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Fever Breaks on Mercury
Shoes that light up, greeting cards that play music, orange paint and crematoria... These are just a few of the surprising items harboring mercury - a heavy metal very much at large in the Bay-Delta environment and fast accumulating in the food chain. Efforts to thwart this contamination are heating up, as government and stakeholders up and down the Estuary wrangle over objectives, science and regulations.
"It's nasty stuff," says Phil Bobel of the Palo Alto Water Quality Plant. "It's a water pollution problem that people respond to more strongly because of the human contact hazards."
Mercury as a deadly pollutant made its most dramatic appearance back in the 1960s in Minamata, Japan, where enough got into the local food chain that it actually poisoned the populace and caused frightful birth defects and symptoms like those of MS. More recently, mercury has been found in Bay fish at levels high enough to lead the state to issue health warnings for consumers.
Where is it coming from? Not only is it hidden in household items like lap top switches and thermometers, but also in our dental fillings and wrinkle creams. Regulators guesstimate that over 1,700 kilograms per year enter the Bay watershed (see table p.6). One big chunk comes sewage, urban runoff and atmospheric fallout from furnaces, crematoria and cement manufacturing. Another chunk flows downstream from decommissioned mines in the watershed while a third chunk lurks in Bay bottom deposits of old hydraulic mining debris (miners used mercury to extract gold and silver from their ores).
Scientists say at least 400 million cubic meters of this debris ended up in San Pablo Bay. According to bathymetric models crafted by the U.S. Geological Survey's Bruce Jaffe and Richard Smith, underwater erosion is fast exposing about 100 square kilometers of the debris up to five meters thick. "We're talking hundreds of tons of mercury at or near the surface of the Bay floor and in contact with the ecosystem," says Jaffe.
Most of this was introduced into the environment as what's called elemental mercury, one of four kinds absorbed into the ecosystem in differing degrees. Elemental and reactive divalent mercury (Hg2+) both convert into the most dangerous and "bioavailable" form, known as methyl mercury, at a faster rate than cinnabar - the mercury sulfide in mine runoff. What kinds of environments and conditions promote mercury methylation are questions scientists now wish to explore. But one thing they do know is that bacteria in marshes along rivers and bayshores spur methylation.
"With some pollution problems the best thing to do is let natural processes remove it, but not in this case," says Jaffe. "Mercury is a moving target." With the marsh-ringed, debris-strewn shallows of the North Bay such a potential breeding ground for the bad stuff, it's no wonder that environmentalists have been raising Cain about mercury in local sewage discharges. To date, BayKeeper has appealed four North Bay discharge permits, both on mercury and other contaminant issues.
The latest of these permit wars flared this May, when the S.F. Regional Water Quality Control Board re-issued Novato's NPDES permit but temporarily increased the amount of dissolved mercury the treatment plant is allowed to discharge from 0.03 to 0.052 parts per billion. The Board then gave Novato seven years to comply with a tougher 0.025 final limit.
Reasons for allowing the increase, according to the Board, were that the old limit was based on since invalidated state objectives rather than on the region's current Basin Plan, and that within the next five years the Board would have a new improved regulatory approach to plug into the equation.
In the meantime, the limits currently in the permit include a new mass mercury limit based on prior performance. Keeping a growing bedroom community to existing performance and giving them a monthly cap is a disturbing idea to many dischargers. "It's a new concept, and one that has our industry very worried, because if you set the mass limit low enough, it's a growth control, which should be the purview of regional land use planning not water quality regulation," says Novato's Tom Selfridge. "We can live with the mass limit in our permit, but we don't like the precedent."
Environmentalists, meanwhile, don't think the North Bay permits go far enough and have accused the Board of backsliding from tougher limits and allowing potential increases in the area's mercury load. "The old myth is that mercury is just a historic legacy of Gold Rush days, and that there's nothing we can do about," says Mike Belliveau of Just Economics for Environmental Health. "But having so much in the system already means we have to crack down harder on what's ongoing. We're long past due to get rid of mercury containing products, especially where alternatives already exist for them."
Palo Alto's sewage plant has proved this can be done. Last year it invited its community to turn in their old mercury thermometers for a coupon good for a digital fever detector. The plant's Phil Bobel says that while the actual reductions in load may be small - only 1,000 thermometers turned in within 18 months - the public awareness value has been great. "It's a way to communicate with the public about something they can understand, and give them something they can do. People come in actually excited to be turning in their thermometer." (Ironically, the recycled thermometers are made into new ones.)
Palo Alto has also asked hospitals and labs to come up with strategies to find substitute equipment for pressure-sensing and other devices containing the offending metal, and found them eager to try. Breaking one mercury thermometer in the wrong place can mean a $500-$1000 hazardous waste clean up, he says. Palo Alto has also conducted a thorough review of sources of mercury to the wastewater entering its treatment plant, and also discovered that the unregulated smoke produced by crematoria may contribute on the order of 100 pounds of mercury per year (via the volatilization of dental fillings). Contemplating possible control strategies - since there's no real technology yet to filter out mercury "smoke" - boggles the mind, if not the soul.
