Organochlorine pesticides (OCPs) in South Asian region: a review

Organochlorine pesticides (OCPs) are semi volatile organic compounds of global concern. During the last decades, their distribution, sources, transformation, toxicity and accumulation in the terrestrial and aquatic ecosystems have gained significant attention. Many of these chemicals are characterized by long range atmospheric transport potential, and their occurrence in remote areas is attributed to transport of chemicals from places where OCPs are still in use. The South Asia region is a place where primarily emissions are still taking place and thus it is important to assess the status of OCPs pollution. This document provides the historical overview and country specific environmental legislation of OCPs from the South Asian region in the context of their illegal use and storage for extended periods and still until to date. In addition, the current review discusses the existing knowledge on the levels and distribution of OCPs in different environmental compartments of South Asian region. Data on OCPs also highlights the risk assessment of these organic contaminants in the regional environment and spans the long range atmospheric transport phenomena based on Himalayas and Northern mountainous glaciers. Paradoxically in the scientific literature sources, distribution and transport of these organic pollutants in South Asian region are very limited compared to the rest of the world.

Organochlorine pesticide content and distribution in coastal seafoods in Zhoushan, Zhejiang Province

Thirteen types of seafoods were collected from four counties (districts) of Zhoushan, Zhejiang Province, China and analyzed for organochlorine pesticides (OCPs). The average concentrations of OCPs in seafoods ranged from 258.3 ng g⁻¹ (lw) to 3459.6 ng g⁻¹ (lw). Hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) were the most abundant compounds in these environments and in total accounted for 8.2-62.2% and 32.1-89.0% of the total OCPs in seafoods, respectively. The total OCP contents were higher in seafoods from Shengsi and Putuo and lower in those from Dinghai and Daishan. The ratios of (DDE+DDD)/DDTs reflected a mixed input of accumulated and fresh DDTs in Shengsi, Putuo. The ratios of o,p'-DDT/p,p'-DDT in seafoods of Shengsi ranged 0.10-0.60 (mean 0.33), indicating that DDTs in seafoods of Shengsi may partly contain dicofol products and other pollutants accumulated in Yangtze Estuary. DDTs are a greater concern for ecotoxicological risk in the study area.

Polychlorinated biphenyls and organochlorine pesticides in human milk samples from two regions in Croatia

We analyzed 20 polychlorinated biphenyls (PCBs) and seven organochlorine pesticides (OCPs) in milk samples collected during 2009-2011 from primiparae living in two different regions in Croatia. p,p'-DDE is the dominant organochlorine pesticide. α-HCH/γ-HCH and p,p'-DDE/p,p'-DDT ratios indicate that there is fresh input of γ-HCH in investigated population on both locations, while this is not applicable to p,p'-DDT. The PCB profile was dominated by higher chlorinated congeners. Non-ortho PCB congeners which have the highest TEF values were not detected in any of individual samples. Toxic equivalents for mono-ortho substituted PCB congeners indicated higher exposure to toxic PCBs in Zadar, but estimated daily intakes for both locations indicate that infants consuming mother's milk are not at risk of adverse effects caused by PCBs and OCPs. Our study builds on the previous research of human milk samples collected in Zagreb and reveals that over 10-year period, levels of investigated organochlorine compounds decreased significantly.

PCDDs, PCDFs, PCBs and OCPs in sediments from selected areas in the Slovak Republic

Within our research project, 34 river bottom sediments were collected in 2006-2007 at five areas across Slovakia with industrial sources of persistent organic pollutants (Košice, Krompachy, Nemecká, Šala, Nováky) and one background area (Starina). Sediments were analyzed for seven 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and 10 dibenzofurans (PCDFs), 12 dioxin-like and 6 indicator polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB) and 1,1,1,-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) with 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE). Analytical procedure based on accelerated solvent extraction followed by a semi-automated clean-up and fractionation was used. Determination of target compounds was performed by HRGC-HRMS analysis. Total WHO toxic equivalent WHO1998-PCDD/F/dl-PCB-TEQ concentrations ranged from 0.26 to 559 pg TEQ g(-1) dry matter (dm), with a median 2.2 pg TEQ g(-1) dm. The sums of six indicator PCBs were in the range 0.56-1014 ng g(-1) dm, with a median 11.8 ng g(-1) dm. The concentrations of organochlorine pesticides HCB and p,p'-DDE/DDT varied from 0.15 to 34.8 ng g(-1) dm, with a median 0.91 ng g(-1) dm and 0.46-34.1 ng g(-1)dm, with a median 6.7 ng g(-1)dm, respectively. The most abundant congeners in all sediment samples among dioxins, furans and PCBs were OCDD, 1,2,3,4,6,7,8-HpCDF, PCB-118 and PCB-153.

