Update: August 1993
Current Massachusetts Regulatory Limit
MMCL = 0.005 mg/L. ORS has adopted the MCL published by the U.S. EPA.
Federal Regulatory Limit
The MCL is based on the 1987 PQL. The MCLG is equal to zero (Fed. Reg. 1987; Fed. Reg. 1991).
Basis for Criteria
The MCLG of zero is based on carcinogenic effects reported in animals. Carbon tetrachloride has been shown to be carcinogenic in rats, mice and hamsters through oral exposure. Hepatocellular carcinomas in several study groups have been observed.
Liver lesions. The RfD is based on an adjusted NOAEL of 0.71 mg/kg/day derived from a subchronic gavage study in rats (Bruckner et al., 1986).
The classification of carbon tetrachloride as a possible human carcinogen is based on evidence in rats, mice and hamsters. Slope factor: 1.3 x 10-1 (mg/kg/day)-1.
PQL: The PQL used as the basis for the MCL is 0.005 mg/L.
502.1, 502.2, 503.1; GC
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.
Bruckner, J.V., W.F. MacKenzie, S. Muraldihara, R. Luthra, G.M. Kyle and D.A. Costa. 1986. Oral Toxicity of Carbon Tetrachloride: Acute, Subacute and Subchronic studies in rats. Fund. Appl. Toxicol. 6 (1) : 16-39.
Federal Register. July 8, 1987. Part II. Environmental Protection Agency. 40 CFR Parts 141 and 142. National Primary Drinking Water Regulations-Synthetic Organic Chemicals; Monitoring for Unregulated Contaminants; Final Rule. (52 FR 25690).
Federal Register. January 30, 1991. Part II. Environmental Protection Agency. 40 CFR Parts 141, 142, and 143. National Primary Drinking Water Regulations; Final Rule. (56 FR 3526).