Unlocking the Mysteries of Selenium
There may be no other substance in nature as vexing as selenium. The naturally occurring trace element gained notoriety more than 20 years ago as it wreaked havoc among birds at the Kesterson Reservoir in California’s Central Valley. The discovery of dead and deformed birds sparked a widespread investigation that revealed the pervasiveness of selenium throughout much of the West; woven into the soil and rock of the landscape.
Researchers have spent years analyzing selenium’s presence in the environment – its impact on fish and wildlife and the pursuit of strategies to mitigate its toxic effects. From California to the intermountain west, people are pursuing actions designed to halt the artificially induced release of selenium to the environment.
“Selenium is one of those things that cross all boundaries,” said Doug Barnum, acting chief scientist for the U.S. Geological Survey’s (USGS) Salton Sea Science Office. “It’s universally a problem and something we have to address head-on.” He spoke at a November Selenium Summit in Costa Mesa sponsored by the Water Education Foundation and the California Department of Water Resources.
Selenium’s paradox is that it is an essential dietary mineral that can adversely affect organisms when accumulations build to toxic levels. The difference between its benefits and detrimental effects may be the narrowest of any element.
“It becomes toxic at dietary concentrations that are not a whole lot higher than the dietary requirements and therein lays the problem,” said Harry Ohlendorf, principal environmental scientist with CH2M Hill in Sacramento.
The problems caused by selenium contamination are often associated with the application of irrigation to large acreages of crops. The drainage, both above and below ground, carries a range of constituents, such as salt, selenium and residual fertilizers and pesticides. In California’s Imperial Valley, irrigation with Colorado River water, which is relatively low in selenium, coupled with a high evaporation rate causes selenium to concentrate in drainage water. Disposal of subsurface agricultural drainage with high concentrations of selenium was ultimately determined as the cause of the avian fatalities and chick deformities at Kesterson.
“It’s really just since we started collecting and discharging subsurface drainage water that the selenium problems have been manifested,” Ohlendorf said.
Working its way through different species in the food chain, selenium levels accumulate in fish and bird species. Control of its dispersal in the environment is being coordinated through total maximum daily loads (TMDLs), a federal Clean Water Act provision designed to limit pollutant contributions to rivers, lakes, streams and the ocean. The problem is also legally addressed by the Endangered Species Act and the Migratory Bird Treaty Act.
Since Kesterson, which closed in 1985, officials have concentrated on identifying selenium “hot spots” throughout the West, devising remediation strategies and furthering the scientific understanding of its effect on fish and other wildlife. The federal government is central to the effort, particularly the U.S. Bureau of Reclamation (Reclamation), which manages many irrigation projects.
Scientific inquiry into the selenium problem has revealed its absolute complexity and the conundrum faced by officials as they seek a regulatory standard that is both attainable and protective of wildlife. The interaction between selenium and other water quality constituents is not well understood. Time and again it has been proven that drawing a straight line between selenium’s presence in an aquatic environment and adverse effects is anything but a foregone conclusion.
“In some water columns it stays, in others it gets removed very quickly,” said Joseph Skorupa, a biologist with the U.S. Fish and Wildlife Service (USFWS) in Arlington, VA. “That’s what is totally vexing about regulating selenium. Using measures of water alone is like playing pin the tail on the donkey. In assessing risk, you are blindfolded.”
The quest for regulations involves navigating and interpreting a web of research data. Federal wildlife biologists have, at times, disagreed with the approach advocated by the U.S. Environmental Protection Agency (EPA), which in December 2004 published a draft selenium criterion based on fish tissue sampling. Skorupa does not disagree with the fish tissue approach but believes the number chosen by EPA is not sufficiently protective.
“EPA is not seeking a standard protective of wildlife,” he said. “EPA is only attempting to protect aquatic life that lives under water [and] has never proposed any selenium standards for protecting wildlife, even though the Clean Water Act requires them to do so.”