Assessment of concentrations and effects of organohalogen contaminants in a terrestrial passerine, the European starling

European starlings (Sturnus vulgaris) are a valuable model species for the assessment of concentrations and effects of environmental contaminants in terrestrial birds. Polybrominated diphenyl ethers (PBDEs) are found in birds throughout the world, but relatively little is known of their concentrations or effects in free-living terrestrial passerines. We used a nest box population of European starlings to 1) measure the variation in egg concentrations of persistent organohalogen contaminants at an agricultural site, and 2) assess whether individual variation in PBDE concentrations in eggs was related to reproductive parameters, as well as maternal or nestling characteristics including body condition, thyroid hormones, oxidative stress, and hematocrit. As PBDEs were the main contaminant class of interest, we only assessed a subset of eggs for other organohalogen contaminants to establish background concentrations. Exposure to organohalogen contaminants was extremely variable over this relatively small study area. Geometric mean wet weight concentrations (range in brackets) of the major contaminants were 36.5 (12-174) ng/g ΣDDT (n=6 eggs) and 10.9 (2-307) ng/g ΣPBDEs (n=14). ΣPCBs at 3.58 (1.5-6.4) ng/g (n=6) were lower and less variable. There were low levels of other organochlorine (OC) pesticides such as dieldrin (2.02 ng/g), chlordanes (1.11 ng/g) and chlorobenzenes (0.23 ng/g). The only form of DDT detected was p,p'-DDE. The congener profiles of PBDEs and PCBs reflect those of industrial mixtures (i.e. DE-71, Aroclors 1254, 1260 and 1262). For all of the contaminant classes, concentrations detected in eggs at our study site were below levels previously reported to cause effects. Due to small sample sizes, we did not assess the relationship between ΣPCBs or ΣOCs and adult or chick condition. We observed no correlative relationships between individual variation in PBDE concentrations in starling eggs and reproductive success, maternal condition, or nestling condition in the corresponding nests.

[Exposure to persistent and non-persistent pesticides in a non-occupationally exposed population in Tenerife Island (Spain)]

OBJECTIVE

Chronic exposure to non-persistent pesticides (NPPs) is of concern because these substances have been associated with chronic diseases. However, few studies have addressed chronic exposure to NPPs in Spanish populations.

METHODS

We determined the presence of 24 pesticide residues by gas chromatography/mass spectrometry in 363 serum samples obtained from non-occupationally exposed adults from Tenerife island in 2007.

RESULTS

Most of the samples (99.45%) showed detectable residues (6 ± 2 pesticides per sample). The most frequently detected pesticides were pyrethrins (96.1%), organophosphates (93.9%) and organochlorines (92.3%). The neurotoxicants bifenthrin and malathion were detected in 81% of the samples and hexachlorobenzene DDT and buprofezin in more than 50%. Malation, an "environmental obesogen", was detected in 82%, and "endocrine disrupter" pesticides were present in 97.2% of the samples.

CONCLUSIONS

Because there is clear, continuous and inadvertent exposure to NPPs that may be inducing adverse effects on human health, NPPs should be included in biomonitoring studies.

Assessment of the exposure to organochlorine pesticides, PCBs and PAHs in six species of predatory birds of the Canary Islands, Spain

In the present study, we investigated the concentrations and distributions of 57 anthropogenic pollutants, including 23 organochlorine pesticides (OCs), 18 polychlorinated biphenyls (PCBs) and 16 polycyclic aromatic hydrocarbons (PAHs) in liver samples from 102 birds of prey of six species that were found dead or that had died during their stay in the Wildlife Recovery Centers of the Canary Islands (Spain) between 2009 and 2012. The dual goal of this work was to determine the occurrence of these contaminants in these six species of birds of prey, and also whether they can be used as bioindicators for monitoring environmental pollution in the region. We found that Accipiter nisus, Falco pelegrinoides and Falco tinnunculus were the most contaminated species. The profiles of contamination among the species were extremely similar in the case of organochlorine contaminants, with DDT and its metabolites as the most abundant compounds. The contamination by DDT and its metabolites, as well as contamination by dieldrin, could be considered high in these animals, much higher than reports from other regions of the planet, which is in agreement with previous reports from our group regarding humans, food and other animals from this area. In contrast, the contamination by PCBs could be considered extremely low and was probably below the threshold of toxicity for these contaminants. The content of carcinogenic/mutagenic PAHs in these animals was clearly dependent on the feeding pattern of the species; however, the levels were also well below the values that were considered toxic in predictive models. This study represents the first report of contamination by PAHs in all these species and is also the first report of PCB levels in Barbary Falcons.

