Summed number of pollutants from water bodies designated as imparied

The nature and the magnitude of the threat and burden posed by sites maintained in GeoTracker vary significantly by site type (e.g., leaking underground storage tank or cleanup site) and status (e.g., Completed Case Closed or Active Clean up). Thus, the indicator takes into account information about both the type of site and its status. 

Common groundwater pollutants found at LUST and cleanup sites in California include gasoline and diesel fuels, chlorinated solvents and other volatile organic compounds (VOCs) such as benzene, toluene, and methyl tert-butyl ether (MTBE); heavy metals such as lead, chromium and arsenic; polycyclic aromatic hydrocarbons (PAHs); persistent organic pollutants like polychlorinated biphenyls (PCBs); DDT and other insecticides; and perchlorate (SWRCB, 2012; DPR, 2011; US EPA, 2002). Dioxins and dioxin-like substances have been detected in groundwater in areas where treated wastewater has been used for irrigation (Mahjoub et al., 2011) and near wood treatment facilities (Karouna-Renier et al., 2007). The occurrence of storage tanks, leaking or not, provides a good indication of potential concentrated sources of some of the more prevalent compounds in groundwater. For example, the detection frequency of VOCs found in gasoline is associated with the number of UST or LUST sites within one kilometer of a well (Squillace and Moran, 2007). The occurrence of chlorinated solvents in groundwater is also associated with the presence of cleanup sites (Moran et al., 2007). Some of these cancer-causing compounds have in turn been detected in drinking water supplies in California (Williams et al., 2002). People who live near shallow groundwater plumes containing VOCs may also be exposed via the intrusion of vapors from soil into indoor air (Picone et al., 2012; Yao et al., 2013).
 
303(d) List of Impaired Water Bodies, State Water Resources Control Board (SWRCB) 

Data source: The SWRCB provides information relevant to the condition of California surface waters. Such information is required by the Federal Clean Water Act. Every two years, State and Regional Water Boards assess the quality of California surface waters. Lakes, streams and rivers that do meet water quality standards, or are not expected to meet water quality standards, are listed as impaired under Section 303(d) of the Clean Water Act.
 

Sensitivity Analysis of the CalEnviroScreen Model and Indicators: OEHHA applied a series of statistical analyses, as well as simpler numerical and graphical comparisons, to answer questions about the CalEnviroScreen model and the confidence in the results. The results of the sensitivity analysis on the January 2013 draft that informed the finalization of Version 1.0 of the CalEnviroScreen are presented in this document. The California Environmental Protection Agency (Cal/EPA) and the Office of Environmental Health Hazard Assessment (OEHHA) announce the availability of the California Communities Environmental Health Screening Tool, Version 1 (CalEnviroScreen 1.0). This tool presents the nation’s first comprehensive screening methodology to identify California communities that are disproportionately burdened by multiple sources of pollution and presents the statewide results of the analysis using the screening tool. A report describing the methodology and results along with an online mapping application are available.