But a certain amount of soul searching may be required if traditionally at-odds dischargers, environmentalists and regulators are to come to agreement on a regional strategy for reducing mercury. To this end, the S.F. Regional Board began work to set a total maximum daily acceptable mercury load (TMDL) for the entire region last year, which is scheduled to complete by 2004. The Central Valley Regional Board is on a similar TMDL track.
"The TMDL is the answer to everyone's questions," says the S.F. Board's Shin Roei Lee. "When it's done, everyone will get their fair share of the waste load."
"The Novato permit continues our trend over the past year of reissuing permits that focus less on compliance with a 'number' and more on ensuring that dischargers take the responsibility to reduce loadings of critical constituents to the maximum extent possible," adds another Board staffer, Bruce Wolfe. "We want them to quit operating in a vacuum and work with other dischargers to coordinate monitoring, and with us to develop an understanding of what their discharge means in their watershed."
Such an understanding should come from the newly-formed, 50-member, stakeholder-based Mercury Watershed Council launched by the Regional Board this March, if everyone stays at the table. The Council's job is to advise on the TMDL proposal, to study options for trading loads among dischargers, and to explore the realities of "virtual elimination" of mercury from the system. To date, the Council has produced a slim ream of research - most notably a list of mercury sources and pollution prevention methods, and a survey of how trading programs work in other states.
"It makes sense for everyone to work on sources they can do something about, using the low-hanging fruit principal - namely, do the things that are easiest and most inexpensive first," says Palo Alto's Bobel. Many dischargers think that more treatment, where the mercury reduced may measure in the nanograms, is much less cost-effective than reducing the pounds and pounds coming out of the mines, or the tons lying on the Bay bottom. Public education, meanwhile, remains an important option but one whose impacts in terms of mercury reduction are hard to quantify.
Measuring gains and losses could be equally tough in the arena of runoff pouring into our rivers and bays from cities and towns. "If a lot the mercury we're seeing is from urban stormwater, then municipalities are going to have to get aggressive about finding sources," says veteran stormwater manager and consultant Roger James. "But what if the biggest sources turn out to be global, third world aerial emissions? Should reducing that ultimately become the responsibility of the discharger, since its coming out of their pipe?"
Some of these issues may be resolved via a proposed banking system that would give mercury credits and debits to dischargers who've exhausted their own local ability to reduce mercury but might be able to pay for reductions elsewhere. To this end, the Council is trying to develop a mass load trading system to complement the TMDL. Key issues for any such program are who can participate, how big will the trading area be (can Bay dischargers trade with Central Valley ones?), when does it kick in (after discharge levels exceed permit requirements? Or only when all local reduction efforts are exhausted?), how to measure gains, and how to make sure ecological impacts aren't just shifted elsewhere.
"If North Bay dischargers buy credits to clean up Cache Creek, it provides no benefit for the immediate Napa River environment, and for those Latino farmworkers fishing in the river," says Mike Belliveau. Yolo County's Cache Creek is a known mercury hot spot in the Delta watershed.
How have other states dealt with pollutant trading questions? Council intern Katy Chamberlain recently investigated ten existing programs in Colorado, Florida, North Carolina and the Great Lakes. Most were focused on nutrients rather than toxics, and very few have been established long enough to evaluate their effectiveness. But Chamberlain did glean some wisdom. According to a memo she wrote to the Council: "The truly successful programs are not only clearly outlined and strictly regulated by the government, but also have a baseline from which emissions must not increase. If a discharger's emissions are over loadings allocated by their NPDES permits, the discharger may buy credits generated through the regulatory agency before the transfer of credit. This reduction in pollutant loadings before the trade is integral to successful trading, otherwise load reductions can be uncertain. To prevent hot spots and high concentrations, trading must only be performed within smaller watersheds."
Despite all the data collected, lists made, and policy drafted, the Board's Lila Tang says "no one is shaking hands and hugging yet." Things could get more painful soon, if similar conflict-ridden efforts to build South Bay consensus on copper and nickel reduction strategies are any indication.
Part of the problem for would-be consensus builders is the current regulatory vacuum on mercury. "Regulations are behind the times on mercury, partly because it's an arena that's so litigious. It's easy for dischargers to retard the regulatory process," says U.S. Fish & Wildlife's Steve Schwarzbach, whose agency recently issued a biological opinion on the proposed California Toxics Rule.
The rule - to be released in draft form by U.S. EPA this fall - will apply everywhere there aren't already regional numbers in place (the Central Valley, for example), and become a default when local objectives are challenged. But the rule's 50 parts per trillion mercury criteria is "orders of magnitude" off the 2 ppt Schwarzbach would like to see to protect fish and wildlife from reproductive and health effects.
