Determination of arsenic levels in lake water,sediment, and foodstuff from selected area of Sindh,Pakistan: Estimation of daily dietary intake

The aim of present study was to develop a database of arsenic (As) in lake water, ground water, sediment, soil, vegetables, grain crops and fish to evaluate the potential human health risks posed by higher level of As, in south east part of Sindh, Pakistan during 2005–2007. The total concentration of As in various samples under study was determined by electrothermal atomic absorption spectrophotometry (ETAAS). The reliability and accuracy of technique was checked by different certified reference materials. The concentration of As in lake and ground water samples exceeded the WHO guideline values. The concentration of As in lake sediment and agricultural soil samples ranged between 11.3–55.8 and 8.7–46.2 mg/kg while acid soluble As (acetic acid 0.11 mol/L) was observed in the range of 1.48–3.54 and 0.34–3.78 mg/kg, respectively. It was observed that the leafy vegetables (spinach, coriander and peppermint) contain higher As levels (0.90–1.20 mg/kg) as compared to ground vegetables (0.048–0.25) and grain crops (0.248–0.367 mg/kg) on dried weight basis. The estimated daily intake of total As in the diet was 9.7–12.2 μg/kg body weight/day.     

Health risk assessment of heavy metals via dietary intake of foodstuffs from the wastewater irrigated site of a dry tropical area of India

The present study was conducted to assess the risk to human health by heavy metals (Cd, Cu, Pb, Zn, Ni and Cr) through the intake of locally grown vegetables, cereal crops and milk from wastewater irrigated site. Milk is not directly contaminated due to wastewater irrigation, but is an important route of food chain transfer of heavy metals from grass to animals. Heavy metal concentrations were several fold higher in all the collected samples from wastewater irrigated site compared to clean water irrigated ones. Cd, Pb and Ni concentrations were above the ‘safe’ limits of Indian and WHO/FAO standards in all the vegetables and cereals, but within the permissible limits in milk samples. The higher values of metal pollution index and health risk index indicated heavy metal contamination in the wastewater irrigated site that presented a significant threat of negative impact on human health. Rice and wheat grains contained less heavy metals as compared to the vegetables, but health risk was greater due to higher contribution of cereals in the diet. The study suggests that wastewater irrigation led to accumulation of heavy metals in food stuff causing potential health risks to consumers.     

Impact of sedimentary arsenic through irrigated groundwater on soil, plant, crops and human continuum from Bengal delta: Special reference to raw and cooked rice

Existence of arsenic-rich (exceeds 2,000 mg/kg) iron pyrite in Bengal delta sediments is responsible for arsenic release in aquifer. Ingestion of contaminated drinking water is not the only elevated source of arsenic to the diet. Irrigation of agricultural fields with arsenic-contaminated groundwater has led to arsenic build-up in soil, with subsequent elevation of arsenic in crops grown on these soils. About 50.7 and 11.2 kg of arsenic are withdrawn per year from 23 and 18 shallow tubewells, used for agricultural irrigation in the studied two districts Murshidabad and Nadia, respectively and deposited on lands throughout the year. Considerable higher amounts of arsenic are accumulated in paddy plants. Mean arsenic concentration in food categories is 107 microg/kg. Arsenic concentrations are high in cooked food and skin of the vegetables. Arsenic concentration in cooked rice increases with water arsenic concentration. About 70.2% of arsenic is recovered by using the analytical speciation extraction method. Inorganic arsenic and DMA contribute 89.5% and 10.5% of the total content of arsenic in food, respectively. About 0.081% and 1.57% of arsenic are accumulated in rice grain from arsenic-deposited lands and contaminated soils. The daily dietary intake of inorganic arsenic (mug/kg body wt./day) by an adult from rice grain itself (2.32) is higher than the WHO recommended PTDI value of inorganic arsenic (2.1) and inorganic arsenic contributes 96.8% of the total dietary intakes of arsenic. Population exposed to arsenic toxicity has been identified.     

