RESUMEN
Self-supply water sources, particularly groundwater sources, play key roles in the water supply ecosystem of developing countries. Recent studies indicate that groundwater sources in coastal communities in Ghana are under threat from improper waste management practices, seawater intrusion and atmospheric aerosol deposition. In this study, Water Quality Index (WQI) and Nemerow's Pollution Index (NPI) were employed to assess groundwater quality in four coastal communities of Ghana. The health risks associated with metal pollution of groundwater were investigated using incremental life cancer risk and hazard quotient. pH of groundwater in all the studied communities were acidic during the rainy season. Electrical conductivity ranged from 0.44 to 2.61 mS/cm in the rainy season and from 0.43 to 2.45 mS/cm in the dry season for the four studied locations. Results also showed brackish conditions and mineralization of groundwater in Winneba, Accra, and Keta. Mean nitrate concentrations in Winneba and Accra were higher than the WHO standards for both the rainy and the dry season. Arsenic was higher than the acceptable level in Accra and Keta during the dry season, while iron was higher than the acceptable levels in Accra in both the rainy and dry seasons. Principal Component Analyses showed that Pb, As, and Fe had the highest loading in the first component in Essiama, while PO4 3-and Pb had the highest loading in the second component in Accra. WQI showed that the quality of groundwater in all the studied communities ranged from marginal to poor indicating that groundwater in the coastal communities often or usually departs from desirable quality. NPI revealed that NO3- , As, and Fe contribute to groundwater deterioration. Health risk assessment showed that As posed a high cancer risk in Accra and potential cancer risk in Essiama, Winneba, and Keta during the dry season. As also posed potential cancer risk in Accra during the rainy season. Non-cancer health risk was observed for As in Accra and Keta. The findings of this study suggest urgent regulations and monitoring strategies to improve groundwater quality in the coastal communities of Ghana.
RESUMEN
A human health risk assessment of artisanal miners exposed to toxic metals in water bodies and sediments in the PresteaHuni Valley District of Ghana was carried out in this study, in line with US EPA risk assessment guidelines. A total of 70 water and 30 sediment samples were collected from surface water bodies in areas impacted by the operations of artisanal small-scale gold mines in the study area and analyzed for physico-chemical parameters such as pH, TDS, conductivity, turbidity as well as metals and metalloids such as As, Cd, Hg and Pb at CSIR-Water Research Institute using standard methods for the examination of wastewater as outlined by American Water Works Association (AWWA). The mean concentrations of As, Cd, Hg and Pb in water samples ranged from 15 µg/L to 325 µg/L (As), 0.17 µg/L to 340 µg/L (Cd), 0.17 µg/L to 122 µg/L (Pb) and 132 µg/L to 866 µg/L (Hg), respectively. These measured concentrations of arsenic (As), mercury (Hg), cadmium (Cd) and lead (Pb) were used as input parameters to calculate the cancer and non-cancer health risks from exposure to these metals in surface water bodies and sediments based on an occupational exposure scenario using central tendency exposure (CTE) and reasonable maximum exposure (RME) parameters. The results of the non-cancer human health risk assessment for small-scale miners working around river Anikoko expressed in terms of hazard quotients based on CTE parameters are as follows: 0.04 (Cd), 1.45 (Pb), 4.60 (Hg) and 1.98 (As); while cancer health risk faced by ASGM miners in Dumase exposed to As in River Mansi via oral ingestion of water is 3.1 × 10(-3). The hazard quotient results obtained from this study in most cases were above the HQ guidance value of 1.0, furthermore the cancer health risk results were found to be higher than the USEPA guidance value of 1 × 10(-4) to 1 × 10(-6). These findings call for case-control epidemiological studies to establish the relationship between exposure to the aforementioned toxic chemicals and diseases associated with them as identified in other studies conducted in different countries as basis for developing policy interventions to address the issue of ASGM mine workers safety in Ghana.