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Health Risk Information for Public Health Goal Exceedance Reports April 2007 Under the Calderon-Sher Safe Drinking Water Act of 1996 (the Act), water utilities are required to prepare a report every three years for contaminants that exceed public health goals (PHGs) (Health and Safety Code Section 116470 The numerical health risk is to be presented with the category of health risk, along with a plainly worded description of these terms. PHGs are published by the Office of Environmental Health Hazard Assessment (OEHHA)(Health and Safety Code Section 116365) as concentrations of contaminants in drinking water that OEHHA, using current risk assessment principles, practices and methods, considers to pose no significant health risk if consumed for a lifetime. This report is prepared by OEHHA to assist the water utilities in meeting their requirements. Numerical health risks. The tables that follow summarize health risks for chemical contaminants in drinking water that have PHGs and state and/or federal regulatory standards. The regulatory standards are maximum contaminant levels (MCLs). The Act also requires that OEHHA publish PHGs based on health risk assessments using the most current scientific methods. As defined in statute, PHGs for noncarcinogenic chemicals in drinking water are set at a concentration “at which no known or anticipated adverse health effects will occur, with an adequate margin of safety.” For carcinogens PHGs are set at a concentration that “does not pose any significant risk to health.” PHGs provide one basis for revising MCLs, along with cost and technological feasibility. OEHHA has been publishing PHGs as they are completed since 1997 and the entire list published to date is shown in Table 1. The Act requires that for chemical contaminants with California MCLs that do not yet have PHGs, water utilities will use the federal maximum contaminant level goal (MCLG) for the purpose of complying with the requirement of public notification. like PHGs, are strictly health based and include a margin of safety. One difference, however, is that the for carcinogens are set at zero because the United States Environmental Protection Agency (U.S. EPA) assumes there is no absolutely safe level of exposure to them. PHGs, on the other hand, are set at a level considered to pose no significant risk of cancer; this is usually a no more than one-in-a-million excess cancer risk (1×10-6) level for a lifetime of exposure. Chemicals with but no PHGs are presented in Table 2. The cancer risks shown are based on the U.S. EPA’s evaluations. ---PAGE BREAK--- Office of Environmental Health Hazard Assessment Page 2 Water Toxicology Section February 2007 Health risk categories. The following information can be used for presenting the health risk categories in “exceedance reports.” The health risks shown in the tables are based on long-term exposures to low levels of contaminants as would occur with drinking water (unless otherwise stated), rather than high doses from a single or short-term exposure. The potential health effects are the most sensitive adverse effects that occur when chemical exposure reaches a sufficient level and duration to produce toxicity. Health goals that protect against these risks also protect against health risks that would occur from short-term exposures. For most health risk categories, the specific health outcome or the organ or system that is affected is also given. The health effects are given in nontechnical terms when possible, and the categories are described below. Acute toxicity - adverse health effects that develop after a short-term exposure to a chemical (minutes to days). Subchronic toxicity – adverse health effects that develop after repeated or longer-term exposures to a chemical (days to months). Carcinogenic - capable of producing cancer. Chronic toxicity - adverse effects that usually develop gradually from low levels of chemical exposure over a long period of time (months to years). Developmental toxicity - adverse effects on the developing organism that may result from exposure prior to conception (either parent), during prenatal development, or postnatally to the time of sexual