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Biological Cycles for Toxic Elements in the Environment

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Abstract

Toxic substances in the environment can be categorized as naturally occurring toxic elements and compounds and toxic compounds that are synthesized industrially. In this article, some of the chemical and biochemical transformations of toxic elements in the environment are described, with particular emphasis being placed on the role played by microorganisms. The author also shows that the present knowledge of biological cycles of toxic elements enables one to predict the behavior of other toxic elements in the environment. Discussed are microbial interconversions of toxic elements, heavy metals, and the metalloids.

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... Volcanic activities near ocean ridges, island arcs, and mantle plumes have released a large number of chemical elements from the deep to the shallow realms of the Earth. Some of them are bio-essential (e.g., C, H, O, N, S, P, etc.), while some are toxic to life (e.g., Hg, As, F, etc.) (Hao et al., 2022;Cui et al., 2021;Grasby et al., 2019;Masuda, 2018;Ernst and Youbi, 2017;Mukhopadhyay et al., 2002;Merian, 1984;Wood, 1974). The boundary between bio-essential and toxic materials is ambiguous, and their concentrations and combination with other elements also play a key role. ...
... When volcanic activities increase (usually during large plume events), the toxic elements and bio-essential elements imported into the shallow atmosphere-hydrosphere-lithosphere system may be over-enriched in a short time (Fig. 6) (Cui et al., 2021;Grasby et al., 2019;Ernst and Youbi, 2017). These volcanic materials are released into the sea, atmosphere, and land, used by the food chain and human production activities, affecting the evolution of the biosphere and the habitability of the planet (Wood, 1974). Some toxic elements increase their Plate Tectonics: The Stabilizer of Earth's Habitability concentration toward the high-level predators along the food chain and are finally decomposed by decomposers and re-enter the inorganic environment after the death of organisms (Mukhopadhyay et al., 2002;Wood, 1974). ...
... These volcanic materials are released into the sea, atmosphere, and land, used by the food chain and human production activities, affecting the evolution of the biosphere and the habitability of the planet (Wood, 1974). Some toxic elements increase their Plate Tectonics: The Stabilizer of Earth's Habitability concentration toward the high-level predators along the food chain and are finally decomposed by decomposers and re-enter the inorganic environment after the death of organisms (Mukhopadhyay et al., 2002;Wood, 1974). The bio-essential elements will also flow along the food chain and interact with the shallow inorganic environment. ...
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Earth is the only planet known to be habitable, and is also unique with its liquid water, and the operation of plate tectonics. The geological record shows that the habitability of our planet can rapidly recover from major disasters or catastrophes, even those that cause mass extinctions. We suggest that plate tectonics, which acts as a link between the shallow and deep, is pivotal for the formation, evolution, and long-term stability of the hydrosphere, atmosphere, lithosphere, and thus life. Plate tectonics links the surface environment with the deep interior of high viscosity, low Reynolds number, low entropy, and low chaos, able to produce a strong healing effect to neutralize catastrophic events. It can transfer the bio-essential elements from the deep interior to the near-surface environment and can recycle toxic elements to the deep. This unique planetary energy and material transfer process of Earth is a continuous, slow-release, and bidirectional cycle, where a change in the surface is slowly buffered by a reaction from the deep, shaping a long-term and stable habitable environment. Therefore, it is considered that plate tectonics is the basic condition for the long-term stable evolution of the Earth’s biosphere and the stabilizer of the Earth’s habitability.
... Pearson Correlation measures the degree of a linear relationship between two variables. The correlation coefficient assumes a value between −1 and +1 [13]. If one variable tends to increase as the other decreases, the correlation coefficient is negative. ...
... The geochemistry of fluoride in groundwater and dental health communities, particularly those depending on groundwater for their drinking water supplies is one of the best known relationship between geochemical and health. Fluoride is considered to be an essential element [13] although dental health problems may arise from an excess of fluoride. Many waters supply schemes particularly in developing countries where hand dug wells and deep boreholes form as much are harmful to dental health [2]. ...
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The occurrence, storage, and distribution of groundwater in the Precambrian basement complex are influenced by different geological factors. Groundwater is never chemically pure; dissolution of substances takes place in the course of its percolation through the rocks leading to its acquisition of some of their chemical constituents. The purpose of the investigation is to determine the suitability of groundwater for domestic and industrial usage. Four samples were collected from boreholes and six from hand dug wells. Samples were analyzed chemically by using the DR/2010 Spectrophotometer and Digital Titrator while physical parameters where determine using the pH meter, and TDS meter. Hydraulic conductivity and transmissivity results range from 4.24 m/day to 72.63 m/day and 23.84 m2/day to 964.0 m2/day. The geochemical result obtained from the analysis of 10 water samples in the study area with an average values pH 6.82. Temp. 310C, colour (TCU) 1.00, Turbidity 1.2, Conductivity 174.5TDS 87.7 mg/l, which revealed that the water physical parameters are below the WHO permissible value. Total Hardness 161.7mg/l, Ca2+ 64.3mg/l Na+ 68.8mg/l, NO3+ 0.1 mg/l Fe2+ 0.04 mg/l CO3 96.4 mg/l Sulphate 47 mg/l Cl- 96 mg/l and F- 0.3 mg/l. Results obtained of the water analysis reveals that the concentration of Total Hardness and F- in some parts of the study area are above the permissible standard for drinking water WHO Standard. Therefore, the water in the affected part of the study area should be subjected to proper treatment. The groundwater flow direction is from higher surface elevation to lower surface elevation.
... Despite being colorless and odorless, heavy metal contamination in soil operates as a latent hazard. Its effects may not be immediately apparent, but when environmental conditions change or tolerance thresholds are exceeded, the activation of heavy metals can unleash severe ecological damage, akin to a chemical time bomb [3]. ...
Article
Heavy metal poisoning in roadside soils is a worldwide environmental issue with serious consequences for both ecological health and human well-being. This study provides a detailed summary of the state of heavy metal pollution along roads, spanning multiple locations and centuries. The research found a pattern of contamination in major and medium-sized cities around the world, with cadmium (Cd), chromium (Cr), zinc (Zn), nickel (Ni), copper (Cu), and lead (Pb) appearing as common pollutants. Temporal dynamics, specifically the impact of road age on heavy metal dosages, are investigated, offering light on the long-term consequences of vehicular traffic on soil pollution. The investigation delves into specific case studies, including the historic levels of lead in Kuala Lumpur and the shift from leaded to unleaded gasoline. Regional disparities in zinc and cadmium concentrations underscore the complex nature of heavy metal contamination, necessitating nuanced, area-specific mitigation strategies. Elevated copper levels in England, Korea, and Greece highlight the triad of concern in various geographical settings. Furthermore, the research compares heavy metal concentrations in Indian cities, emphasizing the influence of regulatory measures on contamination levels. The drastic reduction in lead levels in Kolkata post the discontinuation of leaded petrol signifies the effectiveness of environmental interventions. Conversely, the complex heavy metal predicament in Delhi underscores the intricate relationship between vehicular emissions, traffic congestion, and contamination. The study concludes with a global perspective on heavy metal contamination, emphasizing its meaningful ecological and anthropological health hazards. The regional and temporal variations discovered in this study give essential insights for informed decision-making, regulatory actions, and long-term urban planning to limit the negative consequences of heavy metal pollution in roadside soil. Keywords: Heavy metal contamination, Roadside soil, Cadmium, Chromium, Zinc, Nickel, Copper, Lead, Urban pollution, Environmental health.