Assessment of current dietary intake of organochlorine contaminants and polycyclic aromatic hydrocarbons in killer whales (Orcinus orca) through direct determination in a group of whales in captivity

We determined the levels of 16 polycyclic aromatic hydrocarbons (PAHs), 19 organochlorine pesticides (OCPs) and 18 polychlorinated biphenyls (PCBs) in the plasma of captive adult killer whales and in their food. The goal of this research was the assessment of the dietary exposure of killer whales to these pollutants to gain insight on what is the actual magnitude of the exposure in this species, which is considered among the most contaminated in the planet. Plasma median ∑OCP and ∑PCB contents were 3150.3 and 7985.9 ng g(-1)l.w., respectively. A total of 78.9% of the PCBs were marker-PCBs, and 21.1% were dioxin-like PCBs (6688.7 pg g(-1)l.w. dioxin toxic equivalents). This is the first report of the blood levels of PAHs in killer whales, and their median value was 1023.1 ng g(-1)l.w. In parallel, we also determined the levels of these contaminants in the fish species that are used to feed these animals to estimate the orcas' average daily dietary intake of pollutants. All the contaminants in the fish were detected in the plasma of the killer whales, and proportionality between the intake and the blood levels was observed in all the animals. The calculated intake was extremely high for certain contaminants, which is a concern, giving a glimpse of what possibly occurs in the wild, where exposure to these contaminants can be even higher. Therefore, although many of these chemicals have been banned for decades, even today, the levels of these chemicals could reach very toxic concentrations in the tissues of these endangered animals because of their diet.

Serum levels of organochlorine pesticides in the French adult population: the French National Nutrition and Health Study (ENNS), 2006-2007

BACKGROUND

Although most organochlorine (OC) pesticides were banned in France in the 1970s and 1980s, they remain a source of public concern. Because of their high persistence in the environment, they are still detected in foodstuffs, leading to continued human exposure. The purpose of this study was to assess the distribution of serum organochlorine (OC) pesticides in the French adult population and to identify the main risk factors for p,p'-dichlorodiphenyl dichlorethylene (DDE), β-hexachlorocyclohexane (β-HCH) and hexachlorobenzene (HCB).

METHOD

The selected OC pesticides (HCB, DDE, DDT, α-HCH, β-HCB and γ-HCH) were measured in serum samples collected in 2006-2007 from 386 persons (aged 18-74 years) randomly selected among the participants in the clinical and biological component of the French Nutrition and Health Survey (Etude Nationale Nutrition Santé [ENNS]), a cross-sectional survey carried out in the general population. Collected data included biological samples, socio-demographic characteristics, and data about environmental and occupational exposure factors.

RESULTS

Of the six OC pesticides investigated, the highest concentrations were observed for HCB, β-HCH and DDE. Median serum concentrations were as follows: 22.8 ng/g lipid for HCB, 0.74 and 27.0 ng/g lipid, respectively, for α- and ß-HCH, and 3.8 and 104.6 ng/g lipid, respectively, for DDT and DDE. Lindane (γ-HCH) was detected in approximately 10% of the sample. OC pesticide levels in serum in French adults were higher (except for DDT and DDE) than those observed in American, Canadian and German populations and generally lower than or in the same range as those observed in other European countries. The low serum DDT/DDE ratio in the present study (3.7%) would suggest that the concentrations observed for these two OC pesticides were mainly the result of past exposure. The most important predictors of serum DDE, HCB and β-HCH concentrations among the French adult population included individual factors (age, gender, BMI, etc.), dietary factors of animal and vegetable origin, and domestic use of pesticides (in vegetable gardens and/or fruit trees).

CONCLUSION

For the first time in France, a human biomonitoring study has shown that exposure to OC pesticides remains common in the population. French concentrations were higher (except for DDT and DDE) or were similar to those observed in other developed countries.

The association between prenatal exposure to organochlorine pesticides and thyroid hormone levels in newborns in Yancheng, China

