V2I8P6

Chemical Analysis of Leachates from Municipal Solid Waste Dumpsites and Their Impact on Surrounding Water Bodies during Wet and Dry Seasons. A Case Study of Asaba, Delta State, Nigeria

Ugah Chukwuemeka S.^1*, Anyira-Fasanmi Mary Ifeoma¹

Abstract

Municipal solid waste dumpsites pose significant environmental and public health risks due to the generation of leachates, which often contain a complex mix of organic and inorganic pollutants. This study investigates the physicochemical composition of leachates from the Okwe dumpsite in Asaba, Delta State, Nigeria, and evaluates their impact on nearby surface and groundwater sources. Leachate, surface water, and groundwater samples were collected and analyzed for key parameters including pH, electrical conductivity (EC), total dissolved solids (TDS), biological oxygen demand (BOD), chemical oxygen demand (COD), ammonia, nitrate, phosphate, and selected heavy metals. Results revealed that leachate samples had elevated levels of pollutants, with EC reaching 3,270 µS/cm, TDS at 2,450 mg/L, BOD at 185 mg/L, COD at 650 mg/L, and ammonia at 104.2 mg/L—substantially exceeding WHO permissible limits. Surface water samples showed ammonia concentrations of 18.3 mg/L and nitrate levels of 23.6 mg/L, while groundwater samples had ammonia values of 4.8 mg/L and nitrate up to 10.4 mg/L. Heavy metals such as lead (Pb), cadmium (Cd), and iron (Fe) were also detected in both surface and groundwater above WHO standards, with groundwater lead concentrations ranging from 0.10–0.12 mg/L (WHO limit: 0.01 mg/L). Seasonal analysis indicated higher pollutant concentrations during the wet season, suggesting rainfall-induced leachate mobilization. The findings highlight serious environmental threats associated with unlined and unregulated dumpsites in urban Nigeria. Immediate remediation actions—including leachate treatment systems, groundwater protection strategies, and strict waste management policies—are recommended to safeguard water resources and public health in Asaba and similar regions.

Keywords:

Leachate, Dumpsite, Groundwater pollution, Surface water contamination, Heavy metals, Waste management, Asaba, Nigeria