Health Risk Assessment of Heavy Metal Pollution in Groundwater Around an Exposed Dumpsite in Southwestern Nigeria

摘要

Background. Groundwater quality can be poor in Nigeria due to indiscriminate refusedumping. Exposed dumps serve as point source pollution that discharge potentially toxicheavy metals into the environment.Objectives. The present research aimed to assess the impact of metal pollution ongroundwater quality in hand-dug wells around an active dumpsite and to evaluate the longterm human health effects of this pollution.Methods. Water samples from hand-dug wells used for drinking, irrigation and domesticpurposes were collected around the dumpsite. Two samples were collected at each locationfor cation and anion analyses. Samples for cation analysis were acidified with concentratedhydrochloric acid to preserve the elements in the samples, while those for anion analysiswere not acidified. Collected samples were analyzed using inductively coupled plasma massspectrometry and atomic absorption spectroscopy.Results. Mean concentrations of metals and physical parameters were compared withthe World Health Organization’s standards (2012). All samples were found to be withinpermissible limits, except for arsenic (As) (0.13 mg/L), potassium (K) (29.94 mg/L), lead(Pb) (0.38 mg/L), cadmium (Cd) (0.003 mg/L) and average temperature (31.93oC) as aresult of corroded service pipes containing Pb in the dumpsites and the reaction of leachateswith various materials such as used battery, tins, and electronic wastes which later leakedinto the groundwater. The geoaccumulation index revealed Pb to be moderately to highlycontaminated in groundwater.Conclusions. Heavy metal pollution can cause deleterious health effects that can lead toshort- and long-term diseases such as keratosis (skin hardening), lung cancer, bladder cancerand ultimately death if proactive steps are not taken. Disposal bags should be providedto all houses in the area, as well as guaranteed waste disposal trucks and dispose of wasteat approved sites. In addition, enforcement agents should ensure compliance with rulesand regulations. A centralized, deep, double-cased well should be constructed in a cleanenvironment in the study area for drinking and domestic use.Competing Interests. The authors declare no competing financial interests.