RESUMEN

Among the numerous organochlorines (OCs) applied in the French West Indies (FWI), chlordecone (hydrated form C10Cl10O2H2; CLD) still causes major environmental pollution nowadays. A recent report revealed the unexpected presence in FWI environment of transformation products (TPs) of CLD not routinely monitored due to a lack of commercial standards. Here, we present a method for surface waters and groundwaters to analyze CLD, its main TPs (hydroCLDs, chlordecol (CLDOH), 10-monohydroCLDOH and polychloroindenes) and other OCs. We developed an SPME-GC-SIM/MS method with a PDMS-DVB fiber. Since CLDOH-d commonly used as internal standard (IS) proved unsuitable, we synthesized several IS candidates, and finally identified 10-monohydro-5-methyl-chlordecol as a satisfactory IS for CLDOH and 10-monohydroCLDOH avoiding the use of 13C-labelled analogue. LODs for CLD and its TPs varied from 0.3 to 10 ng/L, equal to or below LODs of the two laboratories, BRGM (the French geological survey) and LDA26 (one of the French Departmental Analytical Laboratories), requested in FWI pollution monitoring that used liquid-liquid extractions and advanced facilities (LLE-GC-MS/MS and LLE-LC-MS/MS methods, respectively). Then, we extended the multi-residue method to 30 OCs (CLD and its TPs, mirex, ß-HCH, lindane, dieldrin, aldrin, HCB, hexachlorobutadiene, TCE, PCE) and applied it to 30 surface and ground waters from FWI. While CLD, 8- and 10-monohydroCLD, CLDOH, 10-monohydroCLDOH, dieldrin, and ß-HCH were detected and quantified, pentachloroindene, another CLD TP, was sporadically found in trace levels. A comparison with BRGM and LDA26 confirmed the interest of the SPME method. Results suggested an underestimation of CLDOH and an overestimation of high CLD concentrations with one of the currently used routine protocol. In light of these findings, previous temporal monitoring of environmental waters in FWI were re-examined and revealed some atypical values, which may indeed be due to analytical bias. These discrepancies call for intensified efforts to reliably quantify CLD and its TPs.

RESUMEN

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.

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

Background: Chlordecone is an endocrine-disrupting chemical with well recognized estrogenic and progestagenic properties. This organochlorine insecticide was extensively used in the French West Indies from 1973 to 1993 to control the banana root borer. Due to its poor degradation in the environment, permanently polluted soil is responsible for the current contamination of the food chain and human beings. We aimed to examine the relationship of in utero exposure to chlordecone and thyroid (thyroid stimulating hormone [TSH], free tri-iodothyronine [FT3], free thyroxine [FT4]), metabolic (insulin growth-factor 1, leptin, adiponectin), and sex-steroid (dehydroepiandrosterone [DHEA], total testosterone [TT], dihydrotestosterone [DHT], estradiol [E2]) hormone levels in children at the age of seven years who participated in TIMOUN, an ongoing birth cohort in Guadeloupe. Methods: Chlordecone concentrations were measured in cord-blood at delivery. Thyroid, metabolic, and sex-steroid hormone levels were determined in the blood of children at seven years of age. Associations between in utero chlordecone exposure and hormone levels at seven years of age were assessed by multiple linear or logistic regression, controlling for confounding factors. Results: Among the study population (210 boys and 228 girls), chlordecone and hormone measurements were available for 124 boys and 161 girls. We found the third quartile of in utero chlordecone exposure relative to the lowest quartile to be associated with elevated TSH levels in girls and elevated DHEA, TT, and DHT levels in both sexes. Complementary non-linear analysis (spline regression) confirmed a significant non-linear trend for TSH in girls and DHEA and DHT in boys. Conclusion: In utero chlordecone exposure was associated with elevated levels of selected thyroid (TSH) and sex-steroid (DHEA, TT, and DHT) hormones at seven years in a non-monotonic dose response (inverted U) relationship. The implications for future health and reproductive function in puberty and adulthood should be determined.