... Approximately fifty three of the ninety naturally occurring elements are called heavy metals [15] and many of these, such as Cu, Mn, Fe, and Zn, are essential micronutrients, but can become toxic at concentrations higher than the amount required for normal growth. 16 Other heavy metals, such as Cd, Hg, and Pb, have so far unknown roles in living organisms, and are toxic even at very low concentrations [16,17]. ...
Article
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Minerals are essential for life to fulfil the needs of growth and production and to replace cells lost during the course of normal metabolism. On this account, they need to be replenished continuously through food, water or supplements. Although not well studied, rural people in Ethiopia have been using soil supplements for ruminants with the assumption to improve livestock production. Therefore, this study was conducted to examine the mineral content in red and brown salty soils used for supplementary food to ruminants in Wolaita Zone and to compare the findings against the national standards, and forward appropriate recommendation. Representative samples of minerals were taken from different sites of SNNPR around Wolaita Zone, Humbo worada, near Lake Abaya to test the contents and concentration of elements. Sixteen Aduwaa(salty soil) samples were collected, air dried, any visible external particles were removed crashed, homogenized, sieved by using 2 mm mesh, accurately weighed, labelled in plastic bags and sent to mechanical and chemical laboratory and tested using XRF spectroscopy in South Africa and Ethiopian Conformity Assessment Enterprise, in Addis Ababa. One way ANOVA was used for test significance. The findings of XRF spectrometry test showed that there are more than forty six (46) elements in the soil sample. Among them Na (1.790-7.562%), Mg (0.461-0.832%), P (0.023-0.092%), S (0.014-0.084%), K (2.722-3.186%), and Ca (0.404-0.844%) are essential macronutrients and Mn (0.190-0.216%), Fe (4.908-7.292%), Cu (0.00026-0.00062%), Co (0.00064-0.00089%) and Zn (0.016-0.032%), are essential micronutrients which can become toxic when the threshold limits for normal growth are exceeded. The study also showed Aduwaa did not contain heavy metals such as Ir and Hg which have; so far, unknown roles in living organisms, and are toxic even at very low concentrations. However, it contained Pb (0.00048-0.00076%), Cd (0.00025-0.00128%) and As (0.00425-0.00528%) in relatively at very low concentration. The sample contained Fe at extremely high concentration which have antagonistic role in copper absorption and metabolism.
... Despite being colorless and odorless, heavy metal contamination in soil operates as a latent hazard. Its effects may not be immediately apparent, but when environmental conditions change or tolerance thresholds are exceeded, the activation of heavy metals can unleash severe ecological damage, akin to a chemical time bomb [3]. ...
Article
Heavy metal poisoning in roadside soils is a worldwide environmental issue with serious consequences for both ecological health and human well-being. This study provides a detailed summary of the state of heavy metal pollution along roads, spanning multiple locations and centuries
... Several of these ions are necessary for growth, metabolism and development.when cells are confronted with either an elevated level of these vital ions or with non-essential ions, wide range of cellular damage can be noticed due to inactivation of bio-molecules by either blocking essential functional groups or by displacement of essential metal ions (Wood, 1974;Adriano et al., 1978;Shi and Sengupta, 1995;Singh and Yunus, 2000). ...
Article
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The present study aims to investigate the effect of Thermal power plant emissions upon two species of plant Alhagi mourorum and Suaeda vermiculata which growth in the region close to Thermal power plant. triplicater samples were collected seasonllys from autumn 2016 up to summer 2017 one time from each season. three station were selected in the study area to execute this study meters. The first station distances 400 meters from the thermal power station, The second station is located 800 meters from the thermal power plant . While, the third station distances 1200 meters from the thermal power plant . Three stations were with prevailing wind direction (north wind) , while control station situated far from the thermal power plant about 12 km. the concentratios of heavy metals Cd, Cu, Pb and Zn were estimate in root and shoot systems for both plants, their concentration in root system more higher than their concentrations in shoot system. its concluded from the present study that thermal electric power station emissions affected upon the plants which growth in the surrounding region with thermal power plant.
... ANOVA revealed insignificant value for the Cr concentration. In the fish or in a living cell heavy metals such as Pb, Cd and Cr have unknown role and become toxic at a low concentration, these elements are usually not available in the living areas of the nature and thus, are introduced into the environment through anthropogenic activities [19][20]. ...
Article
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Heavy metals are raising worldwide concerns owing to their potential effects on the environment. The present research analyzed heavy metals in the estuarine fish (Johnius dussumieri) sampled from the downstream Pasur estuarine Kokilmoni area of the Sundarbans, Bangladesh, during summer (March) and winter (November), 2022. Lead (Pb), Chromium (Cr) and Cadmium (Cd) were measured following a validated and accredited test method using graphite furnace atomic absorption spectrometry (GFAAS; Varian AA Duo 240 FS and Varian 280Z). Mercury (Hg) and Arsenic (As) in fish extracts were determined by cold vapor and hydride generation atomic absorption spectrometry (CVAAS) respectively. Mean concentrations (mg/kg) of Pb, Cd, As, Hg and Cr, were 2.93 ± 0.91, 0.057 ± 0.020, 0.144±0.054, 0.164±0.150 and 1.633± 1.450. ANOVA show that mean concentrations of Pb was significantly (p< 0.001) higher than the FAO and WHO recommended value whereas Cd, As and Hg were significantly (p< 0.001) lower. The Levene's test show winter fish population has significantly higher Pb and Cr concentrations than summer populations (p< 0.05). Pearson Correlation analysis (p<0.05) quantified that Cr is strongly correlated with Pb (r=0.974) and Cd (r=0.612) at the 0.01 level (two tailed), Cd is strongly correlated with Pb (r=0.666). Principal component analysis was executed for the five heavy metals and revealed that two principal components covering 71.86% of the cumulative variance. The PC1 variable loading appeared to strongly be influenced by Pb, Cr, and Cd (0.970, 0.951, and 0.797 respectively). The variables loading on PC2 has influenced by As and Hg. Cumulative variance of component 1 accounts 51.423%, the component 2 accounts 20.445%. Therefore it can be concluded that Pb is supposed to be higher due to anthropogenic influences such as lead-acid battery industries, agricultural pesticides, industrial and different domestic uses of metals in the upstream Pasur. Heavy metals need to be monitored regularly for the sustainable management of the pristine Sundarbans ecosystem. Further time and s
... Anaerobic reductive biomethylation of metals and metalloids is regarded as an alternative bioremediation strategy. Microorganisms biomethylate metals and metalloids under both aerobic and anaerobic conditions [39][40][41][42][43][44][45][46][47][48] in a variety of environments, including metal waste deposits, sewage sludge, and alluvial soils [45,47,48]. The resulting methylated metal compounds differ in solubility, volatility, and toxicity [49][50][51]. ...
