Silicone wristband as a sampling tool for insecticide exposure assessment of vegetable farmers

The use of passive sampling devices (PSDs) as an appropriate alternative to conventional methods of assessing human exposure to environmental toxicants was studied. One-time purposive sampling by a silicone wristband was used to measure insecticide residues in 35 volunteer pepper farmers in the Vea irrigation scheme in the Guinea savannah and the Weija irrigation scheme in the coastal savannah ecological zones of Ghana. A GC-MS/MS method was developed and validated for quantifying 18 insecticides used by farmers in Ghana. Limits of detection (LODs) and quantitation (LOQs) ranged from 0.64 to 67 and 2.2-222 ng per wristband, respectively. The selected insecticides showed a range of concentrations in the various silicone wristbands from not detected to 27 μg/wristband. The concentrations of 13 insecticides were above their LOQs. Chlorpyrifos had the highest detection frequencies and concentrations, followed by cyhalothrin and then allethrin. This study shows that silicone wristbands can be used to detect individual insecticide exposures, providing a valuable tool for future exposure studies. Ghanaian vegetable farmers are substantially exposed to insecticides. Hence, the use of appropriate personal protective equipment is recommended.

Respiratory and non-respiratory symptoms associated with pesticide management practices among farmers in Ghana's most important vegetable hub

The data presented here are from the Offinso North District Farm Health Study (ONFAHS), a population-based cross-sectional study among vegetable farmers in Ghana. The paper addresses knowledge, pesticide handling practices, and protective measures related to pesticide use by self-reported symptoms for 310 adult farmers who completed a comprehensive questionnaire on pesticide management practices and health. In addition, an inventory was prepared using information supplied by pesticide sellers/dealers in this district. We report that cough and wheezing (but not breathlessness) are positively associated with stirring pesticide preparations with bare hands/drinking water while mixing/applying pesticides, and stirring pesticide preparations with bare hands/drinking water/smoking cigarettes while mixing/applying pesticides. There is a significant exposure-response association between the number of precautionary measures practiced while handling pesticides and cough and wheezing but not with breathlessness. We also found unsafe practices to be associated with sexual dysfunction, nervousness, and lack of concentration. The results also suggest a negative association between practice of any precautionary measure when mixing/applying pesticides and sexual dysfunction, nervousness, and lack of concentration. We found that in spite of the fact that farmers have adequate knowledge about the environment and health effects of pesticides, several unhygienic practices are in widespread use, indicating that knowledge is not necessarily always translated in action. Further action is necessary to promote the safe use of pesticides and to replace existing poor management practices among these and other farmers in Ghana.

Ecological risk assessment of agricultural pesticides in the highly productive Ndop flood plain in Cameroon using the PRIMET model

Flood plains can make a significant contribution to food security due to their rich agricultural and aquaculture potentials but the misuse of pesticides in these ecosystems may seriously threaten their sustainability. We have assessed the risk of commonly used pesticides by rice and vegetable farmers on two major streams in the Ndop flood plain in Cameroon using the PRIMET model. Thirty pesticide formulations were identified containing 17 active ingredients belonging to fungicides (7), herbicides (3), and insecticides (7). Out of these, five posed acute and/or chronic risks to the streams. Chlorpyriphos-ethyl (ETR = 655), chlorothalonil (ETR = 250), and cypermethrin (ETR = 190) posed a definite acute risk to both streams. These pesticides also posed possible chronic risks with cypermethrin also posing a definite chronic risk (ETR = 1658) to fish in one of the streams. Mancozeb (ETR = 2.2) and λ-cyhalothrin (ETR = 2.8) posed a possible acute risk to both streams. It was interesting to note that most pesticides, including some of those that posed a risk, were applied at lower doses than their respective recommended doses. Differences in ETRs were also observed in the two streams with higher values occurring in the stream having a lower concentration of suspended solids. The higher velocity of the Ngwala-Mesaw stream did not affect the acute risk posed by pesticides. Pesticide toxicity was an important determinant in the risk posed and we recommend that appropriate mitigation measures be put in place to reduce the risk of these pesticides such as the implementation of an appropriate buffer zone between the edge of field and water body.