Risk Assessment for Dermal Exposure of Organochlorine Pesticides for Local Fishermen in the Rangsit Agricultural Area,Central Thailand

Organochlorine pesticides (OCPs) used in agriculture and for public health purposes were banned in Thailand over the past decade; however, their persistent residues have been found in several agricultural areas of the country. This may result in adverse effects to human populations. This study investigated the concentration of organochlorine pesticides residues (OCPRs) in surface water and evaluated the potential cancer risk associated with dermal contact of the local fisherman fishing in the Khlong 7 canal, Rangsit agricultural area, central Thailand. Water samples were extracted using liquid-liquid extraction (LLE) and then analyzed by gas chromatography with microelectron capture detector (μ -ECD). The results show that low concentrations of OCPRs were detected in parts per billion (ppb or ng/ml) levels, that is, ∑ Endosulfan (α -, β -, and -sulfate) 0.082 ng/ml > DDT and derivatives 0.019 ng/ml > ∑ HCH (α -, γ -, β -, and δ -HCH) 0.014 ng/ml > aldrin and dieldrin 0.007 ng/ml > heptachlor and heptachlor epoxide 0.0068 ng/ml > endrin and endrin aldehyde 0.005 ng/ml > methoxychlor 0.001 ng/ml, respectively. Using the worst-case scenario defined as the reasonable maximum exposure (RME) to assess the potential cancer risk, five OCPs (dieldrin, 4,4′ -DDT, β -HCH, heptachlor, and heptachlor epoxide) may pose a risk of concern on a lifetime human carcinogenesis greater than one in a million.     

Occurrence and distribution of organochlorine pesticide residue levels in water,sediment and aquatic weeds in the Nyando River catchment,Lake Victoria,Kenya

Samples of water, sediments and aquatic weeds were collected from 26 sites in the Nyando River catchment of the Lake Victoria basin in 2005–2006. The objective was to investigate levels of organochlorine pesticides that have either been banned or are restricted for use in Kenya. The pesticides investigated were lindane, aldrin, endosulfan, endrin, dieldrin, DDT, heptachlor and methoxychlor. These pesticides had previously found wide applications in public health and agriculture in Kenya for control of disease vectors and crop pests respectively. Results showed that mean concentrations were highest for methoxychlor (8.817 ± 0.020?µg l^?1) in water, sediments (92.893 ± 3.039 µg kg^?1), and weeds (39.641 ± 3.045?µg kg^?1), the weeds also tended to accumulate aldrin (15.519 ± 3.756?µg kg^?1). The results show that the pesticides are still in use and are detected in the catchment. Stringent management and public awareness measures are required to enforce the ban on the organochlorine pesticides in order to safeguard the environment and ecosystems of Lake Victoria.     

Isolation of four aquatic streptomycetes strains capable of growth on organochlorine pesticides

Ninety-three wild-type isolates identified as actinomycetes were tested against 11 organochlorine pesticides (OPs): aldrin, chlordane, DDD, DDE, DDT, dieldrin, heptachlor, and heptachlor epoxides, lindane, and methoxychlor. Qualitative screening agar assays displayed 62-78% tolerance of strains to OPs. Four strains designed M4, M7, M9 and M15 were selected based on multi-OP-tolerance, and identified as members of the streptomycetes group. Different growth profiles were observed in cultures of the four selected streptomycetes cultured in synthetic medium containing 5-50 microg x l(-1) aldrin or chlordane or lindane. Increase of aldrin removal by the selected microorganisms was concomitant with the 4.8-36.0 microg x l(-1) pesticide concentration range. After 72 h of streptomycete M7 growth in synthetic medium containing 48.0 microg x l(-1) aldrin, the remaining OP concentration in the supernatant was approximately 10% of the initial concentration. Also, in stationary growth phase less than 2.5 microg x l(-1) aldrin residual concentration was detected in the medium.     

