Pesticide Research on Environmental and Human Exposure and Risks in Sub-Saharan Africa: A Systematic Literature Review

Abstract

On the African continent, ongoing agriculture intensification is accompanied by the increasing use of pesticides, associated with environmental and public health concerns. Using a systematic literature review, we aimed to map current geographical research hotspots and gaps around environmental and public health risks research of agriculture pesticides in Sub-Saharan Africa (SSA). Studies were included that collected primary data on past and current-used agricultural pesticides and assessed their environmental occurrence, related knowledge, attitude and practice, human exposure, and environmental or public health risks between 2006 and 2021. We identified 391 articles covering 469 study sites in 37 countries in SSA. Five geographical research hotspots were identified: two in South Africa, two in East Africa, and one in West Africa. Despite its ban for agricultural use, organochlorine was the most studied pesticide group (60%; 86% of studies included DDT). Current-used pesticides in agriculture were studied in 54% of the study sites (including insecticides (92%), herbicides (44%), and fungicides (35%)). Environmental samples were collected in 67% of the studies (e.g., water, aquatic species, sediment, agricultural produce, and air). In 38% of the studies, human subjects were investigated. Only few studies had a longitudinal design or assessed pesticide’s environmental risks; human biomarkers; dose-response in human subjects, including children and women; and interventions to reduce pesticide exposure. We established a research database that can help stakeholders to address research gaps, foster research collaboration between environmental and health dimensions, and work towards sustainable and safe agriculture systems in SSA.

Seasonal Changes in Pesticide Residues in Water and Sediments from River Tano, Ghana

“…This may suggest that the isomers of HCH which were detected in this study were recently applied. The use may be put into malaria control, agricultural, or industrial [ 3 ]. Generally, if the ratio of δ -HCH to γ -HCH concentrations in sediment is below 3, it suggests that the source of HCH to the aquatic ecosystem is a new input [ 29 , 54 ].…”

“…Increasing pesticide use and misapplications of pesticides along river basins pose serious threats to aquatic ecosystems [ 1 , 2 ]. Increasing incidence of vector diseases is contributing to increasing use of pesticides [ 3 – 5 ]. Pesticides are mostly used by farmers in the rainy season to control pests [ 6 – 8 ].…”

“…Pesticides in surface water are known to pose serious environmental and public health-related problems [ 11 – 16 ]. Thus, human exposure to pesticides through ingestion of contaminated water are known to cause health-related problems such as birth defects, endocrine disruption, nerve related problems, and mutation [ 3 , 17 , 18 ].…”

“…Organophosphorus, organochlorine pesticides, and synthetic pyrethroids are usually used for pest control [ 19 , 20 ]. However, organochlorine pesticides have been banned in Ghana and in some Western countries due to their toxicity, bioaccumulation, extensive half-life, low polarity, high stability, and persistence in the environment [ 3 , 17 ]. In spite of the ban on the use of OCP by the Stockholm convention, they are illegally used in some developing countries making the ban ineffective [ 21 ].…”

Interventions to Reduce Pesticide Exposure from the Agricultural Sector in Africa: A Workshop Report

“…To prepare for the workshop, two main activities were conducted. First, a systematic literature review was conducted to map current geographical research hot spots and identify gaps around environmental and public health risks associated with agriculture pesticide use in the Africa Region [ 26 ]. In this review, 391 articles published between 2006 and 2021 were identified that covered 469 study sites with five geographical research hot spots (two in South Africa, two in East Africa, and one in West Africa).…”