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zoom RSS ロケット燃料成分による粉ミルクの汚染/米国

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 米国で販売されている粉ミルク15種類全てにロケット燃料の成分化学物質が発見された。固体のロケット燃料の中の主要な成分である過塩素酸塩のレベルはEPA環境保護局により安全であるとされたが、公衆衛生上の心配がある。過塩素酸塩はヨウ素の吸収を抑制することで甲状線ホルモンの産生を妨げる可能性がある。CDC研究では、牛乳成分主体の粉ミルクには大豆その他の成分由来の粉ミルクより多くの過塩素酸塩を含んでいた。他製品の2倍近く最も高濃度に含まれる2製品の市場占有率は87%だった。
 過塩素酸塩は35州の水道水で発見されていて、野菜からミルクまでのすべてに検出されている。EPAによって安全であると考えられている範囲内であるが、26州の飲料水が高い過塩素酸塩レベルにある。
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Rocket Fuel Chemical Found in Baby Formula
EPA Deems Perchlorate Levels Safe, But Advocacy Group Says Public Is at Risk
By BRIAN HARTMAN
April 3, 2009
http://abcnews.go.com/Health/story?id=7242880&page=1

When a parent puts a bottle of baby formula to a child's lips, the parent might not know exactly what ingredients are in that thick, nutritionally packed mix. But rocket fuel? That's not an ingredient many expect to find.

画像Baby bottle
The Environmental Working Group says millions of babies are at risk after a CDC study finds a rocket fuel chemical present in most powdered infant formula.
(PhotoDisc)

A study by government researchers released Thursday tested 15 different brands of formula and found a chemical -- also found in rocket fuel -- contaminating every single one.

While the levels of the chemical, perchlorate, have been deemed safe by the Environmental Protection Agency, some worry public health is at risk.

Scientists at the Centers for Disease Control and Prevention tested the formula for the presence of perchlorate, a chemical used as the main ingredient in solid rocket fuel. It's a worry because perchlorate can interfere with the production of thyroid hormones by inhibiting the absorption of iodine.

The CDC study found cow's milk-based formula contained more perchlorate than that made with soy or other ingredients.

The two brands with the highest levels -- more than double that of the other milk-based products -- command 87 percent of the market share for infant formula.

The report does not specify the brand names of any formula tested.

Perchlorate has been found in the water supplies of 35 states and has been detected in everything from vegetables to milk. In the case of dairy, the rocket fuel in the water flows into grass, which is eaten by cows, and is then passed along into milk.

The perchlorate was found in levels within a range that's been deemed safe by the Environmental Protection Agency.

CDC researchers write that "this is reasssuring at first glance," but add that it could be problematic because drinking water in 26 states has high perchlorate levels. So, mixing contaminated powdered milk with contaminated water in those places could result in a dangerous exposure.

"The widespread penetrance of these products, and the potential for utilization of water for reconstitution that has even minimal concentrations of perchlorate," the researchers write, "suggest that a significant number of infants consuming bovine milk-based [powdered infant formula] with lactose, will have perchlorate doses in excess of the [recommended limit]."

Advocacy Groups Says Risk Is Understated

The Environmental Working Group, an organization that advocates for stricter limits on a variety of chemicals, contends EPA's recommended limit is set "too high to protect public health" and understates the risk.

"Perchlorate contamination of drinking water is a very serious concern, particularly for infants," said Dr. Anila Jacob, an Environmental Working Group scientist.

Dr. Sheela Sathyanarayana, a pediatrician who works on environmental health issues at Seattle Children's Hospital and at the University of Washington department of pediatrics, said it's difficult to say whether this sort of exposure is dangerous.

"Considered in isolation, these perchlorate concentrations in formula are not concerning for child health," Sathyanarayana wrote in an e-mail to ABC News. "The reason that some may be concerned about health effects to children is that there are several sources of perchlorate in our environment ... and, therefore, the cumulative dose of perchlorate to an infant may be much higher than that found in the formula."

"That being said," she added, "the most well-respected studies (only a handful exist) on perchlorate contamination have not found any link between perchlorate contamination in water and health impacts in children. Therefore, we truly do not know if this kind of contamination may be leading to health problems or not."