Molecular mechanism of Endosulfan action in mammals

Endosulfan is a broad-spectrum organochlorine pesticide, speculated to be detrimental to human health in areas of active exposure. However, the molecular insights to its mechanism of action remain poorly understood. In two recent studies, our group investigated the physiological and molecular aspects of endosulfan action using in vitro, ex vivo and in vivo analyses. The results showed that apart from reducing fertility levels in male animals, Endosulfan induced DNA damage that triggers compromised DNA damage response leading to undesirable processing of broken DNA ends. In this review, pesticide use especially of Endosulfan in the Indian scenario is summarized and the importance of our findings, especially the rationalized use of pesticides in the future, is emphasized.     

Organochlorine pesticides in Cyprinus carpio from Sidi Salem Dam,north-western Tunisia

Cyprinus carpio (Linnaeus, 1758) caught in Sidi Salem Dam in 2011 were analysed for the levels of organochlorine pesticides (OCPs), including hexachlorobenzene (HCB), aldrin, heptachlor, lindane, dieldrin, endrin, and pp′-DDT and its two main metabolites pp′-DDD and pp′-DDE, in order to evaluate the extent of contamination of the dam. Fish were sampled monthly within the dam during 2011. Muscle, liver and gill tissues were analysed by gas chromatography for the determination of OCPs. Samples had variable concentrations of OCPs, ranging from 2.26 to 17.93 ng g?1, 0.59 to 42.67 ng g?1 and 3.30 to 84.27 ng g?1, which were isolated from gills, muscle and liver, respectively. The organochlorine pesticide levels found posed no threat to human health. The highest OCP levels were found in the liver tissues. The pp′-DDE concentrations and their ratios to ΣDDTs indicate aged DDT pollution and suggests that there has been no recent input of technical DDT from the agricultural areas into Sidi Salem Dam.     

A Preliminary Human Health Risk Assessment of Organochlorine Pesticide Residues Associated with Aquatic Organisms from the Rangsit Agricultural Area,Central Thailand

Food consumption is one of the main routes of human exposure to organochlorine pesticide residues (OCPRs). To assess the potential health risks associated with OCPRs contaminants due to freshwater organism consumption, a number of vegetables, prawn, snail, and fish were collected from Khlong 7 (canal), Rangsit agricultural area, Pathum-Thani Province, Thailand. The samples were extracted using a multiresidue extraction method and then analyzed by gas chromatography with microelectron capture detector (μ -ECD). The results show that low concentrations of OCPRs were detected in parts per billion (ppb) levels. Based on a plausible worst-case scenario, the local population could be at risk for cancer due to consumption of fish contaminated by α -, β -HCH, heptachlor, heptachlor epoxide, aldrin, dieldrin, DDD, DDE, and DDT. Likewise, individuals may be at risk from consumption of Lanchester's freshwater prawn Macrobrachium lanchesteri, freshwater snail Filopaludina mertensi, swamp morning-glory Ipomomea aquatica, neptunia Neptunia oleracea, and water lily Nymphaea lotus because these species all contained elevated concentrations of α -, β -HCH, heptachlor, heptachlor epoxide, aldrin, and dieldrin.     

Mechanism of toxicity of pesticides acting at complex I: relevance to environmental etiologies of Parkinson's disease

Parkinson's disease (PD) has been linked to mitochondrial dysfunction and pesticide exposure. The pesticide rotenone (ROT) inhibits complex I and reproduces features of PD in animal models, suggesting that environmental agents that inhibit complex I may contribute to PD. We have previously demonstrated that ROT toxicity is dependent upon complex I inhibition and that oxidative stress is the primary mechanism of toxicity. In this study, we examined the in vitro toxicity and mechanism of action of several putative complex I inhibitors that are commonly used as pesticides. The rank order of toxicity of pesticides to neuroblastoma cells was pyridaben > rotenone > fenpyroximate > fenazaquin > tebunfenpyrad. A similar order of potency was observed for reduction of ATP levels and competition for (3)H-dihydrorotenone (DHR) binding to complex I, with the exception of pyridaben (PYR). Neuroblastoma cells stably expressing the ROT-insensitive NADH dehydrogenase of Saccharomyces cerevisiae (NDI1) were resistant to these pesticides, demonstrating the requirement of complex I inhibition for toxicity. We further found that PYR was a more potent inhibitor of mitochondrial respiration and caused more oxidative damage than ROT. The oxidative damage could be attenuated by NDI1 or by the antioxidants alpha-tocopherol and coenzyme Q(10). PYR was also highly toxic to midbrain organotypic slices. These data demonstrate that, in addition to ROT, several commercially used pesticides directly inhibit complex I, cause oxidative damage, and suggest that further study is warranted into environmental agents that inhibit complex I for their potential role in PD.     

