Agricultural intensification in Lake Naivasha Catchment in Kenya and associated pollution

Abstract

Investments in agricultural intensification in Sub-Saharan Africa aim to fulfill food and economic demands. However, the increased use of fertilizers and pesticides poses ecological risks to water bodies in agricultural catchments. This study focused on assessing the impact of agricultural intensification on nutrient and pesticide pollution in the L. Naivasha catchment in Kenya. The research revealed significant changes in the catchment's agricultural landscape between 1989 and 2019, driven by intensified agricultural expansion. As a result, nutrient and pesticide emissions have worsened the lake's trophic status, shifting it towards hypereutrophic conditions. The study found a weak relationship between total nitrogen (TN) and ∑DDT, indicating that an increase in TN slightly predicted a reduction in ∑DDT. Analysis also showed potential phosphorus (P) limitation at N3 site (Hippo Point) in the lake. Additionally, the observed DDD:DDE and (DDE + DDD):DDT ratios suggest recent use of banned DDT in the catchment. The study concludes that unsustainable agricultural expansion has transformed the L. Naivasha landscape, necessitating the adoption of practices that support water quality management to achieve the UN Sustainable Development Goals.