2013年10月21日 星期一

內分泌干擾物 endocrine disruptors之害如鉛毒 (Damon Winter)

專欄作者

化工企業正在製造另一個鉛毒悲劇


「鉛是您健康的保護神。」
這是幾十年前,前國家鉛業公司(National Lead Company)推銷含鉛家用塗料時用過的廣告詞。然而,如今我們知道,鉛毒害了數百萬兒童,對他們的大腦造成永久性損傷。成千上萬的兒童因此失去生命,更有無數的兒童智力受損。
來自密爾沃基市的男孩山姆(Sam)出生於1990年,根據他的醫療記錄,他曾是個「茁壯成長的嬰兒」。但此後,當他還在蹣跚學步時,便開始時常嚼起含鉛塗料或是吸允沾有鉛塵的手指,他血液中的鉛含量隨之飆升。
山姆的父母搬了家,但毫無用處。3歲時,山姆便因鉛中毒住了五天的院。上幼兒園時,老師發現他有言語障礙。他讀書非常吃力,醫生最後得出結論,稱他的患有「永久性、不可逆轉的」腦功能損傷。
山姆的故事出現在了今年出版的《鉛之戰》(Lead Wars)一書中。該書由傑拉爾德·馬科維茨(Gerald Markowitz)與大衛·羅斯納(David Rosner) 合著。書中記載了制鉛企業在20世紀的極度不負責任行為。最後,經過業界抗議,新規終於出台,禁止使用含鉛汽油。此後幾十年,美國兒童血鉛水平降低了 90%,據學者們的估算,全國兒童平均智商因此上升至少兩個點,甚至超過四個點。
那麼,從這幾十年時間內鉛中毒給人類帶來的災難中,我們可 以吸取哪些教訓呢?在我看來,現今的化工行業就是鉛行業的翻版。埃克森美孚(Exxon Mobil)、杜邦(DuPont)、巴斯夫(BASF)和陶氏化學(Dow Chemical)等化工企業多年來一直在大量生產內分泌干擾素,這些干擾素可模仿人體內荷爾蒙功能。從塑料製品到殺蟲劑,從玩具到化妝品,內分泌干擾物 無處不在。人們對此類物質安全性的擔憂與日俱增。
美國內分泌學會(The Endocrine Society)、美國兒科內分泌學會(Pediatric Endocrine Society)、歐洲兒科內分泌學會(European Society of Pediatric Endocrinology)、美國總統癌症研究小組(President』s Cancer Panel)都曾就內分泌干擾素中的內分泌干擾物(也稱環境內分泌干擾物,簡稱EDCs)發出過警告。世界衛生組織(World Health Organization)與聯合國(United Nations)今年得出結論稱:「胎兒發育與青春期期間接觸EDCs可增加人體染患生殖系統疾病、內分泌相關癌症、包括多動症在內的行為與學習障礙、感 染、哮喘的幾率,可能還有肥胖及糖尿病。
對內分泌干擾物的警惕一度只是邊緣性的科學擔憂,如今這一擔憂日益成為主流。雖然人們對個別化學品是否會造成危害仍不確定,爭論猶存,但總體上,人們對內分泌干擾物的危害的擔憂正與日俱增,尤其是對胎兒和兒童。對成人的擔憂相對較輕。
科學家們也仍然在爭論,舊毒理學模型是否適應於能夠模仿荷爾蒙功能進而引起身體變化的化學藥品,尤其是對胎兒和兒童而言。
我們新聞從業者們大多不擅長關於此類危害的報道。我們早年所做的關於鉛與煙草危害的報道糟糕透頂。我們沒有做好「看門狗」的工作,反像是條「哈巴狗」。
它們的共通點就是產業的貪婪、狡詐,在華盛頓和整個國家都擁有強大的遊說勢力。根據響應性政治中心(Center for Responsive Politics)的數據,去年,整個化工行業的遊說花費高達5500萬美元(約合人民幣3.35億元),是十年前的兩倍。
在去年的報道中,《芝加哥論壇報》(Chicago Tribune)記錄了化工行業如何為了宣傳傢具中阻燃劑的使用演了了一場假把戲。事實上,阻燃劑不僅不能減少火災隱患,反而含有可能對我們的子女健康有害的內分泌干擾物。
這個夏天,18名科學家寫了一封措辭嚴厲的公開信,對歐盟 有關內分泌干擾物的管制大加指責。這凸顯了科學界對其危害性尚不確定,直到《環境健康新聞》(Environmental Health News)披露出這18人中17人存在利益關係,比如從化工行業收受過金錢。以此同時,其他140多名科學家隨後也發出公開信,聲討這18名科學家,並警 告稱內分泌干擾物的確可帶來危害。
《內分泌學》(Endocrinology)雜誌編輯安德烈·C·戈爾(Andrea C. Gore)此前發表的一篇評論稱,企業利益正在內分泌干擾物的問題上濫用科學,手法和當年在鉛的問題上一樣:「製造不確定性」。
她還稱,「內分泌干擾化學物質對人體健康構成威脅的證據不可否認。」
如果連科學家都爭論不休,我們其餘的人自然很難知道該怎麼做。但是我突然想到一點,那就是,許多內分泌學、毒理學或小兒科專家沒有坐等管制規則做出改變。他們不用塑料容器熱飯、減少使用塑料水瓶,並盡量給自己的孩子吃有機食品,從而減少農藥的攝入量。
最後,我想問那些大型化工企業一個問題:你們真的打算重走煙草和鉛行業走過的老路,處處與監管機構作對,再次拿我們子孫後代的將來冒險?
翻譯:裴興朕