maturation. Adverse developmental effects may be detected at any point in the life span of the organism. The major manifestations include: death of the developing organism, structural abnormality (birth defects), altered growth, and functional deficiency. Neurotoxic - capable of adversely affecting or destroying parts of the nervous system or interfering with nerve signal transmission. Effects may be reversible (for example, effects on chemicals that carry nerve signals across gaps between nerve cells) or irreversible (for example, destruction of nerve cells). Reproductive effects - the occurrence of adverse effects on the reproductive system of females or males that may result from exposure to environmental agents. The toxicity may cause changes to the female or male reproductive organs, the regulating endocrine system, or pregnancy outcomes. Examples of such toxicity may include adverse effects on onset of puberty, egg production and transport, menstrual cycle normality, sexual behavior such as sexual urge, lowered fertility, sperm production, length of pregnancy, and milk production. The tables further note whether the health risk category is based on human or animal data. Data on health effects of toxic substances are usually obtained from studies on laboratory animals. For more information on health risks: The adverse health effects for each chemical with a PHG are summarized in each PHG technical support document. These documents are available on the OEHHA Web site (http://www.oehha.ca.gov). Also, U.S. EPA has consumer and technical fact sheets on most of the chemicals having MCLs. For copies of the fact sheets, call ---PAGE BREAK--- Office of Environmental Health Hazard Assessment Page 3 Water Toxicology Section February 2007 the Safe Drinking Water Hotline at 1-[PHONE REDACTED], or explore the U.S. EPA Office of Ground Water and Drinking Water's home page at http://www.epa.gov/OGWDW/hfacts.html. ---PAGE BREAK--- Office of Environmental Health Hazard Assessment Page 4 Water Toxicology Section February 2007 Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs) Chemical Health Risk Category1 (more specific information in parentheses) California PHG (mg/L)2 Cancer Risk3 @ PHG Californi a MCL4 (mg/L) Cancer Risk @ California MCL Alachlor carcinogenicity (cancer) 0.0045 NA6 0.002 NA Aluminum chronic toxicity (increased serum aluminum level) (human data) 0.6 NA 1 NA Antimony chronic toxicity (shortened lifespan) 0.02 NA 0.006 NA Arsenic carcinogenicity (cancer) 0.000004 (4x10-6) 1 x 10-6 (one per million) 0.05 (federal MCL 0.01) 0.01 (1 in a hundred) Asbestos carcinogenicity (cancer) 7 MFL (fibers >10 microns in length) 1 x 10-6 7 MFL7 (fibers >10 microns in length) 1×10-6 Atrazine carcinogenicity (cancer) 0.00015 1×10-6 0.001 7×10-6 (seven per million) 1 Health risk category based on experimental animal testing data evaluated in the OEHHA PHG technical support document unless otherwise specified. 2 mg/L = milligrams per liter of water or parts per million (ppm) (PHGs are expressed here in milligrams per liter for consistency with the typical unit used for MCLs and 3 Cancer Risk = theoretical 70-year lifetime excess cancer risk at the statistical upper confidence limit. Actual cancer risk may be lower or zero. Cancer risk is stated in terms of excess cancer cases per million (or fewer) population, e.g., 1×10-6 means one excess cancer case per million people; 5×10-5 means five excess cancer cases per 100,000 people. 4 MCL = maximum contaminant level. 5 Non-linear approach used for alachlor risk assessment, no cancer risk assumed at the PHG level. 6 NA = not applicable. Noncarcinogenic, or a cancer risk cannot be calculated. The PHG for these chemicals is set at a level that is believed to be without any significant public health risk to individuals exposed to that chemical over a lifetime. 