汽油添加剂甲基叔丁基醚(MTBE)对环境的危害性

甲基叔丁基醚(MTBE)是欧美燃料市场最常用的汽油添加剂。由于其在土壤和地下水中的特殊理化行为,MTBE对人体健康和自然环境的负面影响正受到研究人员的关注。本文根据现有资料就MTBE的环境行为及其对生物的危害性影响进行综合评估。我们认为尽管大部分的MTBE是以气态的形式释放到大气中,但由于其光氧化速度非常快,所以MTBE不会造成空气污染。MTBE在土壤中的不吸附性和极高的水溶性,使其正在成为一种蔓延性的地下水污染物,MTBE在地下水中的半衰期至少需要二年。在适宜的环境条件下,MTBE的有氧微生物降解是可以发生的,但其厌氧降解的机率几乎为零。MTBE对动物是一种致癌物质,目前还没有足够的证据证明其对人类的致癌作用,但是MTBE对人体健康的负面影响是非常明显的。当MTBE浓度大于7.4 mg·L-1,其对水生生物能产生急性毒性作用,而在低浓度条件下(<0.1 mg·L-1),MTBE它们的急性毒性作用是非常有限的。MTBE对陆生植物的毒理学研究目前还十分有限。我们认为全面综合地评估MTBE对生物的毒性作用还需要大量的亚急性和慢性试验数据作为依据。

Review of environmental risk assessment of gasoline oxygenate methyl tert-butyl ether (MTBE)

Increased input of the fuel oxygenate methyl tert-butyl ether (MTBE) into the environment has posed serious risks to human health and the environment. This paper reviews current MTBE research with a heavy emphasis on the environmental behavior and fate of MTBE, and toxicity evaluation and risk characterization. Initial studies indicated that a large amount of MTBE is released to the atmosphere and it will be susceptible to photoxidation with an estimated half-life of 4 days. MTBE is biodegradable under aerobic conditions, but little or no anaerobic degradation of MTBE has been found. Based on current MTBE toxicological data, MTBE has been recognized as the animal carcinogen and no strong evidence has been found to indicate the carcinogenic potential of MTBE for humans. MTBE is toxic to various aquatic organisms at high exposed dosages (> 7.4 mg