PREFACE Drinking Water Public Health Goals

health effects from contaminants in drinking water. PHGs are developed for chemical contaminants based on the best available toxicological data in the scientific literature. These documents and the analyses contained in them provide estimates of the levels of contaminants in drinking water that would pose no significant health risk to individuals consuming the water on a daily basis over a lifetime. The California Safe Drinking Water Act of 1996 (Health and Safety Code, Section 116365) requires the Office of Environmental Health Hazard Assessment (OEHHA) to perform risk assessments and adopt PHGs for contaminants in drinking water based exclusively on public health considerations. The Act requires that PHGs be set in accordance with the following criteria: 1. PHGs for acutely toxic substances shall be set at levels at which no known or anticipated adverse effects on health will occur, with an adequate margin of safety. 2. PHGs for carcinogens or other substances that may cause chronic disease shall be based solely on health effects and shall be set at levels that OEHHA ha

PUBLIC HEALTH GOAL FOR BENZO(A)PYRENE SUMMARY

Contaminant Level (MCL) for BaP is 0.2×10-3 mg/L, or 0.2 ppb. The proposed PHG for BaP is based on carcinogenic effects observed in animals. Significant increases in tumors have been observed in the forestomach of female mice and the liver and forestomach of male and female rats administered BaP by the oral route. BaP was shown to be genotoxic in studies in vivo and in vitro. DNA adducts have been observed in animals following exposure to BaP. Studies of BaP metabolism are extensive, and while still incomplete, link the genotoxic and carcinogenic activity of BaP with its metabolism to reactive forms. Evidence that specifically links exposure to BaP to an increased incidence of cancer in humans is lacking. BaP is a member of a family of structurally related chemicals called polyaromatic hydrocarbons (PAHs). Human exposure to mixtures of PAHs such as diesel exhaust, cigarette smoke and coal tar are linked to increased incidences of cancer. A time-to-tumor model was employed to obtain a lower-bound estimate of the dose associated with a 10 percent increased incidence of tumors of the oral cavity or forestomach and tumors of the liver in male and female rats, and tumors of the oral cavit

AND SCIENTIFIC REVIEW ii June 2007DRAFT PREFACE Drinking Water Public Health Goal

This Public Health Goal (PHG) technical support document provides information on health effects from contaminants in drinking water. PHGs are developed for chemical contaminants based on the best available toxicological data in the scientific literature. These documents and the analyses contained in them provide estimates of the levels of contaminants in drinking water that would pose no significant health risk to individuals consuming the water on a daily basis over a lifetime. The California Safe Drinking Water Act of 1996 (Health and Safety Code, Section 116365) requires the Office of Environmental Health Hazard Assessment (OEHHA) to perform risk assessments and adopt PHGs for contaminants in drinking water based exclusively on public health considerations. The Act requires that PHGs be set in accordance with the following criteria: 1. PHGs for acutely toxic substances shall be set at levels at which no known or anticipated adverse effects on health will occur, with an adequate margin of safety. 2. PHGs for carcinogens or other substances that may cause chronic disease shall b

IN DRINKING WATER SUMMARY

An updated Public Health Goal (PHG) of 1.7 parts per billion (ppb) is established for trichloroethylene (TCE) in drinking water, which is derived from the same studies as the existing PHG of 0.8 ppb, published in 1999. The public-health protective concentrations calculated in the previous PHG and in this document are based on the occurrence of hepatocellular carcinomas and adenocarcinomas in mice in three studies, in both sexes, by inhalation and oral routes of administration, and a linear dose-response approach. However, different, updated cancer models were employed in the current re-analysis. As in the previous PHG calculation, the cancer slope factor (CSF) was based on a geometric mean of four values using a pharmacokinetic dose metric of metabolized dose of TCE. The PHG was set at a level providing a de minimis theoretical lifetime excess individual cancer risk of one in one million (10-6) through ingestion of tap water, plus an allowance for inhalation and dermal exposures to TCE via showering, flushing of toilets, and other typical household uses of tap water. A health-protective value for noncancer toxicity of 1 part per million (ppm) was also calculated, based on the benchmark dose (BMD10) for kidney nephropathy in an ora

By Pamela Wofford, Environmental Monitoring Branch

Lompoc is a small city located in a coastal valley of Santa Barbara County, California, with agricultural fields located in the area between Lompoc and the coast. As with most California coastal valleys, the area is cool with frequent fog or low cloudiness, and winds are predominantly from the west or northwest; Lompoc is downwind from the agricultural area. The Department of Pesticide Regulation (DPR) conducted air monitoring in Lompoc to determine whether, and in what amounts, fumigant pesticides occur in air in residential areas of the city. Three fumigant pesticides are used in the Lompoc area: chloropicrin, methyl bromide, and methyl isothiocyanate (MITC, breakdown product of metam-sodium and metam-potassium). DPR monitored five locations, including two schools in Lompoc, primarily choosing higherrisk sites based on their proximity to agricultural areas. The monitoring plan targeted selected applications, specifically large fumigations in close proximity to Lompoc. DPR monitored six MITC fumigations, and two methyl bromide/chloropicrin fumigations during 2000. For each of the fumigations, DPR monitored for a 72-hour period beginning with the start of fumigation. The 72-hour monitoring period consisted of six alternating 8-hour (day) and 16hou

Comment Coordinator Final Reviewers Web site Posting

health effects from contaminants in drinking water. PHGs are developed for chemical contaminants based on the best available toxicological data in the scientific literature. These documents and the analyses contained in them provide estimates of the levels of contaminants in drinking water that would pose no significant health risk to individuals consuming the water on a daily basis over a lifetime. The California Safe Drinking Water Act of 1996 (Health and Safety Code, Section 116365) requires the Office of Environmental Health Hazard Assessment (OEHHA) to perform risk assessments and adopt PHGs for contaminants in drinking water based exclusively on public health considerations. The Act requires that PHGs be set in accordance with the following criteria: 1. PHGs for acutely toxic substances shall be set at levels at which no known or anticipated adverse effects on health will occur, with an adequate margin of safety. 2. PHGs for carcinogens or other substances that may cause chronic disease shall be based solely on health effects and shall be set at levels that OEHHA ha