Mercury (Hg) contamination from historic mercury processing in and near Huancavelica, Peru is above health-based screening levels in the walls, floors, and indoor air in 75% of sampled earthen homes. Extrapolating this to a citywide level, where 50% of the homes are earthen, there is the potential of about 19,000 people being at risk of mercury exposure and adverse health effects.
The EHC has prepared a Remedial Investigation report (RI), the objective of which is. The objective of the RI is to characterize the extent and magnitude of mercury contamination and to determine the risk to human health from exposure to mercury in people’s homes as well as other sources such as outdoor soil, or contaminated food, such as fish. The RI is a standardized document used by USEPA and US state environmental cleanup programs that follows a specified format.
The EHC’s findings identified significant health risks to people living in contaminated homes from exposure to mercury. The two main exposure routes are incidental ingestion of particulate mercury from dust and debris in the home and inhalation of mercury vapor originating from contaminated floors and walls.
Site-specific risk-based screening levels were developed using site-specific exposure factors for the ingestion pathway and established reference concentrations (RfCs) were used to evaluate the inhalation pathway. The site-specific screening level for total mercury in walls and floors, based on risk to children, and using site-specific bioaccessibility analysis, was determined to be 75 milligrams per kilogram (mg/kg). The World Health Organization (WHO) screening level or RfC of 0.2 micrograms per meter cubed (µg/m3) was used for inhalation of mercury in homes.
Based on the results presented in the Remedial Investigation, approximately 75% of all the earthen homes have the potential to be contaminated at levels above screening levels and pose a risk to human health. In other words, approximately 19,000 people may be exposed to levels of Hg in soil and/or vapor above international health-based screening levels and are potentially at risk for developing adverse health effects.