WETLAND WATER QUALITY DEGRADATION: AN INVESTIGATION INTO SEWAGE DISPOSAL IMPACT IN BONNY ISLAND, NIGERIA.

Abstract

This study investigates the physical and chemical characteristics of water quality in the wetland areas of Bonny Island, Nigeria, with a focus on the impacts of sewage disposal practices. The rapid urbanization and industrialization in the region have led to the unchecked discharge of sewage into wetlands, threatening both environmental sustainability and public health. The research examined five major wetlands: Finima Lighthouse, Workers’ Camp, King William Dappa Pepple, Ayambo, and Iwoama. Water samples were analyzed for key parameters, including pH, temperature, turbidity, total solids, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), and concentrations of heavy metals like lead (Pb), cadmium (Cd), and mercury (Hg). The results revealed significant deviations from World Health Organization (WHO) water quality standards. Turbidity levels ranged from 6.19 NTU to 21.29 NTU, exceeding the WHO limit of 5 NTU, particularly at King William Dappa Pepple. The BOD levels varied between 0.83 mg/L and 1.87 mg/L, while COD levels ranged from 40.4 mg/L to 82.4 mg/L, indicating high levels of organic pollution. Dissolved oxygen (DO) levels were found to be within acceptable limits (5.2 to 5.73 mg/L),heavy metal concentrations, particularly mercury, exceeded WHO limits, with levels as high as 0.031 mg/L compared to the standard of 0.001 mg/L. Total coliform and E. coli levels were alarmingly high across all sites The study concludes that sewage disposal has significantly degraded the water quality in Bonny Island's wetlands, leading to potential health risks such as waterborne diseases like typhoid, cholera, and dysentery. The findings underscore the urgent need for the implementation of sewage treatment facilities and public education on waste management. Addressing these issues is critical to preserving the wetland ecosystems and protecting the health of local communities.