Total Endosulfan Concentrations Research Articles

Spatial distribution of and seasonal variations in endosulfan concentrations in soil, air, and biota around a contaminated site

Soil, air, tree bark, rice, wheat, invertebrates, and chicken tissues around a typical endosulfan-contaminated site were analyzed in each season in each of two years. The total endosulfan (the sum of α-, β-endosulfan and endosulfan sulfate) were significantly different in soil and air samples collected in the four seasons (P < 0.01) and the mean concentrations were 6.53 ng/g dry weight (d.w.) and 2.40 ng/m3, respectively, in autumn, 3.32 ng/g d.w. and 2.48 ng/m3, respectively, in winter, 2.10 ng/g d.w. and 0.93 ng/m3, respectively, in spring, and 1.03 ng/g d.w. and 0.83 ng/m3, respectively, in summer. The total endosulfan concentrations in tree bark, rice, wheat, and invertebrates were 23.0–278 (mean 95.5) ng/g d.w., 7.36–35.5 (mean 17.4) ng/g d.w., 34.3–158 (mean 83.1) ng/g d.w., and 401–4354 (mean 2125) ng/g lipid weight, respectively. The total endosulfan concentrations in the chicken gizzard, heart, liver, and meat samples were 552, 212, 699, and 221 ng/g lipid weight, respectively. The endosulfan concentrations in soil, air, and biota around the site were strongly influenced by endosulfan emissions from the site, and the concentrations had decreased to half the initial concentrations six months after endosulfan production stopped. The invertebrate and chicken bioconcentration and biomagnification factors indicated that endosulfan accumulated in the invertebrates and chicken tissues was slightly biomagnified by chickens.

Health risk associated with the consumption of duck egg containing endosulfan residues.

Eight duck farms and a local market in Suphanburi province, Thailand adjacent to paddy fields were selected for this study. The concentrations of endosulfan isomers (α- and β-endosulfan) and endosulfan sulfate in environmental matrices (water, soil, feed) and duck eggs were determined. Human health risk via the contaminated egg consumption was also evaluated. Analysis of environmental matrices found both endosulfan isomers (α- and β-endosulfan) and endosulfan sulfate in most samples. Endosulfan sulfate was predominantly found in all matrices followed by β- and α-endosulfan, respectively. The total endosulfan concentrations were in the following order: feed > soil > water. However, the levels of endosulfan detected were lower than the regulatory maximum residue limit of endosulfan, except in water (>0.200 ng mL(-1)). Endosulfan sulfate in duck egg samples was also predominantly detected in both yolk and albumin. The average total endosulfan residues (∑endosulfan) in yolk (6.73 ng g(-1)) were higher than in albumin (4.78 ng g(-1)). According to principle component analysis, we found that paddy soil surrounding the duck farms is the suspected source of endosulfan contamination in husbandry water which subsequently contaminates duck eggs. The estimated daily intakes (EDIs) of these endosulfan-contaminated eggs were well below the acceptable daily intake (ADI) for endosulfan (6 μg kg(-1) day(-1)). However, the consumption of this contaminated duck eggs should be of concerns in regard to chronic exposure. Therefore, the better environmental managements to reduce endosulfan residues can play a crucial role for decreasing human health risk.

Legacy and currently used pesticides in the atmospheric environment of Lake Victoria, East Africa