Organochlorine pesticides can interfere with the thyroid hormones that play an important role in early neurodevelopment. Although organochlorine pesticides have been banned in China since 1983, their residues are still detectable in the environment. However, few studies have investigated the adverse health effects of prenatal exposure to organochlorine pesticide residues on newborns in China. The present study, conducted in Yancheng City, Jiangsu Province, China, aimed to examine the association between the levels of organochlorine pesticides in maternal and cord sera and to assess the impact of prenatal exposure to organochlorine pesticides on thyroid hormone levels in cord serum. Eleven organochlorine pesticides in maternal and cord sera were measured in 247 mother-infant pairs recruited from Yancheng City between February 2010 and June 2010. The concentration of the thyroid hormones free triiodothyronine (FT3), free thyroxine (FT4), and thyrotropin (TSH) were determined in cord serum. Among the 11 tested organochlorine pesticides, the detectable levels of hexachlorobenzene (HCB), β-hexachlorocycolohexane (β-HCH) and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) in both maternal and cord sera were above 50%. The levels of β-HCH and p,p'-DDE in maternal sera were positively associated with the levels in cord sera (r=0.421, P<0.01; r=0.288, P<0.01). After adjusting for confounders, the TSH level in cord serum samples was negatively associated with the HCB level (OR=0.535, 95% CI=(0.304-0.941)). Our data demonstrated that DDT, β-HCH and HCB residues bioconcentrate in maternal and cord sera. Moreover, the correlation analysis suggested that organochlorine pesticides in maternal blood can transfer through the placenta and affect newborn thyroid hormone levels.

Plasma concentrations of persistent organic pollutants in the Cree of northern Quebec, Canada: results from the multi-community environment-and-health study

Historically, resource development has had negative impacts on the traditional lifestyle of First Nation Cree Communities in the Province of Quebec, Canada. In response to the perceived need for fisheries restoration and for managing health concerns associated with environmental pollutants, the Mercury Program in the James Bay Region of Quebec was reconstituted in 2001 and broadened to include a wider range of chemicals of concern. Based on comprehensive surveys of the nine Cree Territory (Eeyou Istchee) communities in this region during the period 2002-2009, blood plasma concentrations are presented of Aroclor 1260, PCB congeners 28, 52, 99, 101, 105, 118, 128, 138, 153, 156, 163, 170, 180, 183, and 187, Aldrin, ß-HCH, α-Chlordane, γ-Chlordane, oxy-Chlordane, trans-Nonachlor, cis-Nonachlor, p,p'-DDT, p,p'-DDE, Hexachloro benzene (HCB), Mirex, PBB 153, PBDE 47, PBDE 99, PBDE 100, PBDE 153, Toxaphene 26, and Toxaphene 50. The organohalogenated compounds were extracted using solid-phase extraction and cleaned on florisil columns before high resolution HRGC-MS analysis. Principal component analysis (PCA) was used to reduce the large number of contaminant variables into a smaller number of uncorrelated variables. ANOVA identified significant differences between age groups, with the older participants having higher body burdens of legacy lipophilic contaminants, but not for the PBDEs. In certain female age groups, plasma concentrations of PBDEs were observed to be lower than for males; conversely, DDT was higher. Among communities, concentrations were different (p<0.001) for all contaminants. This work provides a baseline for the James Bay Eeyou Istchee communities who, to varying degrees, rely on food and other resources from the land and therefore are at higher risk of increased body burdens of legacy persistent organic pollutants (POPs).

Concentrations and potential health hazards of organochlorine pesticides in (shallow) groundwater of Taihu Lake region, China

A total of 27 shallow groundwater samples were collected from the Taihu Lake region (TLR), to determine the concentrations of 14 organochlorine pesticide (OCP) species, identify their possible sources, and estimate health risk of drinking the shallow groundwater. All OCP species occurred in the shallow groundwater of TLR with high detection frequency except p, p'-dichlorodiphenyldichlorothane (p, p'-DDD) and p, p'-dichlorodiphenyltrichloroethane (p, p'-DDT). DDTs and hexachlorocyclohexanes (HCHs) were the dominant OCP contaminants in the shallow groundwater of TLR, and they account for 44.2% total OCPs. The low α-HCH/γ-HCH ratio, high β-HCH/(α+γ)-HCH ratio and β-HCH being the dominant HCH isomers for the majority of samples suggest that the HCHs were mainly from the historical use of lindane after a period of degradation. p, p'-DDE being the dominant DDT metabolite for all the samples indicated that the DDTs were mainly from the historical residues. Compositional analysis also suggested that there were fresh input sources of heptachlors, aldrins and endrins in addition to the historical residues. Correlation analysis indicated the hexachlorobenzene (HCB) impurity in the shallow groundwater of TLR was likely from the historical application of lindane and technical HCH (a mixture of HCH isomers that is produced by photochlorination of benzene). Carcinogenic risk values for α-HCH, heptachlor, heptachlor epoxide, aldrins and dieldrin in the shallow groundwater in majority area of TLR were found to be >10(-6), posing a potentially serious cancer risk to those dependant on shallow groundwater for drinking water.

