San Francisco Bay Mercury TMDL
The following is an adaptation of a PowerPoint Presentation we put forth at various California Water Environment Association (CWEA) meetings since 2004.P>
BRIEF HISTORY: SFBRWQCB MERCURY TMDL
- Sep. 14, 2004: Water Board adopted resolution to amend Basin Plan to establish Mercury TMDL and Implementation Plan for SF Bay.
- Sept. 07, 2005: State Water Resources Control Board remanded the Mercury TMDL Amendment back to the Water Board.
WHO IS AFFECTED?
- Municipal wastewater dischargers
- Advance treatment
- Secondary treatment
- Industrial and refinery wastewater dischargers
- Urban stormwater programs
TMDL AMENDMENT CHANGES
- Adopting new objectives for mercury in fish tissue to protect human health and wildlife.
- Vacating the Basin Plan’s existing total marine water quality objective applicable north of the Dumbarton Bridge in San Francisco Bay.
- Establish two numeric mercury water quality objectives for all segments of SF Bay
- 0.2 mg/kg (ppm) fish muscle tissue in tropic level 3&4 fish consumed by humans.
- 0.03 mg/kg small fish (3-5cm, whole) to protect wildlife (California least tern).
TMDL DETAIL: FISH TARGET FOR HUMANS
- Followed same procedure as the EPA used to determine a human health criterion of 0.3 mg of methylmercury per kg of fish tissue (ppm).
- Adjusted formula for Bay Area specific fish consumption rates yields a Basin Plan specific fish criteria of 0.2ppm for human health.
- Water quality objective applies to the five most commonly consumed Bay fish: striped bass, California halibut, jacksmelt, white sturgeon, and white croaker.
- “Target applies to average wet weight fish tissue muscle concentrations in 60 cm long striped bass”
TOUGHER CRITERIA FOR DISCHARGERS
- Revised municipal wastewater allocations (affecting effluent and pretreatment programs)
- Policy decision, not a scientific decision
- POTW Load 17 of 1200 kg/yr load
- Load reduction required into future
- ‘Develop and implement effective programs that include but are not limited to pollution prevention to control mercury sources and loading, a plan and schedule of actions and effectiveness measures applicable for the term of the permit, based on identification of the largest and most controllable sources and updated assessment of source control measures and wastewater treatment technologies.’
MUNICIPAL DISCHARGER REQUIREMENTS
- Requires ‘effective programs to reduce mercury-related risks to humans and wildlife and quantify risk reductions resulting from these activities’
MUNICIPAL DISCHARGER MASS LIMITS: INDIVIDUAL AND AGGREGATE
- Aggregate load reduction from 17 kg/yr to 11 kg/yr
- 10 year interim mass limit 14 kg/yr
- Initial 10 years, individual mass limits shall be the 2000-2003 annual mass discharge levels.
- Enforcement against discharger who exceed individual mass discharge limits.
- Incorporates ten year and twenty year final implementation schedules.
- Advanced and secondary plants must reduce total mercury load by 20% in 10 years.
- If load < 0.1 kg/yr no reduction in mass loading proposed.
- 40% reduction to municipal waste load allocation for plants that only provide secondary treatment.
- 20% reduction to municipal already employing advanced treatment.
- Improvements expected by ‘aggressive pollution prevention and other cost effective mercury reduction methods.
- Those given a 40% reduction to their allocation expected to employ the above, plus WWTP improvements and/or use of state-developed offset program.
MASS OFFSET PROGRAM
- Mass Offset program for those not in compliance with their wasteloadallocations.
- Those seeking to increase their mercury load.
- Offsets are not to be means of forcing dischargers to bear more than their proportional contribution to impairment.
- Does not exist yet
- Expected that the State Board will implement such a program.
- If program does not exist ten years after effective date of TMDL or any time thereafter Water Board will consider modifying schedule for achievement of the wasteloadallocations, or revisions to wasteloadallocations if State Board has not established a pollutant offset program that can be implemented within 20 years required to achieve final wasteloadallocation.