7 MFL = million fibers per liter. ---PAGE BREAK--- Office of Environmental Health Hazard Assessment Page 5 Water Toxicology Section February 2007 Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs) Chemical Health Risk Category1 (more specific information in parentheses) California PHG (mg/L)2 Cancer Risk3 @ PHG Californi a MCL4 (mg/L) Cancer Risk @ California MCL Barium chronic toxicity (hypertension) 2 NA 1 NA Bentazon chronic toxicity (clinical, body weight, liver and intestinal effects) 0.2 NA 0.018 NA Benzene carcinogenicity (leukemia) 0.00015 1 x 10-6 0.001 7 x 10-6 Benzo[a]pyrene carcinogenicity (cancer) 0.000004 1×10-6 0.0002 5×10-5 Beryllium chronic toxicity (gastrointestinal lesions) 0.001 NA 0.004 NA Cadmium chronic toxicity (kidney effects, human data) 0.00004 NA 0.005 NA Carbofuran chronic toxicity (enzyme inhibition, blood chemistry and testis effects) 0.0017 NA 0.018 NA Carbon tetrachloride carcinogenicity (cancer) 0.0001 1×10-6 0.0005 5×10-6 Chlordane carcinogenicity (cancer) 0.00003 1×10-6 0.0001 3×10-6 Copper acute toxicity (gastrointestinal effects in children, human data) 0.17 NA 1.3 (AL)8 NA 8 AL = action level. ---PAGE BREAK--- Office of Environmental Health Hazard Assessment Page 6 Water Toxicology Section February 2007 Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs) Chemical Health Risk Category1 (more specific information in parentheses) California PHG (mg/L)2 Cancer Risk3 @ PHG Californi a MCL4 (mg/L) Cancer Risk @ California MCL Cyanide chronic toxicity9 (no clinical and histopathological effects observed) 0.15 NA 0.15 NA Dalapon chronic toxicity (kidney effects) 0.79 NA 0.2 NA 1,2-Dibromo-3- chloropropane (DBCP) carcinogenicity (cancer) 0.0000017 (1.7x10-6) 1×10-6 0.0002 1×10-4 1,2-Dichloro- benzene (o-DCB) chronic toxicity (liver effects) 0.6 NA 0.6 NA 1,4-Dichloro- benzene (p-DCB) carcinogenicity (cancer) 0.006 1×10-6 0.005 8×10-7 1,1-Dichloroethane (1,1-DCA) carcinogenicity (cancer) 0.003 1×10-6 0.005 2×10-6 1,2-Dichloroethane (1,2-DCA) carcinogenicity (cancer) 0.0004 1×10-6 0.0005 1×10-6 1,1-Dichloro- ethylene (1,1-DCE) chronic toxicity (liver effects) 0.01 NA 0.006 NA 1,2-Dichloro- ethylene, cis Subchronic toxicity (kidney effects) 0.1 NA 0.006 NA 1,2-Dichloro- ethylene, trans Subchronic toxicity (liver effects) 0.06 NA 0.01 NA 9 Cyanide: Acute toxicity of concern is respiratory arrest. Long-term exposure allows for detoxification. ---PAGE BREAK--- Office of Environmental Health Hazard Assessment Page 7 Water Toxicology Section February 2007 Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs) Chemical Health Risk Category1 (more specific information in parentheses) California PHG (mg/L)2 Cancer Risk3 @ PHG Californi a MCL4 (mg/L) Cancer Risk @ California MCL Dichloromethane (methylene chloride) carcinogenicity (cancer) 0.004 1×10-6 0.005 1×10-6 2,4-Dichloro- phenoxyacetic acid (2,4-D) chronic toxicity (liver and kidney effects) 0.07 NA 0.07 NA 1,2-Dichloro- propane (propylene dichloride) carcinogenicity (cancer) 0.0005 1×10-6 0.005 1×10-5 1,3-Dichloro- propene (Telone II®) carcinogenicity (cancer) 0.0002 1×10-6 0.0005 2×10-6 adipate (DEHA) developmental toxicity (disrupted development) 0.2 NA 0.4 NA phthalate (DEHP) carcinogenicity (cancer) 0.012 1×10-6 0.004 3×10-7 Dinoseb reproductive toxicity (uterus and testis effects) 0.014 NA 0.007 NA Diquat chronic toxicity (eye effects) and developmental toxicity (malformation) 0.015 NA 0.02 NA Endothall chronic toxicity (stomach effects) 0.58 NA 0.1 NA Endrin chronic toxicity (liver effects) and neurotoxicity (convulsions) 0.0018 NA 0.002 NA ---PAGE BREAK--- Office of Environmental Health Hazard Assessment Page 8 Water Toxicology Section February 2007 Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs) Chemical Health Risk Category1 (more specific information in parentheses) California PHG (mg/L)2 Cancer Risk3 @ PHG Californi a MCL4 (mg/L) Cancer Risk @ California MCL (phenylethane) chronic toxicity (liver effects) 0.3 NA 0.3 NA Ethylene dibromide carcinogenicity (cancer) 0.00001 1×10-6 0.00005 5×10-6 Fluoride chronic toxicity (tooth mottling, human data) 1 NA 2 NA chronic toxicity (kidney effects) 1 NA 0.7 NA Heptachlor carcinogenicity (cancer) 0.000008 1×10-6 0.00001 1×10-6 Heptachlor epoxide carcinogenicity (cancer) 0.000006 1×10-6 0.00001 2×10-6 Hexachlorobenzene carcinogenicity (cancer) 0.00003 1×10-6 0.001 3×10-5 Hexachlorocyclo- pentadiene (HEX) chronic toxicity (stomach lesions) 0.05 NA 0.05 NA Lead chronic toxicity (neurobehavioral effects in children, hypertension in adults) and carcinogenicity (cancer) 0.002 3x10-7 (PHG is not based