DDT and Its Metabolites in Ethiopian Aquatic Ecosystems: Environmental and Health Implications.

Background: Despite its significant application, DDT and its metabolites pose a potential threat to the environment. Therefore, data on environmental and health concerns must thus be investigated.

Objective: The objective of this study was to assess the environmental and human health risks posed by DDT and its metabolites in Ethiopian surface waters.

Methods: The total amount of DDT and its metabolites consumed as a sum (∑DDT) is calculated by considering their equivalent toxicity. To calculate the human risk from drinking contaminated water, the maximum concentrations in all of Ethiopia's surface waterways were pooled. The average concentration values were added to calculate the human risk from consuming fish contaminated with ∑DDT. Similarly, ∑DDT residues in water can be used to predict the potential environmental risk.

Results: A higher level of ∑DDT in surface water was detected in Gilgel Gibe I hydroelectric dam reservoir and its tributaries with an average concentration of 640 ng/l. There is no health risk associated with drinking these surface waters because the concentrations of ∑DDT were below the WHO's recommended level. In fish samples, B. intermedius accumulated a higher level of ∑DDT (21.47 ng/g ww). With the exception of local infants, ∑DDT does not pose a non-carcinogenic risk to any age group. However, consuming fish contaminated with ∑DDT poses an unacceptable risk of cancer to all age categories. The risk posed by ∑DDT on aquatic species is highly likely. The bioaccumulation factor (BAF) value indicates that fish tissue does not absorb ∑DDT directly from the water.

Conclusion: The prevalence of ∑DDT would link to both historical pollution and their current application in vector control. Ecosystems are frequently exposed to chemical mixes later in life; thus, rather than focusing on the ideal case of exposure to a single toxin, future studies can examine the mixture toxicity of numerous organic contaminants.