Another professor of pediatrics, Keith-Thomas Ayoob of the Albert Einstein College of Medicine, considers the findings "disturbing" and "a wake-up call to municipalities to clean up their water supplies, if at all possible."

At her confirmation hearing in January, EPA Administrator Lisa Jackson agreed to take another look at the safety of perchlorate.

The study appeared in the March 2009 issue of the Journal of Exposure Science and Environmental Epidemiology.

The CDC study is based on a handful of samples bought in one city and includes the caveat: "The results of this study may not be relevant throughout the United States."

Still, Ayoob told ABC News, "This is a perfect example of how polluting one area of the environment can be magnified."

"It's not causing harm to the animals or most consumers, but you can see how the effect can be magnified," Ayoob said. "If we get rid of the perchlorate, then the infants, their parents, all consumers, and even the cows and the farmers will be better off and happier."

Read the Environmental Working Group's analysis of the CDC study.

--------------------------------------------------------
CDC Scientists Find Rocket Fuel Chemical In Infant Formula
http://www.ewg.org/report/CDC-Scientists-Find-Rocket-Fuel-Chemical-In-Infant-Formula
Powdered Cow’s Milk Formula Contains Thyroid Toxin

By Anila Jacob, M.D., M.P.H., April 2009

Researchers from the U.S. Centers for Disease Control and Prevention (CDC) have reported that 15 brands of powdered infant formula are contaminated with perchlorate, a rocket fuel component detected in drinking water in 28 states and territories.

The two most contaminated brands, made from cow’s milk, accounted for 87 percent of the U.S. powdered formula market in 2000, the scientists said.

The CDC scientists did not identify the formula brands they tested.

The little-noticed CDC findings, published in the March 2009 edition of the Journal of Exposure Science and Environmental Epidemiology, raise new concerns about perchlorate pollution, a legacy of Cold War rocket and missile tests. Studies have established that the chemical is a potent thyroid toxin that may interfere with fetal and infant brain development (Kirk 2006).

The CDC team warned that mixing perchlorate-tainted formula powder with tap water containing “even minimal amounts” of the chemical could boost the resulting mixture’s toxin content above the level the Environmental Protection Agency (EPA) considers safe. Many scientists contend that the EPA “safe” level is too high to protect public health.
“Safe” level too high

The risk to infants being fed cow's milk-based formula may be even greater than the CDC assessment suggests. A CDC study in 2006 found that trace perchlorate exposure considerably below the EPA’s “safe” level (0.7 micrograms of perchlorate per kilogram of body weight per day, called the reference dose, or RfD) altered women’s thyroid hormone levels (Blount et al 2006a).

Based on this study, the Environmental Working Group has recommended that EPA promptly set a legally enforceable upper limit on perchlorate contamination in drinking water, consistent with the latest science on perchlorate’s toxic effects.
Obama EPA considering action

At her January 14 confirmation hearing, EPA administrator Lisa Jackson promised California Senator Barbara Boxer, whose state has borne the brunt of perchlorate contamination from old launch sites and aerospace facilities, that she would act “immediately” to reduce perchlorate contamination in drinking water in order to protect children and pregnant women.

Since her confirmation, however, Jackson and EPA have not made public a plan of action.
Pentagon lobbied Bush administration

Last fall, the Bush administration’s EPA leadership touched off a major furor by declaring that perchlorate posed no threat to most Americans and did not need to be regulated as a drinking water pollutant.

The decision was widely regarded as a major victory for the Pentagon and defense and aerospace contractors reluctant to pay clean-up costs that could mount into the hundreds of millions of dollars.

EPA’s move triggered protests from consumers, lawmakers, scientists and medical experts - among them, two of the agency’s prestigious outside science advisory panels.

Melanie A. Marty, a senior career EPA official and chair of EPA’s Children's Health Protection Advisory Committee, declared that the agency’s refusal to regulate perchlorate in drinking water exposed some infants to "the life-long consequences of impaired brain development.”

On January 8, EPA issued a non-binding “health advisory” on perchlorate and asked the National Academy of Sciences to review the issue.

EWG dismissed EPA’s action as “nothing more than an effort to dodge the issue and buy time for the defense, aerospace and chemical industries.”

