Antillean contaminated soils amendment with microwave prepared sargassum biochar: A promising solution to reduce chlordecone transfer to laying hens and piglets?

The use of Sargassum spp., a brown invasive algae, for the production of biochars (BCs) or activated carbons (ACs) and their efficiency to sequestrate chlordecone (CLD) in soil has been recently suggested. The objective of this study was to assess the potential of microwave prepared Sargasso biochar (BCS) amendment in Andosol on the bioavailability of chlordecone in laying hens and piglets, when exposed to this matrix. The efficiency of BCS was compared to a commercial activated carbon, DARCO® (ACD), used as a positive control and to an unamended soil. Samples of CLD-contaminated Andosol were amended with 2% of each carbonaceous matrix and let maturing for 3 months. Thereafter, adequate doses of soil were administered into the laying hens and piglets diets every day during the exposure phase, to simulate involuntary soil ingestion which may happen in practical conditions when animals are reared outside. Finally, bioavailability tests were carried out on target tissue (liver, muscle, adipose tissues and egg yolk). The results showed that the highest reduction of CLD bioavailability was obtained with ACD in both animal species. For laying hens, ACD showed reductions of around 60% (liver: 59%, muscle: 57% and egg yolk: 56%) whereas the BCS showed reduction of around 30% (liver: 31%, muscle: 26% and egg yolk: 30%) compared to the unamended soil. For piglets, only the liver showed interpretable results with reduction of 65% with ACD and 41% with BCS. Overall, BCS is efficient reducing CLD availability but in a lower extend than ACD. This discrepancy may be explained by the variations of physico-chemical characteristics that exist between the two matrices, resulting, from the additional activation phase for DARCO®. Therefore, to improve the efficiency of BCS it would be interesting to move towards DARCO® characteristics by determining out the optimal microwave pyrolysis parameters.

Fate of chlordecone during home cooking processes - Transfer into the liquid and aerial phases by conventional thermal processes

This study focuses on the fate of chlordecone (CLD) during cooking processes. Neat CLD was subjected to thermogravimetric analysis, which revealed that the vast majority of the compound (79 %) was vaporised at temperatures between 55 and 245 °C. In order to monitor the behaviour of CLD during cooking processes, a QuEChERS extraction protocol was optimised for vegetable cooking oil and a heating kinetics experiment was conducted at 195 °C on CLD-spiked cooking oil. The results showed a strong decrease in CLD over time and, for the first time to our knowledge, transformation of CLD into chlordecol. Finally, a comparison was conducted between the cooking of uncured pork with and without vegetable oil. The use of vegetable oil led to a significant decrease in CLD content, but revealed that a fraction of the CLD transferred into the cooking oil. This study provides data that shed light on the fate of CLD during cooking.

Optimization of an HPLC-MS/MS method to analyze chlordecone in bovine serum and correlations with levels in liver, muscle and fat

Chlordecone is an organochlorine pesticide used from 1972 to 1993 in the French West Indies. Its extensive use and high persistence in soils induced massive contamination of the environment and of the food chain, especially in cattle through contaminated soil ingestion. To ensure suitability for consumption of bovine meat, monitoring plans are set up based on perirenal fat concentrations after slaughtering. In the present study, we have investigated an in-vivo monitoring approach by measuring chlordecone levels in serum samples. For this purpose, a sensitive high-performance liquid-chromatography-tandem mass spectrometry (HPLC-MS/MS) method following a QuEChERS extraction method was successfully optimized and validated, reaching a limit of quantification of 0.05 ng g-1 fresh weight. This method was applied to 121 serum samples collected from bovines originating from contaminated areas of Martinique and Guadeloupe. Chlordecone was detected in 88% of the samples, and quantified in 77% of the samples, with concentrations ranging from 0.05 to 22 ng g-1. Perirenal fat, liver, and muscle were also sampled on the same animals and the measured concentrations of chlordecone were statistically correlated to the levels determined in serum. Mean concentration ratios of 6.5 for fat/serum, 27.5 for liver/serum, and 3.3 for muscle/serum were calculated, meaning that chlordecone was not only distribute in fat (as expected), muscle and liver, but also in serum. Good correlations were found to allow prediction of chlordecone concentrations in muscle based on concentrations measured in serum. This study opens the door to possible pre-control of bovines before slaughter. In cases of probable non-compliance with maximum residue levels (MRLs), farm management could proceed to allow for depuration under controlled conditions. This would have a strong impact on both economic and food safety management measures.

Inverse association between plasma chlordecone concentrations and progression of alcoholic liver fibrosis: the role of liver metabolism

BACKGROUND AND AIMS

Chlordecone is a persistent organochlorinated insecticide, extensively used in the French West Indies and has been contaminating the population for more than thirty years. Its potentiation effect on hepatotoxic agents has been demonstrated in animal models. We investigated the relationship between environmental exposure to chlordecone and the progression of liver fibrosis.