on this effect) 0.015 (AL) 2x10-6 Lindane (γ-BHC) carcinogenicity (cancer) 0.000032 1×10-6 0.0002 6×10-6 Monochlorobenzene (chlorobenzene) subchronic toxicity (liver damage) 0.2 NA 0.07 NA Mercury (inorganic) chronic toxicity (kidney effects) 0.0012 NA 0.002 NA ---PAGE BREAK--- Office of Environmental Health Hazard Assessment Page 9 Water Toxicology Section February 2007 Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs) Chemical Health Risk Category1 (more specific information in parentheses) California PHG (mg/L)2 Cancer Risk3 @ PHG Californi a MCL4 (mg/L) Cancer Risk @ California MCL reproductive toxicity (vagina, ovary, uterus and hormonal effects) 0.03 NA 0.03 NA Methyl tertiary- butyl ether (MTBE) carcinogenicity (cancer) 0.013 1×10-6 0.013 1×10-6 Nickel developmental toxicity (increased neonatal deaths) 0.012 NA 0.1 NA Nitrate acute toxicity (methemoglobinemia, human data) 10 as nitrate- nitrogen NA 45 as NO3 NA Nitrite acute toxicity (methemoglobinemia, human data) 1 as nitrite- nitrogen NA 1 as nitrite- nitrogen NA Nitrate and Nitrite acute toxicity (methemoglobinemia, human data) 10 as nitrogen NA 10 as nitrogen NA N-nitrosodimethyl- amine (NDMA) carcinogenicity (cancer) 0.000003 1x10-6 Oxamyl chronic toxicity (body weight effects) 0.05 NA 0.05 NA Pentachlorophenol (PCP) carcinogenicity (cancer) 0.0004 1×10-6 0.001 3×10-6 Perchlorate subchronic toxicity (thyroid and reproductive effects) 0.006 NA NA Picloram chronic toxicity (liver effects) 0.5 NA 0.5 NA ---PAGE BREAK--- Office of Environmental Health Hazard Assessment Page 10 Water Toxicology Section February 2007 Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs) Chemical Health Risk Category1 (more specific information in parentheses) California PHG (mg/L)2 Cancer Risk3 @ PHG Californi a MCL4 (mg/L) Cancer Risk @ California MCL Radium-226 carcinogenicity (cancer) 0.05 pCi/L 1x10-6 5 pCi/L 1x10-4 Radium-228 carcinogenicity (cancer) 0.019 pCi/L 1x10-6 5 pCi/L (combined Ra226+228) 3x10-4 Silvex (2,4,5-TP) chronic toxicity (liver effects) 0.025 NA 0.05 NA Simazine chronic toxicity (reduced body weight) 0.004 NA 0.004 NA Strontium-90 carcinogenicity (cancer) 0.35 pCi/L 1x10-6 8 pCi/L 2x10-5 1,1,2,2- Tetrachloroethane carcinogenicity (cancer) 0.0001 1×10-6 0.001 1×10-5 Tetrachloroethylene (perchloroethylene, or PCE) carcinogenicity (cancer) 0.00006 1×10-6 0.005 8×10-5 Thallium subchronic toxicity (hair loss) 0.0001 NA 0.002 NA Thiobencarb chronic toxicity (body weight, food efficiency and enzyme activity effects) 0.07 NA 0.07 NA Toluene chronic toxicity (liver and thymus effects) 0.15 NA 0.15 NA Toxaphene carcinogenicity (cancer) 0.00003 1×10-6 0.003 1×10-4 1,2,4-Trichloro- benzene (Unsym-TCB) chronic toxicity (effects on adrenal glands) 0.005 NA 0.005 NA ---PAGE BREAK--- Office of Environmental Health Hazard Assessment Page 11 Water Toxicology Section February 2007 Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs) Chemical Health Risk Category1 (more specific information in parentheses) California PHG (mg/L)2 Cancer Risk3 @ PHG Californi a MCL4 (mg/L) Cancer Risk @ California MCL 1,1,1-Trichloro- ethane neurotoxicity (structural changes), reproductive toxicity (fewer chronic toxicity (liver and blood effects) 1 NA 0.2 NA 1,1,2-Trichloro- ethane carcinogenicity (cancer) 0.0003 1x10-6 0.005 2x10-5 1,1,2-Trichloro- ethylene (TCE) carcinogenicity (cancer) 0.0008 1×10-6 0.005 6×10-6 Trichlorofluoro- methane (Freon 11) chronic toxicity (liver effects) 0.7 NA 0.15 NA 1,1,2-Trichloro- 1,2,2-trifluoro- ethane (Freon 113) chronic toxicity (liver effects) 4 NA 1.2 NA Tritium carcinogenicity (cancer) 400 pCi/L 1x10-6 20,000 pCi/L 5x10-5 Uranium carcinogenicity (cancer) 0.43 pCi/L 1×10-6 20 pCi/L 5×10-5 Vinyl chloride carcinogenicity (cancer) 0.00005 1×10-6 0.0005 1×10-5 Xylenes neurotoxicity (effects on senses, mood and motor control, human data) 1.8 (single isomer or sum of isomers) NA 1.75 (single isomer or sum of isomers) NA ---PAGE BREAK--- Office of Environmental Health Hazard Assessment Page 12 Water Toxicology Section February 2007 Table 2: Health Risk Categories and Cancer Risk Values for Chemicals without California Public Health Goals Chemical Health Risk Category1 (more specific information in