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Why is mercury a wastewater issue?
Under Section 303(d) of the Federal Clean Water Act, states are required to develop a list of water bodies with water quality impairments. The water bodies on the list do not meet water quality standards. San Francisco Bay is listed with 12 toxic pollutants including mercury. Because of mercury impairment, fish consumption advisories have been issued for San Francisco Bay.

The California Regional Water Quality Control Board, San Francisco Bay Region (Regional Board) issues the National Pollutant Discharge Elimination System Permit (NPDES Permit) for wastewater treatment plants. The NPDES Permit requires compliance with wastewater discharge limitations for pollutants, including mercury.

The San Francisco Bay Mercury TMDL (Total Maximum Daily Load), which was recently approved by the Environmental Protection Agency (EPA) and Regional Board, requires the Plant to develop and implement an aggressive source control and pollution prevention program to comply with new mercury limits and to maximize the Plant’s control over mercury sources impairing the San Francisco Bay. Studies have shown that approximately 61% of the mercury entering the San José-Santa Clara Regional Wastewater Facility is from dental practices.

In addition, U.S. EPA's Section 503 Sludge Regulations and state and local biosolids regulations require the Plant to meet concentration limits for heavy metals, including mercury. These regulations ensure that biosolids can be safely reused for land application and landfill cover.

Environment - Wastewater - Businesses - Dental Offices

Show All Answers

1. Where can I find a complete list of Best Practices for dental offices?
2. Why is mercury a wastewater issue?
3. Can wastewater treatment plants solve the mercury issue?
4. Will you sample the discharge or require the dental office to sample?
5. How will you assess compliance if no sampling is performed?
6. What is the penalty for non-compliance?
7. Why is disposing of amalgam in the red bag or garbage a problem?
8. Can chair-side traps and vacuum filters capture all scrap amalgam and particulates?
9. What are the regulators doing about the clean-up of abandoned mines? The majority of the mercury is coming from this source.
10. What is the status of the Dental Amalgam Program?
11. Are dental practices being charged a permit fee like large industries?
12. Which amalgam separators are acceptable for compliance?
13. How much will this new requirement cost?
14. Will you sample the discharge or require the dental office to sample?