METHODS

This study included 182 consecutive patients with chronic alcoholic hepatitis whose liver fibrosis was assessed using non-invasive methods. Measured plasma chlordecone concentrations at inclusion were used as surrogate of long-term exposure under steady-state conditions. As the pharmacokinetic processing of chlordecone is largely determined by the liver, we used a human physiologically based pharmacokinetic model to predict plausible changes in the steady-state blood chlordecone concentrations induced by liver fibrosis.

RESULTS

With a median follow-up of 27.1 years after the onset of alcohol consumption, we found a significant decrease in the risk of advanced liver fibrosis with increasing plasma chlordecone concentration (adjusted hazard ratio = 0.56; 95% confidence interval: 0.34-0.95 for the highest vs. lowest tertile, p = 0.04). Changes induced by liver fibrosis influenced the pharmacokinetic processing of chlordecone, resulting in substantial modifications in its steady-state blood concentrations.

CONCLUSION

According to this human model of coexposure to alcohol, reverse causality is the most plausible explanation of this inverse association between plasma chlordecone concentrations and progression of liver fibrosis. This study underlines the importance of considering the pharmacokinetic of environmental contaminants in epidemiological studies when biomarkers of exposure are used to investigate their own impact on the liver.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03373396.

Microwave-enhanced thermal removal of organochlorine pesticide (chlordecone) from contaminated soils

Soil contamination with chlordecone, an organochlorine pesticide, is causing serious health problems, affecting crop production and local livestock valorization in the French West Indies. In-situ chemical reduction (ISCR) processes for soil remediation have shown promise but need improvement in terms of time, cost and effective treatment, particularly for andosol soil types. Our study shows that a 10-min microwave treatment significantly reduces chlordecone concentrations (50-90%) in contaminated andosol and nitisol soils. Dry andosol soils show the highest removal yields and reach a higher final temperature (350 °C). Microwave treatment is in all cases more effective or at least as effective as 60 min of conventional heating at a target temperature of 200 °C. The thermal response of andosol and nitisol to microwave exposure is different, as the former is likely to undergo thermal runaway, reaching high temperatures in a short time, resulting in highly efficient thermal removal of chlordecone. These results encourage further scale-up, particularly for the treatment of andosol soils due to their strong microwave response.

Efficient biodegradation of the recalcitrant organochlorine pesticide chlordecone under methanogenic conditions

Anaerobic digestion (AD) has long been studied as an effective environmental and economic strategy for treating matrices contaminated with recalcitrant pollutants. In the present work, we investigated the bioremediation potential of AD on organic waste contaminated with chlordecone (CLD), an organochlorine pesticide extensively used in the French West Indies and classified among the most persistent organic pollutants. Digestates from animal and plant origins were supplemented with CLD and incubated under methanogenic conditions for over 40 days. The redox potential and pH monitoring showed that methanogenic conditions were preserved during the entire incubation period despite the presence of CLD. In addition, the comparison of the total biogas generated from digestates with and without CLD demonstrated no adverse effects of CLD on biogas production. For the first time, a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction method, followed by GC-MS and LC-HRMS analyses, was developed to quantify CLD and its main known transformation products (TPs) in AD experiments. A decrease in CLD concentrations was evident to a greater extent under thermophilic conditions (55 °C) compared to mesophilic conditions (37.5 °C) (CLD removal of 85 % and 42 %, respectively, after 40 days of incubation). CLD degradation was confirmed by the detection and quantification of several TPs: 10-monohydroCLD (A1), two dihydroCLDs different from 2,8-dihydroCLD (A3), pentachloroindene (B1), tetrachloroindenes (B2, B3/B4), tetra- and tri-chloroindenecarboxylic acids (C1/C2, C3/C4). Determining TPs concentrations using the QuEChERS method provided an overview of CLD fate in AD. Overall, these results reveal that AD processes can efficiently degrade CLD into several TPs from A, B, and C families while maintaining satisfactory biogas production. They pave the way to developing a scaled-up AD process capable of treating CLD-contaminated organic wastes produced by farming, thus stopping any further transfer of CLD.

Chlordecone determination in serum by LC-MS/MS and the importance of low limit of detection

Chlordecone is an organochlorine insecticide that has been used intensively from 1973 to 1993 in the French West Indies banana fields to control root borers. This use has resulted in persistent pollution of soils and waters, and people have been and are still exposed mainly through food. Epidemiological studies showed that this exposure is associated with health disorders, including prostate cancer, prematurity, cognitive or motor development. The measurement of chlordecone in serum is considered as the best surrogate, though no clear and definitive cut-off value has been established. This renders necessary the development of analytical methods with the lowest limit of detection as possible. While most published methods have utilized GC-MS or GC-MS/MS, in the present study we report an LC-MS/MS method based on a simple QuEChERS salts extraction. The whole procedure was validated according to ISO 15189 requirements and reached LOD and LOQ values of 0.007 and 0.02 µg/L, respectively. It was applied to more 10 000 serum samples of French Indies inhabitants. More than a half had a concentration below 0.1 µg/L and more than one third of them exhibiting a concentration below 0.05 µg/L. The capability of this LC-MS/MS method to detect very low concentrations highlights its utility in exploring the health impact of chlordecone.

