Mercury Rising Tackling the Legacy of the Gold Rush
The Gold Rush was a seminal moment in California’s history. The discovery of a few flakes of “color” in John Sutter’s millrace at Coloma set off a migration that transformed the nascent state’s frontier from a sleepy, remote outpost into a magnet that drew fortune-seekers from around the globe. Over the course of decades, intense efforts were focused on washing and prying gold from the hills of the Sierra Nevada – along the way, hardly a stone was left unturned in the pursuit of the hidden riches. Mercury was an essential commodity of gold mining, as it greatly increased the recovery efficiency of primitive mining technology. Mercury, which by fortuitous coincidence was available in plentiful quantity from deposits in the nearby Coast Range, acts as a magnet of sorts, drawing gold to it in a ready-made, easily recoverable amalgam from rock, gravel or soil. Once gathered, miners heated the amalgam to separate the two metals.
More than a century later, the miners have long since departed, but the mercury remains. Oblivious to the passage of time, mercury used in mining lingers in the mountains, like the confetti remnants of a ticker tape parade. Unlike the strips of paper, however, the mercury has caused and continues to cause a deleterious consequence that is the subject of ongoing analysis, monitoring and regulation. Relatively benign in its inorganic form, mercury’s organic cousin methylmercury is a persistent, bioaccumulative toxin that moves through the food chain and can build up in fish tissue to levels that could pose serious health threats to people that eat large amounts of contaminated fish.
“It’s insidious, once unsequestered into the physical and biological environment it doesn’t go away very quickly,” said Chris Enright, senior water resources engineer with the Department of Water Resources (DWR).
While some mercury is naturally occurring, escaping from near surface deposits, volcanoes and hot springs, the majority of what exists in the environment today is the result of industrial activity. Methylmercury’s damaging effects to the human body, particularly its harm to unborn children, has propelled it to being a prime concern among water quality and public health regulatory agencies.
“It’s about people eating fish,” said Khalil Abu-Saba, a senior scientist at Larry Walker Associates, who worked on mercury issues at the San Francisco Regional Water Quality Control Board. Despite the breadth of mercury in the environment, it is “challenging” to communicate the threat level to anglers and consumers, he said.
Bedeviling in its perseverance and well, mercurial nature, methylmercury contamination is a problem of global proportions. In northern California, mercury mined from the Coast Range and sent to the Gold Fields left a swath of contamination so pervasive along both sides of the Sacramento- San Joaquin Valley as to escape the realm of plausible cleanup. Some estimates are that 10 percent of the state’s landmass would have to be dredged or bulldozed to remove all contamination sources.
Faced with such a daunting scenario, efforts are being focused toward increasing the understanding of mercury’s fate in the environment and the most effective ways to keep it from embarking on its toxic path.
“Dredging out every river is not a good control strategy, so we are looking at places that are ‘hot spots,’” said Rick Humphreys, abandoned mines coordinator at the State Water Resources Control Board (State Board). “We’re trying to decide if it’s worthwhile to clean up hot spots in tandem with looking downstream to see if there’s any lowering of the impact on biota.”
Biota is derived from the Greek root biote, or way of life, and it is unto that realm that methylmercury intrudes in a stealthy and subtle manner. Released to the environment, the silvery-white metal most commonly associated with household thermometers finds its way to the sediments of various waterways. Once there, complex chemical reactions create the methylmercury that works its way up the food chain until it reaches the larger predatory fish that people choose to eat. Once in the food chain, methylmercury can be magnified as much as 100,000 times.
Consumed in sufficient quantity, methylmercury-tainted fish causes a litany of ailments centered on the central nervous system. At high levels of exposure, symptoms include loss of coordination, blurred vision or blindness and speech impairment.
“It is a poison, always has been a poison and still is a poison,” said Dr. Jane Hightower, a San Francisco physician who has studied mercury levels in her patients.
Oversight of the issue rests with the federal Food and Drug Administration (FDA) and Environmental Protection Agency (EPA), which in March announced a joint consumer advisory on methylmercury in fish and shellfish for reducing exposure to pregnant women, women who may become pregnant, nursing mothers and young children. The agencies emphasized the nutritional benefits of eating fish but noted “as a matter of prudence” that women should modify the amount and type of fish they consume.
“By following this advice, we’re confident that women and young children can safely include fish as an important part of a healthy diet,” said Dr. Lester M. Crawford, Deputy FDA Commissioner.
In California, the Office of Environmental Health Hazard Assessment urges expectant mothers and young children to be “especially careful” about their intake of freshwater fish although it “should be part of a healthy, balanced diet … consumed in moderation.”
Mercury presents a conundrum of substantial proportion because it’s ubiquitous and not prone to dissipation. Conventional wisdom dictates that it is not created or destroyed simply moved around the planet. State officials are grappling with how to balance wetland restoration efforts with the unintended consequence of worsening the problem because it is the bacteria-rich wetland environment in which mercury converts to methylmercury.
“By far, most of our methylmercury … is formed in the sediments, with wetlands being the prime place,” said Janis Cooke, environmental scientist with the Central Valley Regional Water Quality Control Board.
