Impact of organic contaminants from dumpsite leachates on natural water sources in the Enugu Metropolis, southeastern Nigeria

This study evaluates the impact of leachates from a municipal dumpsite on the quality of domestic water sources in the area for potable use. Concentrations of leachate-associated organic contaminants (such as diethyl–phthalate, total organic halogen (TOH); 2,4-dichlorophenol; nonylphenol–ethoxylate; methyl–ethyl–phthalate; borneol; total organic carbon (TOC); total Kjeldahl-nitrogen (TKN); ammonium–nitrogen (NH₃–N); nitrate (NO₃); nitrate–nitrogen (NO₃–N); and total phosphorus (TP)) in rivers and groundwater in the Enugu Metropolis in southeastern Nigeria were assessed in this study. Results of laboratory analyses indicate that the average values of diethyl–phthalate, borneol, TOH, nonylphenol–ethoxylate and TOC are 0.08 mg/l, 0.04 mg/l, 1.05 mg/l, 0.2 mg/l and 1.64 mg/l, respectively for groundwater and 0.1 mg/l, 0.03 mg/l, 0.74 mg/l, 0.19 mg/l and 1.74 mg/l, respectively, for rivers. Three (diethyl–phthalate, borneol and TOH) out of these major five contaminants, in both rivers and groundwater, exceeded the maximum permissible limits, suggesting that the domestic water sources are marginally contaminated by the leachates. ANOVA test result suggests that the data sources were significantly variable, while principal component and correlation analyses identified TOH, 2,4-dichlorophenol, TKN, NO₃, NO₃–N, TP and borneol, which originated most probably from degradation of plastic materials and organic wastes in the dumpsite, as the priority contaminants. Consumption of domestic water sources within the dumpsite area, in untreated state, could lead to health risks as these priority organic contaminants are mostly carcinogenic, toxic and injurious to human systems.