Chapter
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Shewanella drives a variety of environmentally important processes, including the biogeochemical cycling of carbon, metals, metalloids, and radionuclides. The ability of Shewanella to deliver electrons extracellularly also renders this genus valuable for applications of contaminant remediation and energy generation in water treatment processes. Although the first Shewanella species was isolated and studied as a model metal‐reducing microorganism over thirty years ago, only recently has research focused on employing Shewanella to drive water treatment processes. This article examines current and prospective applications of Shewanella to water treatment issues, highlighting biochemical details associated with each technology. The technologies include the remediation of metal‐contaminated environments, the generation of electricity from wastewater streams, the removal of hazardous contaminants under anaerobic conditions, and precious metal recovery in combination with formation of novel biocatalysts.
... The aqueous concentrations that result from these multiple equilibria can in some cases constitute potential threat to ecosystem and human health. Methylmercury is a neurotoxin demonstrated to present health threat in numerous aquatic systems [70]. ...
Chapter
The Great Salt Lake is terminal, lacking outflow, and is descended from vast Lake Bonneville through evaporation. It is akin to a puddle on the tarmac with a similar surface area to volume ratio. It is an avian wildlife habitat of hemispheric importance, and lies adjacent to a metropolitan population of 2.5 million, with correspondingly increasing water demands and anthropogenic effluents. Engineered partitions spanning the lake generate density‐driven flow among the layered concentrated brines, which show dramatic vertical redox transitions and corresponding contrasts in trace element behaviors, some of which show elevated burdens in the ecosystem. We describe this system in four parts, starting with the geographic and hydrologic framework (Section 1) that determines its limnologic and hydrodynamic characteristics (Section 2) that shape its ecosystem (Section 3), which interacts dynamically with its geochemical characteristics (Section 4).
... In the present study, the correlation analysis (Table 7) pointed out that the faunal population shows a relatively significant correlation with trace metals, which agrees with the toxicity of trace metals as classified by Wood (1974). Elphidium crispum and Nonion faba can survive in less polluted environments, whereas their abundance decreases in intensely polluted environments and becomes a more sensitive taxon (Dimiza et al. 2019b;Jeshma et al. 2017). ...
Article
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The benthic foraminiferal community is an excellent bio-indicator of pollution in coastal and marginal marine settings. Their abundance, diversity and its relationship with environmental parameters, viz. grain size, organic carbon (Corg) and trace metals concentration, from the surface sediment layer of the southwestern shelf of the Bay of Bengal, have been used to understand the marine pollution in this study. A total of 32 surface sediment samples were collected at various water depths.The samples were analysed for grain size distribution, organic matter (OM), foraminiferal and trace metals studies. Statistical analyses such as correlation matrix, PCA (Principal Component Analysis) and cluster analysis show that the foraminiferal species composition is significantly influenced by the organic carbon (Corg), Co, Pb, Zn, Cr, and Ni concentrations. The dominance of stress-tolerant species, viz. Ammonia beccarii, Ammonia tepida, Nonion faba, Bulimina marginata, Bolivina robusta, Elphidium craticulatum and Elphidium advenum, as well as less species diversity, demonstrates the elevated Corg and trace metal pollution in the marine environment.
... Thus, human health status is largely dependent on the quality of groundwater. The potability of groundwater is subject to the quantity of various ions dissolved in it (Wood, 1974). Aquifers with crystalline subsurface are usually enriched with high fluoride groundwater (Edmunds and Smedley, 2005;Jacks et al., 2205). ...
Article
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An overwhelming 90 percent of the population in the Puruliya district is rural and significantly dependent on groundwater as the only source of drinking water. However, the groundwater of all the 20 blocks of this district is contaminated with high-level fluoride. The geographical pattern of fluoride distribution in this study is assessed using Moran's Index, and hotspot analysis on fluoride contamination reports of 2019-20. Fluoride distribution shows a random pattern, and the hotspot zones are spread in blocks, namely Puruliya-I, Puruliya-II, Raghunathpur-I, Raghunathpur-II, Puncha, Balarampur, Para, Hura, Jaipur, Manbazar-I. This study will help to identify the areas with chronic and acute problems that need immediate measures.
... A consequence of this distribution and the eventual behavior of the accessory minerals during cleaning of coal is that the lighter fractions, ostensibly the cleanest coal, may contain substantial amounts of potentially toxic (Wood, 1974) trace elements. During the utilization of the coal these elements may get into the environment despite efforts to prevent that from occurring. ...
... Compared to previously discussed heavy metals (Cd, Co, Cr, and Ni), these elements were less tightly bound to the soil fractions and more accessible to the environment. Their bioavailability and mobility may have been due to anthropogenic disturbances that disturbed the heavy metals' biological cycling [26,84]. The studied areas might have been influenced by nearby agriculture or mining factories. ...
Article
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Accumulation of heavy metals is a concerning issue due to their known persistence in the ecosystem, and there are standard limits established for their maximum allowable concentrations in soils. However, heavy metal accumulation coming from serpentinite soils often exceeds the regulatory values, and there is a lack of knowledge regarding their bioavailability, mobility, and toxicity in the environment. This research applied novel selective sequential extraction and leaching procedures to assess the gaps in knowledge regarding heavy metals accumulation on serpentinite topsoil derived from a few states in Peninsular Malaysia. Based on the total digestion method, the concentration of all studied heavy metals except Mn exceeded the site screening levels issued by the Department of Environment, Malaysia (DOEM). The Geo-accumulation Index categorized Cr, Cd, Ni, and Co as extreme contamination and Cu, Pb, Zn, and Mn as unpolluted to moderate contamination. From the extraction results, Cd was found bounded 100% to a residual fraction. Meanwhile, Ni, Co, and Cr were mostly (≥92%) found to be bound to a residual fraction, with the remaining percentages distributed within non-bioavailable fractions (crystalline Fe oxides, poorly crystalline Fe oxides, and Mn oxides). Nevertheless, Cu, Pb, Zn, and Mn contaminants showed an increase (1–9%) in bioavailability and mobility fractions (soluble–exchangeable, surface-adsorbed, and organic matter) which pose a threat to the environment. The toxicity of the heavy metals greatly surpassed the DOEM standards; however, it was still below the global USEPA toxicity control. This research concluded that, even though the toxicity level of the topsoils had not exceeded the global toxicity limit, the accumulation of heavy metals in the serpentinite soils needs to be addressed due to its high concentration and its being potentially bioavailable and mobile in the environment.
... Sự cân bằng phân bố của kim loại trong nước, các hạt lơ lửng và trầm tích có thể phản ánh chất lượng môi trường tại khu vực [4]. Các đặc tính bền vững của KLN như độ độc cao, không phân hủy sinh học và có khả năng tích tụ đã thu hút sự quan tâm của các nhà khoa học cũng như các nhà quản lý môi trường trong việc đánh giá hàm lượng KLN trong môi trường [5]. ...
Article
This study aimed to assess the accumulation of some heavy metals such as Cu, Pb, Cd, and Cr in the sediments collected from downstream of the Red river from the south of Hanoi city to Nam Truc district, Nam Dinh province. Besides, the geological accumulation index (Igeo) and the potential ecological risk index were calculated to understand the impact of heavy metal content in the sediments on the ecosystem. The results showed that the concentration of several metals (Cu, Pb, Cd, Cr) in 20 sediment samples was lower than the permitted values specified in Technical Regulations on sediment quality (QCVN 43:2017/BTNMT). However, according to the Canadian guidelines, the concentrations of metals in 50% of samples had a low level of effect. The potential ecological risk index of metals ranges from 1.8 to 11.6, revealing that the study area has a low-level metal risk. This data can clarify the area’s potential risk level and provide the scientific basis for recommending measures to control and reduce sources of metal pollution into the aquatic environment.
