**3.4 Health effect due to elevated heavy metals in groundwater**

The distribution of Pb in groundwater appears to be quite widespread. Twentyone (21) representing about 84% of sampled groundwater elevated Pb levels exceeding [7] limit of 0.01 mg/l for potable water in the study area. This presents a potential health hazard to the inhabitants. According to [26], this is because, Pb normally accumulates in human body and builds up over a long period of exposure with no known documented usefulness to human health regardless of the pathway. But instead, exposure to different levels of Pb may predispose children, pregnant women and adults in general to serious health consequences [7]. According to [27], low levels of Pb (Pb ≤ 5 μg/dl) may lead to hearing impairment, malfunctioning of blood cells in children, low IQ and damage to central and peripheral nervous systems. In pregnant women, it may lead to reduced growth of foetus and premature birth. This may put the lives of both the unborn baby and mother at risk. Pb may cause delayed puberty and reduction in IQ in children while there could be incidences of increased blood pressure when humans are exposed to Pb concentrations between 5 and 10 μg/dl. According to [26], exposure to Pb levels exceeding 15 μg/dl may predispose human to nervous disorders, reduced kidney function, low sperm count in men, and delayed conception in women. In this study, measured Pb concentrations fall within 'low Pb level' indicating that ingestion of groundwater by human may predispose especially children and pregnant women to potential health risks such as low IQ, damaged central and peripheral nervous system, impaired hearing and functioning of blood.

The concentration of Ni in sampled groundwaters ranged from 0 to 0.41 mg/l with a mean of 0.059 mg/l. Ten (10) out of the twenty-five (25) groundwater samples, representing about 40% had levels of Ni exceeding [7] permissible limit of 0.02 mg/l. According to [28], the commonest sources of Ni in mining areas may include effluent water generated from mining and smelting operations, runoff from tailing piles, or from utility water used for mine operations. Nickel has an extensive range of carcinogenic mechanisms which include regulation of transcription factors, controlled expression of certain genes and generation of free radicals. Nickel has been shown to be implicated in regulating the expression of specific long non-coding ribonucleic acids (RNA). It has also been demonstrated that nickel can generate free radicals, which contribute to carcinogenic processes. Common adverse health effects when Ni is ingested at high concentrations on humans include chronic bronchitis, lungs and nasal sinus cancer and reduced lung function. The exposure to nickel at high concentrations can be alarming as it causes chronic bronchitis, lungs and nasal sinus cancer and reduced lung function [29].

Cd concentration in the area varied from 0 to 0.03 mg/l with average value of 0.059 mg/l. In the current study, about 32% of groundwater had Cd levels above recommended limits for drinking water. High levels can be linked to the weathering and subsequent dissolution of chalcopyrite and pyrite ores in the area [30]. These minerals are common pathfinder minerals of gold within the meta-volcanics of Ghana [14]. The ingestion of Cd at levels exceeding the [7] permissible limits for drinking water can cause stomach irritation resulting to vomiting and diarrhea, and also lead to degenerate bone disease such as osteoporosis (skeletal damage). Shortterm exposure to inhalation may lead to severe damages to the lungs and respiratory irritation while long-term exposure may lead to deposition in bones and lungs. Cd is highly toxic to the kidney and when accumulated in the proximal tubular cells at higher concentrations may predispose humans to renal dysfunction and kidney disease. Cd is also classified as group 1 carcinogens for humans by the International Agency for Research on Cancer [31].

*Effects of Illegal Artisanal Gold Mining Operations on Groundwater Quality in Ghana… DOI: http://dx.doi.org/10.5772/intechopen.100242*

Values of As in this study varied from 0.003 mg/l to 0.308 mg/l with an average concentration of 0.042 mg/l. Three samples out of twenty-five (25) sampled groundwater, representing about 12% had As values exceeding the recommended limit for potable water. Higher levels of As in groundwater may be due to anthropogenic activities such as mining and processing of gold ores, and naturally from water-rock interactions or soil-water interactions [7]. According to [32], As is commonly associated with ores containing metals, such as copper and lead. The strong positive correlation (0.73) between As and Pb concentration in this study supports this assertion and may indicate a common source. Exposure of As at lower levels can cause nausea and vomiting, reduced production of erythrocytes and leukocytes, abnormal heartbeat, pricking sensation in hands and legs, and damage to blood vessels. Long-term exposure may result in the occurrence of skin lesions, internal cancers, neurological problems, pulmonary disease, peripheral vascular disease, hypertension and cardiovascular diseases, and diabetes mellitus [33].