The Lake Victoria watershed has extensive agricultural activity with a long history of pesticide use but there is limited information on historical use or on environmental levels. To address this data gap, high volume air samples were collected from two sites close to the northern shore of Lake Victoria; Kakira (KAK) and Entebbe (EBB). The samples, to be analyzed for pesticides, were collected over various periods between 1999 and 2004 inclusive (KAK 1999–2000, KAK 2003–2004, EBB 2003 and EBB 2004 sample sets) and from 2008 to 2010 inclusive (EBB 2008, EBB 2009 and EBB 2010 sample sets). The latter sample sets (which also included precipitation samples) were also analyzed for currently used pesticides (CUPs) including chlorpyrifos, chlorthalonil, metribuzin, trifluralin, malathion and dacthal. Chlorpyrifos was the predominant CUP in air samples with average concentrations of 93.5, 26.1 and 3.54ngm−3 for the EBB 2008, 2009, 2010 sample sets, respectively. Average concentrations of total endosulfan (ΣEndo), total DDT related compounds (ΣDDTs) and hexachlorocyclohexanes (ΣHCHs) ranged from 12.3–282, 22.8–130 and 3.72–81.8pgm−3, respectively, for all the sample sets. Atmospheric prevalence of residues of persistent organic pollutants (POPs) increased with fresh emissions of endosulfan, DDT and lindane. Hexachlorobenzene (HCB), pentachlorobenzene (PeCB) and dieldrin were also detected in air samples. Transformation products, pentachloroanisole, 3,4,5-trichloroveratrole and 3,4,5,6-tetrachloroveratrole, were also detected. The five most prevalent compounds in the precipitation samples were in the order chlorpyrifos>chlorothalonil>ΣEndo>ΣDDTs>ΣHCHs with average fluxes of 1123, 396, 130, 41.7 and 41.3ngm−2sample−1, respectively. PeCB exceeded HCB in precipitation samples. The reverse was true for air samples. Backward air trajectories suggested transboundary and local emission sources of the analytes. The results underscore the need for a concerted regional vigilance in management of chemicals.

Agricultural Practice and Pesticide Residues in Soils and Pool Sediments from the Pendjari Biosphere Reserve Area in Benin, West Africa

One consequence of the shift in land use from traditional food production to cotton production in West Africa is the application of different pesticides. The influence of this practice on the formation of pesticide residues in soils and sediments of seasonal dry pools was investigated in 2008 and 2009 in the region of the Pendjari biosphere reserve in Benin. The protected park area, the buffer zone with some sporadic agricultural practice and the agricultural zone of the Pendjari region were compared. GC–electron capture detector method was used to analyze selected pesticides covering the officially supplied pesticides and some organochlorine compounds. Residues of α‐ and β‐endosulfan, endosulfan sulfate, chlorpyrifos, p,p′‐dichlorodiphenyldichloroethane, p,p′‐dichlorodiphenyldichloroethylene (DDE) were detected in soils of cotton fields and in sediments from adjacent pools within the agricultural and buffer zone. Concentrations were in the range of below detection limit (DL) to 150 µg/kg dry mass (dm) for endosulfan and endosulfan sulfate together and of below DL to 12 µg/kg dm for chlorpyrifos. In pool sediments, concentrations of total endosulfan were in a range of below DL to 47 µg/kg dm. The occurrence of the pesticides was directly linked to the cotton growing season. No residues were detected at the beginning of cotton growing season. Concentration levels of p,p′‐DDE were in the range of below DL to 12 µg/kg dm. No pesticide residues were found in the protected park zone.

Concentration, distribution, and human health risk assessment of endosulfan from a manufacturing facility in Huai'an, China

Endosulfan concentrations and its distribution in air, soil, sediment and foodstuffs in the area surrounding a production facility in Huai'an, China were investigated because of its threats to the environment and human health. Air concentrations for endosulfan Ι, endosulfan II and endosulfan sulfate measured in this study were several orders of magnitude higher than those reported previously for this region. Surface soil concentration ranges of endosulfan I, endosulfan II, and endosulfan sulfate were greater than in sediment. Endosulfan II was the greatest contributor to total endosulfan concentrations in both surface sediment and soil followed by endosulfan sulfate and endosulfan Ι. However, a different concentration profile was observed in fish and crop samples, with endosulfan sulfate having the highest concentration followed by endosulfan I and endosulfan II. The concentration of Σendosulfans (endosulfans Ι and II) in soil decreased rapidly with increasing distance from the plant by a factor of 10 within 45km. Trace amounts of Σendosulfans were observed in deep soil layers which implied that these compounds are transported through the leaching of pore water in soil. This demonstrated that emissions from the manufacturing facility can lead to ground water contamination in the area near the plant. A screening level human health risk assessment of Σendosulfans based on the worst-case scenario was performed for people living in the vicinity of the manufacturing facility. The hazard indices were at least 2 orders of magnitude of <1, indicating no adverse health effects are likely to occur at current exposure levels, and the risk to human health is generally acceptable.

