On May 24, the Environmental Assessment and Restoration Division of Florida's Department of Environmental Protection (FDEP) issued a draft report proposing much stricter limits for mercury in Florida's river, stream, lake and coastal waters. The FDEP claims the rules are based on sound science and will improve public health.
However, my studies of mercury and its biologically toxic form, methylmercury, over the past 10 years make it clear that the report is seriously flawed and the new limits are not scientifically defensible. Florida's actions should raise red flags for Sunshine State residents, other states, the United States as a whole and even other countries.
Not only would they drive up emission-mitigation costs for utilities and raise electricity costs for Floridians - with no subsequent health or environmental benefits - the FDEP actions actually would harm people's health.
First, the FDEP is incorrect in claiming that mercury pollution is a new, man-made phenomenon.
The department cites a 2008 paper that found average mercury levels of 0.25 parts per million (ppm) in the hair of Florida Panhandle women of childbearing age (16 to 49). However, a 2002 study of 550-year-old Alaskan mummified bodies found hair mercury levels five to 18 times higher: an average of 1.2 ppm for four adults and 1.44 ppm for four infants - and 4.6 ppm in one mummy.
The FDEP draft report also failed to mention other recent studies that found no significant increase in mercury levels for tuna caught between 1971 and 1998, demonstrating that mercury in fish is not related to human emissions, which continue to decline steadily in the United States.
The draft report also ignored a 17-year-long Seychelles Islands study that found no harm from mercury in children whose mothers ate five to 12 servings of fish per week - far more than most Floridians consume. In establishing methylmercury exposure risks from fish consumption, the researchers concluded that no consistent patterns exist between prenatal methylmercury exposure and detailed neurological and behavioral testing.
They also emphasized that "ocean fish consumption during pregnancy is important for the health and development of children, and the benefits are long-lasting."
Moreover, the latest Centers for Disease Control and Prevention data show blood mercury levels for U.S. women and children are already below the U.S. Environmental Protection Agency's (EPA) "safe" levels for mercury - the most restrictive standards in the world. In addition, selenium in nearly all fish is strongly attracted to mercury molecules and thus protects people against buildups of methylmercury.
By scaring women and children into eating less fish, and thus getting fewer Omega 3 fatty acids, FDEP's misleading literature on "dangerous mercury levels" in fish actually will impair their health.
Second, the FDEP failed to note that natural sources dwarf human mercury emissions.
Forest fires in Florida alone emitted an estimated 4,170 pounds of mercury annually between 2002 and 2006. This single source of local mercury emissions is significantly higher than mercury emitted in 2009 from all man-made mercury sources in Florida, including coal-fired power plants, which emit less than 1,500 pounds per year. Other recent studies calculated that volcanoes, subsea vents, geysers and other natural sources emit up to 2 million pounds of mercury per year.
These natural sources explain why it is unsurprising to find high levels of mercury in samples taken years ago in Florida fish, panthers and raccoons. Mercury has long been part of our environment, in ocean and terrestrial waters and in the earth's rocks and soils.
Today, mercury from natural sources represents the vast bulk of all the mercury in our atmosphere. Even eliminating all mercury from Florida's power plants would bring trifling environmental and health benefits - while raising electricity rates for the state's families, retirees, schools, hospitals and businesses and adversely affecting human health and welfare.
Third, the FDEP is wrong when it says mercury "pollution" is increasing in Florida's watersheds and fish.
Since the 1970s, contaminants in fish have been monitored increasingly each year. More advisories are being issued because of increased sampling, the EPA says, and "not necessarily due to increased levels or frequency of contamination."
Finally, FDEP's proposed new mercury limit for Florida's inland and coastal waters is an unjustifiably low 1.25 parts per trillion. The Department also assumes mercury levels in water are directly related to mercury levels in fish tissue. In fact, no such relationship exists, as even the FDEP draft report admits on Page 58.
One has to wonder why the FDEP is so intent on setting mercury levels below those existing in nature - and why it is so reluctant to disclose, explain or discuss publicly available information from the scientific literature so that all concerned Florida residents can study it themselves.
Scientific inquiry must be above political pressure and partisan advocacy. Good decisions can arise only if the scientific evidence and knowledge are examined fully, without selective bias.
The FDEP needs to reconsider its mercury rule-making, and this time base it on actual science. So do the Environmental Protection Agency and any other states or countries considering similar actions.
Willie Soon is an independent scientist who for the past 10 years has studied the biogeochemical nature of mercury in our environment and its effects on human health.