Validation of an HPLC-MS/MS method with QuEChERS extraction using isotopic dilution to analyze chlordecone in human serum

Until 1993, chlordecone (CLD) was extensively used in banana fields in French West Indies. In a previous study, CLD was detected in 90 % of Martinican and Guadeloupean adult's serum. In order to simplify the analyses of CLD in the serum, a new QuEChERS-HPLC-MS/MS method was implemented and validated by the Pasteur Institute of Guadeloupe (IPG). This method was validated with accuracy profiles according to the French Standard NF V03-110 plus the ISO 15189 and European guidelines. Linearity, repeatability, accuracy, intermediate precision, specificity, limit of detection (LOD), limit of quantification (LOQ) and uncertainty were determined. The accuracy profile allowed the method to be validated between 0.06  µg L-1 and 1.00  µg L-1 of serum. The LOD was 0.02  µg L-1, the LOQ was 0.06  µg L-1 and the uncertainty of the method was 21 %. A comparison of 49 serum samples between the IPG (LC-MS/MS) and the LEAE-CART (GC-HRMS) laboratories demonstrated that this new method can reliably determine CLD in human serum. Stability tests were performed and duration of the storage of raw samples and extracts before analysis by HPLC-MS/MS. Raw samples were stable after collection for at least one week at 5 °C or 25 °C and for at least 3 months at -20 °C. Extracts in acetonitrile were stable for at least 1 month at -20 °C. These stability results facilitate the daily use of the method. This method should help the entire population of Guadeloupe and Martinique by allowing a routinely analyzed for CLD and will be useful for future projects aimed at improving population health monitoring.

Flow patterns and pathways of legacy and contemporary pesticides in surface waters in tropical volcanic catchments

Severe water pollution issues due to legacy and contemporary pesticides exist in tropical regions and are linked to cash crops requiring intensive plant protection practices. This study aims to improve knowledge about contamination routes and patterns in tropical volcanic settings to identify mitigation measures and analyse risk. To this aim, this paper analyses four years of monitoring data from 2016 to 2019 of flow discharge and weekly pesticide concentrations in the rivers of two catchments grown predominantly with banana and sugar cane in the French West Indies. The banned insecticide chlordecone, applied in banana fields from 1972 to 1992, was still the major source of river contamination, while the currently used herbicide glyphosate, its metabolite aminomethylphosphonic acid (AMPA), and postharvest fungicides also exhibited high contamination levels. A value of 0.5 of the Gustafson Ubiquity Score (GUS) was shown to separate contaminant and noncontaminant pesticides, indicating a high vulnerability to pollution by pesticides in this tropical volcanic context. The patterns and routes of river exposure to pesticides differed markedly between the pesticides in accordance with the hydrological behaviour of volcanic islands and the history and nature of pesticide uses. Concerning chlordecone and its metabolites, observations confirmed previous findings of a main subsurface origin of river contamination by this compound but also showed large erratic short-term variations, suggesting the influence of fast surface transport processes such as erosion for legacy pesticides with large sorption capacity. Concerning herbicides and postharvest fungicides, observations have suggested that surface runoff and fast lateral flow in the vadose zone control river contamination. Accordingly, mitigation options need to be considered differently for each type of pesticide. Finally, this study points out the need for developing specific exposure scenarios for tropical agricultural contexts in the European regulation procedures for pesticide risk assessment.

Is a dissipation half-life of 5 years for chlordecone in soils of the French West Indies relevant?

Recently, Comte et al. (2022) re-examined the natural degradation of chlordecone (CLD) in the soils of the French West Indies (FWI) by introducing an additional 'dissipation parameter' into the WISORCH model developed by Cabidoche et al. (2009). Recent data sets of CLD concentrations in FWI soils obtained by Comte et al. enabled them optimizing the model parameters, resulting in significantly shorter estimates of pollution persistence than in the original model. Their conclusions jeopardize the paradigm of a very limited degradation of CLD in FWI soils, which may lead to an entire revision of the management of CLD contamination. However, we believe that their study is questionable on several important aspects. This includes potential biases in the data sets and in the modeling approach. It results in an inconsistency between the estimated dissipation half-life time (DT50) of five years that the authors determined for CLD and the fate of CLD in soil from the application period 1972-1993 until nowadays. Most importantly, a rapid dissipation of CLD in the field as proposed by Comte et al. is not sufficiently supported by data and estimates. Hence, the paradigm of long-term persistence of CLD in FWI soils is still to be considered.

Prenatal and childhood chlordecone exposure, cognitive abilities and problem behaviors in 7-year-old children: the TIMOUN mother-child cohort in Guadeloupe

BACKGROUND

Chlordecone is a highly persistent organochlorine insecticide that was intensively used in banana fields in the French West Indies, resulting in a widespread contamination. Neurotoxicity of acute exposures in adults is well recognized, and empirical data suggests that prenatal exposure affects visual and fine motor developments during infancy and childhood, with greater susceptibility in boys.

