Impacts of Anthropogenic Activities on Ground Water Quality in Onitsha city, Anambra State, South Eastern Nigeria

Abstract

Ground water is transitional water that interfaces between the surface and ground. It infiltrates into the soil and percolate through various soil strata before reaching ground aquifers and water table. Ground water is contaminated through dissolved liquids from the surface, ocean salt water intrusion and contacts with natural occurring mineral substances present in soils. The movement of water between the surface and the ground helps in the recharge and discharge of water, sustenance of the ecosystems and aquatic lives and serves as a potential source of water for domestic and industrial uses. This study aimed to investigate variation in ground water contamination in Onitsha with a view to unraveling the main contaminants present in ground water. Forty water samples were extracted from wells in Onitsha metropolis and analyzed for the presence of Arsenic (Ar.), Cadmium (Cd), Lead (Pb), Mercury (Hg), Water Hardness, Temperature(T) and Potentials of Hydrogen (pH) using Atomic Absorption Spectrophotometer (AAS). The findings all affirmed a nexus between subsurface transport pathways and ground water receptors as the cause of contaminants between surface water, aquifers and water table. The sources of these contaminants are commercial activities and dumping of waste in gutters. These inferred that ground water in Onitsha city is highly contaminated with Arsenic, Lead, Cadmium and Mercury which makes city water unsafe for drinking and must require purification before utilization.