Screening Levels
N/A
Maximum Contaminant Level
The Maximum Contaminant Level (MCL) is the highest level of a contaminant that is allowed in drinking water.
MCL: 5 pCi/L
National Primary Drinking Water Regulations for “Radium 226 and Radium 228 (combined)” (Last Updated by the EPA in May 2009)
Decay Chains
Radium-226
The stable isotope within the Radium-226 decay chain is lead (Pb-206). In an area with Radium-226 contamination, there could also be lead contamination.
Radium-228
Radium-228 is part of the Thorium-232 decay chain. The stable isotope in this chain is lead (Pb-208). In an area with Radium-228 contamination, there could also be lead contamination.
Units
| Abbreviation | Meaning | Notes |
|---|---|---|
| pCi/L | radioactivity of chemical (picocuries, pCi) per volume of water (liter, L) | A Curie is a unit of radioactivity equivalent to that of one gram of radium; pico means one-trillionth |
For more information about these units and their conversion factors, visit https://cfpub.epa.gov/ncer_abstracts/index.cfm/fuseaction/display.files/fileid/14285.