Asunto(s)

RESUMEN

The influence of nitrogen-containing surface groups (SGs) onto activated carbon (AC) over the adsorption of chlordecone (CLD) and ß-hexachlorocyclohexane (ß-HCH) was characterized by a molecular modelling study, considering pH (single protonated SGs) and hydration effect (up to three water molecules). The interactions of both pollutants with amines and pyridine as basic SGs of AC were studied, applying the multiple minima hypersurface (MMH) methodology and using PM7 semiempirical Hamiltonian. Representative structures from MMH were reoptimized using the M06-2X density functional theory. The quantum theory of atoms in molecules (QTAIM) was used to characterize the interaction types in order understanding the adsorption process. A favorable association of both pesticides with the amines and pyridine SGs onto AC was observed at all pH ranges, both in the absence and presence of water molecules. However, a greater association of both pollutants with the primary amine was found under an acidic pH condition. QTAIM results show that the interactions of CLD and ß-HCH with the SGs onto AC are governed by Cl···C interactions of chlorine atoms of both pesticides with the graphitic surface. Electrostatic interactions (H-bonds) were observed when water molecules were added to the systems. A physisorption mechanism is suggested for CLD and ß-HCH adsorption on nitrogen-containing SGs of AC.

RESUMEN

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.

Asunto(s)

RESUMEN

Chlordecone (CLD) is a toxic organochlorine pesticide frequently used in the French West Indies until 1993, resulting in a contamination of soil and food. This study assessed the behaviour of CLD residues and CLD processing factors (PFs) during four home cooking processes: cooking in a conventional oven ("oven"), frying ("pan"), cooking in a microwave oven ("microwave") and grilling ("grill"). These four processes were applied to six types of naturally contaminated beef (kidney, liver, rib, chuck, top-sirloin and sirloin). Targeted analyses with isotopic dilution were carried out by ID-HPLC-MS/MS to determine CLD concentrations before and after each cooking process and the corresponding processing factors. HPLC-HRMS/MS was used to find potential organochlorine degradation by-products and/or CLD metabolites present in samples by target, suspect and non-target screening. Cooking processes and especially microwave cooking led to a significant decrease in the CLD contained in beef (2% < PF < 17%). Traces of 5b-hydro-CLD and of another mono-hydro-CLD were found in the uncooked liver but no CLD degradation by-product was observed in the cooked liver.

Asunto(s)

RESUMEN

Monitoring of water quality over several years has revealed a persistent pesticide contamination of surface and groundwater in several Caribbean Islands, with pesticide concentrations locally over the drinking-water limit set in Europe, i.e. 0.1 µg L-1 per substance. For Martinique, mainly one pesticide, chlordecone (CLD), remains of major concern despite its withdrawal from the market in 1993. Since the first sampling campaign in 1999-2000, time and space variations of CLD concentrations in surface water and groundwater are still not well understood and difficult to correlate with climate, geological or hydrogeological contexts. We carried out a study in the Chalvet catchment (northeast Martinique) in order to understand more precisely how water movements may explain pesticide transfer. Various tools such as δ2H - δ18O and chemical parameters were used. Deuterium excess d was proven relevant for determining how CLD is transported in groundwater; it highlighted the role of the groundwater/surface water interaction in spatial and temporal variability of surface water quality. The resulting conceptual hydrogeological model also helps understanding why CLD still has high concentrations in surface water. The approach proposed here can be used in other Caribbean islands that are poorly equipped for explaining pesticide occurrences in surface waters.

Asunto(s)

RESUMEN

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.

RESUMEN

The consumption of private hold poultry foodstuffs, escaping of official maximum residue limit (MRL) controls in the commercial foodstuff, is an important exposure way for the local populations to chlordecone on the French West Indies. Therefore, chlordecone contamination of different tissues in 42 birds from 32 private holders was determined depending on the contamination of the soil of the outside plot but also surveying the rearing practices of these holders of both islands. Chlordecone contents in tissues increased rapidly with this of the topsoil of the site. The most sensitive tissues to chlordecone presence were egg yolk and liver, followed by abdominal fat and finally leg tissue. The rearing practices varied between the surveyed private holders of both islands. Nevertheless, practices for the distribution of feed and water as well as covering of soil were hardly protective, what would increase the exposure risk of these birds to this potentially present soil-bound contaminant. Although depuration of birds seems possible, the ongoing modelization of the necessary time to meet MRL thresholds indicates that such time lapse seems hardly compatible with acceptable delays for private holders. Therefore, very protective rearing practices are the main way to obtain poultry foodstuffs compliant to MRL, what seems possible if the topsoil is contaminated at less than 0.1 mg kg-1 and perhaps up to 0.5 mg kg-1 if protective practices vis-a-vis of soil exposure are very strict. Nevertheless, a higher contamination of the topsoil seems not compatible with compliant poultry foodstuffs.

