Assessment of human exposure to pesticides by hair analysis: The case of vegetable-producing areas in Burkina Faso

The present work assesses human exposure to pesticides in vegetable-producing areas in Burkina Faso, using hair as an indicator. The study design includes a comparison between operators who are occupationally exposed while working in the fields and a reference population (i.e. not occupationally exposed) to evaluate both oc- cupational and indirect exposures. Hair samples from volunteers (n = 101) were positive for 17 pesticides (38 analyzed). Acetamiprid, desethylatrazine, carbofuran, and deltamethrin were detected for the first time in field samples. With a maximum of 9 residues per sample, pesticide exposure was ubiquitous in both populations. Contamination by acetamiprid, cypermethrin, and lambda-cyhalothrin (used in vegetable production) prevailed in operator samples. For other pesticides, such as imidacloprid and deltamethrin, no significant difference was found. This indicates a potentially large environmental exposure (dietary intake or atmospheric contamination) or the prevalence of other contamination sources. The present findings are concerning, as detected levels are globally higher than those previously reported, and indicate exposure to endocrine disrupting chemicals and probable carcinogens. Hair was found to be a suitable matrix for biomonitoring human exposure to pesticides and assessing dominant factors (i.e. sex, age, and protective equipment) in subgroups, as well as identifying geographical contamination patterns.

Assessment of occupational exposure to pesticides with multi-class pesticide residues analysis in human hairs using a modified QuEChERS extraction method, case study of gardening areas in Burkina Faso

Luiz Felippe De Alencastro, Edouard René Gilbert Lehmann, Jean-Jacques Stéphane Nfon Dibie, Christelle Oltramare

Pesticides have been proved to potentially cause multiple adverse health effects. The present study is part of a global project focusing on pesticides impacts on the environment and human health in gardening in Burkina Faso. In absence of existing monitoring, the present study aims at proposing a comprehensive indicator of occupational exposure to 48 pesticides identified during field campaigns. As a noninvasive and safe indicator of long term exposure, increasing interest is being observed in hair analysis for biomonitoring of human exposure to pesticides. In order to dissociate occupational and environmental exposure in the study area, two study populations have been randomly selected: fifty gardeners (operators) and fifty non users (reference population). The Ethics Committee of the Burkina Faso approved this study and written informed consent was obtained from all donors. Multiresidue extraction procedure using a modified QuEChERS extraction method has been developed and applied to the collected samples. Briefly, hairs were cut on the posterior of the head, subsequently cut in small pieces and spiked with appropriate 13C- or deuterated surrogates. After overnight incubation, they were extracted in acetonitrile, cleaned-up by Dispersive SPE (dSPE), concentrated and separated prior analysis on GC-MS and LC-MS/MS. Each sample was accompanied by a questionnaire on hair care practices. Different incubation, extraction methods and dSPE sorbents have been tested (temperature, type, volume, etc.). The best method was found to be a modified AOAC 2007.01 QuEChERS procedure, including 12h incubation at 37°C followed by dSPE clean-up with Supelco Z-sep/C18® sorbent. The substances detected in collected samples include pesticides commonly used in the study area such as acetamiprid, imidacloprid, cypermethrin, profenofos but also dieldrin a banned persistent organochlorine. These pesticides were detected in hairs of the gardeners but also in the samples of the reference population indicating the occurrence of passive contamination. This study presents a comprehensive assessment of sample preparation, extraction and clean-up procedure for multi-class pesticide residues analysis in human hairs. The modified QuEChERS extraction procedure proposed offers a simple and robust tool suitable to developing countries for monitoring human exposure and evaluation of compliance with policies. The study design, including comparison between reference and operators populations allowed to dissociate the influence of environmental exposure and direct occupational exposure. Results indicate that potential carcinogen, endocrine disruptor, neurotoxic and persistent pesticides have been detected in collected hairs.

2016

Levels of 48 pesticides in vegetables and water and evaluation of health risk resulting from dietary intake in gardening areas in Burkina Faso

Luiz Felippe De Alencastro, Edouard René Gilbert Lehmann

Exceedance of MRLs might induce a risk for the consumers and limits the opportunities of exportation for a sector identified by the authorities as having a great potential for the fight against poverty. In the same way, levels of some water samples exceed both the 0.1 μg/l limit for pesticides taken individually and the 0.5 μg/l limit for the sum of pesticides recommended for drinking water in the EU. Over the 70 individual diets assessed, 3 and 8 yield respectively an acute and chronic cumulative risk for organophosphorus pesticides. Dietary risk was identified for chlorpyrifos in every exposure scenarios and for dieldrin (persistent and forbidden pesticide) for chronic exposure. Chlorpyrifos alone accounts for 81% to 98% of cumulative effects of organophosphorus pesticides. Every scenario exhibits a greater exposure of the consumer through vegetables than water consumption. Processing factor appeared to largely influence the risk occurrence. In this study, 60% was set as default value for cooked commodities (boiled or fried). Further refinements could include the definition of specific processing factors dependent of the local processes and pesticide used. As for dieldrin, multiresidue analysis allowed to detect residues of pesticides not identified by investigators nor gardeners during field surveys. This might imply the existence of other sources that need to be further investigated (lack of knowledge, spray drift, etc.).

2016

Pesticide application in gardening : assessment of resulting impact on water resources quality using grab samples and pocis, case study of Loumbila lake, Burkina Faso

Luiz Felippe De Alencastro, Morgan Fargues, Edouard René Gilbert Lehmann

This study proposes a comprehensive assessment of water resources contamination by pesticides in a gardening area. Multiresidue extraction procedure was developed to quantify 48 pesticides identified during field surveys. Drinking water samples were collected from traditional wells, boreholes and the lake. Levels of azadirachtin, chlorpyrifos, imidacloprid and profenofos in traditional wells exceed the threshold limit of 0.1 μg/l indicating a potential risk for the consumers. Residues of acetamiprid, atrazine, emamectin benzoate and imidacloprid were found in boreholes but in low concentrations. Levels in lake appeared to depend on seasons. Increase during the rainy season, in absence of gardening activity, suggests the contamination by other activities located upstream. In parallel, we conducted an in-situ calibration of Polar Organic Chemical Integrative Samplers (POCIS). Comparison with results from water samples shows that POCIS are suitable for measuring time weighted average concentration for atrazine and its metabolites, in environmental conditions of the study area.

2016

Luiz Felippe De Alencastro, Edouard René Gilbert Lehmann, Jean-Jacques Stéphane Nfon Dibie, Christelle Oltramare

2016