Territory occupancy and breeding success of Peregrine Falcons Falco peregrinus at various stages of population recovery

Organochlorine pesticides disrupted reproduction and killed many raptorial birds, and contributed to population declines during the 1940s to 1970s. We sought to discern whether and to what extent territory occupancy and breeding success changed from the pesticide era to recent years in a resident population of Peregrine Falcons Falco peregrinus in southern Scotland using long‐term (1964–2015) field data and multi‐state, multi‐season occupancy models. Peregrine territories that were occupied with successful reproduction in one year were much more likely to be occupied and experience reproductive success in the following year, compared with those that were unoccupied or occupied by unsuccessful breeders in the previous year. Probability of territory occupancy differed between territories in the eastern and western parts of the study area, and varied over time. The probability of occupancy of territories that were unoccupied and those that were occupied with successful reproduction during the previous breeding season generally increased over time, whereas the probability of occupancy of territories that were occupied after failed reproduction decreased. The probability of reproductive success (conditional on occupancy) in territories that were occupied during the previous breeding season increased over time. Specifically, for territories that had been successful in the previous year, the probability of occupancy as well as reproductive success increased steadily over time; these probabilities were substantially higher in recent years than earlier, when the population was still exposed to direct or residual effects of organochlorine pesticides. These results are consistent with the hypothesis that progressive reduction, followed by a complete ban, in the use of organochlorine pesticides improved reproductive success of Peregrines in southern Scotland. Differences in the temporal pattern of probability of reproductive success between south‐eastern and south‐western Scotland suggest that the effect of organochlorine pesticides on Peregrine reproductive success and/or the recovery from pesticide effects varied geographically and was possibly affected by other factors such as persecution.     

Estimating Pesticide Effects on Fecundity Rates of Wild Birds Using Current Laboratory Reproduction Tests

Regulatory agencies have used laboratory toxicity tests for decades to assess potential risks of pesticide use to wildlife, but questions remain about the ecological significance of test results. Population models may provide a valuable tool for projecting the consequences of pesticide use if information exists on the relationship between exposure and effects on survival and fecundity rates. We review issues of using avian reproduction test results for estimating changes in fecundity rates of wild birds. The avian reproduction test originated from studies focused on eggshell quality and embryotoxic effects of bioaccumulating, organochlorine pesticides. Current pesticides exhibit other potential reproductive effects that are not measured or that are poorly characterized. Because several experimental design features of the laboratory test may lead to overestimation or underestimation of the magnitude of risk of a particular pesticide to wild birds, determination of the magnitude of effects on fecundity cannot be based solely on the results of standardized laboratory tests. Quantifying the overall impact of pesticides on avian fecundity rates for use in population modeling will require additional information from modified laboratory tests that address specific questions, field monitoring or experimental field studies, and simulation models of avian productivity.     