OBJECTIVE

To assess the associations between pre- and postnatal exposures to chlordecone and cognitive and behavioral functions in school-aged children from Guadeloupe.

METHODS

We examined 576 children from the TIMOUN mother-child cohort in Guadeloupe at 7 years of age. Concentrations of chlordecone and other environmental contaminants were measured in cord- and children's blood at age 7 years. Cognitive abilities of children were assessed with the Wechsler Intelligence Scale for Children-IV (WISC-IV), and externalizing and internalizing problem behaviors documented with the Strengths and Difficulties Questionnaire (SDQ) completed by the child's mother. We estimated covariate-adjusted associations between cord- and 7-years chlordecone concentrations and child outcomes using structural equations modeling, and tested effect modification by sex.

RESULTS

Geometric means of blood chlordecone concentrations were 0.13 µg/L in cord blood and 0.06 µg/L in children's blood at age 7 years. A twofold increase in cord blood concentrations was associated with 0.05 standard deviation (SD) (95% Confidence Interval [CI]: 0.0, 0.10) higher internalizing problem scores, whereas 7-years chlordecone concentrations were associated with lower Full-Scale IQ scores (FSIQ) and greater externalized behavioral problem scores. A twofold increase in 7-year chlordecone concentrations was associated with a decrease of 0.67 point (95% CI: -1.13, -0.22) on FSIQ and an increase of 0.04 SD (95% CI: 0.0, 0.07) on externalizing problems. These associations with Cognitive abilities were driven by decreases in perceptive reasoning, working memory and verbal comprehension. Associations between 7-year exposure and perceptive reasoning, working memory, and the FSIQ were stronger in boys, whereas cord blood and child blood associations with internalizing problems were stronger in girls.

CONCLUSIONS

These results suggests that cognitive abilities and externalizing behavior problems at school age are impaired by childhood, but not in utero, exposure to chlordecone, and that prenatal exposure is related to greater internalizing behavioral problems.

Fluorescence Detection of the Persistent Organic Pollutant Chlordecone in Water at Environmental Concentrations

Chlordecone (CLD), a Persistent Organic Pollutant, is still present in water and food chain of the French West Indies (FWI), leading to dramatical public health problems. One of the major issues is the lack of an easy, non-expensive, sensitive and robust method for the detection of chlordecone to ensure chlordecone-free water and foods for the residents of the FWI. Here we report on the development of a fluorescent molecular cage that allows a simple and convenient detection of chlordecone in water at environmental concentration. The specific structural features of chlordecone prompted us to choose hemicryptophanes as receptor. First, we optimized the size, shape of the cavity, as well as the recognition units, to identify the most efficient non fluorescent host for CLD complexation. Then, this selected compound was equipped with fluorophores at different positions in order to find the most efficient system for CLD detection by fluorescence. Among the two most promising fluorescent cages, the newly synthesized hemicryptophane with biphenyl moieties allowed us to develop a fast, easy, reproducible and cheap procedure to detect CLD in water. Its sensitivity and scalability, with modulation of hemicryptophane concentration enabled us to estimate CLD concentrations over five orders of magnitude (10-2 - 103 µg/L) including the environmental levels of contamination and the permissible limit for drinking water in the FWI.

Effects of particle size and amendment rates of Sargassum biochar on chlordecone sequestration in West Indian soils

The use of biochars (BCs) and activated carbons as a way of sequestering soil-bound pollutants such as chlordecone (CLD) is increasingly being studied. This study aims at assessing the impact of Sargassum BC/AC particle size and Sargassum BC amendment rate on CLD adsorption in Nitisol and in Andosol. Four different types of carbonaceous matrices were tested: Sargasso carbon activated by phosphoric acid (SargH3PO4), Sargasso carbon activated by steam (SargH2O), biochar of Sargasso (Ch Sarg700), and a commercial activated carbon (ORBO™). In a first experiment, CLD contaminated Andosol and Nitisol were amended with 2% of each carbonaceous matrix divided into four particles size classes (< 50 µm, 50-150 µm, 150-200 µm, and > 200 µm). In a second experiment, the contaminated soils were amended with the biochar of Sargasso at five application rates (0, 0.25, 0.5, 1, and 2% (w/w)). After a 4-month aging, environmental availability tests were carried out on the soils of both experiments. The results of the first experiment showed that the best reductions of CLD environmental availability were obtained in both soils with the biochar of Sargasso and the ORBO™. More specifically, in nitisol, particle size under 50 µm of biochar of Sargasso and AC ORBO™ showed a CLD environmental availability reduction up to 72 ± 2.6% and 79 ± 2.6%. In Andosol, there was no significant difference between the three particle sizes (< 50 µm, 50-150 µm, and 150-200 µm) of the biochar of Sargasso on the reduction of environmental availability (average reduction of 43 ± 2.5%). The results of the second experiment showed that an amendment rate increase improves the immobilization of CLD. When the amendment rate was increased from 0.25 to 2%, the environmental availability was reduced by 43% in Nitisol and 50% in Andosol.

