IMPACT OF HEAVY METALS RELEASED FROM HOSPITAL WASTEWATER ON GROUNDWATER QUALITY: CUMULATIVE RISK ASSESSMENT FOR DRINKING WATER CONSUMERS

Contamination of natural aquatic ecosystems by hospital wastewater is a major environmental and human health issue. In certain developing countries, hospitals usually discharge their wastewater into septic tanks equipped with diffusion wells. The discharge of chemical compounds from hospital activities into the natural environment can lead to the pollution of water resources and risks for human health. Indeed, Chemical substances used in hospitals for medical purposes and research have been detected in surface and groundwater.

In Port-au-Prince, the impact of heavy metals released from hospital wastewater on groundwater quality and the substantial risk to local resource users have been studied. The presence of heavy metals (chrome, nickel and lead) has been identified in groundwater. Concentrations of lead [40 µg/L], Nickel [250 µg/L] and Chromium [470 µg/L] greater than the respective threshold value of these metals in drinking water, were measured in groundwater. Studies on human exposures to chemicals and associated health effects in drinking water allow to major chemical risks, particularly for children, relating to Pb(II), Cr(III), Cr(VI) and Ni(II) contained in the groundwater. However, this research has been only conducted on single chemicals. The aims of this study were (i) to carry out a brief review of to health impact from exposure to chemical mixtures in order (ii) to evaluate the cumulative risk assessment of heavy metals for human health in drinking water. Hazard index evaluation method (HI) has been used to assess the health mixture effects of the selected heavy metals on hepatic, renal organs on the groundwater consumers. A more-than-additive joint toxic action (HI >1) has been obtained for the hazard index (HI) calculation of the 3 metals on both target organs. These results require monitoring in order to understand and manage the cumulative human health risk by heavy metals in Port-au-Prince’s drinking water.