The hydrogeochemical signatures, quality indices and health risk assessment of water resources in Umunya district, southeast Nigeria

Abstract

The hydrogeochemical characteristics, water quality and health risk statuses of waters in Umunya district, southeastern Nigeria were studied, in attempt to evaluate their suitability for drinking and domestic purposes. Twelve groundwater and 3 surface water samples were analyzed for 26 physicochemical and hydrogeochemical parameters, using standard techniques. Results show that dominance of cations and anions is in the order Ca 2+ > Na + > K + > Mg 2+ and HCO 3-> Cl-> NO 3-> SO 4-, respectively. Order of dominance of the heavy metals is Pb > Zn > Fe > Ni > Mn > Cr > Ba. Eight water types were identified, with Ca-Na-HCO 3 (26.66%) and Na-Cl-HCO 3 (20%) dominating the study area. All the water types characterize five major facies. Further, the result revealed that the physical properties and chemical ionic concentrations in the waters are well below standard maximum permissible limits, although majority of the samples have pH values off the allowable limits of 6.5-8.5, classing the waters as slightly acidic. Generally, the water quality in the study area is deteriorated due to the presence of high levels of heavy metals. Water quality index results show that 46.67% of the water samples are in excellent and good categories. 13.33% are in poor water category, whereas 40% are in category unsuitable for drinking purposes. A good percentage of the waters predispose users to health risks. Stoichiometric and statistical analyses revealed that the variations in chemistry and quality of the waters are due to combined influence of human activities and geogenic processes (silicate weathering and ionic exchanges). Treatment of contaminated waters before use is, therefore, recommended.

Chemometric analysis for pollution source identification and human health risk assessment of water resources in Ojoto Province, southeast Nigeria

“…WQI reveals the multivariate composite influence of individual water quality parameters on the overall quality of water resources for drinking purposes (Rahman et al 2017;Mgbenu and Egbueri 2019;Ukah et al 2019). Using weighted arithmetic quality indexing method, the WQI was calculated to assess the suitability of the various water supplies in Ojoto for drinking purposes.…”

“…In other words, this method classified the water quality of Ojoto according to the degree of purity by calculating the quality index using pH and the analyzed heavy metals used in the health risk assessment. Specific weights (w i ) were assigned to the selected parameters, based on their individual significance in water quality analysis Mgbenu and Egbueri 2019;Egbueri 2020a). The mathematical formula used in calculating the WQI is given as:…”

“…All over the world, the consumption (ingestion) of heavy metals-contaminated waters has been reported to cause serious health issues (disasters) like skin, lung, and bladder cancers; bronchiectasis; intellectual disabilities; neurological, cardiovascular, kidney, and bone diseases; hyperpigmentation of the palm and sole; hypertension; myocardial damage; liver damage; Bowens disease; diabetes, etc. (Rahman et al 2017;Sridharan and Nathan 2018;Mgbenu and Egbueri 2019;Ukah et al 2019;Egbueri 2019cEgbueri , 2020a.…”

“…These trace elements enter water systems through many natural processes and anthropogenic activities (Wagh et al 2018; Barzegar et al 2018;Egbueri 2018Egbueri , 2019aEzugwu et al 2019;Mgbenu and Egbueri 2019). The natural processes that contribute to high concentration of heavy metals in waters include weathering of rocks and soils, decomposition of living matter, and atmospheric fall-out, whereas the anthropogenic activities encompass mining (which can lead to acid mine drainage) and mineral processing, domestic, agricultural and industrial wastes, etc.…”

“…This assessment is often carried out using chemometrics, which basically employs mathematical or statistical principles in solving problems linked to chemical water pollution. In different parts of the world, researchers (Belkhiri et al 2017;Njinga and Tshivhase 2017;Rahman et al 2017;Barzegar et al 2018;Wagh et al 2018;Mgbenu and Egbueri 2019) have successfully used different mathematical and statistical methodologies to assess the health risks of various water supplies. Such methodologies include pollution indices, multivariate statistical analyses, carcinogenic and non-carcinogenic health risk analyses.…”