Pesticides monitoring in surface water of a subsistence agricultural catchment in Uganda using passive samplers

Abstract

Pesticides are intensely used in the agricultural sector worldwide including smallholder farming. Poor pesticide use practices in this agronomic setting are well documented and may impair the quality of water resources. However, empirical data on pesticide occurrence in water bodies of tropical smallholder agriculture is scarce. Many available data are focusing on apolar organochlorine compounds which are globally banned. We address this gap by studying the occurrence of a broad range of more modern pesticides in an agricultural watershed in Uganda. During 2.5 months of the rainy season in 2017, three passive sampler systems were deployed at five locations in River Mayanja to collect 14 days of composite samples. Grab samples were taken from drinking water resources. In these samples, 27 compounds out of 265 organic pesticides including 60 transformation products were detected. In the drinking water resources, we detected eight pesticides and two insecticide transformation products in low concentrations between 1 and 50 ng/L. Also, in the small streams and open fetch ponds, detected concentrations were generally low with a few exceptions for the herbicide 2,4-D and the fungicide carbendazim exceeding 1 ug/L. The widespread occurrence of chlorpyrifos posed the largest risk for macroinvertebrates. The extensive detection of this compound and its transformation product 3,4,5-trichloro-2-pyridinol was unexpected and called for a better understanding of the use and fate of this pesticide. Graphical abstract

Urtica dioica Extract Abrogates Chlorpyrifos-Induced Toxicity in Zebrafish Larvae

“…Indeed, it is commonly monitored in soils, ground water, and surface water, as well as in solid and liquid dietary samples. Thus, there is no doubt that the misuses of CPF and other organophosphate pesticides can have adverse effects on non-target organisms, including humans [ 1 ].…”

Emerging Pollutants in Uganda: A Systematic Review

“…To date, several studies have been conducted in Uganda to investigate the presence and concentrations of emerging pollutants in different environmental systems in Uganda for example in water (27,28), sediments (27,29), surface waters (30)(31)(32), food crops (33,34), edible insects (35), breastmilk (36) and in fish (30). These studies have identified a range of compounds, including pharmaceutical residues (e.g., antibiotics, analgesics) (26,37,38), personal care products (e.g., fragrances, UV filters) (39), pesticides (e.g., herbicides, insecticides) (27,35,40,41), industrial chemicals (e.g., flame retardants, plasticizers) (36,39,42), microplastics and heavy metals (43)(44)(45). The concentrations of emerging pollutants reported in the literature vary depending on the sampling location, environmental matrix, and analytical techniques used.…”

A Systematic Review of Contaminants of Concern in Uganda: Occurrence, Sources, Potential Risks, and Removal Strategies

“…Several studies conducted in Uganda have investigated the sources, presence, and concentrations of CoCs in various environmental systems, including water bodies [31,32], sediments [31,33], surface waters [34][35][36], food crops [37,38], edible insects [39], breastmilk [40], and fish [34]. These studies have identified a range of compounds, including pharmaceutical residues like antibiotics and analgesics [30,41,42], personal care products like fragrances and UV filters [43], pesticides like herbicides and insecticides [31,39,44,45], industrial chemicals like flame retardants and plasticizers [40,43,46], microplastics, and heavy metals [32,47,48]. The reported concentrations of these CoCs exhibit variation depending on the sampling location, environmental matrix, and analytical techniques used.…”