parentheses) U.S. EPA MCLG2 (mg/L) Cancer Risk3 @ MCLG California MCL4 (mg/L) Cancer Risk @ California MCL Chromium chronic toxicity (stomach, liver effects), immunotoxicity (allergic dermatitis) 0.1 NA 0.05 NA Dioxin (2,3,7,8-TCDD) carcinogenicity (cancer) reproductive effects 0 0 0.00000003 1×10-5 Molinate reproductive effects (decreased number of none NA 0.02 NA biphenyls (PCBs) carcinogenicity (cancer) 0 0 0.0005 1×10-4 Selenium chronic toxicity (hair and nail changes, skin lesions, blood effects; human data) and neurotoxicity 0.05 NA 0.05 NA Styrene (vinylbenzene) chronic toxicity (liver, kidney and blood effects) 0.1 NA 0.1 NA Disinfection byproducts (DBPS) bromate carcinogenicity (cancer) 0 0 0.01 NA 1 Health risk category based on experimental animal testing data evaluated in the U.S. EPA MCLG document or California MCL document unless otherwise specified. 2 MCLG = maximum contaminant level goal established by U.S. EPA. 3 Cancer Risk = theoretical 70-year lifetime excess cancer risk at the statistical confidence limit. Actual cancer risk may be lower or zero. Cancer risk is stated in terms of excess cancer cases per million (or fewer) population, e.g., 1×10-6 means one excess cancer case per million people; 5×10-5 means five excess cancer cases per 100,000 people. 4 California MCL = maximum contaminant level established by California. ---PAGE BREAK--- Office of Environmental Health Hazard Assessment Page 13 Water Toxicology Section February 2007 Table 2: Health Risk Categories and Cancer Risk Values for Chemicals without California Public Health Goals Chemical Health Risk Category1 (more specific information in parentheses) U.S. EPA MCLG2 (mg/L) Cancer Risk3 @ MCLG California MCL4 (mg/L) Cancer Risk @ California MCL chloramines acute toxicity (irritation) and chronic toxicity (stomach effects, anemia) 45 NA none NA chlorine acute toxicity (irritation) and chronic toxicity (stomach effects) 4 5 NA none NA chlorine dioxide chronic toxicity (anemia) and neurotoxicity (infants and young children, human data) 0.8 5 NA none NA chlorite chronic toxicity (anemia) and neurotoxicity (infants and children, human data) 0.8 NA 1.0 NA Disinfection byproducts: haloacetic acids (HAA5) chloroacetic acid chronic toxicity (body and organ weight changes) 0.07 NA none NA dichloroacetic acid carcinogenicity (cancer) 0 0 none NA trichloroacetic acid chronic toxicity (liver effects) 0.02 0 none NA bromoacetic acid NA none NA none NA dibromoacetic acid NA none NA none NA total haloacetic acids carcinogenicity (cancer) none NA 0.06 NA Disinfection byproducts: trihalomethanes (THMS) 5 Maximum Residual Disinfectant Level Goal, or ---PAGE BREAK--- Office of Environmental Health Hazard Assessment Page 14 Water Toxicology Section February 2007 Table 2: Health Risk Categories and Cancer Risk Values for Chemicals without California Public Health Goals Chemical Health Risk Category1 (more specific information in parentheses) U.S. EPA MCLG2 (mg/L) Cancer Risk3 @ MCLG California MCL4 (mg/L) Cancer Risk @ California MCL bromodichloro- methane (BDCM) carcinogenicity (cancer) 0 0 none NA bromoform carcinogenicity (cancer) 0 0 none NA chloroform chronic toxicity (liver and kidney effects) 0.07 NA none NA dibromo- chloromethane (DBCM) chronic toxicity (liver and kidney effects) and neurotoxicity 0.06 NA none NA total (sum of BDCM, bromoform, chloroform and DBCM) carcinogenicity (cancer), chronic toxicity (liver and kidney effects), and neurotoxicity none NA 0.08 NA Radionuclides gross alpha particles6 carcinogenicity (cancer) 0 (as of 12/08/2003) (210Po included) 0 15 pCi/L7 (includes 226Ra but not radon and uranium) up to 1x10-3 (for 210Po, the most potent alpha emitter beta particles and photon emitters6 carcinogenicity (cancer) 0 (as of 12/08/2003) (210Pb included) 0 50 pCi/L up to 2x10-3 (for 210Pb, the most potent beta- emitter) 6 MCLs for gross alpha and beta are screening standards for a group of radionuclides. A corresponding PHG was considered inappropriate because risks vary for the individual radionuclides covered by the screening level; see OEHHA memoranda discussing the cancer risks at these MCLs at http://www.oehha.ca.gov/water/phg/index.html. 7 pCi/L = picocuries per liter of water.