Human health risks associated with dietary exposure to persistent organic pollutants (POPs) in river water in Korea

Because of their persistence, bioaccumulation tendency, and toxicity, organochlorine pesticides (OCPs) were banned several decades ago. However, they are still detected in natural water and pose a serious risk to human health and the environment. In the present study, seven OCPs were measured in river water collected from 28 sampling sites between 2010 and 2011 in the Yeongsan (YS) and Seomjin (SJ) Rivers, Korea. Gas chromatography/high-resolution mass spectrometry (HRMS) was used for the chemical analysis. The potential health risks of consuming OCPs in fish were assessed in the monitoring region (YS and SJ River basins) by measuring the residual level of OCPs. The human health risks were characterized by considering both the exposure level and the corresponding cancer slope factors; we incorporated both deterministic and probabilistic approaches. The risks were calculated using the probabilistic Maximum Likelihood Estimation (MLE) method. Risk uncertainty and sensitivity were calculated by performing a Monte Carlo analysis. Of the six OCPs, dieldrin, heptachlor epoxide, and hexachlorobenzene exceeded the acceptable risk level in the heavy and light fish consumer groups. The cancer risks associated with these OCPs were 2.99×10(-6), 5.81×10(-6) and 3.72×10(-6), respectively, using the deterministic approach and 1.64×10(-5), 3.36×10(-2) and 5.52×10(-5), respectively, at the 95th percentile using the probabilistic approach. Because there is a high cancer risk associated with these three OCPs, individuals who consume large amounts of freshwater fish may be subject to a high risk of cancer. However, the calculations may have over- or underestimated the risk because of the uncertainty of the environmental concentration and fish intake rate or the use of left-censored monitoring data.

PBDEs, PCBs and organochlorine pesticides distribution in edible fish from Negro River basin, Argentinean Patagonia

DDTs, endosulfans, HCHs, chlordanes, PCBs and PBDEs levels were determined in different tissues of patagonian silverside (Odontesthes hatcheri) from the Upper (UV), Middle (MV) and Lower (LV) valleys of the Negro River, Argentina. Results showed a direct relation between pollutant levels in fish and land uses along the basin. All tissues showed decreasing levels from headwaters (UV) to downstream (LV). A significant predominance of organochlorine pesticides (306-3,449 ng g(-1) lipid) followed by ΣPCBs (65-3,102 ng g(-1) lipid) and ΣPBDEs (22-870 ng g(-1) lipid) was observed in all tissues and valleys, suggesting agriculture as the main source of pollutants in this basin. Pesticides were dominated by DDTs (90% pp'-DDE) followed by endosulfan (α->β->sulfate), γ-HCH and γ-chlordane showing the prevalence of legacy compounds. Endosulfan levels point out the current use of technical endosulfan in the surrounding areas. The highest PCBs and PBDEs concentrations observed in fish from UV were associated to hydroelectric power plants and industries established upstream. PCB fingerprint presented a prevailing contribution of hexa-CBs (66 ± 7%) and penta-CBs (27 ± 9%), with a similar composition to Aroclor 1254-1260. The predominance of BDE-47 (69 ± 17%) among PBDEs, followed by BDE-100 and BDE-99, suggests possible debromination processes. These results were similar to worldwide trends found in fishes and environmental compartments. PCBs levels in silverside muscles along the Negro River exceeded the maximum limits for safe consumption, suggesting a possible human health risk related to silverside ingest. Therefore, a continued long-term monitoring of organic contaminants in fishes is needed in order to assess the potential risk for human health.

Characterising the individual health risk in infants exposed to organochlorine pesticides via breast milk by applying appropriate margins of safety derived from estimated daily intakes

Milk secretion being an important way of elimination of organochlorine pesticides (OCPs) poses a concern due to potential risk for breastfed infants. This study aims to provide a tool for assessing such risks to infants exposed to OCPs (through accumulation in the mother's body), using calculated individual margins of safety (MoS). Selected OCPs included; p,p'-DDT, p,p'-DDD, p,p'-DDE, β-HCH, γ-HCH and HCB which were analysed in 28 samples of maternal milk. The highest intakes were recorded for p,p'-DDE (at 2.90 μg kg(-1)bw d(-1)) whilst the lowest was for γ-HCH, (at 0.019 μg kg(-1)bwd(-1)). For the risk characterisation purposes MoSs were calculated for the compounds for which toxicological reference values (e.g. ADI, TDI) were adopted. The MoS for average ∑DDT concentrations was found to be relatively low (2.82) somewhat similar to that for HCB at 7.08, and for γ-HCH, the MoS was substantially higher at 263.1. This, however does not take into account the extremely high individual concentrations. Thus, it was decided to calculate estimated daily intake (EDI) values based on OCP levels in individual milk samples. MoS levels of <1 (meaning unacceptable risk) were noted both for HCB in one sample as well as for ∑DDT in 3 samples indicating likely threats to infant's health. The lowest MoS noted for γ-HCH equalled to 60.6, indicating that this compound was not a threat to the health of any of the breastfed infants from the study group.