Endosulfan in the atmosphere of South Florida: Transport to Everglades and Biscayne National Parks

Nutrient inputs from urban encroachment and agricultural activities have been implicated in contributing to the environmental health decline and loss of organism diversity of South Florida ecosystems. Intensive agricultural pesticide use may also challenge these ecosystems. One possible mechanism is pesticide release to the atmosphere after application. The process is enhanced in this region due to the calcareous soils, frequent rainfall, and high humidity and temperatures. This study examined the atmospheric fate of the widely-used insecticide endosulfan. Air samples were collected over a five-year period (2001–2006) at a site within the agricultural community of Homestead, Florida and at sites located in nearby Biscayne and Everglades National Parks (NPs). Mean gas phase air concentrations of α-endosulfan were 17 ± 19 ng m−3 at Homestead, 2.3 ± 3.6 ng m−3 at Everglades NP, and 0.52 ± 0.69 ng m−3 at Biscayne NP. Endosulfan emissions from agricultural areas around Homestead appeared to influence air concentration observations at the NP sites. During an intensive sampling campaign, the highest total endosulfan concentrations at the NP sites were observed on days when air parcels were predicted to move from Homestead towards the sampling locations. The α-endosulfan fraction (α/(α + β)) was used to examine the contribution of pesticide drift versus volatilization to the overall residue level. The formulated product has an α fraction of approximately 0.7, whereas volatilization is predicted to have an α fraction of ≥0.9. The median α- fraction observed during periods of high agricultural activity at Homestead and Everglades NP was 0.84 and 0.88, respectively, and during periods of low agricultural activity the median at Homestead was 0.86, indicating contributions from drift. The median α fraction at Everglades NP was 1.0 during periods of low agricultural activity, while Biscayne NP was 1.0 year round indicating air concentrations are primarily influenced by regional volatilization.

Endosulfan in the Chinese environment: monitoring and modeling

This paper reviews the usage and emissions of endosulfan, the newest member of the persistent organic pollutants (POPs), in China, and its fate and behavior in Chinese environment. Endosulfan usage in China has been estimated to be approximately 25700 t between 1994 and 2004. Concentrations of endosulfan in different environmental compartments in China, such as air, soil, water, and biota, but focusing at air and surface soil, have been summarized. Concentrations of total endosulfan in surface soil across China were ranged from below detection limit (BDL) to 19000 pg·g−1 dry weight (dw), with geometric mean of 120 pg·g−1dw. The results indicated that endosulfan sulfate had highest concentration in Chinese soil, followed by β- and α-endosulfan. Air concentrations of endosulfan in China were ranged 0–340 pg·m−3 for α-endosulfan and 0–121 pg·m−3 for β-endosulfan, with high concentrations occurred in the cotton production areas. Gridded usage inventories of endosulfan on a fine gridded system with a 1/4° longitude by 1/6° latitude resolution were compiled, from which, emission to air and residues in soil of endosulfan were calculated in each grid by using a modified simplified gridded pesticide emission and residue model (SGPERM), an integrated modeling system combining mathematical model, database management system, and geographic information system. Total emissions were around 10800 t from 1994 to 2004. Based on the emission and residue inventories, concentrations of α- and β-endosulfan in Chinese air and agricultural surface soil were also calculated for each grid cell, which are in general consistent with the published monitoring data.

Monitoring and Modeling Endosulfan in Chinese Surface Soil

Endosulfan is a currently used organochlorine pesticide in China, with annual usage of 2300 t between 1994 and 2004. Concentrations of endosulfan (including α- and β-isomers and their metabolite endosulfan sulfate) were reported for surface soil collected in 2005 at 141 sites (6 background, 95 rural, and 40 urban) across China. The concentrations of total endosulfan (sum of α-endosulfan, β-endosulfan, and endosulfan sulfate) at all sites ranged from BDL (below detection limit) to 19000 pg/g dry weight (dw), with geometric mean (GM) 120 pg/g dw. Rural soils had the highest total endosulfan concentrations, with GM 160 pg/g dw, followed by urban soils (GM = 83 pg/g dw) and background soils (GM = 38 pg/g dw). The observed soil concentrations of α-endosulfan (GM = 6.5 pg/g dw) were much lower than those of β-endosulfan (GM = 49 pg/g dw) and endosulfan sulfate (GM = 47 pg/g dw). The fractional abundance of α-endosulfan F(α-endo) [α-endosulfan/(α-endosulfan + β-endosulfan)] for all soils ranged from 0.00040 to 0.91, with GM 0.10, much lower than those in technical products (ranged from 0.67 to 0.7), which most likely reflects that α-endosulfan is more volatile and degrades faster than β-endosulfan in soil. Consequently, half-life of β-endosulfan in soil is expected longer than α-endosulfan. Significant correlation between endosulfan sulfate and its parent isomers suggested that the presence of endosulfan sulfate originated from its parent isomers. Based on multiple linear regression model, inventories of endosulfan sulfate in Chinese agricultural soil in 2004 with a 1/4° longitude × 1/6° latitude resolution are established. Comparison between field measurements and modeling results showed significant correlations between the modeled and measured endosulfan concentrations, and 89%, 83%, and 70% of monitoring data fell between the lowest and the highest modeled concentrations for α- and β-endosulfan and endosulfan sulfate, respectively. The good agreement lends credibility to modeled soil concentrations of endosulfan. To our knowledge, this is the first soil concentration inventory for endosulfan sulfate, which paves the way for further study on its environmental behavior.