Microbial quantities and enzyme activity in soil irrigated with sewage for different lengths of time

Sewage is widely used on agricultural soils in peri-urban areas of developing countries to meet shortages of water resource. Although sewage is a good source of plant nutrients, it also increases the heavy metals loads to soils. Microbial responses to these contaminants may serve as early warning indicators of adverse effects of sewage irrigation on soil quality. The purpose of this study was to assess the effect of time of sewage irrigation on soil microbial indicators. Soil samples were collected from seven soil sites (S1–S7) irrigated with 0 years, 16 years, 23 years, 25 years, 27 years, 32 years and 52 years, respectively in Shijiazhuang of China and analyzed. For each soil sample, we determined the quantities of bacteria, fungi and actinomycete, and enzyme activities of urease, sucrase, phosphatase, dehydrogenase and catalase. Our results showed that the soils of S2–S7 irrigated with sewage effluents for different times (ranged between 16 and 52 years) exhibited higher densities of bacteria, actinomycete, urease, sucrase and phosphatase but lower densities of fungi when compared with S1 irrigated with sewage effluents for 0 years. The soil S7 irrigated with sewage effluents for longest times (52 years) contained lowest activities of catalase when compared with the soils of S1–S6. The densities of bacteria (R = 0.877, p < 0.01), actinomycete (R = 0.875, p < 0.01), sucrase (R = 0.858, p < 0.01) and phosphatase (R = 0.804, p < 0.05) were significantly correlated in a positive manner with time of sewage irrigation. Soil fungi quantities and urease, dehydrogenase and catalase activities did not change significantly with irrigation time. This study confirms that sewage irrigation had negative effects on microbial properties including fungi, catalase and dehydrogenase in the long term, so there is a need for continuous monitoring for sustainable soil health.     

模拟降雨条件下谷子和冬小麦植株对降雨再分配过程的影响

以谷子（Setaria italica）、冬小麦（Triticum aestivum Linn.）为研究对象，利用人工模拟降雨测定了不同降雨强度和生长阶段两种作物植株的穿透雨，采用人工喷雾法测定了不同生长阶段的冠层截留，根据水量平衡法计算了不同观测阶段的茎秆流。结果表明：谷子、冬小麦冠层对降雨的再分配作用显著，谷子冠下穿透雨率平均约为79%，茎秆流率平均约为20%，冠层截留率平均约占1%；冬小麦冠下穿透雨率平均约为79%，茎秆流率平均约为19%，冠层截留率平均约占2%。在其全生育期内，两种作物冠下穿透雨与茎秆流呈彼此消长趋势。穿透雨量和茎秆流量与降雨强度呈显著正相关关系，但是穿透雨率和茎秆流率与降雨强度的关系不显著。茎秆流量和冠层截留量及其二者占总降雨量的比率均与作物叶面积指数呈显著正相关关系，但穿透雨量及穿透雨率随叶面积指数增加呈显著下降趋势。     

广东省与河北省农业结构多样性变化的比较分析

文章利用农业结构指数结合比重法 ,比较分析了广东与河北两省 1 981年到 2 0 0 2年在农业总产值结构、作物类型结构、粮食作物结构、经济作物结构多样性方面的变化情况。结果表明 :(1 )在农业总产值结构上 ,南北两省都在向多元化方向发展。主要原因是农业比重显著下降 ,河北的牧业比重显著提高 ,广东的渔业和牧业比重显著提高。 (2 )在 2 2年间 ,南北两省在作物类型的变化上都在向多元化和均匀化方向发展。主要表现是粮食作物面积的比重显著下降 ,蔬菜、瓜类、饲料等其他类作物面积的比重大幅度提高。 (3 )广东粮食作物结构有向多元化发展的趋势 ,主要是占绝对优势的稻谷比重有所下降 ;河北粮食作物结构有向单一化发展的趋势 ,主要是小麦和玉米的面积比重明显提高。 (4 )南北两省的经济作物结构都在向单一化和非均匀化方向发展。主要原因都是油料作物在经济作物中的面积比重显著提高。     

