Return to Standards Table

CASRN: 72208

Update: November 1993

Current Massachusetts Regulatory Limit
MMCL = 0.002 mg/L. ORS has adopted the MCL published by the U.S. EPA as part of the Phase V rule (57 FR 31776; 7-17-92).

Federal Regulatory Limit
The MCL is equal to the MCLG of 0.002 mg/L.

Basis for Criteria

The MCLG is based on potential adverse effects (clinical signs, mortality) reported in animal studies. It is derived based on the RfD presented below and assumes that a 70 kg adult ingests 2 L/day of drinking water. A 20% relative source contribution factor is incorporated into this value.

RfD: 3 x 10-4 mg/kg/day
UF: 100 (10 for intra-species; 10 for inter-species)
MF: 1 Confidence in RfD: Medium

Critical Effects
The RfD is based on the results of a chronic oral bioassay in dogs (Velsicol 1969) where mild histological lesions in the liver and occasional convulsions were reported. No other adverse health effects were reported. A NOAEL of 0.025 mg/k/day was identified from this study (Fed Reg, 1990, 1992).

Cancer Assessment: 

The database for evaluating the potential cancer effects of exposure to Endrin is inadequate to make either qualitative or quantitative decisions.

Chlorinated Pesticide

Analytical Information
: 0.1 mg/L 

Analytical Methods
U.S. EPA 505; microextraction GC
U.S. EPA 508; GC/ECD
U.S. EPA 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 US EPA Drinking Water Analytical Methods .

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 US EPA Current Drinking Water Health Advisories .

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.

Federal Register. July 25, 1990. Part II. Environmental Protection Agency. 40 CFR Part 141 et al. National Primary and Secondary Drinking Water Regulations; Synthetic Organic Chemicals and Inorganic Chemicals; Proposed Rule. (55 FR 30370)

Federal Register. July 17, 1992. Part III. Environmental Protection Agency. 40 CFR Parts 141 and 142. National Primary Drinking Water Regulations; Synthetic Organic Chemicals and Inorganic Chemicals; Final Rule. (57 FR 31776).

Velsicol Chemical Corporation. 1969. MRID No. 00030198. Available from U.S. EPA. Write FOI, U.S. EPA, Washington, D.C. 20460.