... Among them the metals like Cu, Ni and Zn are considered as essential micronutrients, but become toxic at concentration higher than the amount required for optimal growth. Other metals like Pb, Cd and Cr have so for unknown roles in living organisms and toxic even at low concentration (Wood, 1974). Various aquatic ecosystems, estuaries in particular are heavily impacted by anthropogenic wastes as they tend to act as sinks (Kennish, 2002;Hung and Chmura, 2007) for fine, contaminant-reactive sediments and at the same time they serve as ecosystem filters (Teuchies et al., 2013). ...
Article
Wet and Dry Coastal Plant Communities of West Bengal, India Anirban Roy International Journal of Chemical and Environmental Sciences 3 (4), 30-33, 2022 The coast, marine and terrestrial interface, is one of the important biogeographic regions of India due to its immense economic and ecological services. It is broadly divided into two major systems on the basis of topography and geomorphology: dry coastal ecosystem and wet coastal ecosystem. The dry coast constitutes, i) Sandy coast with sandy beach and sand dunes and, ii) Rocky coast having rocks and vertical cliffs, devoid of beach and dunes. Indian coastline with 7,500 km mostly covers dry sandy coast in eastern region and there are present dry rocky coast in western part. The wet coastal ecosystem is connected with lagoons, backwaters, estuary and deltas. The characteristics as well as types of vegetation in these two zones have been presented in a brief way. The present communication is an attempt to highlight the formation of various plant communities, specially, throughput the coast of Bengal on basis of field exposure and published contributions of previous workers in these fields.
... Selon le type de roche, la concentration d'arsenic peut varier de 0,1 à plusieurs centaines de milligrammes d'arsenic par kilogramme, avec une moyenne de 2-3 mg d'As/kg (Cullen et Reimer, 1989). (Ferguson et Gavis, 1972 ;Wood, 1974). Les activités humaines qui peuvent générer de l'arsenic (Walsh, 1979 ;Cullen et Reimer, 1989;Ravenscroft et al., 2011;Naujokas et al., 2013 ;Jiang et al., 2013) ...
Thesis
In Martinique, some coastal species bivalves are harvested in mangrove swamps and beaches for consumption. Due to their habitat distribution and their life habits, these species are highly bio-accumulators of pollutants. Thus, these fisheries considered a priori, as localized by some authors, provide food resources potentially contaminated by pollutants. However, there are few data on the importance and characteristics of these fisheries; the quantitative assessment of the stock and the state of health of the bivalves being unknown. In addition, since 2011, floating clumps of Sargassum spp are more frequent and therefore lead to increased mortality in coastal biocenoses.These Sargassum algae are known for their ability to accumulate a large amount of metals in their tissues. The released of these substances and in particular arsenic by desorption or by decomposing algal biomass constitute a risk of contamination for coastal biocenoses but also for consumers of bivalves. In this thesis, the importance and characteristics of fisheries as well as of the main species caught were described. The impact of stranding on a bivalve population has been outlined and the state of contamination of the bivalves has highlighted the presence of significant contamination by some metals but especially by arsenic. The exposure of bivalve consumers to these metals has been estimated. These results reveal consumer exposure as the daily intake ranged from1.6 mg.day-1 to 6 mg. day-1 for a meal of 240 g of bivalves. As arsenic has highly toxic chemical species, the proportions of which in the flesh of bivalves could increase in the context of sargassum strandings, the consumption of these bivalves must be limited and away from periods of sargassum strandings. In order to preserve the health of consumers, toxicological reference doses for all the species of arsenic present in the flesh of these bivalves are proposed and discussed. Keywords: traditional fishing practices, consumption of bivalves, bivalves biometrics, arsenic exposure assessment, arsenic speciation in bivalves, sargassum stranding.
... Among them the metals like Cu, Ni and Zn are considered as essential micronutrients, but become toxic at concentration higher than the amount required for optimal growth. Other metals like Pb, Cd and Cr have so for unknown roles in living organisms and toxic even at low concentration (Wood, 1974). Various aquatic ecosystems, estuaries in particular are heavily impacted by anthropogenic wastes as they tend to act as sinks (Kennish, 2002;Hung and Chmura, 2007) for fine, contaminant-reactive sediments and at the same time they serve as ecosystem filters (Teuchies et al., 2013). ...
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Milkfish were sampled during premonsoon (2015) from the Hooghly River mouth Eco-region (HRME) and Saptamukhi River/Creek mouth Eco-region (SRME) on the Northeast of Bay of Bengal. Metal accumulation and its impact on the antioxidant systems of different tissues of the fish were studied. Study showed Zn > Cu > Pb > Fe > Mn > Cd > Ni in the gills, muscles, and liver. Metal concentration in the liver and gills was found to be quite high compared to the muscle. Active responses were recorded in cases of lipid peroxidase, superoxide dismutase, catalase, glutathione peroxidase in gill, liver and muscle. Reduced glutathione and glutathione-S-transferase activities could be attributed to metal induced oxidative stress. Alteration in the antioxidant enzymes, glutathione system and induction of lipid peroxidation underlined the impact of metals contaminants in the fish indicated to the stress experienced by a heavily consumed piscine species such as milkfish.
... As the basic principle of the binding of the DNA-aptamer to the target substances is the same, the flashing with proposed microfluidic heating devices in this study can apply to other DNA-aptamer linked hydrogels. The melting temperature, T m , is different by the number of base pairs bound and the binding force between the target substances and the base pairs, but it could be estimated as in Eq. (2). Proposed microfluidic heating device can apply any thermal stimuli by tuning the current, thus the DNA-aptamer linked hydrogel with different DNA aptamers could also detect the target substances repeatedly. ...
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This paper describes repeatable detection of Ag⁺ ions using a DNA aptamer-linked hydrogel biochemical sensor integrated with a microfluidic heating system. Biochemical sensors that respond to chemical compounds and produce detectable signals have a critical role in many aspects of modern society. In particular, the repeatable measurement of environmental information such as toxic substances including Ag⁺ ions could be expected to improve the environment. The DNA aptamer is an attractive candidate because of the stability and the selectivity of binding to chemicals. However, previous DNA aptamer biochemical sensors could not measure repeatedly because those sensors did not have initializing functions. To overcome this challenge, we proposed a DNA aptamer-linked hydrogel biochemical sensor integrated with the microfluidic heating system enabling repeatable detection of Ag⁺ ions. The binding Ag⁺ ions are dissociated by heating and flushing through the integrated microfluidic heating device. The DNA aptamer-linked hydrogel had the capability to detect a wide range of Ag⁺ ion concentrations (10⁻⁵–10 mM) including a toxic range for various aquatic organisms. Finally, we demonstrated the repeatable detection of the Ag⁺ ions. These results indicated that our proposed biochemical sensor is expected to use for long-term monitoring with high stability in ambient temperature and low power consumption.
... 8 Heavy metals are termed as metals having density of about 5 g/cc or more such as Zn, Cr, Cd, Pb and others. The metals like Pb, Cd etc are toxic having no biochemical role in biotic life 11 while Zn, Cr etc act as micro nutrients but show toxic at higher concentration than the amount for normal growth 12 . These are not, in general easily available for biotic life in nature, but are injected into the ambient environment through various anthropogenic activities and ultimately become a source of pollution with an adverse consequences in natural system, to human or to the living organisms by way of accumulation in soil/sediments,water and biota 13 . ...
