Domestic Wastewater Discharge Effects on Water Quality and Public Health in Choba River, Rivers State, Nigeria
Obunadike Joy C
Department of Agricultural and Vocational Technology, Michael Okpara University of Agriculture, Umudike, Nigeria.
Okpoji Awajiiroijana U. *
Department of Pure and Industrial Chemistry, University of Port Harcourt, Choba, Nigeria.
Dare Blessing E.
Department of Environmental Engineering, University of Ibadan, Nigeria.
Obi Justina N
Department of Chemistry, Federal University of Technology, Owerri, Nigeria.
Udo Johnny J.
Department of Civil Engineering, Akwa Ibom State University, Ikot Akpaden, Nigeria.
Akpan Mary P.
Department of Civil Engineering, Akwa Ibom State Polytechnic, Ikot Osurua, Nigeria.
Garuba Muhammed H.
Department of Chemistry and Industrial Chemistry, Kwara State University, Malete, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Urban rivers in the Niger Delta are increasingly impacted by untreated domestic wastewater due to rapid population growth, inadequate sanitation infrastructure, and unplanned urban development. This study evaluated the effects of domestic wastewater discharge on water quality and public health of the Choba River, Rivers State, Nigeria. Eighteen surface water samples were collected from three representative zones along the river course: an upstream control site, a midstream zone receiving major domestic wastewater inputs, and a downstream post-discharge zone. In situ measurements were conducted using calibrated portable meters, while laboratory analyses of biochemical oxygen demand (BOD), chemical oxygen demand (COD), nutrients, and heavy metals (Fe, Pb, Cd, Cr, Ni, Zn, and Cu) were performed using standard analytical methods and flame atomic absorption spectrophotometry. Microbiological quality was assessed using the membrane filtration technique. The weighted arithmetic water quality index (WQI) and human health risk assessment models were applied to evaluate cumulative pollution and exposure risks. The results showed progressive deterioration in water quality downstream of wastewater discharge points. pH declined from near-neutral conditions upstream (6.8–7.2) to slightly acidic levels downstream (5.9–6.4). Electrical conductivity and total dissolved solids increased markedly downstream, while dissolved oxygen decreased from 5.6–6.8 mg/L upstream to 1.9–3.2 mg/L downstream, indicating hypoxic conditions. BOD and COD increased substantially, reflecting severe organic pollution. Lead and cadmium concentrations exceeded guideline limits at downstream locations, and total coliform counts increased sharply from 120–480 CFU/100 mL upstream to 2,400–6,800 CFU/100 mL downstream. WQI values ranged from 132 (poor) upstream to 412 (unsuitable) downstream. Non-carcinogenic hazard quotients for children exceeded unity for lead (HQ = 1.94) and cadmium (HQ = 2.11). Therefore, domestic wastewater discharge has severely degraded the Choba River, rendering it unsuitable for domestic and recreational use.
Keywords: Domestic wastewater, surface water quality, heavy metals, microbiological contamination, Choba River