Years of federal inaction have prompted some states to set their own mandatory limits for perchlorate in drinking water: California, at 6 ppb and Massachusetts at 2 ppb. While recent scientific research has shown these standards too weak to protect public health adequately, they are far more stringent than EPA’s action in January.
Studies find pollution in people, food

Concern about perchlorate pollution has intensified as a series of studies have found perchlorate in the urine of every American tested by the CDC and in breast milk (Blount et al 2006b, Pearce et al 2007).

In 2008, an EWG analysis found that toddlers were especially vulnerable to perchlorate exposure from contaminated food. Toddlers, who are growing rapidly, consume large amounts of food daily, relative to their size. Moreover, those who live in places like California and Texas, where high perchlorate levels have been measured in some drinking water supplies, are doubly exposed to perchlorate contamination.

EWG’s analysis was based on 2008 federal Food and Drug Administration (FDA) tests that found almost 75 percent of food and beverage samples tainted with perchlorate, possibly from contaminated irrigation water (Murray et al 2008).
CDC finds perchlorate in 15 formula brands

The new CDC study is the first to examine perchlorate exposure of infants fed powdered formula reconstituted with contaminated drinking water. The CDC team tested 15 brands of powdered infant formula in four categories: cow milk-based with lactose, cow milk-based lactose-free, soy-based and elemental.

“Perchlorate was found in all brands and types of infant formula tested,” the scientists said. The worst perchlorate contamination was found in formula based on cow’s milk with lactose.

The CDC team said that combining cow’s milk/lactose formula with water containing perchlorate at just 4 parts per billion (ppb) could cause 54 percent of infants consuming the mix to exceed EPA’s “safe” level.

The number of babies exposed to unsafe levels of perchlorate would rise if, as EWG and many other science and health advocates argue, the EPA “safe” level were lowered to reflect recent scientific studies.
Formula required to contain iodine

While these findings are of concern, the CDC scientists also note that FDA requires infant formula to be supplemented with iodine, a nutrient that can counteract the negative effects of perchlorate on the thyroid gland. The range of required iodine concentrations in formula is between 5 and 75 micrograms per 100kcal of energy.

Iodine supplements at higher levels may offer some protection from the toxic effects of perchlorate. But the CDC scientists estimate that those brands that contain only the minimum iodine concentration of 5 micrograms would leave infants iodine-deficient and thus more vulnerable to the toxic effects of perchlorate. A scenario in which formula contained 40 micrograms of iodine (per 100kcal of energy) would offer more protection for infants, but the scientists stress that even adequate iodine intake among formula-fed infants is not guaranteed to prevent “perchlorate-induced thyroid dysfunction.”
Strict drinking water regulation of perchlorate needed

This study represents perhaps the strongest evidence to date supporting the need for a legally enforceable safe drinking water level that protects pregnant women, infants and others who are most vulnerable to the effects of this harmful chemical.

The new Obama administration leadership at EPA can and should take steps to reduce infants’ exposures to perchlorate pollution in tap water.
References

Blount BC, Pirkle JL, Oserloh JD, Valentin-Blasini L, Caldwell KL. 2006a. Urinary perchlorate and thyroid hormone levels in adolescent and adult men and women living in the Unites States. Environmental Health Perspectives 114(12): 1865-71.

Blount BC, Valentin-Blasini L, Osterloh JD, Mauldin JP, Pirkle JL. 2006b. Perchlorate exposure of the US population, 2001-2002. Journal of Exposure Science and Environmental Epidemiology 17(4): 400-07.

Kirk AB. 2006. Environmental perchlorate: why it matters. Analytical Chimica Acta 567(1): 4-12.

Murray WM, Egan SR, Kim H, Beru N, Bolger PM. 2008. US Food and Drug Administration's Total Diet Study: Dietary intake of perchlorate and iodine. Journal of Exposure Science and Environmental Epidemiology 18(6): 571-80.

Pearce EN, Leung AM, Blount BC, Bazrafshan HR, He X, Pino S, Valentin-Blasini L, Braverman LE. 2007. Breast milk iodine and perchlorate concentrations in lactating Boston area women. Journal of Clinical Endocrinology and Metabolism 92: 1673-77.

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