Ephraim King, director of EPA’s Office of Science and Technology, disputed Skorupa’s claim as “factually erroneous,” but praised him as a “deeply committed, very dedicated” public servant with “strongly held personal views.”
Meanwhile, the question remains of what to do with selenium-impacted drainage. This has created a cottage industry that has resulted in some remarkable and rather ingenious methods by which officials have been able to capture, hold and treat selenium contamination without posing a threat to birds that are naturally drawn to wetlands. At the Tulare Lake Drainage District, which has elevated selenium sediment concentrations in some of its drainage waters, efforts have succeeded in directing birds to hundreds of acres of alternative habitat free of selenium where they can feed and nest “This compensation habitat has been phenomenally effective, far more than we ever imagined,” said Doug Davis, district general manager.
Disposal of selenium-tainted runoff has been an issue of concern from the time the federal government first opened the vast acreage of the Central Valley to irrigated farming via the Central Valley Project. Engineered and constructed but never completed, the San Luis Drain has once again become noteworthy in the wake of a court order for Reclamation to implement a resolution to the drainage problem. Among the options are ocean disposal and the retirement of selenium-plagued farmland. Given the controversial nature of the matter, it is likely that whatever final decision emerges will be the subject of further litigation.
It is believed that selenium is best controlled at the watershed level, where various stakeholders are called upon to pool resources and ideas to achieve the greatest results. This is occurring in different locations, including western Colorado and several communities situated in Orange County, CA. In both places, regulatory agencies and stakeholders are pursuing selenium control measures. Orange County may be one of the few urbanized regions having to manage selenium concentrations.
Conveying the importance of selenium remediation is difficult because of its sometimes subtle reproductive effects on wildlife as well as its standing among other more notable constituents of concern. “Because you can’t see it, it’s hard to convince people this is something you need to treat,” said Terri Reeder, associate engineering geologist with the Santa Ana Regional Water Quality Control Board. The Board is responsible for implementing toxics TMDLs developed by the EPA for the San Diego Creek/Newport Bay watershed in Orange County.
Skorupa, who has studied selenium throughout the West for 20 years, echoed that sentiment, saying that selenium would be a “back burner item” if not for its toxicity to wildlife.
Selenium management in Colorado is aligned with controlling salinity, another constituent of concern in the Lower Colorado River. The landscape’s sedimentary rocks contain salt and selenium that are released through the natural erosion process. Irrigation and the continued residential development of the region have accelerated the weathering process and release of selenium.
“The selenium problem has resulted from the unintended consequences of applying water to selenium rich soils,” said Paul von Guerard, western Colorado office chief of USGS’ Colorado Water Science Center.
That said, officials, scientists and stakeholders are concentrating on what can be done to solve the problem, using available resources, knowledge and collaborative efforts to control selenium at the source to limit its migration into the environment. This issue of Western Water examines that process. Much of the information is drawn from discussions that occurred at the November Selenium Summit, where a variety of experts presented findings and the latest activities from areas where selenium is of primary interest.
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The effects of the storm that hit northern California on New Year’s weekend continue to be felt. Following on the heels of the levee break in the Katrina catastrophe, the storm was enough to get the entire country to pay attention to the condition of the Sacramento area and Delta levees. The fact that Sacramento faces a greater flood danger than New Orleans faced was well known in water circles but less known to the public. Now with the national spotlight on California levees, a serious review of the Central Valley levee system has been initiated. As I write this, we’ve seen several high-profile tours by state and federal elected officials including local Reps. John Doolittle, R-Rocklin, and Doris Matsui, D-Sacramento, U.S. Sen. Dianne Feinstein, D-California, and Gov. Arnold Schwarzenegger. Joining one of the tours were Reps. David Hobson, an Ohio Republican who heads the Appropriations subcommittee on water and energy, which reviews flood control projects, and Jerry Lewis, a longtime Republican lawmaker from San Bernardino County.
