The Minnesota Department of Health has revised its Health Risk Limit (HRL) for Bromodichloromethane (BDCM) based on potential cancer risk; the HRL was lowered to 3.0 µg/L from the value of 6.0 µg/L, established in 1993. BDCM is designated as “likely to be carcinogenic to humans” based on animal studies and studies in humans exposed to total trihalomethanes.
Bromodichloromethane (BDCM) belongs to a group of chemicals called trihalomethanes. Trihalomethanes are byproducts of water disinfection. In the past, BDCM was used as a flame retardant and fire extinguisher fluid, as well as a solvent.
BDCM has been detected in groundwater in Minnesota at levels up to 11 µg/L. There have been a limited number of detections in Minnesota surface water, primarily near landfills. Surface water levels of BDCM were approximately 1 µg/L. BDCM has been detected in
Minnesota drinking water at concentrations between 0.2 µg/L and 56 µg/L.
The US Environmental Protection Agency (EPA) does not have a maximum contaminant level (MCL) for BDCM alone in drinking water, but does have an MCL of 80 µg/L for total trihalomethanes (all trihalomethanes added together, including BDCM) in public water