Soil ingestion, a key determinant of exposure to environmental contaminants. The case study of chlordecone exposure in free-range pigs in the French West Indies

Ingested soil may expose free-range animals to environmental pollutants. In pigs, soil ingestion is few described whereas their burrowing behaviour suggests that it could be high. Although highly productive pigs are generally reared indoor, free-range farming is increasing in view of ethical considerations for animal welfare and is a common practice for subsistence agriculture systems. The experiment lasted 8 weeks (2 for adaptation, 6 for measurements) with 24 growing pigs of Guadeloupean Creole (CR) or Large White (LW) breeds. Pigs were assigned to 3 outdoor treatments: high pasture HP (>60 days of regrowth), low pasture LP (35 days of regrowth), and sweet potato SP (sweet potato field). Titanium (soil marker) and chromium (faecal output marker) contents of faeces, vegetation and soil samples were used to estimate individual daily soil ingestions. The average, 10th and 90th percentiles were 440, 200 and 726 g of dry soil per 100 kg body weight, respectively, without significant differences between the 3 outdoor treatments or the 2 breeds but with a significant period (i.e. week of measurements) × treatment interaction (P < 0.001). In the French West Indies, animals may be exposed to chlordecone (CLD), a very persistent organochlorine insecticide. Simulations of CLD tissue contamination due to ingestion of contaminated soil were carried out and compared to the maximum residue limit. These results show that grazing management needs to be adapted to effectively limit soil ingestion by pigs and the impact of a contaminated environment on the sustainability of pig systems.

Organochlorine POPs sequestration strategy by carbonaceous amendments of contaminated soils: Toward a better understanding of the transfer reduction to laying hens

PCBs, PCDD/Fs, and Chlordecone (CLD) are POPs found in soils and transferred to animals through involuntary soil ingestion. In this frame, the amendment of contaminated soil with porous matrices, like Biochars (BCs) and Activated Carbons (ACs), is a promising technique for reducing this transfer. In this study, the efficiency of 3 biochars and 3 activated carbons was assessed by amending 2% (by weight) of these matrices on (i) CLD or (ii) PCBs and PCDD/Fs contaminated artificial soils. Porosity of the carbon-based materials and molecules physico-chemical characteristics were then linked to the obtained results. The concentrations of pollutants were then measured in the egg yolks of laying hens (n = 3), which were fed on a daily basis pellets containing 10% of soil for 20 days. Overall, no significant transfer reduction was observed with the biochar and the granular AC amendments for all the compounds. However, significant reductions were obtained with the two efficient activated carbons for PCDD/Fs and DL-PCB up to 79-82% (TEQ basis), whereas only a slight reduction of concentrations was obtained with these activated carbons for CLD and NDL-PCBs. Thus, (i) biochars were not proven efficient to reduce halogenated pollutants transfer to animals, (ii) powdered AC amendments resulted in reducing the bioavailability of soil POPs, and (iii) the effectiveness of such strategy depended on both characteristics of the matrix and of the pollutants.

Chlordecone-contaminated epilithic biofilms show increased adsorption capacities

The rivers of Guadeloupe and Martinique (French West Indies) show high levels of chlordecone (CLD) contamination. This persistent molecule has a dramatic impact on both aquatic ecosystems and human health. In these rivers, epilithic biofilms are the main endogenous primary producers and represent a central food source for fish and crustaceans. Recently, their viscoelastic properties have been shown to be effective in bio-assessing pollution in tropical environments. As these properties are closely related to the biochemical composition of the biofilms, biochemical (fatty acids, pigments, extracellular polymeric substances (EPS) monosaccharides) and molecular markers (T-RFLP fingerprints of bacteria, archaea and eukaryotes) were investigated. Strong links between CLD pollution and both biofilm biochemistry and microbial community composition were found. In particular, high levels of CLD were linked with modified exo-polysaccharides corresponding to carbohydrates with enhanced adsorption and adhesion properties. The observed change probably resulted from a preferential interaction between CLD and sugars and/or a differential microbial secretion of EPS in response to the pollutant. These changes were expected to impact viscoelastic properties of epilithic biofilms highlighting the effect of CLD pollution on biofilm EPS matrix. They also suggested that microorganisms implement a CLD scavenging strategy, providing new insights on the role of EPS in the adaptation of microorganisms to CLD-polluted environments.

