Potentially toxic element contamination and risk assessment of borehole water within a landfill in the Nnewi metropolis

Abstract

Borehole water has been used as a vital source of water for many communities. The pollution of these boreholes by potentially toxic elements using unlined solid waste dumpsites has posed a significant risk to the populace living around the dumpsite. This study investigates the environmental impact of potentially toxic elements on borehole water within the vicinity of an unlined dumpsite in the Nnewi metropolis. The upstream and downstream samples (16 each) were collected in wet and dry seasons. The potentially toxic elements analysis wasperformed using the methods of the American Public Health Association (APHA) under the required conditions. The quality of the boreholes was assessed using the World Health Organisation (WHO) acceptable limits for drinking water. The risk assessment was estimated for carcinogenic and non-carcinogenic risks using ingestion and dermal routes. The results show that the borehole water wascontaminated with potentially toxic elements through leachate infiltration, which exceeded the WHO permissible limits for drinking water at both locations and seasons. The upstream borehole samples were more contaminated than the downstream samples for both seasons, due to their proximity to the pollution source. The hazard indices of the ingestion and dermal routes showed that the borehole water poses serious cancer and non-cancer health risks for both locations. The results revealed that children are more susceptible to cancer and non-carcinogenic health threats than adults for both locations and seasons. The pollution indices of borehole water for wet season (9.028 and 5.728) and dry season (7.107 and 5.328) for upstream and downstream samples respectively, were polluted and the pollution was higher in the wet season. The borehole water samples were unsuitable for drinking water and should be treated before use.

Chemical fractionation and mobility factor of some heavy metals in refuse dumpsite soil in Awka Metropolis, Anambra State, Nigeria

“…The speciation of Ni follows the order; Residual > carbonates > Fe-Mn oxide > organic > exchangeable with their fractions to be 7.28±0.02, 7.01±0.01, 4.12±0.02, 3.27±0.03 and 3.07±0.10 respectively. This finding is consistent with some researches [17,20,21,[27][28][29][30][31][32][33].…”

Evaluating the human health risks of heavy metal contamination in copper and steel factory effluents in Nnewi, Anambra State, Nigeria

“…After every 10 samples, a certified standard and a blank solution were run to check for contamination and drift. The analyses were performed in triplicate with the mean concentration of the metal present extrapolated from the standard curve recorded [7] .The heavy metals determination and their instrumentation procedures were applied following standard guidelines [32] . Every batch of samples was prepared similarly to the reagent blanks.…”

“…The main sources of ground water contamination are natural/ geogenic, poor landfill waste and sanitary practice, and the use of agrochemicals [4] . Borehole water has continuously been a primary source of water for drinking and domestic purposes for the residents of Nnewi in Anambra State Nigeria [6] , [7] .…”

“…There are studies conducted in and around Nnewi to examine surface and groundwater quality for drinking and agricultural purpose using different water quality indices [5] , [9] , [10] , [13] , [17] , [18] . Also there are studies on heavy metals content of borehole water within landfill/waste dumpsites in Nnewi [7] , [19] and on soil samples [11] , [20] . There is a remarkable lack of study on metal poisoning resulting from copper and steel factory wastes and its consequences for human health in the study region.…”

Concentration levels and pollution status of selected heavy metals in active dumpsites in Port Harcourt, Rivers State, Nigeria

“…To prevent additional harm to the ecosystem and food chain, ecological risk assessment is crucial for identifying potential threats and dangers posed by heavy metals to the environment. It has been observed that these hazardous heavy metals can have a variety of detrimental impacts on biological systems when exposed to them continuously through diverse pathways [44][45][46][47][48][49][50].…”