Turtles shell out info on mercury
Scientists link high levels to coal-fired local power plants
Scientists link high levels to coal-fired local power plants
David Owens/College of Charleston
College of Charleston graduate student Jeff Schwenter takes samples from turtles. Researchers here and at the Hollings Marine Laboratory are studying mercury levels in turtles.
The Post and Courier
Biologist Russell (Rusty) Day and other researchers have tested turtles for mercury and are finding that they make good indicators for whether an area has a local mercury contamination problem.
Biologists in Charleston have discovered that turtles are reliable detectors of local mercury contamination, a finding that could have major implications in how the toxin is measured and regulated.
Terrapins, a common turtle found in coastal estuaries, "are homebodies," said David Owens, a College of Charleston biology professor working on the research. "In their lifetime, they might stay in a few acres of water. So when you get a terrapin, it becomes a signature for what's going on in that spot."
Owens and his students, along with state and federal researchers here, are taking blood samples and shell scrapings from turtles along the Eastern seaboard and testing these samples for mercury.
So far, they've found that sea turtles captured near the mouths of rivers had higher mercury levels than those caught offshore.
In estuaries they discovered that turtles near coal-fired power plants and other industrial sites also had elevated mercury levels.
Using turtles to monitor mercury levels could add a new twist to the high-stakes debate over whether coal-fired power plants and other industries create local mercury pollution problems.
"Once people link local mercury contamination to local mercury-spewing plants, pressure will increase to clean those plants up, and that costs money," said Blan Holman, a lawyer for the Southern Environmental Law Center.
The Lowcountry has a serious mercury hot spot problem, The Post and Courier revealed in its recent series, The Mercury Connection.
Nearly every major river in the coastal plain has fish contaminated with mercury, and the problem is especially severe in the Edisto-Four Holes Swamp area and along the Little Pee Dee and Lynches rivers.
When The Post and Courier paid for testing of people who eat fish from these mercury hot spots, 17 people had levels higher than the federal safety benchmark. Some frequent fish eaters had levels so high that they rank among the most mercury-tainted people in the nation.
Mercury tends to build up in turtles'
shells over time, just as it does in human hair. But until recently, scientists weren't sure whether measuring these scrapings would be reliable indicators of mercury in turtle tissue.
Rusty Day, one of Owens' former graduate students, decided to find out. "There just wasn't a lot of data on mercury," said Day, now a biologist with the National Institute of Standards and Technology at Fort Johnson.
After collecting blood samples, internal tissues and shell scrapings from sea turtles along the coast, he and other biologists determined these shell scrapings were accurate indicators of mercury in turtle tissues.
In one study, Day and other researchers at the College of Charleston's Grice Marine Laboratory also found that sea turtles caught near mouths of rivers and harbors had higher levels of mercury than those caught in the open ocean.
That made sense, Day said, because wetlands drained by these rivers are sources of methylmercury, a potent form that's more readily absorbed and eaten by fish.
In another study published in October, Day and researchers with the state Department of Natural Resources and Medical University of South Carolina found that mercury may be causing "subtle negative impacts" on sea turtles' immune systems.
In experiments supported by the South Carolina Sea Grant Consortium, researchers at the Grice lab also are studying mercury in diamondback terrapins — turtles often found in brackish waters on the East and Gulf coasts.
Owens said researchers went to an industrial site near Brunswick, Ga., which has a serious mercury contamination problem. "We collected terrapins and had some of the highest mercury levels we had seen." They also collected samples around coal-fired power plants in Virginia. Coal-fired power plants are major sources of mercury emissions. "What we found was that if turtles happened to be near a coal-fired power plant, the mercury levels were significantly higher," Owens said.
He and his students also have taken samples from turtles throughout Charleston Harbor and found different levels in turtles at the harbor's mouth from those in turtles upriver. Mercury contamination "seems very localized from our perspective," he said.
Reach Tony Bartelme at tbartelme@postandcourier.com or 937-5554.
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Comments
pendolf (anonymous) says...
Wait, I am so confused. First, Tony (reporter) says here:
"In estuaries they discovered that turtles near coal-fired power plants and other industrial sites also had elevated mercury levels."
The then from the scientists:
"He and his students also have taken samples from turtles throughout Charleston Harbor and found different levels in turtles at the harbor's mouth from those in turtles upriver. Mercury contamination "seems very localized from our perspective," he said."
