Microplastics React With Water, a New Study Says. That’s a Problem for Biology

One of the reasons plastic has become so ubiquitous is that, generally, it’s very chemically stable, meaning it does not readily react with the substances around it. That’s why this material is so often used for food packaging and water bottles.

塑料之所以变得如此普遍，原因之一是它通常具有极高的化学稳定性，这意味着它不容易与周围的物质发生反应。这就是为什么这种材料经常被用于食品包装和水瓶的原因。

The same was thought to be true of microplastics—those tiny pieces of debris that break off from larger plastic objects and which, according to numerous studies, have spread to virtually every ecosystem on the planet. But scientists at Columbia University and UC Berkeley have just discovered that water can make the surfaces of microplastics chemically active and turn them into a potential hazard.

人们曾认为微塑料也是如此——这些从大型塑料制品上脱落的微小碎片，根据多项研究，已经扩散到地球上几乎每一个生态系统中。但哥伦比亚大学和加州大学伯克利分校的科学家们刚刚发现，水可以使微塑料的表面产生化学活性，并将其转化为潜在的危害。

According to the findings of the article published in Nature, this activity can trigger the spontaneous formation of chemicals capable of altering other molecules, like those that are essential for living organisms. The phenomenon, the authors note, occurs even under normal environmental conditions, without the need for sunlight or other agents that cause plastic degradation.

根据发表在《自然》杂志上的文章研究结果，这种活性可以触发化学物质的自发形成，这些化学物质能够改变其他分子，例如那些对生物体至关重要的分子。作者指出，这种现象即使在正常的自然环境条件下也会发生，无需阳光或其他导致塑料降解的因素。

So how can microplastics be so reactive when bigger plastics generally aren’t? The scientists suggest this has to do with the greater available surface area for these reactions to occur.

那么，为什么大型塑料通常不具备反应性，而微塑料却如此活跃呢？科学家认为，这与发生这些反应所需的更大可用表面积有关。

“As plastic fragments into smaller and smaller particles, its surface area increases enormously,” Wei Min, a professor of chemistry and biomedical engineering at Columbia University, said in a press release. “Then microplastics change the water that surrounds them, generating high-energy, reactive radicals that very likely contribute to biological damage that we see in animals and potentially in humans as a result of microplastic exposure.”

“随着塑料破碎成越来越小的颗粒，其表面积会大幅增加，”哥伦比亚大学化学与生物医学工程教授魏敏（Wei Min）在新闻稿中表示。“然后，微塑料会改变周围的水，产生高能的活性自由基，这很可能导致我们在动物身上看到的生物损伤，并可能导致人类因接触微塑料而受到伤害。”

Among these potentially dangerous chemical products—called reactive oxygen species—a variety known as hydroxyl radicals stands out. They are particularly dangerous because they can snatch electrons from the proteins and fats that make up cell membranes, disrupting their structure and function. These “are textbook examples of the kinds of molecules that can damage animal and human tissue,” added Naixin Qian, a postdoctoral researcher in Min’s lab who helped lead the research.

在这些被称为活性氧的潜在危险化学产物中，一种被称为羟基自由基的物质尤为突出。它们之所以特别危险，是因为它们可以从构成细胞膜的蛋白质和脂肪中夺取电子，从而破坏其结构和功能。在魏敏实验室协助领导这项研究的博士后研究员钱乃馨（Naixin Qian）补充说，这些“是能够损伤动物和人体组织的典型分子案例”。

Our body has some defenses against this kind of damage. This is the biological function of the buzzy molecules known as antioxidants. These neutralize the reactive chemicals, but if the reactive compounds greatly outnumber antioxidants, this line of defense can be overwhelmed.

我们的身体对这种损伤有一定的防御能力。这就是被称为抗氧化剂的流行分子所发挥的生物学功能。它们可以中和这些活性化学物质，但如果活性化合物的数量远远超过抗氧化剂，这一防线就可能被攻破。

This can develop into a scenario called oxidative stress, leading to the damage of cells. Previous research had already identified oxidative stress among the cellular responses associated with exposure to microplastics, although the mechanisms responsible for this damage are not yet fully understood.

这种情况可能会发展成所谓的氧化应激，导致细胞受损。先前的研究已经确定氧化应激是与接触微塑料相关的细胞反应之一，尽管导致这种损伤的机制尚未完全明确。

The extent to which microplastics have pervaded our bodies remains an open debate, with some of the more sensational findings having been called into question. But if even a small amount of microplastics are present in our tissues, they could be reacting with the water in our bodies.

微塑料渗透到我们体内的程度仍是一个悬而未决的争论，一些更耸人听闻的发现也受到了质疑。但即使我们的组织中只存在少量的微塑料，它们也可能正在与我们体内的水分发生反应。

The researchers were particularly concerned with the potential effects on blood, which is largely composed of water. If contact with this fluid can chemically activate the surfaces of microplastics, their presence inside the body could pose an additional danger beyond that of the pollutants they carry or release.

研究人员特别关注其对血液的潜在影响，因为血液主要由水组成。如果与这种液体接触能够使微塑料表面产生化学活性，那么它们在体内的存在可能会带来除其携带或释放的污染物之外的额外危险。

When the researchers exposed red blood cells extracted from mice to different types of microplastics, the cells became deformed and ruptured—a phenomenon known as hemolysis. The effects were greater with plastics that were more reactive with water, indicating that this activity was the cause of cellular damage.

当研究人员将从老鼠身上提取的红细胞暴露在不同类型的微塑料中时，细胞发生了变形和破裂——这种现象被称为溶血。那些与水反应更强烈的塑料所产生的影响更大，这表明这种活性正是导致细胞损伤的原因。

Research into the effects of microplastics has long focused on other chemicals leaching from the particles or on their physical effects, often considering the plastic itself chemically inert. The larger pieces generally are, but these findings challenge the assumption that what is true of plastic on a grand scale is also true of the microscopic pieces it breaks down into.

长期以来，对微塑料影响的研究一直集中在从颗粒中浸出的其他化学物质或其物理影响上，通常认为塑料本身在化学上是惰性的。大型塑料碎片通常确实如此，但这些发现挑战了一种假设，即塑料在宏观尺度上的特性同样适用于它分解后的微小碎片。

This story originally appeared on WIRED en Español and has been translated from Spanish.

本文最初发表于《连线》杂志西班牙语版（WIRED en Español），并由西班牙语翻译而来。