In vitro and in vivo assessment of a CLD sequestration strategy in Nitisol using contrasted carbonaceous materials

Chlordecone (Kepone) (CLD) is a highly persistent pesticide formerly used in the French West Indies. High levels of this pesticide may be found in soils and constitute a subsequent source of contamination for outdoor-reared animals due to involuntary ingestion of consistent amounts of soil. In that context, carbonaceous materials may be used to amend soil to efficiently decrease the bioavailability of such organic pollutants. The present study aims to assess the efficiency of diverse amendments of a contaminated Guadeloupe nitisol using two physiologically based approaches. A set of 5 carbonaceous materials (ORBO, DARCO, Coco CO2, Oak P1.5, Sargasso biochar) was tested and used to amend Nitisol at 2% (mass basis). Bioaccessibility assessment was performed using the Ti-PBET assay (n = 4). The relative bioavailability part involved 24 piglets randomly distributed into 6 experimental groups (n = 4). All groups were exposed during 10 days to a contaminated soil, amended or not with carbon-based matrices. A significant decrease in relative bioaccessibility and CLD concentrations in liver were observed for all amended groups in comparison to the control group, with the exception of the biochar amended soil in the bioaccessibility assay (p < 0.05). Extent of this reduction varied from 22 to more than 82% depending on the carbonaceous matrix. This decrease was particularly important for the ORBO™ activated carbon for which bioaccessibility and relative bioavailability were found lower than 10% for both methodologies.

Prenatal and childhood exposure to chlordecone and adiposity of seven-year-old children in the Timoun mother-child cohort study in Guadeloupe (French West Indies)

BACKGROUND

Exposure to persistent environmental organic pollutants may contribute to the development of obesity among children. Chlordecone is a persistent organochlorine insecticide with estrogenic properties that was used in the French West Indies (1973-1993) and is still present in the soil and the water and food consumed by the local population. We studied the association between prenatal and childhood exposure to chlordecone and the adiposity of prepubertal children.

METHODS

Within the Timoun Mother-Child Cohort Study in Guadeloupe (French West Indies), 575 children had a medical examination at seven years of age, including adiposity measurements. A Structural Equation Modeling approach was used to create a global adiposity score from four adiposity indicators: the BMI z-score, percentage of fat mass, sum of the tricipital and subscapular skinfold thickness, and waist-to-height ratio. Chlordecone concentrations were measured in cord blood at birth and in the children's blood at seven years of age. Models were adjusted for prenatal and postnatal covariates. Sensitivity analyses accounted for co-exposure to PCB-153 and pp'-DDE. Mediation analyses, including intermediate birth outcomes, were conducted.

RESULTS

Prenatal chlordecone exposure tended to be associated with increased adiposity at seven years of age, particularly in boys. However, statistical significance was only reached in the third quartile of exposure and neither linear nor non-linear trends could be formally identified. Consideration of preterm birth or birth weight in mediation analyses did not modify the results, as adjustment for PCB-153 and pp'-DDE co-exposures.

CONCLUSION

Globally, we found little evidence of an association between chlordecone exposure during the critical in utero or childhood periods of development and altered body-weight homeostasis in childhood. Nevertheless, some associations we observed at seven years of age, although non-significant, were consistent with those observed at earlier ages and would be worth investing during further follow-ups of children of the Timoun Mother-Child Cohort Study when they reach puberty.

Chlordecone: development of a physiologically based pharmacokinetic tool to support human health risks assessments

Chlordecone (CD; Kepone™) is a carcinogenic organochlorine insecticide with neurological, reproductive, and developmental toxicity that was widely used in the French West Indies (FWI) from 1973 to 1993 to fight banana weevils. Although CD has not been used there for more than 25 years, it still persists in the environment and has polluted the waterways and soil of current and older banana fields. Today, human exposure to CD in the FWI mainly arises from consuming contaminated foodstuffs. The aims of this study were to develop a physiologically based pharmacokinetic (PBPK) model in the rat and extrapolate it to humans based on available pharmacokinetic data in the literature. A comparison of simulations using the rat model with published experimental datasets showed reasonable predictability for single and repetitive doses, and, thus, it was extrapolated to humans. The human PBPK model, which has seven compartments, is able to simulate the blood concentrations of CD in human populations and estimate the corresponding external dose using the reverse dosimetry approach. The human PBPK model will make it possible to improve quantitative health risk assessments for CD contamination and reassess the current chronic toxicological reference values to protect the FWI population.

Visuospatial processing and fine motor function among 7-years old Guadeloupe children pre- and postnatally exposed to the organochlorine pesticide chlordecone

BACKGROUND

Chlordecone is an organochlorine that was largely used as an insecticide to control a species of root borers, the Banana weevil (Cosmopolites sordidus), in the French West Indies, Guadeloupe and Martinique. Its molecules have been shown to be very persistent in the environment as pollution in soils leading to contamination of water sources and foodstuff will last for several decades. Our team previously reported associations between prenatal chlordecone exposure and poorer fine motor development at two points in time during infancy.

OBJECTIVE

To document whether effects of prenatal exposure to chlordecone previously reported persists until middle-childhood, and whether deleterious effects are observed in domain of visual processing. Associations with postnatal exposure and sex-specific vulnerabilities were also investigated.

