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CASRN: 1912249

Update: August 1993

Current Massachusetts Regulatory Limit
MMCL = 0.003 mg/L. ORS has adopted the MCL published by the U.S. EPA under the Phase II rule. (56 FR 3526; 1-30-91) 

Federal Regulatory Limit
The MCL is equal to the MCLG of 0.003 mg/L. 

Basis for Criteria
The MCLG is based on its potential for adverse health effects (liver and kidney damage) reported in dog and rat studies (Ciba-Geigy, 1987). The MCLG is derived based on the RfD presented below and assumes that a 70 kg adult ingests 2 L/day of water. The MCLG assumes a drinking water contribution of 20% and incorporates a 10-fold uncertainty factor to account for potential carcinogenicity (Fed. Reg., 1991).

RfD = 5 x 10-3 mg/kg/day
UF = 100 (10 - intraspecies; 10 = interspecies); MF = 1

This RfD was developed based on a one-year feeding study in dogs. A NOAEL of 0.48 mg/kg/day was identified from this study.

Critical Effects
A 1-year feeding study in dogs (CIBA-Geigy, 1987) indicated discrete myocardial degeneration at the highest dose and several findings at the middle dose suggestive of a trend toward the development of cardiac pathology.

Cancer Assessment
The U.S. EPA has classified atrazine as a Group C carcinogen (Fed. Reg., 1991). A risk assessment is currently underway through the U.S. EPA for this chemical. 


Analytical Information

Analytical Methods
505; Microextraction GC
507 - GC
525; GCMS

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

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

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 Please note that the information in IRIS may differ from that used in the derivation process as published in the Federal Register notice.

Ciba-Geigy Corporation, Agricultural Division. 1987. MRID No. 00141874, 0057875, 00158930, 40629302. HED Doc. No. 005940, 006937. Available from U.S. EPA. Write to: FOI, U.S. EPA, Washington, DC 20460.

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)

U.S. Environmental Protection Agency. 1993. Integrated Risk Information System (IRIS). U.S. Environmental Protection Agency. Washington, D.C.