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CADMIUM
CASRN: 7440439

Update: August 1993

Current Massachusetts Regulatory Limit
MMCL = 0.005 mg/L. ORS has adopted the MCL published by the U.S. EPA as part of the Phase II rule. 

Federal Regulatory Limit
The MCL is equal to the MCLG of 0.005 mg/L (56 FR 3526) (Fed. Reg., 1991). 

Basis for Criteria
The MCLG is based on reports of renal toxicity in humans, specifically proteinuria (U.S. EPA 1985). The MCLG was derived from the DWEL of 0.018 mg/L which is based on an RfD of 5 x 10-4 and assumes that a 70 kg adult drinks 2 L/day of water. The MCLG incorporates a relative source contribution factor of 25% (U.S. EPA, 1987).

RfD: 5 x 10-4 mg/kg/day
UF: 10 (intraspecies) MF: 1


Critical Effects
In human studies involving chronic exposure, significant proteinuria was noted at a concentration of 200 ug cadmium per gram of wet renal cortex (USEPA 1985). Using a toxicokinetic model, a value of 0.352 mg/day was calculated as a reasonable estimate of the daily cadmium intake that would result in renal dysfunction. For a 70 kg adult ingesting 2 L/day of water, this translates to a dose of 0.005 mg/kg/day. The RfD was calculated assuming an uncertainty factor of 10 for intraspecies toxicity. Although the use of a LOAEL as a basis would normally require application of an additional uncertainty factor of 10, given the relatively low level of uncertainty regarding cadmium toxicity, the EPA decided that a total uncertainty factor of 100 would be too high in this case and that a total of 10 would be more appropriate (U.S. EPA, 1987). 

Cancer Assessment B1 (inhalation) / D (oral)
There is limited evidence of carcinogenicity from occupational epidemiological studies. There is sufficient evidence of carcinogenicity in rats and mice by inhalation and intramuscular and subcutaneous injection. There is no evidence that cadmium is carcinogenic by the oral routes in rodents.

Class
Heavy metal

Analytical Information
PQL
: The PQL used as the basis for the MCL is 0.010 mg/L.

Analytical Methods
200.7 ICP
213.2; AA Furnace

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.

References
U.S. EPA. 1985. Drinking Water Criteria Document on Cadmium. Office of Drinking Water, Washington, D.C. (Final Draft).

U.S. EPA . March 31, 1987. Cadmium. Health Advisory Draft. Office of Drinking Water.

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. 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).