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不仅是海洋 风景如画的淡水湖也正遭塑料之害

更新时间:2018-6-18 10:14:02 来源:纽约时报中文网 作者:佚名

Why pristine lakes are filled with toxins
不仅是海洋 风景如画的淡水湖也正遭塑料之害

In 2016 a team of scientists scoured a dozen beaches around the shores of Lake Geneva in Switzerland – not for flora or fauna, but for litter. In particular, plastic litter.

2016年,一个科考队在瑞士日内瓦湖的十多处堤岸展开了地毯式的搜索——他们找的不是植物,也不是动物,而是垃圾,尤其是塑料垃圾。

It wasn’t hard for them to amass quite the collection of discarded common everyday objects. These included bottle tops, cotton buds, pens, toys and straws. They picked up lesser identified fragments too, such as blocks of polystyrene foam, the kind that keeps fragile goods soft in the post.

队员们不费吹灰之力就收集到了很多废弃的日常用品,包括瓶盖、棉签、笔、玩具和吸管。他们还捡到了一些不那么容易识别的碎片,比如聚苯乙烯泡沫的块状物,这种物质常常用于易碎品的缓冲包装上。

Collecting this debris wasn’t the team’s main goal, says Montserrat Filella from the University of Geneva. Instead, they wanted to assess whether chemicals emitted from these plastics were harmful.

日内瓦大学的菲莱利亚(Montserrat Filella)表示,科考队的主要目标并不是收集废弃物,而是要评估这些塑料挥发出的化学物质是否有害。

Their analysis comes at a time when the world is uncomfortably waking up to the extent of human-caused plastic pollution – from islands of amalgamated plastic in our ocean to the smaller microplastics in riverbeds.

正当他们展开分析之时,全世界开始忧心忡忡地意识到,人类活动所导致的塑料污染已经到了非常严重的地步——海洋中混合塑料堆积成岛,河床中漂浮着体积较小的微型塑料。

We have reached, as the UN has recently dubbed it, a “planetary crisis” that is ruining our ecosystem. Despite the increased awareness of its damage, plastic pollution is already everywhere. While potential solutions like a plastic-eating enzyme – announced in April 2018 – may someday help us cut down waste, there is no guarantee that it could tackle the millions of tonnes of waste already in nature.

联合国近来所称的"地球危机"已经来临,它正在摧毁我们的生态系统。尽管人们对塑料污染的破坏性有了越来越清醒的认识,这种污染其实早已无处不在。潜在的解决方案或许有一天可以帮助我们减少垃圾。2018年4月,科学家宣称获得了一种可降解塑料的酶。然而,没人有十足的把握用这种方式能处理掉已经存在于自然界的数百万吨垃圾。

But marine plastic pollution is much better studied and understood than that found in freshwater sources. “Freshwater systems are increasingly studied but still at a much smaller scale than oceans,” says Filella. This may simple be due to the fact that initial studies focused on the ocean – and so research proposals and grants followed suit.

但是,相比于淡水中的污染源,人们对海洋塑料污染的研究和了解要深入得多。"针对淡水系统的研究越来越多,但和海洋相比,仍然远远不够,"菲莱利亚说。这也许是因为,早期的研究主要以海洋为对象,研究计划和经费也都集中在海洋。

It didn’t take long for the Geneva team to find what they were looking for. Filella and colleagues collected over 3,000 samples. They went on to analyse 670 of these, revealing some worrying results.

日内瓦科考队并没有花费很长时间就找到了他们要找的东西。菲莱利亚和他的同事采集到了3000多个样本,并对其中670个样本进行了分析,得出的结果令人堪忧。

Many of these samples contained hazardous and toxic elements including cadmium, mercury and lead – in some cases in “very high concentrations”, as outlined in a 2018 paper in the journal Frontiers of Environmental Science. A large proportion of these toxic elements are now banned or restricted. This “reflected the age and residence time of the plastic stock in the lake,” says Filella: the plastic waste has been building up over several decades. And as we know, plastic can take hundreds of years to degrade.

