Impact of effluent discharge on recreational beach water quality: a case study of Karachi-Pakistan

The degraded water quality of recreational beaches and associated diseases is a global concern. The discharge of municipal effluents and other wastes has threatened coastal resources irrespective of local authorities colossal investment in their development. Strategic assessment and monitoring of water quality are essential pathways to reduce contaminant level of microbes responsible for waterborne diseases. As in Karachi's case study, two wastewater discharge drains were identified at Sea View, which is famous for recreational activities. These two primary discharge drains contained contaminants, including various pathogens that pollute the marine environment and disturb the ecosystem. The current study aims to assess the water quality along the beach through an in-depth monitoring program lasting from May till September 2020. The assessment focused on total coliform (TC) and faecal coliform (FC) counts; biochemical oxygen demand (BOD5) and chemical oxygen demand (COD). Analysis of the results conclude that both discharge drains contained high levels of TC (1600 MPN or CFU per 100 mL of the sample) and FC (203 MPN per 100 mL). Moreover, COD and BOD levels were found to be high (COD 945 mg/L and BOD 410 mg/L). Hence, recreational activity may not be suitable near these discharge drains, indicating their association with high health risks.