This Is Your Brain on Toxins

“Lead helps to guard your health.”
That was the marketing line that the former National Lead Company used decades ago to sell lead-based household paints. Yet we now know that lead was poisoning millions of children and permanently damaging their brains. Tens of thousands of children died, and countless millions were left mentally impaired.
  • 查看大图 Nicholas D. Kristof
    Damon Winter/The New York Times
    Nicholas D. Kristof
One boy, Sam, born in Milwaukee in 1990, “thrived as a baby,” according to his medical record. But then, as a toddler, he began to chew on lead paint or suck on fingers with lead dust, and his blood showed soaring lead levels.
Sam’s family moved homes, but it was no use. At age 3, he was hospitalized for five days because of lead poisoning, and in kindergarten his teachers noticed that he had speech problems. He struggled through school, and doctors concluded that he had “permanent and irreversible” deficiencies in brain function.
Sam’s story appears in “Lead Wars,” a book by Gerald Markowitz and David Rosner published this year that chronicles the monstrous irresponsibility of companies in the lead industry over the course of the 20th century. Eventually, over industry protests, came regulation and the removal of lead from gasoline. As a result, lead levels of American children have declined 90 percent in the last few decades, and scholars have estimated that, as a result, children’s I.Q.’s on average have risen at least two points and perhaps more than four.
So what are the lessons from the human catastrophe of lead poisoning over so many decades? To me, today’s version of the lead industry is the chemical industry — companies like Exxon Mobil, DuPont, BASF and Dow Chemical — over the years churning out endocrine-disruptor chemicals that mimic the body’s hormones. Endocrine disruptors are found in everything from plastics to pesticides, toys to cosmetics, and there are growing concerns about their safety.
The Endocrine Society, the Pediatric Endocrine Society, the European Society of Pediatric Endocrinology and the President’s Cancer Panel have all warned about endocrine disruptors — also referred to as E.D.C.’s, for endocrine disrupting chemicals. The World Health Organization and United Nations this year concluded: “Exposure to E.D.C.’s during fetal development and puberty plays a role in the increased incidences of reproductive diseases, endocrine-related cancers, behavioral and learning problems, including A.D.H.D., infections, asthma, and perhaps obesity and diabetes in humans.”
Alarm about endocrine disruptors once was a fringe scientific concern but increasingly has moved mainstream. There is still uncertainty and debate about the risk posed by individual chemicals, but there is growing concern about the risk of endocrine disruptors in general — particularly to fetuses and children. There is less concern about adults.
Scientists are also debating whether the old toxicological models are appropriate for chemicals that mimic hormones and thus may trigger bodily changes, especially in fetuses and children.
These are the kinds of threats that we in journalism are not very good at covering. We did a wretched job covering risks from lead and tobacco in the early years; instead of watchdogs, we were lap dogs.
One common thread is industry’s greed, duplicity and powerful lobbying in Washington and around the country. The chemical industry spent $55 million lobbying last year, twice the figure a decade earlier, according to the Center for Responsive Politics.
The Chicago Tribune last year documented how the chemical industry created a fake movement for flame retardants in furniture, supposedly to prevent fires; in fact, flame retardants don’t reduce fires but do contain endocrine disruptors that may be harmful to our children.
This summer 18 scientists wrote a scathing letter railing against European Union regulations of endocrine disruptors. That underscored the genuine scientific uncertainty about risks — until Environmental Health News showed that 17 of the 18 have conflicts of interest, such as receiving money from the chemical industry. Meanwhile, more than 140 other scientists followed up with their own open letters denouncing the original 18 and warning that endocrine disruptors do indeed constitute a risk.
Andrea C. Gore, the editor of Endocrinology, published an editorial asserting that corporate interests are abusing science today with endocrine disruptors the way they once did with lead: for the “production of uncertainty.”
She added that the evidence is “undeniable: that endocrine-disrupting chemicals pose a threat to human health.”
When scientists feud, it’s hard for the rest of us to know what to do. But I’m struck that many experts in endocrinology, toxicology or pediatrics aren’t waiting for regulatory changes. They don’t heat food in plastic containers, they reduce their use of plastic water bottles, and they try to give their kids organic food to reduce exposure to pesticides.
So a question for big chemical companies: Are you really going to follow the model of tobacco and lead and fight regulation every step of the way, once more risking our children’s futures?

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