A California Bay-Delta Authority Mercury Strategy acknowledges that, “indeed, it would be desirable to eventually decrease methylmercury exposure in this ecosystem to a level where wildlife, fishery resources and human health are unaffected. However, the development of an effective approach for achieving such a goal is presently hampered by our very limited knowledge of mercury cycling in this ecosystem.”
Researchers are slowly gathering more knowledge as they investigate sources of mercury, the impact of methylmercury on fish and wildlife and the extent of the threat to human health. Cognizant of its toxicity, the state’s drinking water standard for mercury is set at a stringent 0.002 parts per million (ppm) to protect against adverse health effects related to kidney damage. Mercury is classified as impairing numerous California waters through the federal Clean Water Act’s requirements that the nation’s waters be “fishable” and “swimmable.”
This issue of Western Water examines the presence of mercury in the environment and the challenge of limiting the threat posed to human health and wildlife. In addition to outlining the extent of the problem and its resistance to conventional pollution remedies, the article presents a glimpse of some possible courses of action for what promises to be a long-term problem.
Click here to purchase a copy of the complete article.
One of the most unique programs of the Water Education Foundation is our water tours. For more than 15 years, the Foundation has been the only organization in the West offering a series of three-day water field trips. Getting out and seeing our rivers, reservoirs, farms and urban water uses is the best and easiest way to learn about water issues.
Tour veterans can tell you that the days are packed with sites and speakers. Making contacts with people of varying interests and sharing bus and meal time discussions is valuable and enjoyable. Keeping these tours up to date and coordinating every detail is the job of Judy Maben, our education and tour director. Countless hours go into analysis of places along the way to visit, speakers to pick up and drop off the bus, boats to board and walks to water sites. We run these tours close to cost and we couldn’t do this without the help of our sponsors, who finance everything from beverages to meals to boat rentals, and offer other help along the way.
By the time you get this magazine there will only be three tours left this year. Don’t make the mistake of thinking that any of these tours is the same one you may have taken a few years ago. It may have the same name, but the issues and places visited are always changing.
So, mark your calendar for the June 16-18 Bay-Delta Tour, September 15-17 Northern California Tour or our new October 6-8 Southern California Tour, which will now include surface water issues and sites in addition to groundwater. This new tour will give you the chance to see new surface storage facilities such as Diamond Valley Lake and the innovative new Olivenhain Dam, as well as to learn about desalination and groundwater management issues. Each tour is only held once a year, so don’t miss this unique opportunity. Call us for registration information, (916) 444-6240, or use our secure, on-line registration forms today.
In other Foundation news, note that we now have a new Layperson’s Guide to the State Water Project and are planning our July 15-16 Water Law & Policy Briefing, see page 14 for more information. Also, we are offering sale prices on all of our educational items in recognition of California’s May Water Awareness Month; See the order form on page 15.
In the News
New Look Ag Discharge Waiver Aims to Address Water Quality Issues
Despite skepticism from environmentalists and a lukewarm reception from farmers, the Central Valley Regional Water Quality Control Board (Central Valley Regional Board) is moving ahead with a regulatory program under which farmers will monitor runoff from irrigated agricultural lands. The program is bringing agricultural runoff under a regulatory regime for the first time similar to the one that applies to municipal and industrial dischargers.
Since 1982, irrigated agriculture has been exempted from the waste discharge requirements that regulate discharges from businesses and municipalities. That changed last summer, when the Central Valley Regional Board adopted two “conditional waivers” that require farmers to monitor discharges to surface waters of the state, determine if the water is impaired by the discharges, and take steps to reduce or eliminate any impairment. Farmers have the option of doing the monitoring individually or joining “coalition groups” with other farmers to spread the cost. If they don’t opt for either, they must file a report of waste discharge and will become subject to discharge requirements. Monitoring plans were due April 1.
The shift is expected to be significant for farmers accustomed to working under a less restrictive waiver for the last 20 years. “The success or failure of the new requirements hinges on how much the Regional Board is willing to work with membership groups to address water quality issues at a regional level,” said David Orth, Kings River Conservation District general manager.
Working with farmer groups would more likely ensure compliance and improved water quality “in lieu of the traditional regulatory form of seeking stricter enforcement on individual participants,” he noted.
Environmental groups, which pushed to strengthen regulation of agricultural discharges, remain critical of the new waivers, asserting that they do not do enough to curb discharges of pesticides, animal waste and other pollutants to rivers and creeks in the vast Central Valley region. In February, several environmental groups filed suit against the Central Valley Regional Board and the State Water Resources Control Board, which in January had approved the Regional Board’s plan, claiming that state law requires tighter regulation of agricultural pollution.
Bill Jennings of DeltaKeeper, one of the environmental groups involved in the suit, faulted what he calls the plan’s “lack of immediate goals, interim milestones and performance standards.” Although there is still a need to work toward a solution, the new waiver as it stands “contains the seeds of its own failure,” he added.
– John Speka, WEF Intern