The Risk Assessment Information System

Toxicity Profiles

Condensed Toxicity Summary for SULFATE

NOTE: Although the toxicity values presented in these toxicity profiles were correct at the time they were produced, these values are subject to change. Users should always refer to the Toxicity Value Database for the current toxicity values.

JUNE 1991

Prepared by: Cheryl Bast, Chemical Hazard Evaluation and Communication Group, Biomedical and Environmental Information Analysis Section, Health and Safety Research Division, Oak Ridge National Laboratory*, Oak Ridge, Tennessee.

Prepared for: Oak Ridge Reservation Environmental Restoration Program.

*Managed by Martin Marietta Energy Systems, Inc., for the U.S. Department of Energy under Contract No. DE-AC05-84OR21400.

The sulfate ion, SO4, is one of the major anions occurring in natural waters (Daniels, 1988). The majority of sulfates are soluble in water with the exception of lead, barium, and strontium sulfates. Thus, dissolved sulfate is considered to be a permanent solute of water (WHO, 1984a).

The major health effect observed with sulfate ingestion is laxative action (Daniels, 1988; NAS, 1977), and the cation associated with the sulfate appears to have some effect on the salt's potency as a laxative (Daniels, 1988). Sulfate itself slowly penetrates mammalian cellular membranes and is rapidly eliminated through the kidneys (WHO, 1984a). Pursuant to the Safe Drinking Water Act, the U.S. EPA has proposed Maximum Contaminant Level Goals of either 400 or 500 mg/L to protect infants (based on Chien et. al., 1968; Peterson, 1951; and Moore, 1952), and has identified a LOAEL (Lowest-Observed-Adverse-Effect-Level) of 630 mg/L based on diarrhea in infants receiving formula made with high-sulfate water (U.S. EPA, 1990). The Drinking Water Standards of the U.S. Public Health Service recommend that sulfate in water should not exceed 250 mg/L, except when no more suitable supplies are or can be made available.

Sulfates can contribute to an undesirable taste in water. The taste threshold for the sulfate ion in water is 300-400 mg/L (NAS, 1977), and a guidance value of 400 mg/L based on aesthetic quality has been suggested (WHO, 1984b). The current U.S. EPA national Secondary Maximum Contaminant Level for sulfate, based on organoleptic effects, is 250 mg/L (U.S. EPA, 1990).

No inhalation, or developmental toxicity data were available, and no carcinogenicity data were located.

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Last Updated 2/13/98

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