MUNICIPAL DISCHARGER ‘TRIGGER CONCENTRATION’
- Secondary treatment
- Daily max. 0.065 ug/l
- Monthly avg. 0.041 ug/l
- Advanced treatment
- Daily max. 0.02 ug/l
- Monthly avg. 0.01ug/l
MUNICIPAL DISCHARGER MASS LIMITS: INDIVIDUAL AND AGGREGATE
- Discharger required to submit an explanatory report if either trigger concentration or load allocation is exceeded.
- No waste load reduction proposed
- Correct aggregate load from 3 kg/yr to 1.3 kg/yr
- ‘Confirm performance is above average for the U.S.’
- If not above average performance, Water Board to consider reducing load allocation next review cycle for TMDL.
- No load reduction because
- Total load from industry 1.3kg/yr out of more than 1200 kg/yr to bay.
- Hypothesize that they are performing as well or better than counterparts elsewhere in California and US.
- 2000-2003 baseline
- Refineries contributed 68% of mean annual mercury load discharged by industrial and petroleum refinery facilities.
- Wasteload allocation will not include mass from once-through cooling water.
- Required to ‘develop and implement effective programs to control mercury sources and loading including demonstration that discharge levels represent good performance based on an updated assessment of source control measures and wastewater treatment technologies.’
- Required to ‘Develop and implement effective programs to reduce mercury related risks to humans and wildlife and quantify these risk reductions resulting from these activities.’
- Requires Bay Area refineries to collaborate with the Water Board to investigate the environmental fate of mercury in crude oil and report within five years.
INDUSTRIAL WASTEWATER ‘TRIGGER CONCENTRATION’
- Daily max 0.062 ug/l
- Monthly avg. 0.037 ug/l
URBAN RUNOFF ALLOCATION
- Allocation 82 kg/yr, reduction 78 kg/yr
- Develop and implement a mercury source control program
- Evaluate source of contamination
- Quantify loads and reduce
- Conduct or cause studies Hg fate & transport
- Annual reports of progress
- Quantify Hg loading over rolling 5 yr avg
- Quantitatively demonstrate that the Hg concentration of suspended sediments that best represents sediment discharged with urban runoff is below the suspended sediment target.
- No net increase in total or methyl mercury to Bay.
- Demonstrate compliance that project meets goal by pre and post project monitoring.
METHYL MERCURY REQUIREMENT
- Interim monitoring required in draft 13267 letter
- Total and methyl mercury in effluents using methods 1631 total and 1630 methyl.
- Data to support research
- Does discharge quantity cause environmental concern?
- Are there local effects at discharge locations?
PRETREATMENT AND POLLUTION PREVENTION
- POTWs to update assessment of source control measures and treatment technologies aimed at reducing amount of mercury discharged to Bay.
- Quantify the mercury load avoided or reduced.
- Collect total and methyl mercury samples of effluent
- Monthly for dischargers > 5 mgd
- Quarterly for dischargers < 5 mgd
- Use EPA draft 1630 method
- Use RL of 0.05 ng/L
IMPLICATIONS TO YOUR MONITORING PLANS
- Effluent: primarily addition of methyl mercury for informational purposes.
- Effluent: additional emphasis on EPA 1669 ‘clean hands / dirty hands’, cleanest sampling protocol possible can only help.
- Source control efforts:
- Can be lots of variability in raw influents due to imperfect distribution of mercury bound to solids.
- More samples can provide greater precision on the resulting concentration value.
- Most useful in screening where to put your efforts
SUMMARY OF WHAT IS NEW
- Reduction of loading of total mercury for the POTW and stormwater dischargers.
- Increased emphasis on pretreatment program and source reduction.
- Increased demand for studies.
- Requirement of methyl mercury analysis
SUMMARY OF KEY POINTS
- TMDL is for total mercury, methyl is only being monitored for information at this time.
- TMDL requires all POTWs to reduce mercury load 20% by ten years from implementation.
- A key ‘out’ of the reduced load limit is the yet undeveloped offset program.
Online source of documents.