Microplastics are everywhere. These tiny pieces of plastic – the usual definition is anything under 5mm in length – are a by-product of the over-production of synthetic polymers, and there is increasing evidence that they are infiltrating the entire ecosystem. A recent study found them in 90% of protein types sampled by researchers, while a study from 2020 found them in fruit and vegetables. Another study, published this year suggests that bottled water could contain up to 100 times the amount of plastic particles previously thought, and some studies have even found microplastics in prenatal human placentas. So is this an unstoppable problem? Are there implications for our health that we are only just beginning to see? And if so, is it already too late to do anything about it?
微塑料无处不在。这些微小的塑料片：通常的定义是长度在 5 毫米以下的任何东西，是合成聚合物过度生产的副产品，越来越多的证据表明它们正在渗透到整个生态系统。最近的一项研究发现，研究人员采样的 90% 的蛋白质类型中都含有它们，而 2020 年的一项研究则在水果和蔬菜中发现了它们。今年发表的另一项研究表明，瓶装水中的塑料颗粒含量可能是之前认为的 100 倍，一些研究甚至在产前人类胎盘中发现了微塑料。那么这是一个无法阻止的问题吗？我们才刚刚开始看到这些对我们健康的影响吗？如果是这样，现在采取任何行动是否已经太晚了？
To start with the bad news: yes, the problem is worse than previously thought. “Everyone knew there were microplastics in our sea water and on our beaches, but we’re now finding them in the freshwater system and as far afield as the Arctic,” says Prof Catherine Wilson, an expert in microplastics at the School of Engineering, Cardiff University. “This is raising questions about how they are being transported in the air. We’re also seeing – as we use recycled sludge, a nutrient-rich waste product from sewage treatment, as a fertiliser in agriculture – that microplastics are being recycled in the environment, which may mean they are building up in the soil on farmland.”
先来说坏消息：是的，这个问题比之前想象的更严重。 “每个人都知道我们的海水和海滩上存在微塑料，但我们现在在淡水系统和远至北极的地方发现了它们，” 卡迪夫大学，工程学院微塑料专家凯瑟琳·威尔逊教授说。 “这引发了人们对它们如何在空中运输的疑问。我们还看到，当我们使用回收污泥（一种来自污水处理的营养丰富的废物）作为农业肥料时，微塑料正在环境中被回收，这可能意味着它们正在农田的土壤中积聚。 ”
So how bad are microplastics for humans? There are two clear mechanisms through which microplastics might hurt us: either by chemically disrupting the normal running of our body systems, or by piling up in enough quantities to block our circulatory, respiratory or digestive systems. Increased cancer risk, for instance, is a key concern – but it’s not clear just how worried we should be. “Links to the carcinogenic potential of microplastics and nanoplastics, which are barely visible to the eye even under a powerful microscope, has been demonstrated in vitro [laboratory test-tubes or similar] in human cells and in vivo [in a living body] for animal and plant models,” says Prof Jo Cable, head of division at the School of Biosciences, Cardiff University. “But it’s worth saying that the effects in most of these studies were induced by concentrations of plastic far higher than those detected in the bloodstream in some of the most recent studies.”
那么微塑料对人类到底有多糟糕呢？微塑料可能通过两种明显的机制伤害我们：要么通过化学方式破坏我们身体系统的正常运行，要么堆积到足以阻塞我们的循环、呼吸或消化系统。例如，癌症风险增加是一个关键问题，但尚不清楚我们应该有多担心。 “即使在强大的显微镜下，肉眼也几乎看不到微塑料和纳米塑料的致癌潜力，这已在人体细胞的体外（实验室试管或类似物）和体内（活体）中得到证实。卡迪夫大学生物科学学院系主任乔·凯布尔教授说：“动物和植物模型。” “但值得一提的是，大多数研究中的影响是由塑料浓度引起的，其浓度远远高于最近一些研究中在血液中检测到的浓度。”
Similarly, it is not clear whether microplastics are having a significant effect on, for example, the production of immune cells or the appetite, although all these possibilities are a concern. “Further work is needed to determine the effects of this level of exposure – as well as whether microplastics continue accumulating or are eventually expelled from our bodies,” says Cable. “We also need to understand whether better alternatives are possible – for instance, the Plastic Fish project at Cardiff University is investigating whether bio-based plastics and associated additives often marketed as ‘greener’ than traditional plastics are, in fact, healthier for the environment and organisms if and when exposure occurs. Evidence is mounting that they may not be.”
同样，目前尚不清楚微塑料是否对免疫细胞的产生或食欲等产生显着影响，尽管所有这些可能性都令人担忧。凯布尔说：“需要开展进一步的工作来确定这种暴露程度的影响，以及微塑料是否会继续积累或最终从我们的身体中排出。” “我们还需要了解是否有更好的替代品——例如，卡迪夫大学的塑料鱼项目正在调查经常被标榜为比传统塑料“更绿色”的生物基塑料和相关添加剂实际上是否对环境更健康和生物体（如果发生暴露）。越来越多的证据表明它们可能并非如此。”
What can we do? Unfortunately, this is a societal problem: the sheer ubiquity of microplastics mean there is little chance of avoiding them. Plastics are an essential and often life-saving commodity, but we’ve been using them unsustainably for years, and left a legacy for future generations that could be difficult to tackle. On a global level, we need to shift towards plastic products that are either biodegradable – ie break down naturally – or structurally easier to chemically recycle; and consumers and businesses need to be incentivised to embrace them. It’s not an easy problem to deal with, but as it is likely to affect everyone who swims, eats or breathes, it concerns us all.
我们可以做什么？不幸的是，这是一个社会问题：微塑料无处不在，意味着几乎没有机会避免它们。塑料是一种必不可少的、常常能拯救生命的商品，但多年来我们一直以不可持续的方式使用它们，并为子孙后代留下了可能难以解决的遗产。在全球范围内，我们需要转向可生物降解（即自然分解）或结构上更易于化学回收的塑料产品；需要激励消费者和企业接受它们。这不是一个容易处理的问题，但由于它可能影响每个游泳、进食或呼吸的人，因此它关系到我们所有人。
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