Associations of organochlorine pesticides and polychlorinated biphenyls in visceral vs. subcutaneous adipose tissue with type 2 diabetes and insulin resistance

Background exposure to organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs) has been linked to type 2 diabetes. As OC pesticides and PCBs mainly accumulate in adipose tissue and there are physiological and clinical differences between visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT), we explored if there were associations of OC pesticides and PCBs in VAT or SAT with type 2 diabetes and insulin resistance. Participants were 50 patients with or without type 2 diabetes who underwent surgery for either cancer or benign liver or gallbladder lesions. We analyzed 14 OC pesticides and 22 PCB congeners in both VAT and SAT. Insulin resistance was estimated using homeostasis model assessment (HOMA). Although concentrations of OC pesticides and PCBs were strongly correlated between VAT and SAT, absolute concentrations differed substantially between them. In particular, concentrations of all PCBs were consistently about 5-10 times higher in VAT than SAT, but these patterns were independent of diabetes status. Some OC pesticides or PCBs, such as dichlorodiphenyltrichloroethanes (DDTs), chlordanes, and PCBs with 5 or less chlorides showed significant associations with diabetes or insulin resistance. For example, when tertiles of concentration-based summary measures were used, adjusted ORs were 1.0, 2.3, and 9.0 (P trend=0.02) for DDTs in VAT and 1.0, 2.1, and 5.7 (P trend=0.08) for PCBs with 5 or less chlorides. This study generally confirmed previous findings using serum concentrations. It would be useful to study pharmacodynamics of POPs in VAT and SAT further.

Influence of prenatal exposure to environmental pollutants on human cord blood levels of glutamate

Some chemicals released into the environment, including mercury and some organochlorine compounds (OCs), are suspected to have a key role on subclinical brain dysfunction in childhood. Alteration of the glutamatergic system may be one mechanistic pathway. We aimed to determine whether mercury and seven OCs, including PCBs 138, 153, and 180, DDT and DDE, hexachlorobenzene (HCB), and beta-hexachlorocyclohexane (β-HCH) influence the cord levels of two excitatory amino acids, glutamate and aspartate. Second, we evaluated if this association was mediated by glutamate uptake measured in human placental membranes. The study sample included 40 newborns from a Spanish cohort selected according to cord mercury levels. We determined the content of both amino acids in cord blood samples by means of HPLC and assessed their associations with the contaminants using linear regression analyses, and the effect of the contaminants on glutamate uptake by means of [(3)H]-aspartate binding in human placenta samples. PCB138, β-HCH, and the sum of the three PCBs and seven OCs showed a significant negative association with glutamate levels (decrease of 51, 24, 56 and 54%, respectively, in glutamate levels for each 10-fold increase in the contaminant concentration). Mercury did not show a significant correlation neither with glutamate nor aspartate levels in cord blood, however a compensatory effect between T-Hg and both PCB138, and 4,4'-DDE was observed. The organo-metallic derivative methylmercury completely inhibited glutamate uptake in placenta while PCB138 and β-HCH partially inhibited it (IC50 values: 4.9±0.8 μM, 14.2±1.2 nM and 6.9±2.9 nM, respectively). We conclude that some environmental toxicants may alter the glutamate content in the umbilical cord blood, which might underlie alterations in human development.

Estimation of measurement uncertainty of polychlorinated biphenyls, polycyclic aromatic hydrocarbons and organochlorine pesticides in the atmosphere using gas chromatography-mass spectrometry and gas chromatography-electron capture detector

Estimation of uncertainty of measurement is a crucial issue to achieve accurate measurement results. When the target has adverse environmental and health effects, accuracy of the results become more important. POPs are the pollutants that have toxic effects and unfortunately, there is a lack of information about uncertainty of the method for determining POPs in air samples. In this work, uncertainty calculations were carried out for PCBs, OCPs, and PAHs in air samples analyzed by using GC-MS and GC-ECD. The main dominant sources for combined uncertainty were calibration curve, recovery and repeatability. The relative uncertainties were found to be in the range of 23-52% for PCBs, 24-59% for OCPs and 23-90% for PAHs.