Environmental Risk of Pesticides: Applying the DelAzulPestRisk Model to Freshwaters of an Agricultural Area of Argentina

DelAzulPestRisk is a risk-based chemical ranking model based on human and local biota toxicities that estimates the integrated risk of pesticides in water from their extensive (concentration, risk) and intensive (persistence, bioaccumulation) chemical properties. The model is built on two modules: human health risk factor (estimated based on the probabilistic cancer and non-cancer health risk by using U.S. Environmental Protection Agency models applied to a bathing exposure scenario) and biota health risk factor (quantified on the basis of the probabilistic toxicity exposure ratio –PEC/PNEC– for three local representatives of water biota multiplied by an amplification factor supported by the persistence and bioaccumulation potential). The model was applied to shallow creeks of Tres Arroyos County, Argentina, which flow across wheat and soybean agricultural lands, and in whose waters were detected many organochlorine pesticides (α, γ, y, δ-HCH, aldrin, heptachlor, γ-chlordane, endosulfan, endosulfan sulphate, dieldrin, and DDD). Dieldrin, aldrin, and heptachlor generated the worst potential effects—due mainly to the cancer and non-cancer dermal health risk—although this was not a significant environmental threat. DelAzulPestRisk is a screening assessment tool for water management purposes that become useful in countries lacking efficient water quality control systems.     

Biotransformation of the organochlorine pesticide trans-chlordane by wood-rot fungi

There is very limited information on the biotransformation of organochlorine pesticide chlordane by microorganisms, and no systematic study on the metabolic products and pathways for chlordane transformation by wood-rot fungi has been conducted. In this study, trans-chlordane was metabolized with the wood-rot fungi species Phlebia lindtneri, Phlebia brevispora and Phlebia aurea, which are capable of degrading polychlorinated dibenzo-p-dioxin and heptachlor epoxide. At the end of 42 days of incubation, over 50% of trans-chlordane was degraded by the fungal treatments in pure cultures. These fungi transformed trans-chlordane to at least eleven metabolites including a large amount of hydroxylated products such as 3-hydroxychlordane, chlordene chlorohydrin, heptachlor diol, monohydroxychlordene and dihydroxychlordene. P. lindtneri particularly can metabolize oxychlordane, a recalcitrant epoxide product of chlordane, into a hydroxylated product through substitution of chlorine atom by hydroxyl group. The present results suggest that hydroxylation reactions play an important role in the metabolism of trans-chlordane by these Phlebia species. Additionally, transformation of trans-chlordane and production of hydroxylated metabolites were efficiently inhibited by the addition of cytochrome P450 inhibitors, piperonyl butoxide and 1-aminobenzotriazole, demonstrating that fungal cytochrome P450 enzymes are involved in some steps of trans-chlordane metabolism, particularly in the hydroxylation process.     

Monitoring and Risk Assessment of Pesticide Residues in Tea Samples from China

In the present study an effort was made to monitor the residue levels of 32 pesticides in tea samples collected from three representative tea districts of China during 2010 to 2012. A total of 223 samples of green tea, pu-erh tea, black tea, and oolong tea were determined using gas chromatography with mass spectrometry (GC-MS). Among 223 samples, 198 samples contained pesticide residues, and 39 samples had residue levels that were more than the European Union (EU) maximum residue limits (MRLs). The most positive and violated MLRs were observed in Oolong tea. The highest detection rates and the most often exceeding the MRLs were observed for the residues of bifenthrin. Ten pesticides were not found in the 223 tea samples. The potential health risks to consumers due to tea consumption in three representative cities were estimated. The results suggested that non-cancer hazards of organophosphorus, organochlorines, and pyrethroids and the cancer risks from exposure to hexachlorobenzene, heptachlor, chlordane, and pp’-DDT were clearly below the safe limit. Nevertheless, an investigation into continuous monitoring and tighter regulation of pesticide residues in tea samples are almost always desirable or even necessary for public health protection.     

