Update: May 2004
Current Massachusetts Regulatory Limit
ORSGL = 0.0004 mg/L
Federal Regulatory Limit
The U.S. EPA has not published an MCL for 1,3-dichloropropene.
Basis for Criteria
1,3-dichloropropene is likely to be carcinogenic to humans. Under the old U.S. EPA classification system, it was designated as a B2 carcinogen. The ORSGL is calculated based on the IRIS chronic oral cancer potency factor and corresponding to the Drinking Water Program's target excess lifetime cancer risk of one in a million.
- Oral Cancer Potency Factor = 1 x 10-1 (mg/kg/day)-1 (U.S. EPA, 2004)
- Converted to Unit Risk factor for ingestion of drinking water:
1 ug/L x 1 mg/1000 ug x 2 L/day/70 kg x 0.1 (mg/kg/day)-1 = 2.8571 x 10-6
- One in a million risk level calculated: 1 x 10-6 x 1 ug/L/2.8571 x 10-6 = 0.35 ug/L (0.0004 mg/L)
carcinogenicity (see below)
Likely To Be Carcinogenic to Humans/B2
The cancer classification is based on observations in F344 rats (for stomach, adrenal and thyroid tumors and liver nodules) and B6C3F1 mice (forestomach, urinary bladder and lung tumors), positive mutagenic activity, and structural similarity to known oncogens that produce similar types of tumors in rodents.
The U.S. EPA recommended a cancer slope factor of 0.1 (mg/kg/day)-1 on 5/25/00.
PQL: 0.0005 mg/L
503; GC-purge and trap
524; GC/MS-purge and trap
PQLs and analytical methods may have been updated since this guidance value was last revised. Updated analytical methods for drinking water and their associated PQLs may be found at http://www.epa.gov/safewater/methods/methods.html
Other Regulatory Data
Any Health Advisories, Reference Doses (RfDs), cancer assessments or Cancer Potency Factors (CPFs) referenced in this document pertain to the derivation of the current guidance value. Updated information may be obtained from the following sources:
Health Advisories - The U.S. EPA provides guidance for shorter-term exposures for chemicals based on their non-cancer effects. Current health advisories may be more current than those used to derive MCLs and may be found at http://www.epa.gov/waterscience/drinking/standards/dwstandards.pdf
RfDs, cancer assessments and CPFs - For specific information pertaining to derivation of drinking water criteria, consult the Federal Register notice that announces the availability of the most current guidance for that chemical. In addition, information on other current RfDs and CPFs as well as cancer assessments for specific chemicals may be found in the U.S. EPA Integrated Risk Information System (IRIS) at http://www.epa.gov/iris/. Please note that the information in IRIS may differ from that used in the derivation process as published in the Federal Register notice.
U.S. EPA (U.S. Environmental Protection Agency). 2004. Integrated Risk Information System (IRIS). Washington, D.C http://cfpub.epa.gov/ncea/iris/index.cfm.