Article
Anthropogenic activities like industrialization, unplanned urbanization, deforestation and profit oriented capitalism have resulted introduction of many undesirable substances into our immediate environment creating environmental degradation to a great extent. Normally, nature takes the responsibility of reducing the adverse effect of these substances through the operation of many physical, chemical and biological processes such that these substances can be partitioned in various biotic and a-biotic components of an environmental ecosystem. Present study is an attempt to highlight the extent of partitioning of some heavy metals in the compartments of water, sediments, macrophyte and fishes of a sewage-fed fishery pond in East Kolkata Wetland (EKW). Study distinctly revealed that all heavy metals show a common preference to be deposited on the sediments with higher values (28.5 to 56.5%) followed by macrophytes (20.3 to 35.4%), fishes (15.7 to 43.2%) and water (less than 1.0%). Similar types of partitioning might be observed in each higher plants and animals. As an example, in fishes, higher accumulation of heavy metals were in viscera (27.5 to 69.2%) followed by bone (4.6 to 47.7%), gill (8.1 to 30.6%) and least in flesh (< 1.0 to 19.0%). Again, in cases of toxic metals, it has been observed that flesh contains less than 1% and while the essential group of metals (Zn and Cr) showed comparatively higher degree of accumulation (11.3 to 19.5 %). Thus, the study evidently forecasted that redistribution of heavy metals in large number of inter and intra compartments of natural biotic and abiotic agents, could be considered as the most effective mechanism for reducing the undesirable consequences of heavy metals or any toxic waste along with passage of time.
... existence of even a trace amount of inorganic heavy metal elements such as mercury (Hg), cadmium (Cd), arsenic (As), nickle (Ni), lead (Pb), or chromium (Cr) in soil may pose risks and hazards to humans and the ecosystem (Dufus, 2002). In particular, potentially toxic trace elements such as Cd, Cu, Pb, Zn, and As are persistent in the environment and are non-biodegradable; thus, they can accumulate at toxic levels, causing adverse impacts to natural ecosystems (Alloway, 2012;Wong et al., 2002;Wood, 1974). They can decrease soil fertility (Ljung et al., 2006), reduce crop productivity (Khan et al., 2008), and have a harmful influence on human health through bio-accumulation (McLaughlin et al., 1999). ...
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Trace elements occur naturally in rocks and soils, but increasingly higher quantities of elements are being released into the environment by anthropogenic activities. In particular, urban soils are marked with elevated levels of trace elements due to vehicular emissions, industrial disposals, urban waste, chemical fertilizers, and construction materials. This study reports the concentration of twenty elements including highly toxic heavy metals (Mg, Al, P, Ca, Fe, K, Si, Na, S, Ti, V, Se, Cr, Cu, Ni, Mn, As, Pb, Zn, and Cd) in the surface soil (0–20 cm) of Kathmandu Valley, Nepal. Three soil pollution indices (geo-accumulation index, single pollution index, and enrichment factor) were employed to determine the severity of trace element contamination. Our results suggested that the studied sites are under strong to moderate contamination in the order of Cd > As > Pb > Zn > Cr > Mn > Ni > Cu. We observed a high concentration of Pb, Zn, As, and Cd in the surface soil of the Kathmandu Valley mainly due to anthropogenic activities. The concentration of As and Cd was found several times higher than the global average background value and a deficient amount of P, S, and Mn was observed.
... 1 In an anoxic environment, inorganic Hg can be methylated into highly neurotoxic methylmercury (MeHg) by anaerobic microorganisms with the hgcAB gene cluster, 2 especially sulfate-reducing bacteria, 3 iron-reducing bacteria, 4 and methanogens. 5,6 Furthermore, MeHg is bioaccumulative and can be biomagnified through the aquatic food web, 7,8 threatening the health of aquatic biota and humans worldwide. 9,10 Fortunately, MeHg in surface water and sediments can also be demethylated before its incorporation into the aquatic food web through chemical 11 and microbial pathways. ...
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The method of isotope dilution and tracing, based on ethylation-purge and trap-gas chromatography (GC)-inductively coupled plasma mass spectrometry (ICP-MS), has been widely used for the accurate analysis of methylmercury (MeHg) and for tracking its environmental fates (e.g., formation/degradation). However, the tedious ethylation derivatization and purge and trap processes limit analytical throughput. In this work, an automatic ethylation derivatization and purge and trap method, followed by GC separation, pyrolysis, and ICP-MS detection, was developed for MeHg analysis. The throughput and detection limits of this proposed method for MeHg were 7.5 min/sample and 0.03 ng L-1 , respectively, with a relative standard deviation of 3.7%. The accuracy of the developed method was validated by the analysis of a spiked water sample and a certified reference material (DORM-4, Fish protein) using isotope dilution (Me 201 Hg). In addition, anaerobic Geobacter sulfurreducens PCA-mediated methylation of Hg 2+ and demethylation of MeHg was monitored by using double-enriched isotope tracing (199 Hg 2+ and Me 201 Hg). This automatic ethylation-purge and trap-GC-ICP-MS method is promising for routine MeHg analysis with isotope dilution/tracing.
... INTRODUCTION Mercury (Hg) is a toxic and widespread heavy metal of natural and anthropogenic origins that accumulates in soils and sediments 1 . The methylmercury (MeHg), largely produced from methylation of inorganic mercury by anaerobic microorganisms 2 , is of special concern since this compound is highly toxic and biomagnifies in aquatic food webs, generating a health hazard to wild animals and humans 3 . ...
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... If the air and water are polluted, the pollution problem can be reversed certainly by dilution and self-purification after switching off the sources of pollution. But, it is difficult to use dilution or self-purification techniques to eliminate heavy metal contamination and to get soils improved [11]. Heavy metals are currently of much environmental concern. ...
... It indicates neuropathology when the adults are exposed to unnecessary amounts, either occupationally or unintentionally. In the human body, there is a link between Pb and a rise in adult blood pressure (Wood, 1974). This increase in biochemical deficiencies and blood pressure-related diseases may have been contributing to the high occurrence of diseases springing up in Ghana recently (Bortey-Sam et al., 2015;Obiri et al., 2010). ...
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Trace metals contamination has recently been a major issue due to its damaging effects on public health and environmental receptors. This study focussed on the health risk assessment of trace metals (As, Pb, Cr, and Ni) associated with the direct intake of some selected food crops (namely cocoyam and plantain) at Abuakwa South Municipal, Ghana. The food crops and soil samples were selected randomly from three reclaimed mined sites and one non-mining site in the study area. Results from the trace metal concentration analyses in the soil samples showed that As, Cr, and Ni were above the control. The daily intake of metals (DIM), target hazard quotient (THQ), and carcinogenic risk (CR) assessments of health risks accompanied by the continuous ingestion of the selected food crops polluted through these trace metals were evaluated. 0.23 mg/kg and 0.05 mg/kg, 0.11 mg/kg and 0.02 mg/kg, 0.78 mg/kg and 0.65 mg/kg, and 0.23 mg/kg and 0.09 mg/kg were recorded for As, Cr, Ni, and Pb in that order in the cocoyam and plantain, respectively. The As and Pb concentrations in the food crops were above the WHO recommended limits. This implies that individuals within the vicinity are exposed to high levels of As and Pb through food intake which could result in varying health implications. The DIM and THQ for the studied trace metals were below their permissible limits suggesting that there is a tolerable non-carcinogenic adverse health risk level for adults and children within the studied area. In addition, the lifetime probability of contracting cancer by ingesting Ni, Pb, and Cr in plantain grown in the study area is high. It is recommended that regular monitoring of these trace metals in food crops be carried out in preventing their excessive accumulation.
