Recently, the U.S. Geological Survey (USGS) National Water-Quality Program updated information on Health-Based Screening Levels (HBSLs) for sources of drinking water. The updated information is available in its searchable database. The information has been updated to consider EPA’s most recent methods and exposure assumptions for establishing drinking water guidelines.
As the USGS website explains, HBSLs are non-enforceable water-quality benchmarks that can be used to (1) supplement Environmental Protection Agency (EPA) Maximum Contaminant Levels (MCLs) and Human Health Benchmarks for Pesticides (HHBPs), (2) determine whether contaminants found in surface-water or groundwater sources of drinking water may indicate a potential human-health concern, and (3) help prioritize monitoring efforts. HBSLs were developed by the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Project for contaminants without USEPA MCLs or HHBPs.
HBSLs were updated in May 2018 in order to:
- Update toxicity information and benchmarks, when possible, for the 808 contaminants included in the online searchable HBSL database, including 31 new contaminants added since the last HBSL update in 2014.
- Update all HBSLs to be consistent with new EPA methods and exposure assumptions.
- Replace HBSLs for 4 contaminants that have new EPA Chronic Noncancer or Carcinogenic HHBPs.
The searchable table contains over 800 contaminants, of which 175 have HBSLs. Click here to learn more about HBSLs and guidance on their use.