Distribution of trace metals at two abandoned mine sites in Korea and arsenic-associated health risk for the residents

Two abandoned mine sites in Jeongseon, Korea were investigated to determine the distribution of six trace metals such as Cu, Cr, Cd, Pb, Hg, and As in soil, water, and rice, and to assess the health risks for the residents of the mine sites from their exposure to As via possible exposure pathways. Lead and arsenic were found to be the major contaminants. Health risk assessments conducted on As through soil ingestion, water ingestion, rice ingestion, and dermal contact with soil or water showed high non-carcinogenic (HI values of 12.8 and 8.3) and carcinogenic (risks of 22.0 ×10^?4 and 14.3×10^?4) at both mine sites, suggesting that the residents have high chance of developing adverse health effects from their chronic exposures. The ingestion of polished rice grown in the contaminated paddy soils accounted for 90% or higher of the total risk values. Therefore, appropriate measures need to be taken to prevent possible health effects, in particular from the ingestion of crop plants grown in the contaminated soils.     

Factors affecting the soil arsenic bioavailability,accumulation in rice and risk to human health: a review

Arsenic (As), a class one carcinogen, reflects a disastrous environmental threat due to its presence in each and every compartment of the environment. The high toxicity of As is notably present in its inorganic forms. Irrigation with As contaminated groundwater in rice fields increases As concentration in topsoil and its bioavailability for rice crops. However, most of the As in paddy field topsoils is present as As(III) form, which is predominant in rice grain. According to the OECD-FAO, rice is the second most extensively cultivated cereal throughout the world. This cereal is a staple food for a large number of populations in most of the developing countries in sub-Saharan Africa, Latin America, South and South-east Asia. Rice consumption is one of the major causes of chronic As diseases including cancer for Asian populations. Thus, this review provides an overview concerning the conditions involved in soil that leads to As entrance into rice crops, phytotoxicity and metabolism of As in rice plants. Moreover, the investigations of the As uptake in raw rice grain are compiled, and the As biotransfer into the human diet is focused. The As uptake by rice crop represents an important pathway of As exposure in countries with high rice and rice-based food consumption because of its high (more than the hygienic level) As levels found in edible plant part for livestock and humans.     

Protective Role of Native Rhizospheric Soil Microbiota Against the Exposure to Microcystins Introduced into Soil-Plant System via Contaminated Irrigation Water and Health Risk Assessment

Microcystins (MCs) produced in eutrophic waters may decrease crop yield, enter food chains and threaten human and animal health. The main objective of this research was to highlight the role of rhizospheric soil microbiota to protect faba bean plants from MCs toxicity after chronic exposure. Faba bean seedlings were grown in pots containing agricultural soil, during 1 month under natural environmental conditions of Marrakech city in Morocco (March–April 2018) and exposed to cyanobacterial extracts containing up to 2.5 mg·L⁻¹ of total MCs. Three independent exposure experiments were performed (a) agricultural soil was maintained intact “exposure experiment 1”; (b) agricultural soil was sterilized “exposure experiment 2”; (c) agricultural soil was sterilized and inoculated with the rhizobia strain Rhizobium leguminosarum RhOF34 “exposure experiment 3”. Overall, data showed evidence of an increased sensitivity of faba bean plants, grown in sterilized soil, to MCs in comparison to those grown in intact and inoculated soils. The study revealed the growth inhibition of plant shoots in both exposure experiments 2 and 3 when treated with 2.5 mg·L⁻¹ of MCs. The results also showed that the estimated daily intake (EDI) of MCs, in sterilized soil, exceeded 2.18 and 1.16 times the reference concentrations (0.04 and 0.45 µg of microcysin-leucine arginine (MC-LR). Kg⁻¹ DW) established for humans and cattle respectively, which raises concerns about human food chain contamination.     

