Q: How does EPA’s study and assessment report define drinking water resources?
A: The study employs a broad definition of drinking water and is not limited to domestic wells or public water supplies. For this study, drinking water resources are defined as any water that now serves, or in the future could serve, as a source of drinking water for public or private use. This includes both surface water resources and groundwater resources. “Groundwater” includes water found underground, usually in aquifers, which can supply wells and springs. “Surface water” includes all water naturally open to the atmosphere, such as rivers, lakes, reservoirs, etc.
Q: There are a lot of chemicals used in hydraulic fracturing that we don’t have any information for when it comes to toxicity. Why don’t we know more about these chemicals?
A: The lack of peer-reviewed toxicity data presents a significant limitation in assessing the severity of impacts on drinking water resources from activities in the hydraulic fracturing water cycle. Of the 1,606 chemicals considered in the final assessment report, 173 chemicals (11%) have chronic oral toxicity values that can be used for human health risk assessment. It should be noted that chemicals used in other industries also often lack a similar amount of human health data.
EPA’s ACToR database contains a large and disparate amount of public data on chemicals, ranging from federal toxicity reference values developed by EPA that have undergone extensive peer review to study and test results that have undergone little to no peer review. Of the 1,606 chemicals considered in the final assessment report, 735 (46%) have at least some relevant public data available in ACToR (including some data-poor chemicals), which may help to fill data gaps in the ongoing effort to understand potential hazards of hydraulic fracturing chemicals.