Impact of informal settlement on the water quality of Diep River in Dunoon

Abstract

More than 80% of the world’s largely untreated wastewater is dumped into the environment and water bodies such as rivers and lakes. Unfortunately, many governments have been struggling to meet the increasing water demands due to rapid population growth in urban areas. One major problem has been poor sanitation and poor waste disposal practices in informal settlements, which led to the contamination of water resources. This research aimed to investigate the impact of the Dunoon informal settlement on the water quality of the Diep River in South Africa. It also demonstrates the health and environmental risks associated with poor sanitation and the use and consumption of contaminated water in the Dunoon informal settlement and seeks ways to mitigate such risks. The research used both qualitative and quantitative methods. The Diep River is used daily, mainly for farming and recreational activities. For this research, monthly water samples were collected from four strategic points of the river and sent to a laboratory to determine the concentration levels of water quality-related parameters inclusive of nitrate, phosphates, chemical oxygen demand, total suspended solids, dissolved oxygen, ammonia, and E. coli. On some occasions, the pH, dissolved oxygen, electrical conductivity, turbidity, salinity, and temperature were measured on the field using a multi-parameter reader. The results were compared with the South African water quality guidelines for aquatic ecosystems, recreation, and agriculture, and South African National Standards. Raw data of samples collected by Outa (Organization Undoing Tax Abuse) was also analysed using SPSS, and compared to the researcher’s findings. The average concentrations of E. coli, DO, electrical conductivity, salinity, ammonia, turbidity, and chemical oxygen demand exceeded the recommended limits in both the wet and dry seasons. The recommended limit for E. coli is 0 cfu/100 mL for irrigation and 0-130 cfu/100 mL for recreation purposes, but the average highest E.coli count was 1436.3 cfu/100 mL in the wet season and 11737.5 cfu/100 mL in the dry season, which was way above the recommended limits. The average COD in the wet season was 250.5 mg/L and 186.8 mg/L in the dry season, higher than the recommended limit of ≤ 75 mg/L. The EC averages in the wet season (2453.3 μS/cm) and the dry season (32208 μS/cm) were both higher than the recommended limit of 0 – 40 mS/m, equivalent to 0 - 400 μS/cm, while the turbidity averages in the wet season (60.18 FNU) and the dry season (257.04 FNU) were also greater than the acceptable limits of 3 NTU for recreational purposes and 0-1 NTU for domestic purposes (where NTU is equivalent to FNU). The average ammonia in the wet season was 9.2 mg/L and 6.1 mg/L in the dry season. The averages in both the wet and dry seasons were higher than the recommended limit of ≤1.5 mg/L. The findings also revealed that the Dunoon informal settlement has contributed to the decline of water quality in the Diep River because of inadequate waste collection sanitation and other activities. Questionnaires and observations were also used to collect data from the residents of Dunoon informal settlement and the data was also analysed using SPSS. The findings revealed that the community perceived Diep River water as polluted, and this has compromised the health of the Dunoon informal settlement residents and degraded the environment as per their responses. Given these findings, some of the recommendations are to frequently monitor and manage waste products discharged into the neighbouring aquatic environments. The lack of knowledge about legislation and water resources management amongst communities needs to be addressed through educational programs and various media platforms. Microbial, parasitic, and virus-related diseases have been spreading because of contaminated water and poor processes in the Dunoon informal settlement. Most of the community members in the Dunoon informal settlement have indicated that they suffer from skin-related diseases, diarrhoea, cholera, and other diseases due to poor sanitation and inadequate waste collection.