守護空氣品質 美30年來首度緊縮排鉛標準 | 台灣環境資訊協會-環境資訊中心

守護空氣品質 美30年來首度緊縮排鉛標準

2008年10月22日
摘譯自2008年10月16日ENS美國華府報導;鄭佳宜編譯;莫聞審校

為保護民眾健康,尤其是兒童對鉛中毒格外敏感,美國環保署30年來首次緊縮空污排放含鉛標準。

鉛中毒可能造成器官、腦部和神經系統損傷,此外還會降低智力、破壞免疫系統、造成高血壓和心臟疾病;目前主要的鉛污染排放源包括汽機車廢氣、鉛冶煉廠、焚化爐和鉛酸電池製造廠。
新標準比1978年制定的舊容許值嚴格十倍,從每立方公尺空氣含1.5微克鉛降為0.15微克(1微克=百萬分之一公克)。

環保署是在聽取「清淨空氣科學諮詢委員會」(Clean Air Scientific Advisory
Committee)的報告與民眾意見,決定從嚴把關的。環保署這次同時修訂了兩種標準,維持健康的基本標準,以及保障公眾權益和環境的二級標準,均訂定每立方公尺1.5微克的容許值。

環保署這次的行動起源於四年前的一場訴訟,當時密蘇里州瓦頓夫婦(Leslie and Jack
Warden)向聯邦政府請願,希望制定更嚴格的空氣中鉛含量標準。瓦頓家族原本住在赫庫蘭尼姆鎮(Herculaneum),靠近多伊蘭公司(Doe Run
Co.)所營運、美國當時唯一的鉛冶煉廠。當時,鎮上已有工作場地和街道受鉛污染,許多兒童出現鉛中毒徵狀。 瓦頓訴訟案指控政府並未按照清淨空氣法(Clean Air
Act)所要求的,每五年重新檢討空氣中的鉛排放標準,聯邦大法官同意這點──也就是說,環保署自1978年制定標準後,從未修訂過。

不過,相關人士也不諱言地說,新標準的意義完全取決於執法程度,他們擔心環保署並沒有足夠強悍的把關能力。清淨空氣機構全國聯會(National
Association of Clear Aire Agencies)執行長貝克(Bill
Becker)表示:「根據清淨空氣科學諮詢委員會的專業評估,我們建議環保署將新排鉛標準定在每立方公尺空氣0.15微克,但我們也很失望新規則阻礙民眾知的權利,民眾無法得知他們呼吸的空氣是否安全。」

環保署16日坦承,許多區域目前具備的空氣監測網路無法測出空氣中的鉛含量是否符合新標。根據新制,環保署規範改變每季鉛含量平均值的計算方式,新制採用浮動標準,限定三個月內不可超過的某個最大排放量,以三年為評估時間單位。

環保人士警告,新制彷彿開了一個小洞讓鉛毒滲入環境之中。「環保署的決策讓人失望,我不敢相信他們竟然採用三個月平均值,」自然環境資源保護協會(Natural
Resources Defence Council)資深科學家所羅門博士(Gina
Solomon)認為:「這變相放任鉛冶煉廠和其他污染源在平均值符合新標的情況下,短期排放大量鉛毒,污染後院和兒童遊戲場所的土地。」

New Regulation Cuts Allowable Lead in the Air Ten-Fold
WASHINGTON, DC, October 16, 2008 (ENS)

Today, for the first time in 30 years, the U.S. EPA strengthened the nation's air quality standards for lead, improving public health protection, especially for children, who are particularly vulnerable to lead poisoning.
Lead is a pollutant that can cause organ, brain and nerve damage, lower intelligence, suppress the immune system, cause high blood pressure and increase heart disease. The major sources of lead emissions have been motor vehicles and lead smelters, waste incinerators, utilities, and lead-acid battery manufacturers.
The new standards reduce the allowable lead level 10 times to 0.15 micrograms of lead per cubic meter (ug/m3) of air. The previous standards, set in 1978, were 1.5 micrograms of lead per cubic meter of air.
EPA strengthened the standards after a review of the science on lead, advice from the Clean Air Scientific Advisory Committee, and consideration of public comments.
EPA's action sets two standards: a primary standard at 0.15 ug/m3 to protect health and a secondary standard at the same level to protect the public welfare, including the environment.
The EPA action results from a lawsuit filed four years ago by Leslie and Jack Warden, Missouri residents who sought to get the federal government to consider tougher standards for lead in the air.
The Wardens used to live in Herculaneum, which is near the nation's only primary lead smelter, run by the Doe Run Co. Many Herculaneum children have suffered from lead poisoning, and lead has contaminated yards and streets of the town.
The Wardens' lawsuit alleged, and a federal judge agreed, that the Clean Air Act requires the air quality standard for lead to be reviewed every five years, and the government had not done so. The EPA first set the standard in 1978 and it has not changed since.
The new air lead standard is only as strong as its enforcement, and concerns were expressed today that the EPA's monitoring capacity is not up to the job.
Bill Becker, executive director of the National Association of Clean Air Agencies, said, "We commend EPA for setting the primary and secondary lead standards at 0.15 micrograms per cubic meter, which is within the range recommended by the agency's science advisors on the Clean Air Scientific Advisory Committee. However, we are disappointed that the rule has obstructed the public's ability to know whether the air they breathe is safe."
The EPA acknowledged today that the existing monitoring network for lead is not sufficient to determine whether many areas of the country would meet the revised standards.
In the new regulation, the EPA changed the calculation method for the averaging time to use a "rolling" three month period with a maximum not-to-be-exceeded form, evaluated over a three-year period. This replaces the current approach of using calendar quarters.
But environmentalists warn that represents a loophole in the new standards through which lead can enter the environment.
"I am disappointed that EPA will allow averaging of lead exposures over a three-month period," Solomon said. "That means that large but brief 'spikes' of lead emissions from smelters and other polluters could contaminate the soil of playgrounds and backyards even in some areas that are in attainment of the new standard."