But in the "in-depth" mercury P&C articles, the super mysterious "mercury triangle" is far up river in Florence / Horry County. There are no coal-fired power plants near it.
What gives? Data is all over the place and don't let reporters with little or no science background make conclusions. DHEC has a mercury rule to reduce mercury emissions. Just let it work.
November 3, 2007 at 8:15 a.m. ( permalink | suggest removal )
waterbug (anonymous) says...
I read the quotes. What has DHEC done ? Sounds like Pendolf has a DHEC connection.
November 3, 2007 at 9:23 a.m. ( permalink | suggest removal )
beespencer (anonymous) says...
I believe SCE&G has 2 plants that connects to Edisto River and Ashley River
November 3, 2007 at 12:57 p.m. ( permalink | suggest removal )
csor (anonymous) says...
This is litle more than a rehash of their original article on fish in mercury; just substitute "turtle" for "fish". For those that want to look at real science vs. P&C's ongoing scare tactics, look here:
http://www.epa.gov/mercury/control_em...
From the above reference...
"Much of the mercury circulating through today's environment is mercury that was released years ago, when mercury was commonly used in many industrial, commercial, and residential products and processes. Land and water surfaces can repeatedly re-emit mercury into the atmosphere after its initial release into the environment."
If memory serves, there was a lot of panning for gold in South Carolina rivers in the 1700's and 1800's. Part of the process for panning for gold involved using mercury to form an amalgam with the gold. Where do you think the excess mercury was dumped? You'd think somebody would have put together a study to see if that residual mercury was still in the rivers.
"U.S. anthropogenic mercury emissions are estimated to account for roughly three percent of the global total, and emissions from the U.S. power sector are estimated to account for about one percent of total global emissions. (United Nations Environment Programme (UNEP). Chemicals, Global Mercury Assessment, Geneva, 2002.)."
Okay, so if we shut all of the coal fired power plants down, we'll reduce mercury concentrations by one percent? It would seem to me you would still have a mercury problem.
November 3, 2007 at 4:57 p.m. ( permalink | suggest removal )
csor (anonymous) says...
Some more scientific research...
http://agresearch.umd.edu/CFNAP/realm...
"Although how methylmercury is formed and accumulates in fish is still poorly understood, it is believed that the methylation occurs deep in the ocean where mercury resides in the sediment. For this reason, many experts studying methylmercury concentrations in fish report that these levels have remained consistent over time and are not correlated with mercury levels in the air or atmosphere. Supporting this scientific position are a number of published studies, including the following:
A Princeton University study, funded by the Environmental Protection Agency and published in Environmental Science and Technology in 2003, compared the methylmercury levels in Yellowfin tuna caught off Hawaii in 1971 and the concentrations of the tuna caught in 1998. The researchers found that the mercury levels were unchanged;
A study reported in the journal Science in 1972 found that fish in the Smithsonian Museum that were caught in the late 1800s had average methylmercury levels of 0.38 parts per million (ppm). In comparison, fish samples analyzed by the Food and Drug Administration (FDA) in 1978 contained an average of 0.16 ppm of methylmercury while more recent tests conducted by FDA found an average of 0.12 pmm in the 25 most commonly consumed fish;
A study of hair samples on 550-year-old Alaskan mummies found a mean methylmercury level of 1.2 ppm, whereas the methylmercury concentration in today's Alaska population is 0.6 ppm.
At the same time, scientists have been looking at how methylmercury accumulates in fish and have determined that freshwater fish tend to accumulate more mercury than saltwater varieties. This is because the characteristics and sulfate-reducing bacteria in many freshwater bodies stimulate mercury production. It is also well known that as larger fish eat smaller ones in the aquatic food chain, methylmercury levels in their systems rise. This is why large, older fish in both oceans and freshwater have higher mercury levels than their smaller and younger counterparts."
I wonder what 550 year old coal fired power plant was causing that mummy's mercury issue...
November 3, 2007 at 5:06 p.m. ( permalink | suggest removal )
angryinjun (anonymous) says...
Wow, CSOR, that's a lot of research on mercury. How did the Post & Courier miss all of that? Did they have a story already and didn't want to bother with the facts?
November 24, 2007 at 4:16 p.m. ( permalink | suggest removal )
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