"The mercury objective should be the guiding light, the regulatory end point, which says this is where we need to be," he says. "If you've got the wrong destination from the start, it doesn't help."
No statewide numbers are in place either - California's water quality standards were remanded by a lawsuit in 1994 and never reinstated. Exacerbating this regulatory vacuum, meanwhile, are pending changes in how the feds want mercury levels measured and risks assessed.
Amid all this regulatory uncertainty, however, are two signs of movement on mercury. First, EPA has suddenly cracked down on discharges to water bodies officially listed as "impaired" under the Clean Water Act due to the presence of mercury, copper, dioxin and other contaminants. Both the North and South Bays are officially "impaired."
For years, deepwater dischargers such as Tosco have enjoyed what's called a "dilution credit" which allows them to assume a certain amount of dilution of problem contaminants at the end of the pipe by the receiving waters. For years, organizations like BayKeeper have been challenging such credits.
As of now, EPA is sending out the first warning letters that such dilution credits will soon no longer be given for mercury and other offenders. This isn't new law, just proper implementation of existing law, says EPA's Terry Oda. "If the water body itself is already exceeding the limit, we can't give them a credit for dilution. It flies in the face of the whole Clean Water Act concept of not contributing to further impairment." he says. "We won't sock them right between the eyes, we know they need time to come into compliance. In the interim they can still operate within current conditions but in the end they'll have to meet either the metal criteria or TMDLs without the dilution credit."
The second new regulatory move on mercury came this July, when the S.F. Board amended stormwater discharge permits for Contra Costa and San Mateo counties to improve mercury control and mandate more pollution prevention. "Stormwater permits usually only require BMPs (best management practices), but for the first time these permits say the counties have to monitor and assess mercury loadings," says the Board's Shin Roei Lee "It's putting stormwater people in a point source category."
BayKeeper doesn't think the permits go far enough, however, and is appealing them for, among other things, their failure to control increases in mercury discharges from new developments.
Another source that may need to moved into the point source category are the mines upstream, where Bay fingers have long pointed when it comes to mercury. Preliminary results of some new science confirm the importance of these mines, and reveal likely hot spots upstream of the Delta.
The three-year U.C. Davis study is investigating Delta tracts flooded inadvertently by storm events over the past 75 years to determine if methyl mercury distribution and bioaccumulation varied with watershed source, salinity, time since flooding, vegetation and other factors.
"We were afraid we'd end up with a dull project, and find mercury concentrations uniform everywhere in the Delta," says co-author Darell Slotton."But the news is we found real low spots and real high spots, and the most dramatic high spots so far correlate with Cosumnes River and Yolo Bypass inflows."
It's ironic that one of the Estuary's last remaining wild and undammed rivers, the Cosumnes, should have some of the highest mercury concentrations for the very same reason (dams trap and contain mercury-laced sediments), says Slotton. The Cosumnes' small flows and gentle gradient also play a role is encouraging the mercury to hang around, he adds. The Yolo Bypass, meanwhile, conveys flows from that known mercury bad guy: Cache Creek.
One surprise, says Slotton, was to find higher levels of mercury upstream of the city of Stockton than below it on the San Joaquin River: "We thought we'd see a signal from the city, especially with all its organic matter (sewage) and low oxygen level problems. All these factors should contribute to mercury methylation, but go figure. It looks like more is coming from the mines upstream on the Merced and Stanislaus than from the city."
The study's authors conclude that regions demonstrating enhanced bioavailability may not be the most desirable locations for large-scale wetland restoration (too bad the Cosumnes is the Miss America of the restoration universe). Further research on upstream mercury sources and methylation is planned courtesy of a $3.8 million CALFED grant, part of the biggest mercury research project undertaken nationwide since similar projects in the Great Lakes and Everglades.
The conclusions of the U.C. Davis study are echoed by Jaffe's and Smith's mapping of North Bay mining debris, spots planners should be beware of when restoring wetlands or dredging. Either activity could increase the ecosystem's exposure to mercury and mercury methylation. "If you flood dry soils to make a wetland, we know that there's an instant pulse of methyl mercury that can last up to a decade," says the Geological Survey's Sam Luoma.
So with mercury in our air, water and land, with little regulatory guidance in place, and with only fledgling science at our fingertips, there seem to be more questions than answers available to those trying to purge our small estuarine universe of this slippery silver poison.
"Science may not give us all the answers and our environmental community won't wait," says the Board's Lila Tang. "So our strategy's going to have to be based on our best judgment, and the work of our stakeholder Council. Luckily mercury has a lot of potential in the pollution prevention arena, unlike dioxin which is a by-product of many processes and used less purposefully. If we start reducing mercury use now, our grandchildren may see some benefit."
Contacts: Phil Bobel (650)329.2285; Mike Belliveau (650)728.5728; Bruce Jaffe (650)329.5155; Darell Slotton (530)756.1001 or Lila Tang (510)622.2425.
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