Asunto(s)

RESUMEN

Intensive use of the chlorinated pesticide chlordecone from the 1970s to 1993 to prevent crop damage in banana plantations of Guadeloupe and Martinique led to diffuse pollution of soils and surface waters, affecting both fauna and human beings in the contaminated areas. Since 2001, drinking water production plants have been equipped with filters containing activated carbon that must be treated after saturation. The objective of this work is to produce a hybrid material composed of activated carbon and vitamin B12 (VB12) for the degradation of chlordecone (CLD). The preparation of such a hybrid material is carried out by non-covalent fixation to achieve an eco-friendly solution for the serious environmental problem of contamination by chlorinated pesticides. It is thus proposed to degrade CLD by a physico-chemical treatment allowing salvage of the catalyst, which is adsorbed on the carbon surface to generate less waste that is inexpedient to treat. Activated carbon (AC) is produced locally from available sugarcane bagasse subjected to phosphoric acid activation. The main characteristics of this material are a major mesoporous structure (0.91%) and a specific (BET) surface area ranging from 1000 to 1500 m2 g-1. The experimental results showed that BagP1.5 has a high adsorption capacity for VB12 due to its large surface area (1403 m2 g-1). The binding of VB12 to the bagasse-derived AC is favoured at high temperatures. The adsorption is optimal at a pH of approximately 6. The maximum adsorption capacity of VB12 on the AC, deduced from the Langmuir model, was 306 mg g-1, confirming the high affinity between the two components. The hybrid material was characterised by FTIR, Raman, X-ray fluorescence spectroscopy and SEM analysis. CLD removal by this hybrid material was faster than that by VB12 or BagP1.5 alone. The CLD degradation products were characterised by mass spectrometry.

Asunto(s)

RESUMEN

Recent evidence suggests that prenatal exposure to chlordecone, a persistent organochlorine pesticide that was used intensively in the French West Indies, affects infant neurodevelopment. The aim of the present study was to evaluate the association between prenatal and postnatal chlordecone exposures on visual contrast sensitivity in 285 children aged from 7.1 to 8 years old (mean age = 7.68 ±â€¯0.21 years; sex ratio = 54 % girls) in a Guadeloupean prospective birth cohort (TIMOUN). The Freiburg Visual Acuity and Contrast Test (FrAcT) was used to assess visual contrast sensitivity. Chlordecone concentrations were measured in blood samples at birth (cord blood) and in children at testing time to estimate pre- and postnatal exposure, respectively. Exposures were categorized into three groups and were also log-transformed and considered as continuous variables. Multiple linear regression models were performed on all children taking into account various potential confounders, including maternal characteristics (age, education, intellectual functioning, alcohol and tobacco use during pregnancy). Potential moderation effect of sex was also examined. Results showed that higher cord plasma chlordecone levels were associated with lower contrast sensitivity. Although child chlordecone levels was not associated with the FrAcT, sex-specific stratified analyses revealed significant associations in boys. Associations between postnatal exposure and FrACT scores in girls were null. This study indicates that exposure to chlordecone in utero and during childhood may impair visual contrast sensitivity at school age, particularly in boys.

Asunto(s)

RESUMEN

The use of chlordecone (CLD), a chlorinated polycyclic pesticide used in the French West Indies banana fields between 1972 and 1993, resulted in a long-term pollution of agricultural areas. It has been observed that this persistent organic pollutant (POP) can transfer from contaminated soils to food chain. Indeed, CLD is considered almost fully absorbed after involuntary ingestion of contaminated soil by outdoor reared animals. The aim of this study was to model toxicokinetics (TKs) of CLD in growing pigs using both non-compartmental and nonlinear mixed-effects approaches (NLME). In this study, CLD dissolved in cremophor was intravenously administrated to 7 Creole growing pigs and 7 Large White growing pigs (1 mg kg-1 body weight). Blood samples were collected from time t = 0 to time t = 84 days. CLD concentrations in serum were measured by GCMS/MS. Data obtained were modeled using Monolix (2019R). Results demonstrated that a bicompartmental model best described CLD kinetics in serum. The influence of covariates (breed, initial weight and average daily gain) was simultaneously evaluated and showed that average daily gain is the main covariate explaining inter-individual TKs parameters variability. Body clearance was of 76.7 mL kg-1 d-1 and steady-state volume of distribution was of 6 L kg-1. This modeling approach constitutes the first application of NLME to study CLD TKs in farm animals and will be further used for rearing management practices in contaminated areas.

