Update: March 1996
Current Massachusetts Regulatory Limit
MMCL = 0.003 mg/L. ORS has adopted the MCL published by the U.S. EPA (56 FR 3526: 1/30/91).
Federal Regulatory Limit
The MCL for toxaphene is based on its detection limit of 0.003 mg/L. The MCLG is equal to zero.
Basis for Criteria
An MCLG of zero is assigned for toxaphene based on the evidence for carcinogenic potential. The MCLs for group B2 carcinogens are set as close to zero as feasible. The MCL is based on the toxaphene PQL of 0.003 mg/L.
Acute exposure to toxaphene produces effects on the central nervous system, liver and kidney. The critical target organ, upon subchronic and chronic exposure, is the liver. The critical effect from exposure to toxaphene is a potential increase in the incidence of cancer. The excess lifetime cancer risk at the MCL of 0.003 mg/L is approximately 1 in ten thousand.
Cancer Assessment: B2
Under the Proposed Guidelines for Carcinogen Risk Assessment, chloroform is The cancer assessment is based on hepatocellular carcinomas and neoplastic nodules in male mice (Litton Bionetics 1978). The oral slope factor is 1.1 (mg/kg/day)-1.
PQL: 0.003 mg/L
U.S. EPA 505; Microextraction/Gas Chromatography
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.
Federal Register. November 13, 1985. Part IV. Environmental Protection Agency. 40 CFR Part 141. National Primary Drinking Water Regulations: Synthetic Organic Chemicals, Inorganic Chemicals and Microorganisms; Proposed Rule. (50 FR 46936).
Federal Register. May 22, 1989. Part II. Environmental Protection Agency. 40 CFR Parts 141, 142, and 143. National Primary and Secondary Drinking Water Regulations; Proposed Rule. (54 FR 22062).
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).
Litton Bionetics. 1978. Carcinogenic evaluation in mice. Toxaphene. Final Report. Prepared by Litton Bionetics, Inc., Kensington, MD for Hercules, Jr. Wilmington DE. LBI Project No. 20602.