Canadian Water Quality Guidelines for the Protection of Aquatic LifeĦ. USEPA (Office of Pesticide Programs) Aquatic Life Benchmarksĥ. USEPA Ambient Water-Quality Criteria for the Protection of Aquatic OrganismsĤ. USEPA Recreational Water-Quality Criteriaģ. USEPA Ambient Water-Quality Criteria for the Protection of Human HealthĢ. Minnesota Department of Health Pharmaceutical Water Screening Valuesġ. Canadian Guidelines for Drinking Water QualityĦ. USEPA Regional Screening Levels for Chemical Contaminants at Superfund Sitesĥ. USEPA Human Health Benchmarks for PesticidesĤ. USEPA Drinking Water Regulations and Health AdvisoriesĢ. Users are encouraged to consult the online sources for background information on the technical basis for the benchmarks being used, and any underlying assumptions, to better interpret what it means if a measured concentration exceeds a benchmark.Ĭlick on the links below or scroll down the page to see specific benchmarks listed, with links to more information.ġ. (See Characteristics and Limitations of Screening-Level Assessments section.) In general, effective use of benchmarks in water-quality assessment requires an understanding of how the benchmarks were derived and information about the specific hydrologic system being studied. Concentrations that exceed a benchmark do not necessarily indicate that adverse effects are occurring-they indicate that adverse effects might occur and that sites where benchmarks are exceeded may warrant further investigation. Rather, comparisons of measured or estimated concentrations with water-quality benchmarks provide an initial perspective on the potential for adverse effects, as well as a framework for prioritizing additional investigations that may be warranted. Screening-level assessments are not a substitute for either risk assessments, which include many more factors (such as additional avenues of exposure), or site-specific studies of effects. Environmental Protection Agency (USEPA) screening-level assessments for pesticides, which USEPA uses in early stages of ecological risk assessments to evaluate the potential impact of pesticides to non-target organisms. This approach has been used for many years by the USGS National Water Quality Program (such as in USGS Circular 1291, Pesticides in the Nation’s Stream and Ground Water 1992-2001), and it is similar in concept to U.S. Use of Benchmarks in Interpreting Water-Quality DataĬontaminant benchmarks can be used in screening-level assessments, in which site-specific estimates of contaminant exposure (concentrations or concentration statistics) determined from measurements of contaminants in various sampling media are compared to water-quality benchmarks. Examples of these include whole-fish benchmarks for protection of wildlife, or human health benchmarks for pharmaceuticals. However, a few types of benchmarks from the States or the general scientific literature also are included, for particular sampling media and beneficial uses that have few or no national guidelines. This web page focuses on national-scale benchmarks established for freshwater systems in the United States or Canada. Guideline: threshold values that have no regulatory status but are issued in an advisory capacity.Ĭriteria: within the U.S., criteria are part of the definition of a water-quality standard in Sec 303(c) of the Clean Water Act (CWA). Also, 304(a) criteria are published values that reflect scientific knowledge on the effects of priority pollutants on health and welfare, including effects on aquatic life, plants, wildlife, shorelines, beaches, esthetics and recreation the concentration and dispersal of pollutants or their byproducts and the effects on biological community diversity, productivity, and stability (Section 304(a) of CWA). Government or Canada. Within the U.S., the National Primary Drinking Water Regulations (NPDWR) include standards and treatment techniques that apply to public water systems as part of the Safe Drinking Water Act (SDWA). Standard or regulation: threshold values that are legally enforceable by agencies of the U.S. “Benchmark” is a generic term, and can include any of the following: Sampling medium: drinking water, ambient surface water, bed sediment, whole fish, or edible fish tissue andīeneficial use: the use that the benchmark is designed to protect, for example, drinking water, recreation, aquatic life, or wildlife. Benchmarks typically apply to a specific contaminant(s) in a specific sampling medium for a specific beneficial use:Ĭontaminant: contaminant classes for which benchmarks are available include pesticides, volatile organic compounds (VOC), pharmaceuticals, polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), metals, and nutrients A water-quality benchmark is defined here as a threshold value against which measured concentrations can be compared to help assess the potential effects of contaminants on water quality.
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