Survival Time Analysis of Least Killifish (Heterandria formosa) and Mosquitofish (Gambusia affinis) in Acute Exposures to Endosulfan Sulfate

Single-species flow-through toxicity tests were conducted to determine the times-to-death of two indigenous fish to South Florida--least killifish (Heterandria formosa) and mosquitofish (Gambusia affinis)--from acute exposure to endosulfan sulfate. Mortalities were recorded within 8-h periods from test initiation to termination at 96 h. The 96-h LC(50)s for least killifish and mosquitofish estimated using the trimmed-Spearman-Karber method were 2.0 and 2.3 microg/l, respectively. An accelerated failure time model was used to estimate times to death at selected concentrations. Data were fit to log-normal, log-logistic, and Weibull distributions. Acute toxicity data fit to the Weibull distribution produced a better relative fit than log-normal or log-logistic distributions for both toxicity tests. The survival-time profiles and associated statistics illustrate the benefit of considering exposure duration as well as concentration when predicting acute risk to species' populations. Both toxicity tests had similar outcomes from exposure to endosulfan sulfate, with least killifish being slightly more likely to die at lower concentrations and shorter time periods than mosquitofish. From the models generated by the toxicity tests, times-to-death for least killifish and mosquitofish were estimated for environmentally relevant concentrations of total endosulfan at a site of concern in South Florida. When the results from the current toxicity tests were compared to environmental concentrations from previous screening-level ecological risk assessments, the durations necessary to potentially kill 10% or more of the populations of the two native south Florida fish species were estimated to be 77 and 96 h for least killifish and mosquitofish, respectively. However, the exposure values included the alpha and beta isomers as well as endosulfan sulfate; therefore, an understanding of their toxicity might be important in understanding the survival dynamics of fish species in endosulfan sulfate-contaminated sites.

Fate and toxicity of endosulfan in Namoi River water and bottom sediment.

Endosulfan (6,7,8,9,10,10,-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepine-3-oxide) sorption (standardized to 1% total organic carbon and dry weight) was significantly (P < 0.05) more concentrated on the large (>63 microm) particle fraction compared with smaller size fractions (<5 microm and 5-24 microm) of bottom sediments from the Namoi River, Australia. Following completion of the particle size fractionation (6 to 12 wk) and a sediment toxicity assessment (2 wk), the sediments showed large decreases in concentrations of alpha-endosulfan that coincided with an increase in endosulfan sulfate concentrations and minimal changes in beta-endosulfan concentrations. In the Namoi River, similar patterns were observed in the composition of total endosulfan in monthly measurements of bottom sediments and in passive samplers placed in the water column following runoff from cotton (Gossypium hirsutum L.) fields. The toxicity of endosulfan sulfate in river water indicated by the nymphs of the epibenthic mayfly Jappa kutera, was more persistent than the alpha- and beta-endosulfan parent isomers due to its longer half-life. This suggests that endosulfan sulfate would contribute most to previously observed changes in population densities of aquatic biota. Measured concentrations of total endosulfan in river water of up to 4 microg L(-1) following storm runoff, exceed the range of the 96-h median lethal concentration (LC50) values in river water for both alpha-endosulfan (LC50 = 0.7 microg L(-1); 95% confidence interval [CI] = 0.5 to 1.1) and endosulfan sulfate (LC50 = 1.2 microg L(-1); 95% CI = 0.4 to 3.3). In contrast, the 10-d LC50 value for total endosulfan in the sediment toxicity test (LC50 = 162 microg kg(-1); 95% CI = 120 to 218 microg kg(-1)) was more than threefold higher than the highest measured concentration of total endosulfan in field samples of bottom sediment (48 microg kg(-1)). This suggests that pulse exposures of endosulfan in the water column following storm runoff may be more acutely toxic to riverine biota than in contaminated bottom sediment.