METHODS

We examined 410 children from the TIMOUN mother-child cohort in Guadeloupe at 7 years of age. Concentrations of chlordecone and other environmental contaminants were measured in cord- and children's blood at age 7 years. Fine motor function was assessed using the Bruininks Oseretsky Test of Motor Proficiency Second Edition (BOT-2). The Computerized Adaptive Testing System (CATSYS) was used to evaluated postural hand tremor, while non-verbal visuospatial processing was measured using the Stanford Binet copying (S-B copying) test. We used adjusted multiple linear regressions to test the relationship between children's scores and both continuous and categorical blood chlordecone concentrations, adding child sex as a moderator in continuous models.

RESULTS

Cord chlordecone concentrations are associated with a regular frequency pattern of subtle hand tremors in both hands, and not related to visual processing and fine motor precision. Chlordecone concentrations in blood sample collected at testing time are associated with poorer visual processing when copying geometric figures, but not significantly related to poorer fine movement precision in tasks requiring pencil, scissors and paper. No sex-specific vulnerability was reported in any of the outcomes.

CONCLUSIONS

These results at school aged expand those previously reported in the same cohort during infancy at age 7- and 18 months, and corroborate the negative effects of chlordecone exposure on fine motor function in absence of intoxication. Our results support the need to continue public health efforts aimed at reducing exposure especially among women of child bearing age and young children.

Characterization and quantification of chlordecone elimination in ewes

To reduce the exposure of the French West Indies population to the organochlorine insecticide chlordecone (Kepone; CLD), the contamination of currently consumed foodstuffs must be reduced. Depuration of contaminated animals before slaughter could be a strategy to obtain safe animal products. The aim of this study was to characterize and quantify CLD elimination in contaminated ewes during depuration process. Experiments A and B consisted in a single intravenous (i.v.) administration of CLD (n = 5) and CLDOH (chlordecol; n = 3) followed by a 84-d and 3-d depuration period respectively with collection of blood, faeces and urine samples. After CLD administration, CLD and conjugated-CLDOH (CLDOH-C) were quantified in serum and urine and CLD and CLDOH were quantified in faeces. Based on calculations of faecal, urinary and body clearances of CLD and CLDOH-C, faeces appeared as the major route of CLD excretion with 86 % of the CLD administered dose eliminated in faeces, either as CLD (51 %) or as CLDOH (35 %).

Correlation between endemic chlordecone concentrations in three bovine tissues determined by isotopic dilution liquid chromatography-tandem mass spectrometry

Chlordecone (CLD) is an organochlorine pesticide widely used from the 1970s to the 1990s in the French West Indies that induced long-term pollution of the ecosystem. Due to involuntary soil ingestion, some species bred in open-air areas can be contaminated. As CLD is distributed in various tissues depending on the breeding species, this study focuses on the distribution of CLD in bovines. For this purpose, three tissues, i.e. fat, muscle, and liver, from 200 bovines originating from Martinique and Guadeloupe were sampled in 2016 to determine their endemic contamination levels. Analyses were performed with the official method for veterinary controls, isotopic dilution liquid chromatography-tandem mass spectrometry, which has been fully validated and which reaches a limit of quantification of 3 μg.kg^-1 fresh weight (fw). Irrespective of the matrices, CLD was detected in 68% of samples (404 samples above the LOD) and quantified in 59% of samples (332 samples above the LOQ). Regarding contamination levels, the liver had a broader range of concentrations (LOQ up to 420.6 μg.kg^-1 fw) than fat (LOQ up to 124.6 μg.kg^-1 fw) and muscle (LOQ up to 67.6 μg.kg^-1 fw). This confirms the atypical behaviour of CLD compared to other persistent organochlorine pollutants. Statistical processing demonstrated a correlation between CLD concentrations among the three studied tissues. The CLD concentration ratios were 0.54 for muscle/fat, 3.75 for liver/fat, and 0.14 for muscle/liver.

Characterization of chlordecone distribution and elimination in ewes during daily exposure and depuration

To reduce the exposure of the French West Indies population to the pollutant chlordecone (CLD), the contamination of consumed products must be reduced. One of the strategies to secure safe animal products is related to the depuration of contaminated animals. In order to set up this strategy in situ, characterizing CLD distribution and elimination appears to be essential. The aim of this study is to characterize CLD distribution and elimination in ewes, and establish correlations between CLD concentrations in tissues following a continuous oral contamination period and a depuration period. The experiment consisted in a 90-d period of CLD exposure via daily feeding at 0.01 mg kg^-1 body weight, followed by a 127-d period of depuration. A total of 24 ewes were sequentially slaughtered and serum, liver, perirenal fat, subcutaneous fat, shaft muscle, longissimus dorsi muscle and heart samples were collected. CLD concentrations in serum and tissues were analyzed by GC-MS/MS and LC-MS/MS, respectively. Whatever the time of sampling, CLD concentrations in liver were significantly higher than in other collected tissues. However, the results showed that fat tissues stored the higher portion of CLD body burden, followed by muscle, liver, serum and heart. CLD half-lives did not differ significantly between tissues including serum and ranged between 20.2 ± 4.0 and 24.1 ± 4.9 d. Two linear models were developed to estimate CLD concentration in tissues from a blood sample. This study illustrates the theoretical methodology to estimate the time required to decontaminate farm animals from a blood sample.