... Para ello se utilizó la sustancia o sustancias que habían sido explotadas en cada una de ellas y que ya estaban registradas en la base de datos. Estas sustancias fueron clasificadas según su grado de potencial toxicidad, utilizando la categorización realizada por Wood (1974) para los metales pesados en tres categorías: 1) no crítico, 2) tóxico insoluble, 3) muy tóxico. En este procedimiento se realizaron consultas de selección mediante SQL a la base de datos. ...
Chapter
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The concentrations of heavy metals in the form of free elements or oxides, as well as arsenic in samples of atmospheric aerosols, collected in northern Tajikistan in the period from 2013 to 2019, are determined. Local sources of heavy metals, mainly anthropogenic (motor vehicles, metallurgical industrial plants, open tailing dumps, etc.) in origin, are discussed. It is accepted that metals of natural origin usually have low coefficients of variation, while metals associated with anthropogenic sources are characterized by high CVs and reflect a heterogeneous distribution of concentrations.
Chapter
Soil health is a global concern in today’s world, despite the advancements in artificial intelligence and rapid industrialization. Agriculture, the most traditional method for sustainable survival, remains essential. Soil health directly impacts agricultural productivity but faces numerous challenges due to the influx of pollutants from both natural and human activities. While supplementing soil with nutrients and minerals can improve its health, pollution poses a significant obstacle. Unhealthy soil, even with added nutrients, cannot enhance productivity due to factors such as heavy metal pollution. Industries such as processing, pharmaceuticals, textiles, and natural processes introduce heavy metals into the soil, which persist for years. The hazardous and indestructible nature of heavy metals necessitates their removal. Various chemical and physical methods exist, but they are costly and generate substantial waste, leading to the need for waste management systems. This situation has pushed researchers to find alternative, cost-effective, and eco-friendly ways to eliminate pollutants. Microorganisms have emerged as a promising solution. They are part of the ecosystem, environmentally friendly, and require minimal investment, making them a preferred choice. This chapter explores the crucial role of microbial degradation in remediating heavy metal pollution and restoring soil health.
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Using waste materials in the mixture of building materials is an approach aligned with the circular economy, a viewpoint that creates sustainable building industries, especially in developed countries. This study concentrated on the application of laponite (LAP), fly ash (FA), and bentonite (BENT) materials in the mixture of cement pastes. The first step used experimental practices to examine the metrics of toughness, three-point bending, and compressive strength with different percentages of added LAP, FA, and BENT after the characterization of samples by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The next step entailed assessment of cement paste specifications through some regressive equations obtained by the application of 2D curve fitting and sensitive analysis of additive (FA, LAP, and BENT) fluctuations in the structure of cement paste. The results show that linear polynomial equations are the best for the evaluation of cement paste terms as per different percentages of the additives. The environmental impact assessment (EIA) of nine prepared samples demonstrated that LAP created the safest condition in comparison to others. However, the ordered weighted averaging (OWA) computations applied for the sustainability assessment (SA) of the samples showed that the LAP is the most appropriate option for use in the structure of cement paste. Using experimental analysis and mathematical modeling, the behavior of cement paste interacting with mineral additives is evaluated. Sustainable mixtures are then presented based on EIA.
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Description With the signing of the Toxic Substances Control Act in 1976, this timely publication will assist anyone involved in the assessment of hazards chemicals to pose to aquatic life-whether from industry government, or academia. Topics covered include toxicological effects, environmental concentration, environmental fate, hazard assessment and evaluation of proposed test procedures for estimating hazards to aquatic life.
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Collembola are well-established models in ecotoxicological research, extensively employed to investigate the effects of various contaminants, including heavy metals. The Multixenobiotic Resistance Mechanism (MXR) is a physiological response based on transmembrane efflux proteins that play a pivotal role in pumping xenobiotics and conferring resistance. This mechanism is firmly established as a biomarker of aquatic contamination and has recently shown promise as a soil biomonitoring tool. In this study, we aimed to assess the feasibility of utilizing the MXR mechanism as a biomonitoring tool, specifically by investigating the response of two Collembola species exposed to soil contaminated in a real-life situation. Soil samples were obtained from the site of Brazil’s largest mine disaster, a dam rupture in Brumadinho-MG. We explored MXR activity in the model species Folsomia candida and a tropical native species, Cyphoderus sp. Our findings reveal efflux activity in both species, confirmed by model MXR protein inhibitors. Moreover, we observed distinct MXR activity levels corresponding to the degree of heavy metal contamination in the soil samples. Consequently, our results underscore the potential of combining an established soil bioindicator, such as Collembola, with the physiological response of a molecular biomarker like MXR. This approach may represent a valuable strategy for biomonitoring terrestrial ecosystems.
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Chapter
Mercury (Hg) is a global pollutant threatening our water resources and human health. Every one of us contains some levels of Hg or methylmercury (MeHg) in our body from consumption of contaminated food such as fish and rice in some countries. Our understanding of the behavior of Hg in natural aquatic environments is limited because the key factors controlling microbial uptake and conversion of inorganic Hg to neurotoxic MeHg remain obscure. MeHg concentrations in water can bioaccumulate up to eight orders of magnitude in the food chain. Metallic or elemental Hg can evaporate and be transported around the globe, plus it readily undergoes chemical, photochemical, and biological transformations (i.e. oxidation, reduction, methylation, and demethylation) in water and sediments. Natural dissolved organic matter (DOM) plays a critical role in mediating these transformations because of its exceptionally strong binding affinity for Hg and its dual functional roles in reducing and oxidizing Hg. Recent discovery of Hg‐methylation genes has significantly advanced our understanding of MeHg biosynthesis, although the simultaneous degradation of MeHg at low concentrations (i.e. picomolar to nanomolar) by anaerobic and methanotrophic bacteria is also recognized now as a potentially important process for controlling net MeHg production, a key factor that determines Hg concentrations and bioaccumulation in biota. Treatment technologies for Hg removal from water are available, but they are mostly applicable to industrial waste streams and at contamination sites with high Hg concentrations (i.e. micromolar to millimolar). Reductions in Hg human exposure might be achievable by decreasing anthropogenic releases, such as coal combustion, over the long‐term since Hg methylation responds to Hg inputs, particularly to freshly deposited Hg in natural aquatic systems.