Riverine endosulfan concentrations in the Namoi River, Australia: Link to cotton field runoff and macroinvertebrate population densities

AbstractPopulation densities of six dominant macroinvertebrate taxa (mayfly nymphs Jappa kutera, Atalophlebia sp., Tasma‐nocoenis sp., Baetis sp. and the caddisfly larvae Cheumatopsyche sp. and Ecnomus sp.) were negatively correlated to total endosulfan concentrations in the Namoi River (New South Wales, Australia) in the 1995/96 and 1997/98 cotton growing seasons (November‐March). Total endosulfan concentrations measured in solvent‐filled polyethylene bags (passive samplers) at the exposed sites correlated with rainfall, suggesting that endosulfan entered the riverine environment in runoff from land. At the start of both surveys, in November 1995 and November 1997, there was no significant difference (p &lt; 0.05) between the reference and exposed sites for both total endosulfan concentrations and mean population densities of the combined study taxa. This indicates distance downstream, which was negatively correlated with exposure, was not an important variable in explaining the significantly higher population densities in other months at the reference sites compared with those at sites subsequently exposed to increased (10–25‐fold) total endosulfan concentrations. The multivariate analysis of the 1997/98 data with the principal response curves (PRC) method indicated that endosulfan explained a significant proportion (25%) of the variation in the total macroinvertebrate community. Principal components analysis (PCA) indicated other covariables were involved, including river discharge. River discharge was positively correlated to increased densities of the mayfly taxa at the reference sites in the 1995/96 survey, but these correlations were reduced to near zero, except for Baetis sp., in the 1997/98 survey.

Effect of Endosulfan Runoff from Cotton Fields on Macroinvertebrates in the Namoi River

Of the several pesticides used in the pest management strategy for cotton, endosulfan is ranked as having the greatest impact on the riverine ecosystem. A survey of changes in the densities of six abundant macroinvertebrate taxa (ephemeropteran nymphsJappa kutera, Atalophlebia australis, Tasmanocoenissp., andBaetissp. and two trichopteran larvae,Cheumatopsychesp. andEcnomussp.) between upstream and downstream zones of the cotton-growing region in the Namoi River was conducted between November 1995 and February 1996. In November and December 1995, there were few differences in population densities between all sites. In January and February 1996, population densities of the study taxa increased 7- to 10-fold higher at the two reference sites, with low concentrations of endosulfan in sediment and in passive samplers placed in the water column. In contrast, densities of these taxa at sites with exposure to 25-fold higher concentrations of endosulfan remained static and were between one and two orders of magnitude lower than densities at the reference sites in January and February. Population densities ofBaetissp., a mobile ephemeropteran, did not indicate any inverse relationship with endosulfan concentrations. Multivariate redundancy analysis indicated that endosulfan concentrations were the leading environmental predictor of changes in density of the five benethic taxa. Laboratory 48-h LC50values of technical endosulfan in river water were 0.6, 1.3, and 0.4 ppb for early-instar nymphs ofA. australisandJ. kutera, and larvae ofCheumatopsychesp., respectively. Endosulfan sulfate formed a large proportion of the total endosulfan concentrations measured fromin situpassive samplers, indicating that its main route of entry into the river is through surface runoff during storm events.

Determination of endosulfan and its metabolites in human urine using gas chromatography–tandem mass spectrometry

A method was developed for determining the occupational exposure to endosulfan and its main metabolites (endosulfan-ether, -lactone and -sulfate) in human urine using dieldrin as an internal standard. Solid phase extraction (SPE) and gas chromatography–tandem mass spectrometry (GC–MS–MS) have been used due to their high sensitivity and selectivity in avoiding most matrix interferences. The recovery efficiencies of the tested compounds yielded more than 89.2 % at the fortification level of 10 ng ml −1 in urine and their relative standard deviations were between 9.1 and 12.8 %. The detection limit of each compound ranged between 6 and 18 pg ml −1. Urine samples from nine pest control operators were analysed and total endosulfan concentrations between 94 and 2038 pg ml −1 were found.