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

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.

Pesticides use in gardening areas in Burkina Faso and evaluation of the resulting risk for the operator using the new AOEM proposed by EFSA guidelines

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

Pesticides are widely used in gardening to maintain high yield, prevent diseases and control pests and rodents. Field surveys conducted in Burkina Faso have underlined the lack of knowledge regarding good agricultural practices and the use of unsuitable and obsolete pesticides. Improper packaging and high illiteracy rate in rural areas also hamper the compliance with recommended doses, application rates and safety measures provided on original manufacturer’s labels. Pesticides operators are persons who mix, load and apply the pesticides. These phases are critical and present great risks in terms of pesticide exposure. In practice, exposure will be influenced by specific conditions under which pesticides are handled (packaging, environmental conditions, personal protective equipment, etc.). Because of their work, operators are subject to receive the greatest exposure which put them at higher risk for acute intoxication but also long term adverse health effects. The present study aims at assessing occupational exposure to pesticides in gardening areas and to develop a database of pesticides use in Burkina Faso. Many predictive models have been used in other areas to estimate operator exposure. In 2014, the EFSA (European Food Safety Authority) Panel on Plant Protection and their Residues proposed a new guidance document that supports the use of a new predictive agricultural operator exposure model (AOEM) based on a statistical analysis of exposure studies conducted between 1999 and 2009. In order to supply the model with specific local data, a survey have been conducted on 460 gardeners located in four gardening areas. The questionnaires aimed at identifying culture types, agricultural practices (crop calendar, watering, etc.), pesticides use (type, quantity, frequency of application, equipment used, environmental conditions, etc.) and observed intoxication symptoms. Two complementary surveys directed toward pesticides resellers (n=25) and health care centers (n=20) have been conducted to identify pesticides available on local market and recorded intoxication cases.76 % of the quantity applied exceed the doses recommended by the manufacturer. 50% of gardeners wear no personal protective equipment (PPE) and 37% only a muffler in synthetic fabric. Two scenarios have been evaluated for acute and chronic risk: Current agricultural practices (S1) and Use of appropriate PPE (S2). The acute and chronic risk indexes exceed the unity for respectively 75% and 17% of the cases in S1 indicating that the acceptable operator exposure levels (Acute Reference Dose (ARfD) and Acceptable Operator Exposure Level (AOEL)) were exceeded. The risk index under the unity for nearly 98% of the cases in S2 indicates that the lack of proper PPE increases exposure inducing unacceptable acute and long term risks for the operator. As the knapsack model is not dependent on pesticide dose, this study underlines that availability of suitable PPE and training of the pesticides operators would drastically improve the situation.

2016

La contamination du Léman par les micropolluants – revue de 40 ans d’études

Luiz Felippe De Alencastro

Lake Geneva pollution by micropollutants – a review of 40 years of study. – Lake Geneva drains a watershed of about 8000 km2, subject to anthropogenic pressures due to a large population, agriculture, and industries. Contaminants released by these activities may eventually end up in the lake water, sediments and biota. For more than 40 years, the International Commission for Lake Geneva Protection (Commission Internationale pour la Protection des Eaux du Léman), and research institutes located around the lake, look after these contaminants by following the evolution of analytical technics. This review particularly focuses on the evolution of the lake contamination by mercury, PCBs, pesticides, drugs and some emerging pollutants. Mercury and PCBs were the first contaminants detected in sediments in the 1970s. These contaminants were particularly targeted because of their propensity to bioaccumulate in organisms and biomagnify in the food chain, and because of their high ecotoxicity. If the contamination of fish by mercury seems controlled with values ~10 times lower than the legal limits, PCBs still pose problems for fatty fish such as Arctic char (Salvinus alpinus). Improved techniques for analyz- ing organic products revealed the presence in the waters of more than one hundred pesticides and thirty pharmaceuticals. In addition, contamination of Foramsulfuron in 2005, from industry, has almost reached the legal limit for drinking water. This review shows that the contamination of the lake over the last 40 years has evolved with the growing presence of many contaminants, either by the release of new substances or by improving analytical techniques. Monitoring of water quality is essential to act early enough to reduce inputs in the lake. And special vigilance must be maintained for both ‘old’ pollutants (Hg, PCBs) and emerging contaminants such as pharmaceuticals, microplastics, and products of industrial synthesis.

2013

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

Pesticides use in gardening areas in Burkina Faso and evaluation of the resulting risk for the operator using the new AOEM proposed by EFSA guidelines

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

2016

La contamination du Léman par les micropolluants – revue de 40 ans d’études

Luiz Felippe De Alencastro

2013