Evaluating the Environmental and Health Risks of Agrochemical Use in the Mile 4 Water Catchment, Limbe I, Southwest Cameroon

Abstract

Chemical-intensive agriculture has become increasingly prevalent in Sub-Saharan Africa as farmers strive to enhance yields amid rapid urbanization and climate variability. However, its environmental and public health consequences remain under-investigated in peri-urban settings. Over 70% of residents in the study area depend on surface water for domestic use, concerns about agrochemical contamination of water catchments are rising. Despite this, empirical data linking land use, water quality, and health outcomes are scarce. This study assessed the impact of chemical-intensive farming on water catchment quality and associated health risks. Field sampling was conducted across ten sites during both dry and wet seasons, with laboratory analyses of nitrates, phosphates, pesticide residues, lead, and pH. Health surveys and stakeholder interviews were used to triangulate findings. The results revealed widespread exceedance of WHO standards during the wet season: nitrates (58.7 mg/L), phosphates (3.1 mg/L), pesticides (0.26 µg/L), and lead (0.05 mg/L). Strong correlations among key pollutants (r = 0.76–0.85) indicate common sources, chiefly runoff from agrochemical applications. Health data showed high incidences of diarrhea (63%), typhoid (47%), and skin irritation (35%), pointing to significant exposure-related illness. These findings underscore the ecological vulnerability and public health implications of unsustainable agricultural practices. The study highlights the urgent need for integrated catchment management, agroecological alternatives, and regulatory enforcement. Future research should focus on longitudinal exposure assessments and the viability of sustainable farming models in similar agro-ecological zones.