.074 g / kg crop production, respectively, and mean annual use of insecticides, herbicides and fungicides & bactericides were 0.221, 0.69 and 0.32 kg / ha, respectively. Globally, the cost / benefit of dithiocarbamates, bipiridils, carbamates insecticides, and organo-phosphates, and the use of dithiocarbamates, bipiridils, and carbamates insecticides have significantly declined since 2007, and conversely, the cost / benefit of triazoles / diazoles and the use of triazoles / diazoles, plant growth regulators, and amides, have significantly increased since 2007. Of the major countries, the averaged annual cost / benefit of pesticide use (total) of Brazil during 2010 to 2014 was the greatest (1.883), followed by Japan (1.846), Mexico (1.678), China (1.243), Canada (0.979), USA (0.8733), France (0.708), Germany (0.673), UK (0.55), and India (0.089). The averaged annual pesticide use (total) (kg / ha) of Japan during 2010 to 2014 was the greatest (18.94), followed by China (10.45), Mexico (7.87), Brazil (6.166), Germany (5.123), France (4.859), UK (4.034), USA (3.886), and India (0.261). Profile of development, production and use of pesticides in China was discussed in detail. Various trends were analysed and a variety of valuable data were provided.
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To protect crops from pests, pesticides are used. Pesticides also cause toxicity to crop plants and persist in plant parts in the form of pesticide residues. Brassinosteroids (BRs) are known for their protective role in plants under various abiotic stresses like heavy metal, drought, temperature, pesticide etc. BRs ameliorate pesticide toxicity in intact plants by activating the antioxidative defence system. BRs also enhance the degradation of pesticides that leads to reduction in pesticide residues in plant parts. Present review gives an updated information about the protective roles of BRs in plants and the underlying mechanisms under pesticide stress.
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Agrochemicals have enabled to more than duplicate food production during the last century, and the current need to increase food production to feed a rapid growing human population maintains pressure on the intensive use of pesticides and fertilizers. However, worldwide surveys have documented the contamination and impact of agrochemical residues in soils, and terrestrial and aquatic ecosystems including coastal marine systems, and their toxic effects on humans and nonhuman biota. Although persistent organic chemicals have been phased out and replaced by more biodegradable chemicals, contamination by legacy residues and recent residues still impacts on the quality of human food, water, and environment. Current and future increase in food production must go along with production of food with better quality and with less toxic contaminants. Alternative paths to the intensive use of crop protection chemicals are open, such as genetically engineered organisms, organic farming, change of dietary habits, and development of food technologies. Agro industries need to further develop advanced practices to protect public health, which requires more cautious use of agrochemicals through prior testing, careful risk assessment, and licensing, but also through education of farmers and users in general, measures for better protection of ecosystems, and good practices for sustainable development of agriculture, fisheries, and aquaculture. Enhanced scientific research for new developments in food production and food safety, as well as for environmental protection, is a necessary part of this endeavor. Furthermore, worldwide agreement on good agriculture practices, including development of genetically modified organisms (GMOs) and their release for international agriculture, may be urgent to ensure the success of safe food production. © 2017 John Wiley & Sons Ltd and the Association of Applied Biologists.
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Urban stormwater samples were collected from five aquatic systems in Melbourne, Australia, on six occasions between October 2011 and March 2012 and tested for 30 herbicides and 14 trace metals. Nineteen different herbicides were observed in one or more water samples from the five sites; chemicals observed at more than 40% of sites were simazine (100%), MCPA (83%), diuron (63%) and atrazine (53%). Using the toxicity unit (TU) concept to assess potential risk to aquatic ecosystems, none of the detected herbicides were considered to pose an individual, group or collective short-term risk to fish or zooplankton in the waters studied. However, 13 herbicides had TU values suggesting they might have posed an individual risk to primary producers at the time of sampling. Water quality guideline levels were exceeded on many occasions for Cd, Cu, Cr, Pb and Zn. Similarly, RQmed and RQmax exceeded 1 for Cd, Cr, Cu, Mn, Ni, Pb, V and Zn. Almost all the metals screened exceeded a log10TU of −3 for every trophic level, suggesting that there may have been some impact on aquatic organisms in the studied waterbodies. Our data indicate that Melbourne’s urban aquatic environments may be being impacted by approved domestic, industrial and sporting application of herbicides and that stormwater quality needs to be carefully assessed prior to reuse. Further research is required to understand the performance of different urban stormwater wetland designs in removing pesticides and trace metals. Applying the precautionary principle to herbicide regulation is important to ensure there is more research and assessment of the long-term ‘performance’ standard of all herbicides and throughout their ‘life cycle’. Implementing such an approach will also ensure government, regulators, decision makers, researchers, policy makers and industry have the best possible information available to improve the management of chemicals, from manufacture to use.
Heavy metal (HM) and pesticide contamination in the soil is of major concern in the present era. Both of these contaminants disturb soil microflora and adversely affect the growth and development of plants. The soil contamination can be reduced by ecofriendly techniques. The use of endophytic bacteria (EB) in the rhizosphere is one such technique where EB reduce the HM and pesticide contaminants in the soil. They can efficiently reduce the HM and pesticide concentration in the soil by enhancing the phytoremediating efficiency of plants. Moreover, EB can also degrade the pesticides in soil by producing various hormones and enzymes which ultimately result in promotion of the growth of plants. Hence, keeping in mind the efficiency of EB in reducing the HM and pesticide contamination in soil, the present review gives a detailed view of HM and pesticide detoxification by these bacteria.
