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 at 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.”

1.1. How does the author present the issue in the first paragraph?

A By quoting an expert.

B By defining a concept.

C By giving examples.

D By providing statistics.

解析：选C。推理判断题。第一段先提出“微塑料已成为全球性常见污染源”的核心观点，随后通过列举微塑料沉积在深海、喜马拉雅山脉、火山岩中，填满海鸟胃部、落入南极新雪，甚至出现在人体内等具体实例，展现微塑料污染的广泛性。该段既无专家引言、概念定义，也无数据统计，因此作者是通过举例子的方式呈现问题。故选C。

2.2. What determines the effectiveness of trapping microplastics in water?

A The hardness of water.

B The length of cooling time.

C The frequency of filtering.

D The type of plastic in water.

解析：选A。细节理解题。根据第三段的“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”可知，去除微塑料的效果取决于水中碳酸钙的含量，而碳酸钙含量是衡量水的硬度的关键指标。文中未提及冷却时长、过滤频率、塑料类型对去除效果有决定性影响。故选A。

3.3. What does the author try to illustrate by mentioning bottled water in paragraph 4?

A The importance of plastic recycling.

B The severity of the microplastic problem.

C The danger in overusing pure water.

D The difficulty in treating polluted water.

解析：选B。推理判断题。第四段开头指出“减少微塑料暴露的任务正变得越来越困难”，随后提及瓶装水的微塑料含量比原先认为的高出10至1000倍。作者通过这一例子，进一步凸显微塑料污染无处不在，即微塑料问题的严重性。故选B。

4.4. What is Gauchotte-Lindsay’s suggestion about?

A Choice of new research methods.

B Possible direction for further study.

C Need to involve more researchers.

D Potential application of the findings.

解析：选D。推理判断题。根据最后一段Caroline Gauchotte-Lindsay的表述，她认可该研究中煮沸除微塑料的原理，同时建议“升级饮用水处理厂，使其具备去除微塑料的功能”。这一建议是将研究成果转化到实际应用场景中，属于研究发现的潜在应用方向。故选D。