Chapter
Arsenic found in environmental segments like lithosphere, hydrosphere and in atmosphere in various inorganic and organic forms like Arsenate (AsV), Arsenite (AsIII), Monomethylarsine (MMA), Dimethylarsine (DMA), Trimetylarsine (TMA, Gossiogas), Trimethylarsineoxide (TMAO), AB (Arsenobetaine), AC (Arsenocholine) etc. Some forms are toxic while others are less toxic. In this review, we studied about biotransformation of various organic and inorganic arsenic species in aqueous environment, soil and atmosphere. Marine organisms like fishes, lobsters, fungi, bacteria, cytoplasm of microorganisms, yeast, some enzymes like, ArsC, algae, genes like aos, aio, aox, photosynthetic microorganisms etc., do biotransformation of arsenic as oxidation and reduction in inorganic arsenic species and do methylation in organic arsenic. Many researchers proposed different pathways of arsenic biotransformations. Arsenic speciation generally completes in three steps i.e. extraction, separation, and detection. There are several techniques for arsenic extraction, separation and detection. Voltametric methods i.e. DPP (Differential pulse polarography), CSV (Cathodic stripping Voltametry), ASV (Anodic stripping Voltametry) and Hydride generation (HG) are the main techniques for extraction. Similarly for separation and detection chromatography are used with spectroscopic detection systems.KeywordsArsenic biotransformationArsenic speciationMethylation of arsenicSpeciation techniques
Chapter
The term heavy metals is used arbitrarily to summarize a group of metals, whereby a clear, scientifically accepted definition is lacking. Mercury is the best known toxic heavy metal in the environment. Environmental quality standards as well as natural and anthropogenic occurrences are discussed. Lists of heavy metals often include semimetals such as arsenic and thallium. Selenium and uranium completed the compounds discussed in the chapter.
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The inorganic chemistry of the cobalt corrinoids, derivatives of vitamin B12, is reviewed, with particular emphasis on equilibrium constants for, and kinetics of, their axial ligand substitution reactions. The role the corrin ligand plays in controlling and modifying the properties of the metal ion is emphasised. Other aspects of the chemistry of these compounds, including their structure, corrinoid complexes with metals other than cobalt, the redox chemistry of the cobalt corrinoids and their chemical redox reactions, and their photochemistry are discussed. Their role as catalysts in non-biological reactions and aspects of their organometallic chemistry are briefly mentioned. Particular mention is made of the role that computational methods - and especially DFT calculations - have played in developing our understanding of the inorganic chemistry of these compounds. A brief overview of the biological chemistry of the B12-dependent enzymes is also given for the reader's convenience.
Experiment Findings
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This research was conducted in an attempt to embrace the following points: 1- Monitoring the residues of the following pesticides Organochlorine (Dieldrin, Chlordene, Dicofol - Endosulfan , O,P´ –DDE - P´P´-DDA -P´P´-DDT - DDD - Endrin -Heptachlor BETA HCH - gamma HCH - DELTA HCH - Chlordene Dicofol and Endosulfan ) Organophospate (Dichlorvos Acephate, -Dimethoate, Diazinon, Chlopyrifos-methyl, Fenitrothion, Pirimiphos-methyl, Malathion and Azinphos-methyl). Carbamate and pyrethroids (Oxamyl, Bendiocarb, Carbofuran, Carbaryl, Methomyl, Thiocarb, Permethrin, Deltamethrin, Fenvalerate, Esfenvalerate and Cypermethrin). On different vegetables (tomatoes, cucumber, green pepper, scald, cabbage, lettuce and squash) and fruits including (apples, grapes, peaches and plumes) collected from different markets in eastern part of Libya (Derna, Elbaid and El maraj) also monitoring of some heavy metals (copper - lead - zinc and cadmium) in the same fruits and vegetables in different seasons in order to. 2- Determine the expected daily intake(EDI) and compared it with the acceptable daily intake (ADI) . 3- Determine Risk ratio of each pollutant 4- Determination residue level for some pesticides and heavy metals in soils and water in different sites in eastern part of Libya. The results of tested chlorinated pesticide residues and heavy metals in vegetables and fruits samples in all seasons (autumn, summer , Winter and spring) at all regions (Derna, Albaida and Almarje) show that, all residues for tested pesticide were less than maximum residue level (MRLs). Statistical analysis of data showed that highly significant differences between seasons and vegetables the highest polluted area was in Derna followed by El Beida and the least polluted was Al Marg. The highest vegetable samples contaminated were tomatoes, followed by lettuce, cucumbers and differed significantly than squash, peppers and cabbage. The results of expected daily intake of pesticide residues and heavy metals in vegetables and fruits in the eastern region of Libya showed that no hazards ratio were observed in all tested pesticides and heavy metals But must have routine analysis to more pesticide and fruits. Residues O.P. pesticides in seven different vegetable samples and four fruits species collected from four major markets located in each area (Derna, El Beida and Al- Marg) at four seasons. The results can be summarized as following: Derna samples showed that Residues of Acephate in tomato, pepper, and cucumber was exceeded MRLs. Vegetables collected from EL Bieda market show that squash, cucumber, pepper, cabbage, lettuce, and scald were found above MRLs with Acephat, Dimethoate, Dichlorofos and Diazinon. Vegetables collected from AL Marg markets show that Fenetrothion residues was detected in cabbage and lettuce and Acephate in cucumbe were found above MRLs. Analysis of variance to all results showed that O.P. insecticide residues are more significant in spring and summer than winter and autumn. Also results showed that pepper, cabbage, cucumber and tomatoes were contaminated with Malathion, Chloropyriphos, Chloropyrifos methyl and Acephate with the high level of contamination. Primefos methyl has lowest. Fruits collected from Derna Market show that Fenitrothion residues were above MRLs in (grape and peache) and fruits collected from EL Bieda Markets indicated that Diazinon and Dichlorvos residues were above MRLs in (grape and plume) also fruits from EL Marg Markets showed that from all analyzed samples 35% were free from pesticides (not detected) and 65 % from the samples were contaminated and among of these samples (28%) were found above the MRL values. There are significant differences between seasons and crops showed that anO.P. insecticides residues is more significant in summer followed by spring fruits. The least residues were found in autumn fruits. The data of fruits illustrated that the intakes were much lower than the ADIs and the exposure level to whole pesticide residues was below the level to produce health risk. Analysis of carbamated and synthetic pyrothroid pesticides in vegetable samples collected from Derna market showed that, Carbofuran, Esfenvalverate, Carbaryl was detected in cucumber and cabbage more than the maximum residues limits (MRLs) and vegetables collected from EL-Bieda market showed that samples of lettuce were contaminated with Methomyl and Fenvalerate, Carbofura, Esfenvalverate, in concentration more than MRLs. in cucumber, squash and cabbage. Residues of carbamate and pyrethroids pesticides in vegetables from Al-Marj Markets indicated that only Oxamyl insecticides detected in cucumber above MRLs. Residues in fruits collected from Derna market during different seasons indicated that from all tested samples 88.64 % were not contaminated and 11.36 %were contaminated and 6.81% from these samples were exceeded or equal MRLs limits. Residues of carbamates and pyrethroids pesticides in Fruits from El-Beida Market during different seasons indicated that From all tested samples 90.09 % from the samples were not contaminated and 9. 