Persistent organic pollutants were assessed in Humboldt Penguins ( Spheniscus humboldti) from the Punta San Juan Marine Protected Area, Peru, in the austral winter of 2009. Plasma samples from 29 penguins were evaluated for 31 polychlorinated biphenyl (PCB) congeners and 11 organochlorine pesticides (OCPs) by using gas chromatography coupled to an ion trap mass spectrometer and for 15 polybrominated diphenyl ether (PBDE) congeners by using gas chromatography coupled with high-resolution mass spectrometry. The detection rate for PCBs in the samples was 69%, with congeners 105, 118, 180, and 153 most commonly detected. The maximum ΣPCB concentration was 25 ng/g. The detection rate for DDT, DDD, and/or DDE was higher than for other OCP residues (90%; maximum concentration=10 ng/g). The detection rate for PBDEs was 86%, but most concentrations were low (maximum ΣPBDE concentration=3.81 ng/g). This crucial breeding population of S. humboldti was not exposed to contaminants at levels detrimental to health and reproductive success; however, the identified concentrations of legacy and recently emerged toxicants underscore the need for temporal monitoring and diligence to protect this endangered species in the face of regional human population and industrial growth. These results also provided key reference values for spatial comparisons throughout the range of this species.
Herbicide resistant weeds have been observed since the early years of synthetic herbicide development in the 1950's and 1960's. Since that time there has been a consistent increase in the number of herbicide resistance cases and the impact of herbicide resistant (HR) weeds. While the nature of crop production varies widely around the world, herbicides have become a primary tool for weed control in most areas. Dependence on herbicides continues to increase as global populations migrate away from rural areas into cities and the agricultural labor force declines. This increased use of herbicides and concurrent selection pressure has resulted in a rise in cases of multiple resistance leaving some farmers with few or no herbicide options for certain weed infestations. Global population and economic forces drive many farmer choices regarding crop production and weed control. The challenge is how to insert best management practices into the decision making process while addressing various economic and regulatory needs. This review endeavors to provide a current overview of herbicide resistance challenges in the major crop production areas of the world and discusses some research initiatives designed to address portions of the problem.
The triazine herbicide atrazine (2-chloro-4-ethylamino-6-isopropyl-amino-s-triazine) is one of the most used pesticides in North America. Atrazine is principally used for control of certain annual broadleaf and grass weeds, primarily in corn but also in sorghum, sugarcane, and, to a lesser extent, other crops and landscaping. Atrazine is found in many surface and ground waters in North America, and aquatic ecological effects are a possible concern for the regulatory and regulated communities. To address these concerns an expert panel (the Panel) was convened to conduct a comprehensive aquatic ecological risk assessment. This assessment was based on several newly suggested procedures and included exposure and hazard subcomponents as well as the overall risk assessment. The Panel determined that use of probabilistic risk assessment techniques was appropriate. Here, the results of this assessment are presented as a case study for these techniques. The environmental exposure assessment concentrated on monitoring data from Midwestern watersheds, the area of greatest atrazine use in North America. This analysis revealed that atrazine concentrations rarely exceed 20 μg/L in rivers and streams that were the main focus of the aquatic ecological risk assessment. Following storm runoff, biota in lower-order streams may be exposed to pulses of atrazine greater than 20 μg/L, but these exposures are short-lived. The assessment also considered exposures in lakes and reservoirs. The principal data set was developed by the U.S. Geological Survey, which monitored residues in 76 Midwestern reservoirs in 11 states in 1992-1993. Residue concentrations in some reservoirs were similar to those in streams but persisted longer. Atrazine residues were widespread in reservoirs (92% occurrence), and the 90th percentile of this exposure distribution for early June to July was about 5 μg/L. Mathematical simulation models of chemical fate were used to generalize the exposure analysis to other sites and to assess the potential effects of reduction in the application rates. Models were evaluated, modified, and calibrated against available monitoring data to validate that these models could predict atrazine runoff. PRZM-2 overpredicted atrazine concentrations by about an order of magnitude, whereas GLEAMS underpredicted by a factor of 2 to 5. Thus, exposure models were not used to extrapolate to other regions of atrazine use in this assessment. The effects assessment considered both freshwater and saltwater toxicity test results. Phytoplankton were the most sensitive organisms, followed, in decreasing order of sensitivity, by macrophytes, benthic invertebrates, zooplankton, and fish. Atrazine inhibits photophosphorylation but typically does not result in lethality or permanent cell damage in the short term. This characteristic of atrazine required a different model than typically used for understanding the potential impact in aquatic systems, where lethality or nonreversible effects are usually assumed. In addition, recovery of phytoplankton from exposure to 5 to 20 μg/L atrazine was demonstrated. In some mesocosm field experiments, phytoplankton and macrophytes were reduced after atrazine exposures greater than 20 μg/L. However, populations were quickly reestablished, even while atrazine residues persisted in the water. Effects in field studies were judged to be ecologically important only at exposures of 50 μg/L or greater. Mesocosm experiments did not reveal disruption of either ecosystem structure or function at atrazine concentrations typically encountered in the environment (generally 5 μg/L or less). Based on an integration of laboratory bioassay data, field effects studies, and environmental monitoring data from watersheds in high-use areas in the Midwestern United States, the Panel concluded that atrazine does not pose a significant risk to the aquatic environment. Although some inhibitory effects on algae, phytoplankton, or macrophyte production may occur in small streams vulnerable to agricultural runoff, these effects are likely to be transient, and quick recovery of the ecological system is expected. A subset of surface waters, principally small reservoirs in areas with intensive use of atrazine, may be at greater risk of exposure to atrazine. Therefore, it is recommended that site-specific risk assessments be conducted at these sites to assess possible ecological effects in the context of the uses to which these ecosystems are put and the effectiveness and cost-benefit aspect of any risk mitigation measures that may be applied.