CHROMIUM FACT SHEET ON A DRINKING WATER CHEMICAL CONTAMINANT GENERAL INFORMATION Synonyms • None Chemical Description: • A relatively rare, naturally occurring element (occurs as various salts) in the earth's crust Properties: • A metal which exists in tnvalent and hexavalent valence (oxidation) stats??, thQ tnvalent being the more i>rp-v(:l»r-1 state • Exists principally us fn- and hexavalent chromium salts, both of which are stable in water and exist in dynamic equilibrium with each other • Water solubility of chromium salts is compound specific « Tnvalent chromium (Crlll) is oxidized to hexavalent chromium (CrVI) in the presence of chlorine at concentrations similar to those used to disinfect drinking water Production and Use: • Chromium and its salts (chromite is the most widely used ore) have a variety of uses • chrome alloys, metal refmishing. and corrosion resistance • in the leather tanning industry • in the textile industry • in pigments and paints • in fungicides and wood preservatives ENVIRONMENTAL PROFILE Occurrence: • Estimated that occurrence above the MCI in drinking water is negligible • Naturally occurs in soil and, as a consequence, in food • Data indicates that detection of chromium in surface and ground water supplies are usually the result of naturally-occurring chromium leaching from mineral deposits • Exists mainly in the tnvalent or hexavalent states in natural bodies of water Releases: • Contamination of water by chromium is generally a result of runoff from old mining operations and improper waste disposal from plating operations Environmental Fate: • Released to air will adsorb to particulars matter in air; not expected to exist in gaseous form, likely to be relatively unreactive. removed from air by wet and dry deposition • Released to toll: limited soil mobility (will ocii-uri:' fo soil particles) and is likely to remain ii. tlifc upper 5 cm. of soil, uptake of chromium in plante is generally low. not likely to migrate to ground water • Released to surface waters: highly persistent in water, will adsorb to suspended paniculate matter and ultimately be deposited in sediments • High potential for bioaccumulation, especially in fish and other aquatic organisms HEALTH EFFECTS Humans: • Crlll is an essential nutrient for the metabolism of carbohydrates when consumed within the Recommended Daily Intake range of 0 05-0 2 mg/day • Only CrVI crosses cell membranes, it is reduced to Crlll intracellularly • CrVI compounds are generally more toxic than Crlll compounds: • Chronic inhalation of dust or air containing CrVI may cause respiratory problems • Chronic and subchronic dermal exposure to solutions containing high levels of CrVI may cause skin irritation and/or ulceration of the skin Experimental Animals: • Low oral toxicity because it is not well absorbed in the gastrointestinal tract • Both short-term, and long-term drinking water studies with high levels of both Crlll and CrVI showed no adverse health effects • High mutagenic potential • Equivocal evidence on whether mgestion of drinking water contaminated by chromium causes cancer ------- REGULATORY PROFILE Existing Standards: •Ciean Air Act (CAA): Not regulated •Ciean Water Act (CWA): Criteria established ‘Resource Conservation arid Recovery Act (RCRA): Not regulated • Superfund (CERCLA): • Hazardous waste SARA: Toxic chemical • Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA): Registered (Chromium compounds) ‘Toxic Substances Control Act (TSCA): Not regulated HEALTH INFORMATION Maximum Contaminant Level Goals (MCLG): • Non-enforceable levels based solely on an evaluation of possible health risks and exposure, and taking into consideration a margin for public safety • Set at 0 1 mg/L to protect against adverse health effects MCLG for Chromium = 0.1 mg/L (effective July 1992) Maximum Contaminant Levels (MCL): • Legally enforceable levels for contaminants in public drinking water supplies • Based on health risks associated with the contaminants, analytical methods for their assay, and water treatment feasibility and practicality aspects • Exceedance of the MCL in drinking water may result in adverse effects which will depend upon the contaminant concentration in water, amount of water/contaminant ingested. length of exposure, and other biological parameters • Current MCL = 0.05 mg/I MCL for Chromium = 0.1 mg/L (effective July 1992) EPA Health Advisories (HA): • Shoit-term HAs: Provide acceptable concentrations of contaminants in water for up to 10 day exposures, primarily to evaluate the public health nsk resulting from an accidental spill or an emergency contamination situation • Longer-term HAs: Provide guidance for persistent water contamination situations to cover a period of up to 7 years • Lifetime HAs: Derived in the same way as on MCLG Health ‘ aviscries Short-term HA for a child = 1 mgi I Longer-term HA for a child = 0.2 mg/I Longer-term HA for an adult = 0.8 mg I Lifetime HA 0.1 mg/I ANALYTICAL METHODS • Graohite Furnace Atomic Absorbtion EPA Method 2182 • Inductively Coupled Plasma EPA Method 200 7 WATER TREATMENT Permanent Treatment lest Available Technology (SAl): • Coagulation/Filtration • Lime Softening • Reverse Osmosis • Ion Exchange SHORT-TERM HAZARD ELIMINATION • If the drinking water standards ore exceeded. install BAT or use on alternative drinking water supply such as bottled water ADDITIONAL HELP • State or county health officials can indicate a certified laboratory for testing • Experts in the state Department of Environmental Protection or Natural Resources may also be of help • The EPA has toll-free numbers for further information on drinking water Quality. treatment technologies, for obtaining Health Advisories, and for other regulatory information • EPA Hotlines are available Monday through Friday Safe Drinking Water • National Pesticides: • Sup.ifund/ RCRA: • For information on the Clean (202) 260-7301 • For information on the Toxic Substances Control Act, call (202) 554-1404 • For information on the Clean Air Act, call (919) 541-2777 800.426.4791 800-858-7378 800.424-9346 Water Act, call ------- |