Microplastics have become a common source of pollution across the Earth — they have settled in the deep sea and on the Himalayas, stuck inside volcanic rocks, filled the stomachs of seabirds and even fallen in fresh Antarctic snow. They are even appearing inside humans.
Now, new research suggests that a simple, cheap measure may significantly reduce the level of microplastics in water from your tap (水龙头): boiling and filtering (过滤) it. In a study published Wednesday in Environmental Science & Technology Letters, researchers from China found that boiling tap water for just five minutes — then filtering it after it cools — could remove at least 80 percent of its microplastics.
Crucially, this process relies on the water containing enough calcium carbonate (碳酸钙) to trap the plastics. In the study, boiling hard water containing 300 milligrams of calcium carbonate led to an almost 90 percent drop in plastics. But in samples with less than 60 milligrams of calcium carbonate, boiling reduced the level of plastics by just 25 percent. Additionally, the research didn’t include all types of plastics. The team focused only on three common types — polystyrene, polyethylene and polypropylene — and they didn’t study other chemicals previously found in water such as vinyl chloride.
Still, the findings show a potential path forward for reducing microplastic exposure — a task that’s becoming increasingly difficult. Even bottled water, scientists found earlier this year, contains 10 to 1,000 times more microplastics than originally thought.
Scientists are still trying to determine how harmful microplastics are — but what they do know has raised concerns. The new study suggests boiling tap water could be a tool to limit intake. “The way they demonstrated how microplastics were trapped through the boiling process was nice,” Caroline Gauchotte-Lindsay, an environmental engineer of the University of Glasgow in Scotland who was not involved in the research, tells New Scientist. “We should be looking into upgrading drinking water treatment plants so they remove microplastics.”
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答案
A
解析
【详解】 细节理解题。根据文章第二段中“Crucially, this process relies on the water containing enough calcium carbonate (碳酸钙) to trap the plastics. In the study, boiling hard water containing 300 milligrams of calcium carbonate led to an almost 90 percent drop in plastics. But in samples with less than 60 milligrams of calcium carbonate, boiling reduced the level of plastics by just 25 percent. (至关重要是，这一过程依赖于含有足够碳酸钙的水来截留塑料。在这项研究中，将含有300毫克碳酸钙的硬水煮沸后，塑料含量下降了近90%。但在碳酸钙含量低于60毫克的样品中，煮沸只降低了25%的塑料含量)”可知，决定在水中截留微塑料的有效性的是水的硬度。故选A。