Assessment of Dichlorodiphenyltrichloroethane (DDT) and its Isomers in Water and Sediments: A case study of River Kibos-Nyamasaria, Kisumu County-Kenya

Abstract

This study aimed determining the concentration of banned or restricted DDTs isomers in water and sediments in river Kibos-Nyamasaria during the wet and dry seasons. The isomers were analyzed using gas chromatography with a Mass Spectrophotometer detector. A total of six DDT isomers or metabolites were detected in the water and sediments. The DDT compounds (o, p’- DDT, p, p’ - DDT, o, p’- DDD, p .p’- DDD, o, p’ - DDE, p, p’- DDE) were detected in all the samples, with p, p'- DDD metabolite recording the highest concentration in both seasons with a concentration of 0.09±0.02 μg/L in wet season and 0.03±0.02 μg/L in the dry season. The DDTs isomers had high concentration in wet season than dry season in water samples and most of DDTs were above WHO maximum residues limits (MRLs) at the swamps or entry point to the Lake. p, p’- DDD recorded the highest concentration of 3.28±0.06 μg/kg in dry season at the swamps or entry point to Lake Victoria in sediments while o, p’- DDE had the least concentration of 0.21±0.08 μg/kg during the wet season. Soil organic carbon, soil organic matter and pH in water samples determined, ranges from 2.14±0.09% to 5.47±0.07%, 3.69±0.17% to 9.43±0.11% and 7.26±0.16 to 7.90±0.02 respectively in both season. The levels of the DDTs increased downstream as the river approached Lake Victoria. Since some of the DDTs metabolites were at levels beyond the recommended limits, frequent monitoring of pesticide residues in the area is necessary for preventing, controlling, and reducing environmental pollution to minimize health risks.

Keywords: DDTs Metabolites or Isomers, Organochlorine pesticides (OCPs), Persistent Organic Pollutant (POP),