Dear EarthTalk: Instances of people with thyroid problems seems to be on the rise. Is there an environmental connection? -- Dora Light, Waukesha, Wisc.

The American Cancer Society reports that thyroid cancer is one of the few cancers that have been on the rise in recent decades, with cases increasing 6 percent annually since 1997. Many researchers, however, attribute these increases to our having simply becoming better at detection. Regardless, exposures to stress, radiation and pollutants have been known to increase a person's risk of developing thyroid problems.

Thyroid disease takes two primary forms. Hyperthyroidism occurs when the thyroid produces too much of the T3 and T4 hormones that regulate metabolism. This can cause a racing heart, weight loss, insomnia and other problems. In cases of hypothyroidism, the body produces too few hormones, so we feel fatigued and may gain weight, among other symptoms. According to the American Thyroid Association, many people with thyroid problems don't realize it, as symptoms can be mistaken for other problems or attributed to lack of sleep. Thyroid problems in children can delay or impair neurological development.

Doctors are not sure why some people are prone to thyroid disease while others aren't, but genetics has much to do with it. One recent UCLA study found that genetic background accounts for about 70 percent of the risk. However, researchers have begun to find links between increased risk of thyroid disease and exposure to certain chemicals, especially among women. "Pesticide Use and Thyroid Disease among Women in the Agricultural Health Study," published in the American Journal of Epidemiology in 2002, found that Iowa and North Carolina women married to men using such pesticides as aldrin, DDT and lindane were at much higher risk of developing thyroid disease than women in non-agricultural areas. According to Dr. Whitney S. Goldner, lead researcher on the study, 12.5 percent of the 16,500 wives evaluated developed thyroid disease compared to between 1 and 8 percent in the general population.

It's not just farm women who should worry. Trace amounts of chemical pesticides and fertilizers most certainly end up in some of the food we eat. The non-profit group Beyond Pesticides warns that some 60 percent of pesticides used today have been shown to affect the thyroid gland's production of T3 and T4 hormones. Commercially available insecticides and fungicides have also been implicated.

Likewise, some chemicals used in plastics and flame retardants contain toxins shown to trigger thyroid problems in those genetically predisposed. And a 2007 study at the University of Texas Health Sciences Center at San Antonio found that triclosan, an anti-bacterial agent found in everything from hand soaps to facial tissues to toys -- it's present in the bloodstreams of three out of every four Americans -- could be causing some mothers' thyroid glands to send signals to fetuses that may in turn contribute to autism.

An increasing number of doctors now believe that hypothyroidism could be precipitated by a dietary deficiency in iodine, a trace element found in the thyroid's T3 and T4 hormones and essential in small amounts for good health. Besides eating more seafood, switching to iodized salt and/or taking iodine supplements can boost iodine intake without the need for medications. But too much iodine is not healthy, so always consult with your doctor before embarking on any new health or diet regimen.

Contacts: ATA,; Beyond Pesticides,

Dear EarthTalk: I understand that, among mining's other problems, like providing climate-warming coal and endangering miners' lives, it is also a serious water polluter. Can you enlighten? -- Richard Moeller, Salt Lake City

Mining disasters have grabbed a lot of headlines of late, but mines pose another insidious threat that tends to get little press attention: pollution of the nearby environment which, in turn, threatens the health of the people who live nearby. Environmentalists are particularly concerned about water pollution from mines.

Mining operations use large amounts of fresh water to process recovered ore; the resulting mine effluent is typically a stew of hazardous acid-generating sulphides, toxic heavy metals, waste rock impoundments and water -- and it is often deposited nearby in large free-draining piles where it can pollute land and water supplies for decades to come. When this waste water drains into local streams and aquifers, it can kill living organisms and render formerly pristine local waters unsafe to swim in or drink.

Increased soil erosion around mines also leads to excessive sedimentation of nearby waterways. This reduces the productivity of fisheries while limiting the availability of irrigation sources.

"Mining by its nature consumes, diverts and can seriously pollute water resources," reported the nonprofit Safe Drinking Water Foundation (SWDF). --¦ mining has become more mechanized and therefore able to handle more rock and ore material than ever before," reported SWDF. "Therefore, mine waste has multiplied enormously." The group warns that "as mine technologies are developed to make it more profitable to mine low grade ore, even more waste will be generated in the future."

Here in the U.S., increasing recognition of the water (and other types of) pollution problems caused by various forms of mining led the Environmental Protection Agency to issue much more stringent guidelines in April 2010 regarding how and where mines on American soil must dispose of waste.

In January 2011 the EPA got the opportunity to walk its talk when it vetoed a permit that would have allowed the largest "mountaintop removal" mining operation in the history of West Virginia coal mining to go forward. Mountaintop removal is an aggressive form of coal mining that strips a mountain bare of vegetation and then blasts off the top of the mountain with explosives. It is the most destructive and polluting form of mining. Environmentalists praised the EPA for not only standing up to industry but also for saving some 2,000 forested mountaintop acres and nearly seven miles of riparian habitat while sparing surrounding communities from the effects of polluted land and water.

Meanwhile, environmentalists have been pushing Congress to pass the Clean Water Protection Act, a bill first introduced in 2009 that aims to protect fresh water supplies from mining contamination by sharply curtailing mountaintop removal. Green groups including Kentuckians for the Commonwealth, Appalachian Voices and the Sierra Club are lobbying Congress heavily to consider the bill sooner rather than later.

Contacts: SDWF,; Appalachian Voices,; Kentuckians for the Commonwealth,; Sierra Club,

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