Modulation of CPP32 activity and induction of apoptosis in Human CEM X 174 lymphocytes by heptachlor, a chlorinated hydrocarbon insecticide

Heptachlor is an organochlorine insecticide used worldwide for the control of pests both agriculturally and domestically. Its lipophilic structure allows it to bioaccumulate and pass through the food chain, exposing those who come in contact with it to its tumor promoting and possible carcinogenic effects. As a mechanism of tumor promotion, we explored the possibility of heptachlor suppressing the apoptotic process in human CEM x 174 lymphocytes. In this article, we describe the effect of heptachlor on the activity of the apoptosis protease CPP32. We show that heptachlor by itself was able to stimulate CPP32 activity at relatively high concentrations. When combined with the chemotherapeutic agent doxorubicin, a known CPP32 activator, a dual effect was observed. Low concentrations of heptachlor (5 microM-10 microM) suppressed doxorubicin-induced CPP32 activity, and high concentrations of heptachlor (80 microM-120 microM) augmented it. We also showed that heptachlor alone at relatively high concentrations induced apoptosis-associated changes in CEM x 174 cells including high molecular weight (HMW) DNA cleavage and chromatin condensation. From these results, it appears that heptachlor has tumor promoting-like effects at lower concentrations, and at higher concentrations induces apoptosis as a mechanism of cytotoxicity.     

Alteration of thrombine-signaling mechanism by heptachlor in human platelets

Heptachlor is a persistent organochlorine insecticide that has been detected in human tissues and fluids. The ability of heptachlor to interfere with platelet phosphoinositides metabolism and related signaling events stimulated by thrombin was evaluated. In vitro incubations with a concentration range of 1-100 microM heptachlor, prior to platelets activation, were performed. Experiments showed that 10 microM increased protein Kinase C (PKC) activity and phosphatidylinositolbiphosphate and phosphatidic acid phosphorylation. Simultaneously phosphatidylcholine and phosphatidylethanolamine breakdown were prevented. Similar effects were observed with HC 1 microM. However, heptachlor 100 microM increased phosphatidylinositolbiphosphate phosphorylation but reduced serine/threonine kinases activity. We propose that signal transduction steps downstream phospholipase C (PLC) are unphysiologically activated by heptachlor and facilitated by the increase in phosphatidylinositolbiphosphate, the substrate for PLC activity, thus producing an accumulation of phosphatidic acid. The elevated level of this compound itself or the transient increase in diacylglycerol produced may cause calcium mobilization and the activation of PKC. In contrast with the alterations observed in phospholipids and protein phosphorylation, no changes in aggregation properties were observed.     

Acute human lethal toxicity of agricultural pesticides: a prospective cohort study

Background

Agricultural pesticide poisoning is a major public health problem in the developing world, killing at least 250,000–370,000 people each year. Targeted pesticide restrictions in Sri Lanka over the last 20 years have reduced pesticide deaths by 50% without decreasing agricultural output. However, regulatory decisions have thus far not been based on the human toxicity of formulated agricultural pesticides but on the surrogate of rat toxicity using pure unformulated pesticides. We aimed to determine the relative human toxicity of formulated agricultural pesticides to improve the effectiveness of regulatory policy.

Methods and Findings

We examined the case fatality of different agricultural pesticides in a prospective cohort of patients presenting with pesticide self-poisoning to two clinical trial centers from April 2002 to November 2008. Identification of the pesticide ingested was based on history or positive identification of the container. A single pesticide was ingested by 9,302 patients. A specific pesticide was identified in 7,461 patients; 1,841 ingested an unknown pesticide. In a subset of 808 patients, the history of ingestion was confirmed by laboratory analysis in 95% of patients. There was a large variation in case fatality between pesticides—from 0% to 42%. This marked variation in lethality was observed for compounds within the same chemical and/or WHO toxicity classification of pesticides and for those used for similar agricultural indications.

Conclusion

The human data provided toxicity rankings for some pesticides that contrasted strongly with the WHO toxicity classification based on rat toxicity. Basing regulation on human toxicity will make pesticide poisoning less hazardous, preventing hundreds of thousands of deaths globally without compromising agricultural needs. Ongoing monitoring of patterns of use and clinical toxicity for new pesticides is needed to identify highly toxic pesticides in a timely manner. Please see later in the article for the Editors'' Summary     

Organochlorine Pesticide Residues in Human Fat in Great Britain

In order to assess the trend in the body load of organochlorine pesticide residues in Great Britain, between July 1965 and June 1967 samples of fat were taken during routine necropsies on 247 subjects over 3 years old and on 44 stillborn or premature babies and infants below the age of 3. The levels of the three main pesticides, B.H.C., dieldrin, and D.D.T., were lower than those found in an earlier survey carried out in 1963 and 1964. No marked differences were observed in levels throughout Britain, but the levels in man were higher than those in women. Britain compares favourably with other countries in which similar surveys have been done.     

