Toxic elements in groundwater of Lagos and Ogun States, Southwest, Nigeria and their human health risk assessment

Abstract

A good quality drinking water is essential for human survival. However, a large percentage of the populations in most developing countries (Nigeria inclusive) do not have access to potable water. This study was therefore conducted to assess the extent of risk arising from consumption of toxic elements in groundwater samples collected from Lagos and Ogun States, Southwest, Nigeria. Twelve toxic elements concentrations (As, Mn, Cd, Cr, Pb, Ni, Al, Ti, V, Hg, Li, and Sn) were determined from 170 groundwater samples using inductively coupled plasma-mass spectrometry, and the physicochemical parameters were determined using standard methods. The pH results revealed that most of the water samples were slightly acidic. Of the twelve toxic elements, only Mn, Cd, Pb, Ni, and Al have concentrations higher than the WHO recommended limit in drinking water. The average dose of Mn and Al consumed daily from groundwater by an adult in Lagos state is 3.4 and 23.2 (μg/kg body weight), respectively. Similarly, an adult in Ogun State consumed an average daily dose of 6.09 and 25 (μg/kg body weight) Mn and Al, respectively. A greater threat was posed to children and infants. The order for risk of cancer in groundwater from Lagos State was Pb > Cr > As > Cd while the order in Ogun State groundwater was Cr > Cd > As > Pb. The relative high concentrations of Mn, Al, and Pb obtained in this study can be attributed to industrial and anthropogenic activities in the study area. Treatment of groundwater before consumption is recommended to avoid possible adverse cumulative effect. Improved waste disposal methods and regular monitoring of toxic elements in groundwater of the study area should be adopted to safeguard human health.

Assessment of major ions and trace elements in groundwater supplied to the Monterrey metropolitan area, Nuevo León, Mexico

“…Studies performed in Pakistan indicate that more than 74 million inhabitants are subjected to health risk from As, Cd, Cr, Fe, Mn, Ni, and Pb contamination of groundwater (Bhowmik et al 2015). Similarly, other studies carried out in highly populated states of Nigeria (more than 16 million inhabitants) suggest a high risk of cancer development due to the ingestion of groundwater with elevated levels of Cr, Pb, As, and Cd (Ayedun et al 2015). In addition, studies carried out by the US Geological Survey in public-supply wells distributed across 35 states of the USA indicated that the chemical mixtures in groundwater that had the greatest potential toxicity were primarily composed of trace elements (including As, Sr, and U) (Toccalino et al 2012).…”

Human health and environmental assessments of small-scale and artisanal mining activities in the Gold City of Ijeshaland, Southwestern Nigeria

“…), IR = Ingestion rate of water or fish; water = 2 L day −1 for an adult, 1 L day −1 for a child, 0.75 L day −1 for an infant (Ayedun et al 2015); Fish = 24.7 g day −1 for an adult based on the Food and Agriculture Organization (FAO) annual per capita fish consumption statistics for Nigeria given as 9.0 kg (FAO 2008). C = Concentration of trace metals in water (μg L −1 ) or fish (μg kg −1 ) samples, BW = Body weight (kg); 60 kg for an adult, 10 kg for a child, 5 kg for an infant (Ayantobo et al 2014a).…”

Review of Drinking Water Quality in Nigeria: Towards Attaining the Sustainable Development Goal Six

“…Drinking water contamination by different microorganisms such as coliforms (Kumpel et al, 2016), Staphylococcus aureus and Pseudomonas species (Igbeneghu and Lamikanra, 2014) have been reported in Nigeria. Also, the presence of metals like iron, calcium, chromium and aluminum have been found in surface water (Titilawo et al, 2018) and sachet-packed water (Emenike et al, 2018), including cadmium, lead, manganese and nickel in groundwater (Ayedun et al, 2015) above permissible levels for drinking water. Other contaminants such as fluoride (Emenike et al, 2018) and light polycyclic aromatic hydrocarbons have also been reported to be present in groundwater in levels above permissible limits in some locations in Nigeria (Adekunle et al, 2017).…”