VOA科学技术2024--Are Microplastics Harmful?

Extremely small pieces of plastic called microplastics are in the ocean and the air, as well as in our food and water. Scientific study has discovered microplastics in human body tissues also, including the heart, liver and kidneys¹.

Some researchers worry that microplastics harm human health, although they say that science has not found clear evidence of that. Still, they say questions remain about the possible health effects of microplastics.

Manufacturers mostly use oil or other petroleum² products to make plastic. The material is used to make a huge number of different products: water bottles, car parts, children's playthings, clothing, electronics³ and more. Heat, weather, and even animal digestion⁴ break down plastic into smaller and smaller pieces.

Microplastics can be 5 millimeters long at most or as small as one micrometer. A micrometer is one-one thousandth of a millimeter. Microplastics have been found in salt, sugar, honey, rice and seafood⁵. They have also been found in milk, soil, and drinking water.

Risks to the human body

Researchers disagree about how much plastic people might be breathing in or taking in as food and drink. Still, many studies find evidence of plastics in body tissues.

Tracey Woodruff is a researcher at the University of California at San Francisco. She said, "Microplastics have been measured in pretty much all of the body tissues that have been evaluated."

Scientists are still trying to answer the question of how harmful microplastics might be. In 2022, a World Health Organization report found no clear risk to human health, based on the available evidence.

There is also not clear evidence of widespread public health effects.

However, researchers only recently began to measure plastic levels in the human body and learn about their possible effects. Woodruff of U.C. San Francisco said it makes sense that microplastics are harmful because they contain poisonous chemicals. The researcher was part of an investigative team that examined nearly 2,000 studies about microplastics at the request of California state lawmakers.

Some evidence suggests plastics can increase inflammation and other changes in the body. Such changes could increase the risk of heart attack and stroke.

Reducing exposure to microplastics

Researchers say there are ways to reduce possible contact with microplastics.

Take off your shoes before you go into your home. This helps prevent the spread of microplastics inside. Eat foods - especially fresh fruits and vegetables - that you prepare at home. Do not heat foods in plastic containers, Woodruff said. And, she added, use metal or glass water bottles, instead of plastic.

Words in This Story

digestion -n. the breaking down and absorption of food in the body

evaluate -v. to measure, judge, or analyze⁶

inflammation -n. an increase in size of body tissues that results from infection, injury, or illness

1 kidneys   

肾形矿脉； 肾，肾脏( kidney的名词复数 )； （可食用的动物的）腰子

参考例句：

• The function of the kidneys is to excrete wastes from the body. 肾的功能是排泄人体里的废物。
• She got a very dangerous disease of kidneys. 她得了一种很危险的肾病。

2 petroleum   

n.原油，石油

参考例句：

• The Government of Iran advanced the price of petroleum last week.上星期伊朗政府提高了石油价格。
• The purpose of oil refinery is to refine crude petroleum.炼油厂的主要工作是提炼原油。

3 electronics   

n.电子器件，电子学，电子技术

参考例句：

• About 45000 people worked in electronics in Scotland.苏格兰约有4.5万人在电子行业工作。
• He wants to brush up his knowledge of electronics.他想温习他的电子学知识。

4 digestion   

n.消化，吸收

参考例句：

• This kind of tea acts as an aid to digestion.这种茶可助消化。
• This food is easy of digestion.这食物容易消化。

5 seafood   

n.海产食品，海味，海鲜

参考例句：

• There's an excellent seafood restaurant near here.离这儿不远有家非常不错的海鲜馆。
• Shrimps are a popular type of seafood.小虾是比较普遍的一种海味。

6 analyze   

vt.分析，解析 (=analyse)

参考例句：

• We should analyze the cause and effect of this event.我们应该分析这场事变的因果。
• The teacher tried to analyze the cause of our failure.老师设法分析我们失败的原因。