Use of transgenic GFP reporter strains of the nematode Caenorhabditis elegans to investigate the patterns of stress responses induced by pesticides and by organic extracts from agricultural soils

As a free-living nematode, C. elegans is exposed to various pesticides used in agriculture, as well as to persistent organic residues which may contaminate the soil for long periods. Following on from our previous study of metal effects on 24 GFP-reporter strains representing four different stress-response pathways in C. elegans (Anbalagan et al. Ecotoxicology 21:439?C455, 2012), we now present parallel data on the responses of these same strains to several commonly used pesticides. Some of these, like dichlorvos, induced multiple stress genes in a concentration-dependent manner. Unusually, endosulfan induced only one gene (cyp-34A9) to very high levels (8?C10-fold) even at the lowest test concentration, with a clear plateau at higher doses. Other pesticides, like diuron, did not alter reporter gene expression detectably even at the highest test concentration attainable, while others (such as glyphosate) did so only at very high concentrations. We have also used five responsive GFP reporters to investigate the toxicity of soil pore water from two agricultural sites in south-east Spain, designated P74 (used for cauliflower production, but significantly metal contaminated) and P73 (used for growing lettuce, but with only background levels of metals). Both soil pore water samples induced all five test genes to varying extents, yet artificial mixtures containing all major metals present had essentially no effect on these same transgenes. Soluble organic contaminants present in the pore water were extracted with acetone and dichloromethane, then after evaporation of the solvents, the organic residues were redissolved in ultrapure water to reconstitute the soluble organic components of the original soil pore water. These organic extracts induced transgene expression at similar or higher levels than the original pore water. Addition of the corresponding metal mixtures had either no effect, or reduced transgene expression towards the levels seen with soil pore water only. We conclude that the main toxicants present in these soil pore water samples are organic rather than metallic in nature. Organic extracts from a control standard soil (Lufa 2.2) had negligible effects on expression of these genes, and similarly several pesticides had little effect on the expression of a constitutive myo-3::GFP transgene. Both the P73 and P74 sites have been treated regularly with (undisclosed) pesticides, as permitted under EU regulations, though other (e.g. industrial) organic residues may also be present.     

Genotoxicity of wastewaters used for irrigation of food crops

In most towns of India, wastewater coming from both industrial and domestic sources and without any treatment is used to irrigate the agricultural crops. This practice has been polluting the soil, and pollutants could possibly reach the food chain. For the above reasons, the wastewaters of Ghaziabad City (India), which is used for irrigation, were sampled (at two different sites) and monitored for the presence of genotoxic agents from January 2005 to June 2007. Gas chromatographic analysis showed the presence of certain OC (DDE, DDT, Dieldrin, Aldrin, and Endosulfan) and OP (Dimethoate, Malathion, Methlyparathion, and Chlorpyrifos) pesticides in both the sampling sites. Wastewater samples were concentrated using XAD resins (XAD-4 and XAD-8) and liquid-liquid extraction procedures, and the extracts were assayed for genotoxic potential by Ames Salmonella/microsome test, DNA repair defective mutants, and bacteriophage lambda systems. The test samples exhibited significant mutagenicity with TA98, TA97a, and TA100 strains with the probable role of contaminating pesticides in the wastewater. However, XAD-concentrated samples were more mutagenic in both sites as compared to liquid-liquid-extracted samples. The damage in the DNA repair defective mutants in the presence of XAD-concentrated water samples were also found to be higher to that of liquid-liquid-extracted water samples at the dose level of 20 muL/mL culture. All the mutants invariably exhibited significant decline in their colony-forming units as compared to their isogenic wild-type counterparts. The survival was decreased by 81.7 and 75.5% in polA(-) strain in site I, and 76.0 and 73.5% in site II in polA(-) under the same experimental conditions after 6 h of treatment with XAD-concentrated and liquid-liquid-extracted samples, respectively. A significant decrease in the survival of bacteriophage lambda was also observed when treated with the test samples.     