据2018年《环境科学前沿》(Frontiers of Environmental Science)的一篇论文概述,许多样本含有有害及有毒元素,包括镉、汞和铅——这些元素在部分样本中的 "浓度非常高"。这些毒性元素中很大一部分现在已经被禁止使用,或者限制使用。这"反映了塑料物在淡水湖中产生的时间以及存留时间,"菲莱利亚说:这些塑料垃圾累积了数十年。众所周知,塑料需要数百年时间才能降解。

These types of plastics are in line with what washes up on many beaches. But there was one major difference. The hazardous elements the team found “appear to occur in higher abundance in the plastics retrieved from Lake Geneva” than in samples from the ocean, says Filella.

这些塑料和那些被冲上海滩的塑料类型一致。但两者有一个主要区别。"科考队从日内瓦湖中采集到的塑料样本中,有害元素的含量似乎高于海洋中的塑料样本,"菲莱利亚说。

Its effect on wildlife therefore remains a major concern. Plastic’s prevalence in water and on the shorelines of beaches, lakes and rivers, means that it can, and often is, ingested by wildlife. If an animal swallows it, their stomach acids might speed up how quickly the plastic degrades – potentially thereby also releasing the hazardous elements faster. Then there is the effect on the animal itself. Due to the lack of studies, it’s not yet entirely clear how freshwater organisms cope when they ingest plastic waste.

正因为此,塑料对于野生生物的影响成为了人们关注的焦点。塑料大量存在于水中、海边、湖岸以及河滩,可能会被野生动物摄入体内,而这种情况经常发生。如果动物将塑料吞食,其体内的胃酸可能会加速降解塑料,而这将导致塑料更快地释放有害元素,并且对动物自身也会造成影响。由于缺乏研究,人们至今尚未完全清楚淡水生物如何处理摄入体内的塑料垃圾。

Martin Wagner of the Norwegian University of Science and Technology spends much of his time looking at the effects of this. He was pleased to find that only when exposed to much higher concentrations of microplastics than are currently found in lakes and rivers did the species he examined appear to suffer.

挪威科技大学的瓦格纳(Martin Wagner)花了大量时间研究微塑料对生态造成的影响。他发现,只有当存在于湖泊和河流中的微塑料远高于现有含量时,他所研究的生物才会受到影响。这一点令他感到欣慰。

He’s still concerned. His study was on one small invertebrate species – and we know that there are many other effects of ingesting plastic already documented in marine animals. Studies show that sea turtles routinely die when plastic blocks their digestive tracts, for instance. Plastics can also damage stomach linings, block digestive tracks or can cause entanglement. Filella suspects this is happening in fresh water too.

但他仍然深感忧虑,因为他的研究对象只是一种小型无脊椎动物。而已经有研究记载,摄入塑料还会对海洋生物造成许多其他影响。例如,有研究表明,如果塑料阻塞了海龟的消化道,通常会导致海龟死亡。塑料不仅会阻塞消化道,还会损伤消化道黏膜,或者缠绕其中。菲莱利亚估测,这些情况同样会在淡水中发生。

“You might need a lot of plastic to kill a water flea, but that does not tell you the long-term consequences and the ecological implications,” he says.

"大量塑料会导致水蚤死亡,但这并不能解答塑料会带来哪些长期影响,或者对生态会造成什么潜在后果,"他说。

“Plastics will not go away. They are in the environment and will stay there for decades.”

"塑料不会消失。它们会在环境中存在几十年。"

Lake Geneva is not an outlier. Other lakes show similar levels of pollution. Italy’s Lake Garda, for example, also has high levels of plastic waste. A sample from the northern part of the lake contained 1,000 large plastic particles and 450 smaller particles (microplastics) per square metre.

