Probabilistic human health risk assessment of groundwater contamination due to metal leaching: A case study of Indian dumping sites

Abstract

In the present study, a probabilistic human health risk assessment (HHRA) due to metal leaching was conducted for five major dumping sites of India. Observed data of leachate/groundwater samples near dumping sites were used in calculating the non-carcinogenic hazard quotients (HQs) for the children and adults via oral ingestion and dermal contact exposure scenario using 10,000 Monte Carlo type simulations. Variance attribution analysis was performed to determine the uncertainty contribution of input parameter towards variance in the hazard quotient. HQs for fly-ash open dump, Nashik were found to be varying from 1 to 9000, indicating a cause of concern for people living nearby. The ranking order of dumping sites for posing a risk was found as Fly-ash dumping site, Nashik > Ariyamangalam open dump > Okhla, Delhi > Ghazipur, Delhi > Bhalswa dump, Delhi. Variance attribution analysis indicated that the body weight (BW) and exposure duration (ED) contributed about 35% to 55% towards the overall uncertainties of estimated HQs for the child subpopulation, while, for adult subpopulation, ED was observed to be a primary contributor (>95%). Results indicated that more information is required for characterizing the exposure duration of children and adults for effective HHRA that can help risk managers.

Keywords:

• Metal leaching
• human health risk assessment
• uncertainty analysis
• Monte Carlo simulation
• variance attribution

Acknowledgments

First author would like to acknowledge Professor Arun Kumar, Department of Civil Engineering, IIT Delhi for teaching concepts related to human health risk assessment and Dar Tafazul Islam for reviewing the manuscript. The authors would also like to thank the anonymous reviewers and Editor for their comments and suggestions that were helpful in improving the manuscript.