Química Moderna e Aplicações

Abstrato

Investigation of Selected Organic Compounds Influence on Water Quality Along the Olifants River in South Africa

Shadung J Moja1, David Odusanya, Fanyana M Mtunzi and Christelle T Mulanga

Water is a crucial natural resource, indispensable to food production, life, the environment, power generation, industry, sanitation and hygiene. Organochlorine Pesticides (OCPs) in the environment are not wanted due to their negative effects on human beings and animals. As a result, there is a need to continuously monitor their presence in the environment. In this study, surface water samples were collected once a month during the dry season and during wet season from selected five points along the Olifants river in South Africa and stored at a temperature of ≤ 5°C before analysis. The OCPs were extracted with dichloromethane (DCM) using the Liquid-Liquid Extraction (LLE) method. After undertaking the sample through the clean-up process, the crude extracts obtained were put into the column chromatography and eluted with hexane and about 1.5 μL of the purified extracts were analysed by the Gas Chromatographic-Mass Spectrophotometer (GC/MS).

The percentage recoveries, varied from 32-116% for p,p’-DDT and 4,4'-DDD respectively in triply spiked water samples. The standard deviation for most of the compounds is less than ± 0.04, with the exclusion of Heptachlor (± 0.14). The seasonal variability of OCPs show that during the dry season, the Olifants River is mostly polluted at the Oxford site with (BHC-beta, Aldrin, Heptachlor-epoxide, Endosulfan-alpha and Endrin), at the Ga-Selati site with (Heptachlor-epoxide and Endrin) and at the Wolvekrans site with (Endosulfan-alpha). The summer season data show that most pollution happen at the Ga-selati site with BHC-beta and at the Waterval site with (Heptachlor and BHC-gamma) respectively. The OCPs that reached the river catchment were significantly above the WHO drinking water quality guidelines and its cause for concern for those who are exposed or use it.