Although the West is an arid land, it has always been subject to surprising floods. The 100-year standard flood protection now is seen by many as not enough, certainly not enough to protect the houses being built next to many levees designed decades ago to protect agricultural lands. So the debate is now about the necessity of 200-year protection in floodplains. The 200 year protection is the level provided to the Santa Ana watershed, which includes Disneyland, as a result of a $1.4 billion federal project that included a dry dam that fills only in high water years. This is twice the level of protection for the state capital. Lewis played a major role in securing federal funds for that project.
A recent report from the American Society of Civil Engineers gave a “D” grade for 2,600 miles of Central Valley levees, including some levees in the Delta. Within days, the governor declared a state of emergency calling for immediate strengthening of 24 eroded levees – identified by the Army Corps of Engineers and California Department of Water Resources – before the next flood season.
As the Foundation’s Judy Maben and I hiked along a few of these levees during the New Year’s storm, it was clear that fixing key levees will only be the start of the solution and the beginning of a debate that may bring up old proposals (Auburn Dam and the Peripheral Canal) and new fixes. One major issue society faces is how to keep houses, farms and water supply in the Central Valley – the land the American Indians and pioneers called the winter “Inland Sea” – above the flood line.
In the News
Flood Issues High on 2006 Legislative Agenda
California lawmakers this year will address various aspects of flood protection through a raft of proposed legislation that aims to avoid the catastrophe that struck the Gulf Coast last year in the wake of Hurricane Katrina.
“Post Katrina, there is a universal understanding that California needs to better address flood prevention, both fiscally and in terms of coordination of state and local efforts,” said Assemblywoman Lois Wolk, D-Davis, the author of several flood-related bills. “We need to set priorities on how the state will spend its annual budget as well as the governor’s proposed bond issue, or any future bonds, to keep Californians out of harms way, and not wait until the next flood hits.”
The bills run the gamut of policymaking, from the debate about the appropriate means of paying for flood control improvements, whether mandatory insurance should be required and the degree to which new development in flood plains should be limited. Wolk’s AB 802 would require local governments to incorporate a flood management component into their general plan, upon its revision.
Another proposal, AB 1898 by Assemblyman Dave Jones, D-Sacramento, would require mandatory flood insurance for anyone owning property in a zone with a 1-in-200 chance of flooding. If signed into law, the requirement would affect much of Sacramento and other low-lying portions of the Central Valley. Implementation will be an issue, as it may take some time to map the state’s 200- year flood plains. Another question is how to enforce the mandate on people who have paid off their mortgages.
Meanwhile, legislation that would reform the state Reclamation Board is being carried by Sen. Dean Florez, D-Shafter. Written in the aftermath of last year’s purge of the previous board by Gov. Arnold Schwarzenegger, SB 1796 is designed to revise the process by which members are appointed to the board, which oversees the flood control apparatus of the Sacramento and San Joaquin rivers. The bill would rename the Reclamation Board the Central Valley Flood Protection Board and require its members to be experts in geology, hydrology and other related fields, and to undergo confirmation by the Senate.
Of particular importance to the fragile Delta levees is Wolk’s AB 798, which would extend until 2008 the state’s subventions program. The program is a cost share partnership with local reclamation districts for the levee maintenance and upgrades. It is scheduled to expire July 1 of this year.
Another Wolk measure, AB 1899, would require local agencies in charge of development to include a discussion of whether the proposed project is situated in an area with a 200-year level of protection. If such is not the case, the bill requires local officials and development interests to ensure the area meets the standard prior to its development. The bill has raised concerns by some that it could in fact become a de facto moratorium on future development.
Republicans have concentrated their focus on streamlining levee repairs, which they say are hampered by burdensome environmental regulations. Toward that end, AB 2026 by Assemblyman Greg Aghazarian, R-Stockton, would require the Reclamation Board to give “the highest consideration” in protecting lives and property and “due consideration” to fish, wildlife, recreation and environmental factors. As such, routine levee maintenance items would be exempt from the California Environmental Quality Act.
“AB 2026 will ensure that human lives are not put in jeopardy because of burdensome regulations that prioritize lawsuits and delay over the safety and security of California families,” Aghazarian said.