Effect of vitamin D and β-sitosterol on immune function of macrophages

Among the many functions of vitamin D (VD) is its role in the immunomodulation of macrophage. As VD deficiency is a wide-spread nutritional problem, there is a tendency for the public to overdose with vitamin D supplementation which can result in hypercalcemia and several associated disorders. The present study was designed to investigate the possibility that combining low doses of vitamin D with β-sitosterol (SIT), a common phytosterol in the diet without toxicity, enhances the efficacy of the vitamin. Murine macrophages were stimulated with LPS and supplemented with VD3 (80 nM) and SIT (8 μM) for 24 hr and examined for cell proliferation, release of nitric oxide (NO) and cytokines and the activation of NFκB. SIT (8 μM) was found to reduce cell proliferation by 62% while VD3 was found to be not effective. In combination, SIT and VD3 reduced cell proliferation by 75%.The amount of NO released, as influenced by 8 μM SIT or 80 nM VD3 treatments, was not significantly different from control. Combining SIT and VD3, resulted in a 220% greater increase in NO release compared to control. The SIT + VD3 treatment brought about significant increase in all the cytokine release, regardless of whether they were pro- or anti-inflammatory. The effects were either additive or synergistic. We conclude that SIT enhances the action of VD3 on the immune function of macrophages which could be beneficial to vitamin D deficient individuals and to those with autoimmune diseases such as multiple sclerosis.     

Ecology and Population Biology of Aflatoxigenic Fungi in Soil

Soil serves as a reservoir for Aspergillus flavus and A. parasiticus, fungi that produce carcinogenic aflatoxins in agricultural commodities. Populations in soil are genetically diverse and individual genotypes show a clustered distribution pattern within fields. Surveys over large geographic regions suggest that climate and crop composition influence species density and aflatoxin‐producing potential. Aflatoxigenic fungi reside in soil as conidia, sclerotia and hyphae, which act as primary inocula for directly infecting peanuts or for infecting aerial crops (corn, cottonseed, tree nuts) through wind and insect dispersal. Infected crops periodically replenish soil populations during drought years.     

Toxicologic studies associated with the agricultural use of municipal sewage sludge and health effects among sewage treatment plant workers

The proposed use of municipal sewage sludges as soil amendments on agricultural land involves potential health risks. Sludges may contain toxic heavy metals, synthetic organics, and pathogens. Studies of animals inhabiting sludge-amended soils, or foraging on crops grown on such soils, have shown an increased deposition of cadmium and polychlorinated biphenyls in animal tissues, hepatic microsomal enzyme induction, altered blood profiles, appearance of mutagens in blood and excreta, and lowered feed intake, feed efficiency, and milk production. Epidemiologic evidence of possible adverse health effects among sewage plant workers exposed to aerosolized pathogens or synthetic organic vapors during wastewater treatment or land spreading of sludge is still inconclusive. Other possible deleterious environmental effects include pollution of groundwater and toxicity to birds consuming worms or insects inhabiting sludgetreated soils.     

Is specific immunotherapy safe and effective in children?

BACKGROUND: The effectiveness and safety of specific immunotherapy (SIT) in allergic diseases such as asthma have been increasingly questioned, some authors practically advocate to eliminating SIT as a therapeutic option for allergic patients, since the risks associated with this form of asthma treatment might be higher than the possible positive effects. OBSERVATIONS: We emphasize that several authors comment on the frequency of reactions to SIT without a sound competence. Therefore, the scope of the present study was to ascertain whether this form of therapy is safe and effective in pediatrics. Denying SIT is a misleading issue since in children not cured with SIT a risk factor for persistence of respiratory symptoms is the ongoing sensitivity to allergens. CONCLUSION: SIT consists in the administration of specific allergic extracts at progressively higher doses, with the aim to achieve a state of immunological tolerance and subsequently a reduction of clinical manifestations caused to the patients by the same allergens. We demonstrate that SIT is safe and effective in children.     

