First diet survey in Niger River valley and acute risk assessment for consumers exposed to pesticide residues in vegetables

Abstract

To control pests and crops diseases, small scale farmers in the Niger River valley use a wide range of plant protection products which could induce harmful impacts on human health and environment. Dietary exposure to plant protection products residues was assessed in Niger River valley using the 24-hour recall method. Portion sizes were estimated using a collection of pictures previously prepared according to the local usual diet. A total of 45 samples of eight types of vegetables, representative of the most consumed in the study area (Niamey) during the dry hot and the dry cold season were collected. Samples were analyzed using a multi-residue method (QuEChERS) by gas chromatography-mass spectrometry (GCMS/MS) and liquid chromatography-mass spectrometry (LC-MS/MS) that can detect more than 540 active ingredients. Residues of insecticides were detected in 64.4% of the analyzed samples. Among them, 26.7% contained residues above maximum residue limits (MRLs), 35.5% below MRLs, 2.3% of samples had residue equal to the MRLs. Chili peppers, tomatoes, moringas, head cabbages, sorrel leaves and peppers were the most contaminated vegetables. Their residue levels were, respectively, 4.6 mg/kg of chlorpyrifos-ethyl, 0.29 mg/kg of dichlorvos, 1.8 mg/kg of cypermethrin, 1 mg/kg of chlorpyrifosethyl, 0.46 mg/kg of acetamiprid and 0.41 mg/kg of dichlorvos. To evaluate the intake and characterize the risk level for adults and children, the EFSA PRIMO model spreadsheet (Pesticide Residue Intake Model) was used. The exposure results based on consumptions at the 97.5th percentiles show that the highest predicted exposure values for a short-term intake (PSTI) was obtained in the case of consumption of head cabbages (532% of ARfD) for adults and tomatoes (1052% of ARfD) for children. Whatever the product, the risk of exposure was higher for children than for adults for all detected residues.

Keywords

• acute exposure
• consumers
• Niger River valley
• pesticide residues
• risk assessment