Environmental Engineering Reference
In-Depth Information
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Consumer right-to-know of the presence of carcinogens or reproductive toxins in con-
sumer products
Community right-to-know of large quantities of dangerous chemicals stored and used by
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local industries
This chapter reviews the full complement of regulations and regulatory guidance thresholds for
1,4-dioxane, with an emphasis on the derivation of water quality standards.
6.1 DRINKING WATER REGULATIONS FOR 1,4-DIOXANE
Water quality standards are mandated by the Clean Water Act
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and preserve the benei cial uses of a
water body by designating criteria to protect it against degradation from pollutants. A water quality
standard accounts for
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The designated benei cial uses of the water body (i.e., recreation, drinking water supply,
aquatic life, and agriculture)
The water quality criteria to protect benei cial uses (numeric pollutant concentrations and
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narrative requirements)
The maintenance and protection of existing benei cial uses and high quality waters
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(antidegradation policy)
Practical implementation issues (i.e., low l ows, variances, mixing zones) (USEPA,
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2006a)
The National Pollution Discharge Elimination System (NPDES), a permit program that controls
water pollution by regulating point-source discharges into waters of the United States, is the pri-
mary framework for water quality standards from the Clean Water Act.
The Safe Drinking Water Act of 1974 (SDWA) authorizes the U.S. Environmental Protection
Agency (USEPA) to establish national health-based standards for drinking water to protect against
both naturally occurring and anthropogenic contaminants in drinking water. The SDWA was
amended in 1986 to include specii c health goals and dei ned approaches for risk management. The
SDWA also outlines criteria for adding chemicals to the list of contaminants regulated by Maximum
Contaminant Levels (MCLs). Prior to the 1996 amendments to the SDWA, USEPA was required to
regulate an additional 25 contaminants every 3 years. Currently, USEPA has the l exibility to deter-
mine whether to regulate a contaminant after completing a required review of at least i ve contami-
nants every 5 years.
USEPA uses three criteria in its review to determine whether to regulate a contaminant:
1. The contaminant adversely affects human health
2. The contaminant is likely to occur in public water systems at sufi cient frequency and
concentrations to create a public health concern
3. Regulation of the contaminant presents a meaningful opportunity for health risk reduction
(USEPA, 2006a)
USEPA must also establish criteria for monitoring of unregulated contaminants and must issue
an Unregulated Contaminant Monitoring Requirement (UCMR) list of not more than 30 contami-
nants every 5 years. In order to add a new contaminant to the list of regulated compounds, USEPA
must conduct cost-benei t analyses and use the “best available, peer-reviewed science and support-
ing studies” to set standards.
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The Clean Water Act or CWA is the Federal Water Pollution Control Act Amendments of 1972 and 1977.
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