Department of Chemistry and Environmental Research Center, Missouri University of Science and Technology, 400 West 11th Street, Rolla, MO 65409, USA.
Environ Sci Pollut Res Int. 2010 Aug;17(7):1323-30. doi: 10.1007/s11356-010-0312-4. Epub 2010 Mar 23.
BACKGROUND, AIMS, AND SCOPE: Heavy metal contaminants in environment, especially in drinking water, are always of great concern due to their health impact. Due to the use of heavy metals as catalysts during plastic syntheses, particularly antimony, human exposure to metal release from plastic bottles has been a serious concern in recent years. The aim and scope of this study were to assess metal contaminations leaching out from a series of recycling plastic bottles upon treatments.
In this study, leaching concentrations of 16 metal elements were determined in 21 different types of plastic bottles from five commercial brands, which were made of recycling materials ranging from no. 1 to no. 7. Several sets of experiments were conducted to study the factors that could potentially affect the metal elements leaching from plastic bottles, which include cooling with frozen water, heating with boiling water, microwave, incubating with low-pH water, outdoor sunlight irradiation, and in-car storage.
Heating and microwave can lead to a noticeable increase of antimony leaching relative to the controls in bottle samples A to G, and some even reached to a higher level than the maximum contamination level (MCL) of the US Environmental Protection Agency (USEPA) regulations. Incubation with low-pH water, outdoor sunlight irradiation, and in-car storage had no significant effect on antimony leaching relative to controls in bottle samples A to G, and the levels of antimony leaching detected were below 6 ppb which is the MCL of USEPA regulations. Cooling had almost no effect on antimony leaching based on our results. For the other interested 15 metal elements (Al, V, Cr, Mn, Co, Ni, Cu, As, Se, Mo, Ag, Cd, Ba, Tl, Pb), no significant leaching was detected or the level was far below the MCL of USEPA regulations in all bottle samples in this study. In addition, washing procedure did contribute to the antimony leaching concentration for polyethylene terephthalate (PET) bottles. The difference of antimony leaching concentration between washing procedure involved and no washing procedure involved (AC) was larger than zero for samples A to G. This interesting result showed that higher antimony concentration was detected in experiments with no washing procedures compared with those experiments with washing procedures. Our study results indicate that partial antimony leaching from PET bottles comes from contaminations on the surface of plastic during manufacturing process, while major antimony leaching comes from conditional changes.
The results revealed that heating and microwaving enhance antimony leaching significantly in PET plastic bottles. Plastic bottle manufacturers should consider the contaminations during manufacturing process and washing bottles before first use was strongly recommended to remove those contaminants.
背景、目的和范围：由于重金属对健康的影响，环境中尤其是饮用水中的重金属污染物一直受到极大关注。由于在塑料合成过程中使用重金属作为催化剂，特别是锑，因此近年来，人们对从塑料瓶中释放的金属对人体的暴露问题一直非常关注。本研究的目的和范围是评估一系列回收塑料瓶在处理过程中溶出的金属污染物。
在这项研究中，测定了来自五个商业品牌的 21 种不同类型的回收塑料瓶中 16 种金属元素的浸出浓度，这些塑料瓶由 1 号至 7 号回收材料制成。进行了多组实验以研究可能影响塑料瓶中金属元素浸出的因素，这些因素包括用冷冻水冷却、用沸水加热、微波加热、用低 pH 值水孵育、户外阳光照射和车内储存。
与对照相比，加热和微波处理可导致 A 至 G 瓶样本中锑的浸出量明显增加，有些样本甚至达到美国环保署（USEPA）法规规定的最大污染物水平（MCL）之上。与对照相比，用低 pH 值水孵育、户外阳光照射和车内储存对 A 至 G 瓶样本中锑的浸出没有显著影响，检测到的锑浸出水平低于 6 ppb，即 USEPA 法规规定的 MCL。根据我们的结果，冷却对锑的浸出几乎没有影响。对于其他感兴趣的 15 种金属元素（Al、V、Cr、Mn、Co、Ni、Cu、As、Se、Mo、Ag、Cd、Ba、Tl、Pb），在本研究的所有瓶样本中，均未检测到明显浸出，或浸出水平远低于 USEPA 法规规定的 MCL。此外，清洗程序确实会影响聚对苯二甲酸乙二醇酯（PET）瓶中的锑浸出浓度。有清洗程序和无清洗程序的 A 至 G 瓶样本之间的锑浸出浓度差值（AC）大于零。这一有趣的结果表明，与有清洗程序的实验相比，无清洗程序的实验中检测到的锑浓度更高。我们的研究结果表明，部分 PET 瓶中的锑浸出来自于制造过程中塑料表面的污染，而主要的锑浸出则来自于条件变化。
结果表明，加热和微波处理显著增强了 PET 塑料瓶中锑的浸出。塑料瓶制造商应考虑制造过程中的污染问题，并强烈建议在首次使用前清洗瓶子，以去除这些污染物。
