Public Health Protective Concentration for para-Chlorobenzene Sulfonic Acid

Feb 2, 2015

The Office of Environmental Health Hazard Assessment (OEHHA) is identifying a public health protective concentration of 3 parts per million (ppm) for the chemical para-chlorobenzene sulfonic acid (pCBSA) in drinking water. pCBSA is a by-product of the production of dichloro-diphenyl-trichloroethane (DDT) and is often found in soil at former DDT manufacturing sites. pCBSA is highly water soluble and has contaminated aquifers beneath these sites.

A public health protective concentration is a health-based advisory level that OEHHA develops for a chemical in drinking water for which there is no public health goal or formal regulatory standard. Like a public health goal, a public health protective concentration is based on a risk assessment using the most current principles, practices and methods in the fields of toxicology, epidemiology and risk assessment. The susceptibility and exposure of infants and children is explicitly incorporated into the assessment. A public health protective concentration differs from a public health goal in that it does not undergo formal public review and comment, or an external scientific peer review.

Regulatory entities can use a public health protective concentration as guidance in their management of potential drinking water sources where the chemical may be present. Like a public health goal, a public health protective concentration is not a boundary line between a "safe" and "dangerous" level of a contaminant. Drinking water can still be considered acceptable for public consumption if it contains a chemical at a level exceeding the public health protective concentration.