Asunto(s)

RESUMEN

The In Situ Chemical Reduction (ISCR) process was tested in a nitisol in a French Caribbean banana plantation using five different soil amendments. The addition of 2.8% or 4.0% of Zero Valent Iron (ZVI; dw/dw, 2 different trial plots) in the 0-40-cm soil layer lowered the initial chlordecone (CLD) concentration by up to 74% or 69% in 37 days or 94 days, with 75% of the decrease achieved after only 21 or 24 days of treatment depending on the trial plot. The addition of commercially available Daramend® was also tested by applying the 6% dose (dw/dw) recommended by the manufacturer and using either the regular alfalfa-based product or a bagasse-based product specifically formulated for the study. Both significantly lowered CLD concentrations, but to a lesser extent than with the ZVI-only amendment. A bagasse-ZVI mixture prepared on site produced results slightly better than the two Daramend®. The percentage decreases in CLD concentrations were correlated with the negative redox potentials achieved. In all the trial plots, dechlorinated transformation products appeared in the soil and soil water as the CLD concentrations decreased, with H atoms replacing up to 4 and 7 of the 10 Cl atoms, respectively. None of these degradation products appeared to accumulate in the soil or soil water during the treatment. Instead, the reverse occurred, with an overall downward trend in their concentrations over time. The effects of ISCR treatment on agronomic and human health-related parameters were measured in three different crops. The radishes produced with some treatments were visually of lower quality or smaller in size than those grown in the control plots. Lower yields were observed for the cucumbers and sweet potatoes grown after applying the bagasse-based amendments. Mortality among cucumber seedlings was observed after treatment with ZVI only. Simple operational solutions should suffice to remedy these negative agronomic effects. As regards human health-related effects, the CLD concentrations in radishes grown with three of the amendments were significantly lower than in the two control plots and well below the maximum residue level (MRL), which was substantially exceeded in the radishes grown on untreated soil. For cucumbers, the treatments with regular Daramend® and with a local bagasse-ZVI mixture produced fruits with CLD below the MRL and also below the concentrations in one of the two control plots. As for the sweet potatoes, adding a bagasse-ZVI mixture had a significant positive effect by decreasing contamination below the levels in the two control plots and below the MRL.

Asunto(s)

RESUMEN

Chlordecone (CLD) is an organochlorine pesticide widely used in the past to control pest insects in banana plantations in the French West Indies. Due to its persistence in the environment, CLD has contaminated the soils where it has been spread, as well as the waters, and is still present in them. The objective of our study was to evaluate the effects of chronic exposure to environmentally relevant CLD concentrations in an animal model, the freshwater hydra (Hydra circumcincta). In a multi-marker approach, we have studied the expression of some target stress genes, the morphology, and the asexual reproduction rates. Our data showed that exposure to low concentrations of chlordecone leads to (i) a modulation of the expression of target genes involved in oxidative stress, detoxification, and neurobiological processes, and (ii) morphological damages and asexual reproduction impairment. We have observed non-monotonic dose-response curves, which agree with endocrine-disrupting chemical effects. Thus, "U-shaped" dose-response curves were observed for SOD, GRed, Hym355, and potentially GST gene expressions; inverted "U-shaped" curves for GPx and CYP1A gene expressions and reproductive rates; and a biphasic dose-response curve for morphological damages. Therefore, in the range of environmental concentrations tested, very low concentrations of CLD can produce equally or more important deleterious effects than higher ones. Finally, to our knowledge, this study is the first one to fill the lack of knowledge concerning the effects of CLD in Hydra circumcincta and confirms that this diploblastic organism is a pertinent freshwater model in the risk assessment.

Asunto(s)