Assessing the Spatio-temporal variation of water quality over time at Malelane area in the lower catchment of the Crocodile River, Mpumalanga, South Africa

Freshwater is a limited resource experiencing accelerated contamination in several nations due tovarious reasons, including both natural and human-induced influences such as climate, topography,mining, industry, and agriculture. South Africa is characterized by water scarcity, a conditionexacerbated by its status as a developing nation. Consequently, the country has the dual task ofsafeguarding water quality while simultaneously striving to enhance water supply and sanitationinfrastructure. This study aims to assess the impact of agricultural activities on the water qualityof the Crocodile River by using physiochemical tests and a water quality index tool. The grabsampling methodology was utilized on-site to collect water quality parameters which were analysedat a SANAS (South African National Accreditation System) laboratory. Statistical analysis wasperformed using the Seaborn software due to the extensive dataset contained in the present study.Highest concentrations of NO2+NO3were recorded in the Autumn season between 2020 and 2022with levels ranging between 1,2 to 0.7 mg/l. While spring and summer of 2018 and 2019 recordedthe lowest concentration of NO2+NO3at<0.4 mg/L, the low concentrations could be due to thedilution of the summer rainfalls as compared to the high concentrations that were recorded inthe drier season of the year leading into winter. This could also explain significant concentrationof PO4(0.35 mg/L) that were recorded during the winter of 2016. The findings indicate thatthroughout the autumn of 2017 and spring of 2019, the reported ammonia nitrate concentrationexceeded 0.225mg/L. The WQI results revealed that the water quality at Malelane is regular at avalue of 62.18, which suggests that the quality of the water is average to below standard.