&EPA
United States
Environmental Protection
Agency
Office of Water   EPA- 821-F-14-002
                                                    www.epa.qov
                                                                    September  2014
   Effluent Limitation Guidelines and Standards for the
                                Dental Category
Summary
EPA is proposing technology-based
pretreatment standards under the Clean Water
Act for discharges of pollutants into publicly
owned treatment works (POTWs) from existing
and new dental practices that involve the
discharge of dental amalgam. The proposal
would require dental practices to comply with
requirements for controlling the discharge of
dental amalgam pollutants into POTWs based on
the best available technology or best available
control technology and Best Management
Practices.

EPA is also proposing to amend selected parts of
the General Pretreatment Regulations (40 CFR
Part 403) to streamline oversight requirements
for the dental sector. EPA expects compliance
with this proposed rule would reduce the
discharge of metals to POTWs by at least 8.8
tons per year, half of which is mercury. EPA
estimates the annual cost of the proposed rule
would be $44 to $49 million.

Why is EPA proposing this rule?
When dentists remove old amalgam fillings
from cavities,  or when dentists place a new
filling, mercury in the form of dental amalgam
enters the waste water of the dental office.
Studies have shown that dental offices are the
largest source of mercury discharges to POTWs,
contributing about half of the mercury received
by POTWs. Mercury is a persistent and
bioaccumulative pollutant with well-documented
effects on human health. When in water, certain
microorganisms can change mercury into
methylmercury, a highly toxic form that builds
up in fish, shellfish and animals that eat fish.
Fish and shellfish are the main sources of
methylmercury exposure to humans.

The proposed  rule would require all affected
dentists to control mercury discharges to
POTWs by reducing their discharge of dental
                           amalgam to a level achievable through the use of
                           the best available technology (amalgam
                           separators) and the use of Best Management
                           Practices. In order to simplify compliance with,
                           and enforcement of the numeric reduction
                           requirements, the proposed rule would allow
                           dentists to demonstrate compliance by installing,
                           operating and maintaining amalgam separators.
                           The proposal also includes a provision by which
                           dental offices that have already installed
                           amalgam separators that do not meet the
                           proposed amalgam removal efficiency would
                           still be considered in compliance with the rule
                           for the life of the amalgam separator. Removing
                           concentrated sources of mercury to POTWs
                           opportunistically, such as through low-cost
                           amalgam separators at dental offices (average
                           annual cost per dental office: $700), is a
                           common sense solution to managing mercury
                           that would otherwise be released to air, land, and
                           water.


                              Proposed Pretreatment Standards for the
                                    Dental Category Include:

                              •   Technology-based pretreatment standards for
                                 discharges of pollutants into POTWs from
                                 existing and new dental practices that involve
                                 the discharge of dental amalgam
                              •   Dental offices covered by this proposed rule
                                 could control mercury discharges to POTWs
                                 by reducing their discharge of dental
                                 amalgam to a level achievable through the
                                 use of the best available technology
                                 (amalgam separators) and the use of Best
                                 Management Practices.
                              •   Amendments to selected parts of the General
                                 Pretreatment Regulations (40 CFR Part 403)
                                 to streamline oversight requirements for the
                                 dental sector and to eliminate discharge
                                 monitoring for the dentists.

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For More Information
You can view the Federal Register Notice at
http://www.epa.gov/guide/dental. In addition,
the proposed rule will be available at
http://www.regulations.gov under Docket ID:
EPA-HQ-OW-2014-0693. Upon Federal
Register publication, EPA will accept public
comments on this proposed rule for 60 days.

You may also contact Damon Highsmith at
Highsmith.Damon@epa.gov.

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