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QINGDAO TODAY
在线翻译:
szdaily -> Speak Shenzhen -> 
Tea bags release microplastics into your cup
    2019-10-01  08:53    Shenzhen Daily

Every time you use a tea bag, you could be dosing yourself with billions of microplastic and nanoplastic particles. That’s the conclusion of researchers at McGill University in Montreal.

The research, published in the American Chemical Society journal Environmental Science & Technology, centered on four different types of plastic mesh tea bags, of the kind recently preferred by some premium brands. Having been emptied of the tea itself, the bags were placed in water heated to 95 degrees Celsius.

Researchers were surprised to find each bag released around 11.6 billion microplastics and a further 3.1 billion even smaller nanoplastics. These levels were, says the report, “thousands of times higher than plastic loads previously reported in other foods.”

Microplastics are any plastic debris less than 5mm in length, while nanoplastics are less than 100 nanometers. (A nanometer, or nm, is a millionth of a millimeter; for comparison, a human hair is about 75,000nm thick.)

Primary microplastics tend to come from manufacturing and packing, but can also come from clothing fibers or microbeads: sub-1mm particles added to cosmetics as exfoliating agents and pharmaceutical drugs to make them easier to swallow.

In addition, most plastic will degrade via chemical or physical processes over time, and “secondary” microplastics are created when larger fragments degrade to below 5mm. This type of disintegration is implicated in the tea bag research, with the McGill team suggesting that the near-boiling water could be releasing more into beverages.

Although microplastics are recognized as an environmental problem — their size means they easily wash into the hydrological system and food chain — and they have previously been detected in tap water, bottled water and some foods, not much is known about the possible health effects to humans of ingesting microplastics. The World Health Organization has suggested particles in drinking water do not seem to pose a risk, but that their findings are based on “limited information” and that far more research is required.

The McGill team tested the effect of the released tea bag particles on tiny water fleas, which are often used as model organisms in environmental studies. Given various doses of the tea-bag microplastics, the fleas exhibited anatomical malformations and behavioral abnormalities.

Words to Learn 相关词汇

【给…服用】gěi … fúyòng dose with give (someone) a dose of

【去角质】qù jiǎozhì exfoliate remove (a layer of bark or skin, for example) in flakes or scales

每次喝袋泡茶时,你可能喝进去的是数十亿微塑料和纳米塑料颗粒。这是蒙特利尔的麦吉尔大学研究人员得出的结论。

发表在美国化学学会期刊《环境科学与技术》上的这项研究聚焦于四种不同的塑料网眼茶袋,是一些优质品牌近来喜欢使用的那种茶袋。研究人员将茶袋里的碎茶取出,将茶袋放入加热至95摄氏度的水中。

研究人员惊讶地发现,每个茶袋释放出大约116亿个微塑料和31亿个更微小的纳米塑料。报告称,这一水平“比先前报道过的其他食物塑料含量高出数千倍”。

微塑料是长度小于5毫米的塑料微粒,而纳米塑料是长度小于100毫微米的塑料微粒。(1毫微米等于1毫米的100万分之一;比如,人类的一根头发粗细大约是7.5万毫微米。)

微塑料主要来源于制造业和包装业,但也来自服装纤维或微珠 —— 小于1毫米的颗粒,可以添加在化妆品中用来去角

质,或者加入药品中使其更容易被吞咽。

此外,随着时间流逝,大多数塑料都会通过化学或物理过程发生降解,当大块塑料分解成5毫米以下的碎片时,就产生了“二级”微塑料。这项茶袋研究就与这种分解过程有关。麦吉尔大学的研究团队指出,接近沸腾的水可能会使茶袋在茶水里释放更多微塑料。

尽管微塑料被视为一种环境问题 —— 微小的体积意味着它们很容易就会被冲洗到水文系统和食物链中 —— 过去也曾在自来水、瓶装水和一些食物中检测到微塑料--但是科学家对于人类摄入微塑料对健康带来的影响知之甚少。世界卫生组织指出,饮用水中的微塑料似乎不会对人体造成危害,但是他们的发现基于“有限的信息”,还需要进一步的研究。

麦吉尔大学的研究团队检测了茶袋释放出的微塑料对微小的水蚤的影响,水蚤经常在环境研究中被作为模式生物。在接触到多个茶袋释放出的微塑料后,水蚤表现出了解剖畸形和行为异常。

(chinadaily.com.cn)

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