The eggshell features and clutch viability of the broad-snouted caiman (Caiman latirostris) are associated with the egg burden of organochlorine compounds

Organochlorine compounds (OCCs) are toxic and have been identified as endocrine-disrupting chemicals (EDCs). The broad-snouted Caiman (Caiman latirostris) is an oviparous species widely distributed in South America with potential to accumulate OCCs. The eggshell is formed during passage of the eggs through the oviduct. Since the oviduct is a target of hormone actions, exposure to OCCs could modify eggshell quality, thus affecting clutch viability. Eight clutches were collected from wetlands of Parana River tributaries, in north-eastern Argentina. Two to four eggs per clutch were used to establish the burden of OCCs, eggshell thickness and eggshell porosity. The remaining eggs were incubated in controlled conditions. Ten days after hatching, hatchling survival was assessed. Organochlorine pesticide residues (OCPs) were found in all clutches, while polychlorinated biphenyls (PCBs) were present in all but one clutch. The principal contributors to the OCP burden were members of the DDT family and oxychlordane. Eggshell thickness was 400.9±6.0 μm and, unexpectedly, no association between eggshell thickness and the OCC burden was found. The number of pores in the outer surface was 25.3±4.3 pores/cm². A significant inverse correlation between porosity and OCC burden was found (Pearson r= -0.81, p= 0.01). Furthermore, a decrease in caiman survival with decreased pore density was observed (Pearson r= 0.73, p= 0.04). Our findings highlight another potential negative impact of current and past use of OCCs on wildlife species.

Long-term exposure to organochlorine pesticides and thyroid status in adults in a heavily contaminated area in Brazil

Organochlorine (OC) pesticides are endocrine disruptors altering the thyroid hormonal system. The aim of this study is to investigate the relationship between exposure to OC pesticides and thyroid status in adults from a rural area in Rio de Janeiro, Brazil, heavily contaminated with OC pesticides. A cross-sectional study was carried out in 303 men and 305 women >14 years old. Concentrations of 19 OC pesticides and levels of free thyroxine (T4), total triiodothyronine (T3), thyroid-stimulating hormone (TSH), anti-thyroperoxidase (TPOAb) and anti-thyroglobulin (TgAg) antibodies were analyzed in serum samples. Associations between OC pesticides concentrations and values of biochemical thyroid parameters were determined using multivariate regression models stratified by gender. Prevalence of subclinical hyperthyroidism and the presence of TPOAb antibodies were higher than those described for euthyroid populations elsewhere. After adjusting for confounders, total T3 levels were associated with lower concentrations of endosulphan 2 in men and with higher alpha-chlordane, p,p'-dichlorodiphenyltrichloroethane (DDT), endosulphan 2, and methoxychlor in women. Levels of free T4 showed inverse association with beta-hexachlorocyclohexane (HCH) and p,p'-DDT in men, and were positively associated with hexachlorobenzene (HCB), heptachlor, o,p'-DDT, and p,p'-DDT in women. TSH levels were associated with higher beta-HCH in men. A positive association was observed between exposure methoxychlor in males and presence of TPOAb, but no association with TPOAb was found in women. These results suggest that OC pesticides can affect the thyroid system through gender-specific mechanisms that may differ among compounds. Further detailed investigations and health monitoring should be warranted for this population.

Chlordecone fate and mineralisation in a tropical soil (andosol) microcosm under aerobic conditions

Chlordecone is a persistent organochlorine insecticide that, even decades after its ban, poses a threat to the environment and human health. Nevertheless, its environmental fate in soils has scarcely been investigated, and elementary data on its degradation and behaviour in soil are lacking. The mineralisation and sorption of chlordecone and the formation of possible metabolites were evaluated in a tropical agricultural andosol. Soil microcosms with two different soil horizons (S-A and S-B) were incubated for 215 days with 14C-chlordecone. At five different times (1, 33, 88, 150 and 215 days) the extractability of 14C-chlordecone was analysed. Mineralisation was monitored using 14CO2 traps of NaOH. The appearance of metabolites was studied using thin layer and gas chromatography techniques. At the end of the experiment, the water soluble 14C-activity was 2% of the remaining 14C-chlordecone for S-A and 8% for S-B. Only 12% of the remaining activity was non extractable and more than 80% remained extractable with organic solvents. For the first time to our knowledge, a significant mineralisation of chlordecone was measured in a microcosm under aerobic conditions (4.9% for S-A and 3.2% for S-B of the initial 14C-activity). The drastically lower emission of 14CO2 in sterilised microcosms indicated the biological origin of chlordecone mineralisation in the non-sterilised microcosms. No metabolites could be detected in the soil extracts. The mineralisation rate of chlordecone decreased by one order of magnitude throughout the incubation period. Thus, the chlordecone content in the soil remained large. This study confirms the existence of chlordecone degrading organisms in a tropical andosol. The reasons why their activity is restricted should be elucidated to allow the development of bioremediation approaches. Possible reasons are a heterogeneous distribution a chlordecone between sub-compartments with different microbial activities or a degradation of chlordecone by co-metabolic processes controlled by a limited supply of nutrients.

