National Park Service officials have found "extraordinarily high levels of mercury" in the invasive python snakes taking root in the Everglades. It appears that the Everglades is doing its job as a marsh, filtering out pollutants like mercury. Only trouble is, methylmercury is bioavailable and bioaccumulated. Sulfur-based fertilizers used by Florida sugarcane farmers may be the source of increasing methylmercury production in the Everglades. U.S. Geological Survey had a report in 2004 that high concentrations have been found in panthers and game fish and that they were doing additional research investigating the mercury cycle in South Florida "to gain a better understanding of the microbial and geochemical controls regulating methylmercury degradation."
5 comments:
Yikes, at least we can still eat Lionfish!
((extremly invasive as of late)
At least we have our scientist, hard-working head of the Fish and Wildlife Commission to keep us safe. It's not like he's busy putting on the Super Bowl or trying to get the zoning on his land changed or anything like that.
Many thanks to Crist for picking Rodney Barreto again! We know he's looking out for the environment!
Well, does it take a snake to know a snake? Maybe Rodney is the correct person for the Glades.
Although Arthur Keys does not know that, scientists and administrators in the state Department of Health and the DEP do: They are all too familiar with WCA 2 and 3. Their written warnings to anglers -- not posted on public signs -- include the following recommendations:
• Never consume bass, bowfin, or gar caught in WCA 2 and 3.
• Eat no more than one eight-ounce helping of other fish per month, unless you're a full-grown male. Then you can eat one per week.
The need for such extreme rationing grew with the 20th Century. For 100 years mercury has been slipping into the South Florida environment like an invisible enemy, impossible to track accurately to its source, says Tom Atkeson, the bureau chief of the mercury program at the DEP. A metal sometimes known as quicksilver, it arrives by air, reaching the soil in the abundant wash of South Florida's rain. Once on the ground, an unusual bacteria converts the metal to its organic form, methylmercury. The organic form -- odorless and invisible -- can be deadly if consumed in abundance. Atkeson's job is to organize and direct research that ultimately might identify the causes of mercury pollution and propose ways to stop them.
http://www.browardpalmbeach.com/content/printVersion/130606
Found this on a listserve:
There are two reasons why pythons may have especially high levels of
mercury. They concentrate it by two processes:
1. Biomagnification, with at least a ten-fold increase in concentration along each link in a food chain. So a top predator is at the highest risk.
2. Bioaccumulation in an individual through its life as it gets older, and in the case of fish and reptiles, larger. Again top predators are at the most risk since they are large and often long-lived.
Of the fish in the Everglades large-mouth bass have among the highest mercury
levels.
Of the marine fish swordfish have among the highest levels of mercury.
The research article misses the second reason for mercury concentration and
equates bomaginificaton to bioaccumulation. They are different and
complementary.
Dr. Thomas L. Poulson
Emeritus Professor, Ecology & Evolution Section
Department of Biological Sciences, U. Illinois - Chicago
Post a Comment