Effect of environmental exposure of arsenic on cattle and poultry in nadia district, west bengal, India

A study was undertaken to evaluate an alternative source of arsenicosis in human food chain through livestock. Thirty milch cattle and 20 poultry birds along with their eggs were selected randomly from two endemic villages of Nadia district and one nonendemic villages of Hooghly district in West Bengal, India. Milk, feces, urine, and hair samples of cattle and feed materials, such as water and straw, were collected to analyze arsenic status. Arsenic concentration in egg yolk and albumen from poultry eggs and different poultry organs after culling was estimated. Distribution of arsenic in animal body indicates that major portion of arsenic was eliminated through feces, urine, and milk. Poultry egg yolk, albumen, and poultry products retain arsenic in all organs. Cows and poultry birds reared in endemic zone retain significantly higher concentration of arsenic. Consumption of egg, agricultural produces grown in contaminated soil, and milk might have produced arsenicosis and may be considered as alternative source of arsenic contamination.     

The burden-of-illness study on osteoporosis in the Slovenian female population

Study objective This burden-of-illness study on osteoporosis was performed with the main goal to estimate the economic implications of osteoporosis for the Slovenian healthcare system. Methods A variety of sources was used to quantify the utilization of resources in 2003, and the appropriate unit costs were assigned to the identified resources. Main outcome measures The study included all direct and indirect costs that arise from treatment of osteoporosis and consequent hip, spine and wrist fractures in total Slovene postmenopausal population in 2003. Results We estimated the total burden of postmenopausal osteoporosis in Slovenia for 2003 to be over SIT 7.55 billion (approximately €31.5 million); among that, 45% or SIT 3.39 billion (€14.2 million) belong to drug expenditures for osteoporosis treatment and prevention; 29% or SIT 2.2 billion (€9.2 million) include indirect costs for osteoporosis morbidity and mortality, and 26% or SIT 1.95 billion (€8.1 million) belong to direct costs for treatment, hospitalization, and rehabilitation of osteoporotic fractures. Total costs on osteoporotic fractures were however subject to an approximation due to the expert panel-based estimate of proportion of osteoporosis-caused fractures and the limited data on resource utilization for fracture treatment. Conclusion Osteoporosis is a costly disease with a significant burden to society and needs to be viewed as an important problem with a complex long-term impact.     

Effects of Irrigation with Microcystin-Containing Water on Growth,Physiology, and Antioxidant Defense in Strawberry Fragaria vulgaris under Hydroponic Culture

Over the last years, the use of artificial lakes and ponds to irrigate agricultural crops has been intensified and cultivation methods have been diversified. Hydroponics is a type of hydroculture which usually involves growing plants in an inert substrate, by using nutrient-enriched water to support plant growth. However, irrigating plants in hydroponic-based culture must be accompanied by monitoring the quality of irrigation water. The human health risks involved are mainly related to the proliferation of microcystin-producing cyanobacteria that contaminate water used for irrigation purposes. Strawberry (Fragaria vulgaris L.) is a widely cultivated plant of an increased economically importance worldwide. Its fruits provide essential elements for human nutrition; therefore, the study of its sensitivity to microcystins (MCs) is of paramount importance. The objective of this study was to evaluate the effects of MCs in irrigation water on the growth, physiology, and antioxidant defense system in F. vulgaris. In this study, strawberry seedlings at the three-leaf stage were grown in pots containing perlite under controlled conditions. Plants were exposed to a crude extract of Microcystis aeruginosa bloom at different concentrations of MCs (1, 5, 10, and 20 μg/L) for 60 days of exposure. The results showed that the highest concentrations of 10 and 20 μg/L induced a decrease in growth parameters. They resulted in root/shoot length decrease as well as number of leaves, roots/leaves dry and fresh weight. Furthermore, MCs reduced chlorophyll/carotenoid content, stomatal conductance, fluorescence, and total protein content of strawberry plants. At the same time, a significant increase in Malondialdehyde (MDA) (an indicator of lipid peroxidation), polyphenol, and sugar content were recorded in strawberry plants exposed to MCs at 5, 10, and 20 μg/L compared with the control. Additionally, superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), Polyphenoloxydase (PPO), and ascorbate peroxidase (APX) activities significantly increased in plants under MCs exposure. The oxidative stress was higher in plants exposed to 10 and 20 μg/L of MCs from the second harvest (after 60 days of exposure) compared to those from the first harvest (after 30 days). Overall, the results obtained in this study indicate an increasingly negative effect of MCs on strawberry plants grown in hydroponics even at concentrations (10 and 20 µg/L). This effect is more damaging on the roots after exposure (60 days).     