A Pragmatic Approach to Assess the Exposure of the Honey Bee (Apis mellifera) When Subjected to Pesticide Spray

Plant protection spray treatments may expose non-target organisms to pesticides. In the pesticide registration procedure, the honey bee represents one of the non-target model species for which the risk posed by pesticides must be assessed on the basis of the hazard quotient (HQ). The HQ is defined as the ratio between environmental exposure and toxicity. For the honey bee, the HQ calculation is not consistent because it corresponds to the ratio between the pesticide field rate (in mass of pesticide/ha) and LD₅₀ (in mass of pesticide/bee). Thus, in contrast to all other species, the HQ can only be interpreted empirically because it corresponds to a number of bees/ha. This type of HQ calculation is due to the difficulty in transforming pesticide field rates into doses to which bees are exposed. In this study, we used a pragmatic approach to determine the apparent exposure surface area of honey bees submitted to pesticide treatments by spraying with a Potter-type tower. The doses received by the bees were quantified by very efficient chemical analyses, which enabled us to determine an apparent surface area of 1.05 cm²/bee. The apparent surface area was used to calculate the exposure levels of bees submitted to pesticide sprays and then to revisit the HQ ratios with a calculation mode similar to that used for all other living species. X-tomography was used to assess the physical surface area of a bee, which was 3.27 cm²/bee, and showed that the apparent exposure surface was not overestimated. The control experiments showed that the toxicity induced by doses calculated with the exposure surface area was similar to that induced by treatments according to the European testing procedure. This new approach to measure risk is more accurate and could become a tool to aid the decision-making process in the risk assessment of pesticides.     

Assessment of organochlorine pesticides and metals in ring‐tailed lemurs (Lemur catta) at Beza Mahafaly Special Reserve,Madagascar

Like most of Madagascar's endemic primates, ring‐tailed lemurs (Lemur catta) face a number of threats to their survival. Although habitat loss is of greatest concern, other anthropogenic factors including environmental contamination may also affect lemur health and survival. In this study, we examined ring‐tailed lemurs from the Beza Mahafaly Special Reserve (BMSR), southern Madagascar for exposure to organochlorine (OC) pesticides and metals and examined differences in contaminant concentrations between sexes and among age groups, troops, and habitats. A total of 14 pesticides and 13 metals was detected in lemur blood (24 individuals) and hair (65 individuals) samples, respectively. p,p′‐DDT, heptachlor, aldrin, heptachlor epoxide, endrin aldehyde, and endrin were among the most prevalent pesticides detected. Surprisingly, the persistent metabolite of p,p′‐DDT, p,p′‐DDE, was not detected. The most commonly detected metals were aluminum, zinc, boron, phosphorus, silicon, and copper, whereas metals considered more hazardous to wildlife (e.g. arsenic, cadmium, lead, selenium, vanadium) were not found above detection limits. Overall, concentrations of OC pesticides and metals were low and similar to those considered to be background concentrations in other studies examining the ecotoxicology of wild mammals. Few inter‐sex, ‐age, ‐troop, and ‐habitat differences in contaminant concentrations were observed, suggesting a uniform distribution of contaminants within the reserve. Several statistically significant relationships between lemur body size and contaminant concentrations were observed, but owing to the lack of supportive data regarding contaminant exposure in wild primates, the biological significance of these findings remains uncertain. Results of this study document exposure of ring‐tailed lemurs at BMSR to multiple OC pesticides and metals and provide essential baseline data for future health and toxicological evaluations of lemurs and other wild primates, especially those in regions with expanding agricultural and mining operations. Am. J. Primatol. 71:998–1010, 2009. © 2009 Wiley‐Liss, Inc.