Anthropogenic pollution influences on the physical and chemical quality of water and sediments of the umdloti river system, Kwazulu-Natal

Abstract

River catchments are always under pressure from ongoing anthropogenic activities in these areas to the detriment of the water quality. This study focused on water quality studies of the uMdloti River system, KwaZulu-Natal as influenced by existing anthropogenic activities. The physico-chemical and geochemistry characteristics from 15 selected sampling sites showed elevated of parameters at some of the sampling sites and land use zones. Metal analysis from sediment samples showed high levels of Cd in the agricultural zone (6.03 μg/mg) which exceeded the 0.6 μg/mg the International Sediment Quality Guideline (ISQG) in February, high levels of Cr in the agricultural (42.26 μg/mg) and industrial zones (40.05 μg/mg) which exceeded the 26 μg/mg ISQG in February, high levels of Mn in the agricultural (1140.49 μg/mg) and peri-urban zones (1415.6 μg/mg) exceeded the 460 μg/mg ISQG in February, as well as high levels of Ni (47.6 μg/mg) in the industrial land use zone over the February sampling period which exceeded the ISQG of 11 mg/L. Contamination Factor (CF), Pollution Load Index (PLi), and grain size analysis of bottom sediments as part of geochemical analysis showed that CF revealed elevated metal concentrations in the industrial and agricultural land use zones such as Se (CF > 6) in the June sampling period. Grain size analysis of the sediments indicated that the system is dominated by larger grained sediments. The study showed that various parameters exceeded set TWQR, and ISQG acceptable levels, and were somehow linked to anthropogenic influences on river water and sediments.