Biological Control of Aflatoxin Contamination of Crops

Aflatoxin contamination of crops compromises the safety of food and feed supplies and causes significant economic losses each year. Of the many research approaches being studied to reduce and, ultimately, eliminate aflatoxin contamination, biological control is one of the more promising, particularly for the near‐term. Numerous organisms have been tested for biological control of aflatoxin contamination including bacteria, yeasts, and nontoxigenic strains of the causal organisms, Aspergillus flavus and A. parasiticus. Most of the field successes to date have been achieved by applying certain nontoxigenic strains of A. flavus and A. parasiticus to soil of susceptible crops, such as peanuts, cotton, and corn. The applied strains occupy the same niche as the naturally occurring toxigenic strains and competitively exclude them when crops are susceptible to infection. Various formulations have been used to apply the nontoxigenic strains to soil, but the most effective methods have been to combine the desired strain with a carrier/substrate, such as a small grain. This was done either by minimally growing the desired strain on sterilized grain or by coating the surface of the grain with conidia of the strain. After application to the field and uptake of moisture, the fungus completely colonizes the grain, and abundant sporulation provides inoculum levels sufficient to achieve a competitive advantage for the nontoxigenic strain. In several years of field studies, particularly with peanuts and cotton, significant reductions in aflatoxin contamination in the range of 70–90% have been achieved consistently. Two separate products have recently received EPA registration as biopesticides to control aflatoxin contamination in cotton (AF36) and peanuts (afla‐guard®).     

Ecotoxicological study of arsenic and lead contaminated soils in former orchards at the Hanford site,USA

The purpose of this study was to assess ecotoxicity of former orchard soils contaminated with lead arsenate pesticides at the Hanford Site in Washington state (USA). Surface soil, plant, and invertebrate samples were collected from 11 sites in former orchard areas. Mean (standard deviation [SD]) for As and Pb in soil were 39.5 (40.6) and 208 (142) mg/kg dry wt, respectively (n = 11). These concentrations exceeded Hanford background levels but were similar to orchard soils elsewhere. In our study, As and Pb soil concentrations were positively and significantly correlated (r = 0.87, Bonferroni P < 0.05). Speciation of total inorganic As in soil (n = 6) demonstrated that As+5 was the dominant form (>99%). Mean (SD) for As and Pb in cheatgrass were 3.9 (7.9) and 12.4 (20.0) mg/kg dry wt, respectively (n = 11), while mean (SD) for As and Pb in darkling beetles were 5.4 (2.6) and 3.9 (3.0) mg/kg dry wt, respectively (n = 8). Linear regressions were constructed to estimate soil to cheatgrass and soil to darkling beetle uptake for As and Pb. These were significant (Bonferroni P < 0.05) only for cheatgrass versus soil (As) and darkling beetle versus soil (Pb). Standardized lettuce seedling and earthworm bioassays were performed with a subset of soil samples (n = 6). No significant effects (P > 0.05) were observed in lettuce survival or growth nor in earthworm survival or sublethal effects. Based on these bioassays, unbounded no observed effect concentrations (NOECs) in soil for As and Pb were 128 and 390 mg/kg dry wt, respectively. However, our range of soil concentrations generally overlapped a set of ecotoxicological benchmarks reported in the literature. Given uncertainty and limited sampling related to our NOECs, as well as uncertainty in generic benchmarks from the literature, further study is needed to refine characterization of As and Pb ecotoxicity in former orchard soils at the Hanford Site. © 2011 Wiley Periodicals, Inc. Environ Toxicol 29: 10–20, 2014.