日内瓦湖并非特例。其他湖泊也有类似的污染情况。例如,意大利的加尔达湖(Lake Garda)也存在严重的塑料垃圾。从该湖北部采集到的样本显示,每平方米含有1000个大型塑料颗粒和450个较小的塑料颗粒(即微塑料)。

Microplastics are particularly pernicious, as highlighted in a 2015 study. These are tiny fragments, often 5mm or smaller, often the broken-down pieces of larger plastics. They are widely found in lakes and riverbeds, particularly in the sediment, and are easily mistaken for food. Some come from plastic fibres from our clothing, others from cosmetic products that contain microbeads (now banned in the UK). One study even found microplastics in drinking water. Another discovered them in beer and honey.

2015年的一项研究强调,微塑料贻害无穷。微塑料是指一些小型的塑料碎片,长度通常不超过5毫米,由较大的塑料拆解而来。微塑料广泛分布于湖泊和河床,特别是沉积物中,很容易被动物误食。微塑料有些来自于衣服中的塑料纤维,有些来自于含塑料微珠的化妆产品(英国现已禁用)。一项研究甚至在饮用水中发现了微塑料。另一项研究则在啤酒和蜂蜜中发现了该物质。

But “the extent and relevance of their impacts on aquatic life” is not yet understood, the 2015 study reported. Nor is it clear how this might impact human health, something the authors say is “concerning”. The team’s leader Dafne Eerkes-Medrano explains that when it comes to freshwater, the more we look for plastic pollution, the more we will find. Even in the remote Mongolian Lake Hovsgol, microplastics are abundant – samples revealed a maximum of 44,435 microplastics discovered per square km, almost as much as in Lake Geneva, which had 48,146 per square km. Some of these are distributed by wind from the more populated parts of the lake, an analysis found.

然而,2015年的这项研究表明,人们至今还未能厘清"微塑料对水生生物的影响程度及相关性"。目前也尚不清楚,微塑料将会如何影响人类健康,但研究人员对此表示担忧。日内瓦湖科考队的队长梅德拉诺(DafneEerkes-Medrano)表示,就淡水而言,我们对塑料污染的探索越多,收获越大。即使是在偏远的蒙古库苏古尔湖中,微塑料的含量也相当高——抽样显示,每平方公里含有的微塑料多达44435个,这几乎相当于日内瓦湖中的微塑料含量(每平方公里48146个)。分析发现,其中一些微塑料是在风的作用下,从湖边人口较多的区域吹过来的。

It is now becoming clearer that much of the plastic that ends up in the ocean starts off in freshwater bodies in the first place – estimates suggest it could be as much as 70-80%. It can originate from industrial plants next to rivers, says Wagner.

现在,人们正越来越清楚地认识到,海洋中的塑料有很大一部分都来自于淡水水体——据估计,这一比例可以高达70-80%。瓦格纳表示,这些塑料可能来自于邻近河流的工厂。

There is no single solution for our plastic problem, particularly as plastic is so abundant in many everyday products we use. That’s why Wagner urges us all to “go back to the source of the problem” to think more about how we reduce our use of plastic, from the packaging on our food to single-use coffee cups. “We should abandon the logic of producing, using and throwing away, but try to create an economic system where it all goes back” into use, he says.

目前还没有解决塑料问题的方案,这主要是因为,很多日常生活用品中都含有大量塑料。正因为此,瓦格纳呼吁我们大家"追根溯源",更多地去思考怎样减少使用塑料,比如减少食品的塑料包装,少用盛装咖啡的一次性杯子。"我们不应该再用'生产-使用-丢弃'的逻辑来考虑问题,而是应该尝试创建一个可以循环利用的经济体系,"他说。

Reducing our use of plastic may slow down the waste that washes up on beaches – and plastics we use today are less toxic than they were in the past. But as the insights into Lake Geneva reveal, for many decades, at least, the plastic at the bottom of lakes will continue to release toxic elements.

减少使用塑料可以随之减少被冲上海滩的垃圾——人们现在使用的塑料,其毒性要小于以前的塑料。然而,日内瓦湖的科考研究指出,至少在长达几十年的时间里,湖底的塑料都会不断地释放毒性元素。

“It might take decades to get rid of the problem,” says Filella.

"要解决这个问题,可能需要花上几十年,"菲莱利亚说。

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