Developmental exposure to chlordecone induces transgenerational effects in somatic prostate tissue which are associated with epigenetic histone trimethylation changes

BACKGROUND

Chlordecone (CD), also known as Kepone, is an organochlorine insecticide that has been used in banana crops in the French West Indies. Due to long-term contamination of soils and water, the population is still exposed to CD. Exposure to CD in adulthood is associated with an increased risk of prostate cancer (PCa).

OBJECTIVES

We examined the transgenerational effects of CD on murine prostate tissue.

METHODS

We exposed pregnant Swiss mice to CD. The prostates from directly exposed (F1) and non-exposed (F3) male progeny were analyzed. We used immunofluorescence, RNA-seq and ChIP-seq techniques for the comprehensive analyses of chromatin states in prostate.

RESULTS

We observed an increased prostatic intraepithelial neoplasia phenotype (PIN) in both F1 and F3 generations. Transcriptomic analysis in CD-derived F1 and F3 prostate using RNA-seq revealed that 970 genes in F1 and 218 in F3 genes were differentially expressed. The differentially expressed genes in both datasets could be clustered accordingly to common biological processes, "cell differentiation", "developmental process", "regulating of signaling", suggesting that in both generations similar processes were perturbed. We detected that in both datasets several Hox genes were upregulated; in F1, the expression was detected mainly in Hoxb and Hoxd, and in F3, in Hoxa family genes. Using a larger number of biological replicates and RT-qPCR we showed that genes implicated in testosterone synthesis (Akr1b3, Cyp11a1, Cyp17a1, Srd5a1) were dramatically upregulated in PIN samples; Cyp19a1, converting testosterone to estradiol was elevated as well. We found a dramatic increase in Esr2 expression both in F1 and F3 prostates containing PIN. The PIN-containing samples have a strong increase in expression of self-renewal-related genes (Nanog, Tbx3, Sox2, Sox3, Rb1). We observed changes in liver, F1 CD-exposed males have an increased expression of genes related to DNA repair, matrix collagen and inflammation related pathways in F1 but not in F3 adult CD-derived liver. The changes in RNA transcription were associated with epigenetic changes. Specifically, we found a global increase in H3K4 trimethylation (H3K4me3) and a decrease in H3K27 trimethylation (H3K27me3) in prostate of F1 mice. ChIP-seq analysis showed that 129 regions in F1 and 240 in F3 acquired altered H3K4me3 occupancy in CD-derived prostate, including highest increase at several promoters of Hoxa family genes in both datasets. The alteration in H3K4me3 in both generations overlap 73 genes including genes involved in proliferation regulation, Tbx2, Stat3, Stat5a, Pou2f3 and homeobox genes Hoxa13, Hoxa9.

CONCLUSIONS

Our data suggest that developmental exposure to CD leads to epigenetic changes in prostate tissue. The PIN containing samples showed evidence of implication in hormonal pathway and self-renewal gene expression that have the capacity to promote neoplasia in CD-exposed mice.

Laboratory study on the mobility of chlordecone and seven of its transformation products formed by chemical reduction in nitisol lysimeters of a banana plantation in Martinique (French Caribbean)

The contamination by chlordecone (CLD) of soils and water in the French Caribbean (FC) has major environmental and human health impacts. In Situ Chemical Reduction (ISCR) is a promising method to degrade CLD but it generates transformation products (TPs). Here, the fate and transport of CLD and its TPs have been studied using three lysimeters, 65-70 cm-long and 20 cm in diameter, collected from a CLD contaminated nitisol in the FC. A simulated ISCR remediation process (Sim-ISCR) was applied to the top 15 cm layer. An equivalent of 9.8 years of effective rainfall was simulated during the 451 days of the experiments. CLD and seven TPs were analyzed in soils, soil pore waters and outflow waters of the lysimeters before and after the Sim-ISCR. CLD concentration in the soil pore waters increases with depth. In the Sim-ISCR treated layer, the CLD contamination was lowered by 41 to 47% in the soil and by 48 to 73% in the soil pore water. In the lysimeters outflow, however, the CLD concentration was lowered by only 13 to 25%, the flux of CLD from the untreated 50-55 cm of the profile concealing much of the beneficial impact of treating the top 15 cm. Remediating by ISCR the topsoil only will therefore not be sufficient for preventing further CLD contamination of the underlying groundwater. Sim-ISCR generated 5-hydroCLD in soils and waters and, to a much lesser extent, a trihydroCLD, a tetrahydroCLD, a pentahydroCLD and a heptahydroCLD. 5-hydroCLD is more mobile than CLD, but it still interacts strongly with the soil. The 5-hydroCLD values measured in the outflow were up to a factor of 4.4 lower than in the treated soil pore waters, indicating some natural attenuation.