Feasibility of using low density polyethylene sheets to detect atmospheric organochlorine pesticides in Alexandria, Egypt

Egypt is a major agricultural country in Africa with a known past of organochlorine pesticides (OCPs) application, yet data on atmospheric levels of OCPs in Egypt is sparse. Low density polyethylene (LDPE) passive samplers were therefore deployed for 3 weeks each at 11 locations in July, 2010 and January, 2011 in Alexandria to screen for gas-phase OCPs. Performance reference compounds were used to investigate the uptake kinetics. Field-derived sampler-air partitioning coefficients (KPE-As) for OCPs were significantly correlated against the compounds' subcooled liquid vapor pressure (log PL): [log KPE-A = -0.77 ± 0.07 log PL + 6.35 ± 0.13 (R(2) = 0.90; n = 17; SE = 0.19; p < 0.001)]. Estimated and measured OCP concentrations in Alexandria agreed well (factor difference ≤ 2) indicating the feasibility of monitoring OCPs using LDPEs. OCP concentrations ranged from <LOD to 168 pg/m(3). Calculated isomeric ratios indicated recent usage of chlordanes and endosulfans.

Passive air sampling of organochlorine pesticides and polychlorinated biphenyls in the Yangtze River Delta, China: concentrations, distributions, and cancer risk assessment

The Yangtze River Delta (YRD) has been quickly industrialized and urbanized. Passive air sampling of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) was carried out in the YRD in 2010-2011 to investigate their spatiotemporal distributions and estimate the risk of cancer from their inhalation. Annual concentrations were 151, 168, 18.8, 110, 17.9, and 35.0 pg m(-3) for HCB, ∑DDTs, ∑HCHs, ∑chlordane, mirex, and PCBs, respectively. The highest OCP and PCB concentrations were generally detected in the autumn and winter. The average concentrations of OCPs and PCBs for the different site groups followed the order urban ≈ urban-rural transition > rural. The lifetime excess cancer risks from the inhalation of OCPs and PCBs were <1.0 × 10(-6). The predicted cancer cases per lifetime associated with the inhalation of OCPs and PCBs are 12, 7, and 4 per ten thousand people for urban, urban-rural transition, and rural areas, respectively.

Assessing the spatial variability, level and source of organic chemical contaminants in bivalve fishing grounds on the Galician coast (NW Spain)

Polychlorinated biphenyls, organochlorine pesticides, organotin compounds and triazines were quantified in sediments and bivalves collected in four areas on the Galician coast. One or several species were analysed at each site depending on their availability, including mussels (Mytilus galloprovincialis), cockles (Cerastoderma edule), clams (Venerupis pullastra and Ruditapes decussatus) and razor shells (Ensis siliqua). The general spatial distribution of contaminants was consistent in spite of the different sources of contamination. High inter-species variability was also observed. M. galloprovincialis and V. pullastra showed the highest levels of contaminants and intra-spatial variability, which highlights them as suitable species to be used as sentinel organisms. The area of O Burgo showed some worrisome results: PCB sediment concentrations were within the range that could cause biological effects. Also the level of heptachlor observed in V. pullastra was above limits accepted on edible seafood. Finally TBT concentration in mussels correlated with concentrations causing imposex in snails.

Contamination profile of DDT and HCH in surface sediments and their spatial distribution from North-East India

Contamination status and spatial distribution of DDTs and HCHs were investigated in sediments collected from ponds and riverine system from districts Nagaon and Dibrugarh, North East India. A total of 113 surface sediment samples were collected from both the districts including 43 from ponds/wetlands and 70 from rivers/streams. Based on dry weight (dw), the mean concentration of ∑HCH and ∑DDT in sediments were found to be 287 ng/g (71.2-834 ng/g) and 321 ng/g (30.1-918 ng/g) for district Dibrugarh while 330 ng/g (39.2-743 ng/g) and 378 ng/g (72.5-932 ng/g) for district Nagaon, respectively. DDTs and HCHs in sediments were well influenced by total organic carbon, clay and silt content of sediments. Source identification revealed that sediment residue levels have originated from long and recent mixed source of technical HCH and Lindane for HCHs and mainly technical DDT for DDTs. Majority of samples exceeded the sediment quality guidelines (SQG) for γ-HCH, p,p'-DDT and ∑DDT indicating potential environmental risk. This baseline data can be used as reference for regular ecological and future POPs monitoring program.