Update: March 1996
Current Massachusetts Regulatory Limit
MMCL = 1 mg/L. ORS has adopted the MCL published by the U.S. EPA.
Federal Regulatory Limit
The MCL for toluene is equal to the MCLG of 1 mg/L.
Basis for Criteria
The MCLG is derived based on the RfD presented below and assumes that a 70 kg adult ingests 2 L/day of drinking water. A relative source contribution factor of 20% is incorporated into the final value.
RfD: 2 x 10-1 mg/kg/day
UF: 1000 (10 = interspecies; 10 = intraspecies;10 = limited reproductive/development data)
MF: 1 Confidence in RfD: Medium
Acute exposure to toluene has produced central nervous system depression, and effects on the lung, liver and kidneys. Chronic exposure has produced similar effects, although mostly in the liver and lungs (if exposure is via inhalation) (50 FR 46936: November 13, 1985). The MCL for toluene is based on a 1989 NTP study in which rats were exposed to toluene via gavage in corn oil, five days per week for thirteen weeks, at dose levels of 0, 312, 625, 1,250, 2,500 or 5,000 mg/kg. Liver-to-brain ratio was increased significantly in males exposed to the 625 mg/kg dose. A NOAEL of 312 mg/kg/d (adjusted to 223 mg/kg/d for 5 days/week exposure) was established (NTP, 1989).
Cancer Assessment: D
Toluene is currently classified as a Group D carcinogen based on negative results in an animal study and inadequate data on ingestion exposure.
PQL: 0.005 mg/L
U.S. EPA 502.2; gas chromatography
U.S. EPA 503.1; gas chromatography
U.S. EPA 524.2; gas chromatography-mass spectrometry
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).
NTP. 1989. Toxicology and carcinogenesis studies of toluene in F344/n rats and B6C3F1 Mice. Technical Report Series No. 271. Research Triangle Park, N.C.