91 % from these samples were contaminated but not exceeded MRLs values except Carbofuran in grape samples was exceeded MRL limits. Fruits collected from AL- Marj Markets at different seasons. Bendiocarb and Carbofuran were detected in apple and plume with concentrations exceeded MRLs limits. The analysis of variance to all results collected from all markets to all tested fruits in all seasons showed that no significant differences between seasons, crops and markets. The potential health risk associated with the exposure to these pesticide residues was calculated and results obtained showed that only the Carbofuran and Oxamyl are showing the health risk associated with vegetables and fruits. Thus, Carbofuran appears to have some health risk (1.8) associated with it and Oxamyl (1) also while rest of pesticides where found to be under safe limit. Determinant of some Organchlorine pesticide residues in soils in some regions at El-Gabal El-Akhdar Were determined for samples collected from four seasons from different locations of Jabal Al Akhdar (Al Hania, Al Wasita, Marawa , Al Marj Plain, Butraba and Al Abyar). Using the HPLC, six pesticides were estimated (2,4-D, Dieldrin, DDA, DDD, Endrin, Dicofol) Only 2,4-D pesticide was detected in all seasons and in three regions (Al Hania, Marj Plain and Butraba), all values were less than the permissible limit in soil (0.05 µ / ml) according to the Food and Agriculture Organization. The results of the electrical conductivity and pH number showed that there is a strong relationship between these indicators and the presence of the pesticide in the soil .Evaluation Of Soil Contaminate By Some Heavy Metal (Cu, Pb, Zn, Cd) In Different Altitude Levels from Al-Jabal El-Akhda . The results show that all elements did not reach the maximum limits according to the World Health Organization (WHO) but there are a significant differences between cultivated soils and uncultivated soils at (P<0.05), Determining the levels of some heavy metals in surface and groundwater collected from different regions in seasons (dry and wet). Results showed the presence of heavy metal residues in two seasons (dry-wet) in the regions during the study in surface and groundwater. The zinc (Zn), cadmium (Cd), and Copper (Cu) values were below permissible limits, according to the World Health Organization (WHO), Libyan National Center for Standardization (LNCSM), and Food and Agriculture Organization (FAO). Monitoring of some pesticide residues in surface and ground water in some regions at the eastern of Libya. This study was designed to monitor residues of organochlorine (OC) pesticides (2,4-D, p, p′-DDE, p, p′-DDT, p, p′-DDD, Dicofol and Heptachlor) in surface and groundwater The results showed that 74.07 % of the surface water were contaminated with 2, 4-D. and it was higher than the MRL’s (maximum residue limits) according to WHO (World Health Organization) and LNCSM (Libyan National Centre for Standardization Metrology) in the following regions (Wadi Darna, Karsa, Aldabusia, Apouloana Shahhat I, Saylun Massa III and Tolmeita II). In groundwater detected 80.95% of the samples were contaminated with 2,4-D residue. 26.98 % of the 2, 4-D residue was above the MRL’s (maximum residue limits) in the following regions (Shahhat II, Shahhat III, Qandula I, Qandula II, Marawa II, Wasita I, Wasita II, Tolmeita I, Alabyar I, Alabyar II and Alabyar III). The results suggested that the inhabitants in the eastern region of Libya are exposed to concentrations higher than the permitted limits of pesticide 2, 4-D which can be associated with chronic diseases. Based on the results of this study, the responsible bodies such as environmental protection and public health should follow pesticide residues in surface and groundwater water to protect the individual from the unintended use of pesticides. Furthermore, a long-term future study is required to know more in-depth information on the extent of surface and groundwater compatibility for human consumption.
Article
Contaminated soil containing toxic metals and metalloids is found everywhere globally. As a consequence of adsorption and precipitation reactions, metals are comparatively immobile in subsurface systems. Hence remediation techniques in such contaminated sites have targeted the solid phase sources of metals such as sludges, debris, contaminated soils, or wastes. Over the last three decades, the accumulation of these toxic substances inside the soil has increased dramatically, putting the ecosystem and human health at risk. Pollution of heavy metal have posed severe impacts on human, and it affects the environment in different ways, resulting in industrial anger in many countries. Various procedures, including chemical, biological, physical, and integrated approaches, have been adopted to get rid of this type of pollution. Expenditure, timekeeping, planning challenges, and state-of-the-art gadget involvement are some drawbacks that need to be properly handled. Recently in situ metal immobilization, plant restoration, and biological methods have changed the dynamics and are considered the best solution for removing metals from soil. This review paper critically evaluates and analyzes the numerous approaches for preparing heavy metal-free soil by adopting different soil remediation methods.
Chapter
Anthropogenic activities like the unbalanced use of fertilizers, agricultural chemicals like pesticides, and other industrial activities such as drilling, steelmaking, and burning of fossil fuels as well as the use of untreated wastewater from different industries have resulted in soil pollution with heavy metals (HMs). This important ecological restriction has contributed to reduced agricultural production and decreased nutritional quality due to the bioaccumulation of HMs in the plant body. Medicinal plants are being recommended for alternative products with non-food staple crops in potentially toxic elements contaminated environments. Despite their ability to bioaccumulate higher concentrations of HMs in their plant body, the plant parts used for medicinal purposes are transferring HMs into the food chain and have ultimately resulted in biomagnification through bioaccumulation in the food chain. Under HM stress, there is an increased production of reactive oxygen species, which pose oxidative stress on the membranous organelles, resulting in lipid peroxidation, protein denaturation, and nucleic acids destruction, damaging their structure and function and ultimately disrupting various metabolic processes involved in growth and development. In order to combat oxidative stress, medicinal plants activate the antioxidant system, which includes the secretion of enzymatic (ascorbate peroxidase, dehydroascorbate reductase, catalase, glutathione S-transferase, superoxide dismutase, glutathione reductase, and glutathione peroxidase) and non-enzymatic (carotenoids, glutamate, ascorbate, phenolics, or tocopherol) antioxidants. Chapter 8 summarizes the effects of HMs on the growth and physiological functions of medicinal plants and defence mechanisms against HM stress at morphological and molecular levels, both of which can contribute to improved bioactive compound yields.
Chapter
Heavy metal contamination demands remediation using appropriate cost‐effective methods to eliminate the contaminants or convert them into lesser toxic forms to avert the potential hazards arising from such contaminations. Certain plants have a high potential for accumulating metals and phytotechnologies that can make use of such potentials, thereby offering a nature‐based and cost‐effective solution for remediation of contaminated soil. Phytotechnology such as phytomining also offers prospective means for cost‐effective recovery or beneficiation of metals. Such technologies draw on the natural processes in the rhizosphere and physiological and metabolic mechanisms in plants that regulate the chemical dynamics of such contaminants. They attempt to exploit plants'capabilities to remove, reduce, sequester, immobilize, detoxify, or degrade the pollutants. Thus, phytotechnologies and their scientific, technological, and operational advantages are an appropriate basket of nature‐based solutions for ameliorating contamination in soil systems. However, hurdles are many to be addressed for their wider success, such as low understanding of the biological mechanisms, soil properties, even the prevalent terminology‐related issues, concepts, and operationalization strategies. It is apparent that, for the wider and successful application of these technologies, scientific improvements are obligatory together with changes at policy and regulatory levels. This chapter highlights the need for amalgamation of such technologies for wider use. Here, we review different phytotechnologies and their underlying biological mechanisms to bring out the potentials of the technology as economically viable and ecologically amending. The review also highlights future research, imperative to develop these technologies coherently and effectively. The need for changes in regulatory provisions, improvement in knowledge gaps in soil chemistry, microbial and plant physiology, and transfer of phytotechnologies to the commercial sector are also discussed in this chapter. With new developments in interdisciplinary research, knowledge base, legal frameworks, and social aspects, phytotechnologies will prove to be effective in decontaminating the environment from metal contamination in a long‐run.
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unpublished reports prepared for the Government of Ontario for analysis of St. Clair River sediments
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