VOA健康报道2024--Study Finds Small Plastic Pieces in Bottled Water

Study Finds Small Plastic Pieces in Bottled Water

The average liter of bottled water has nearly a quarter million invisible pieces of very small plastic known as nanoplastics, a recent study says.

Researchers found the nanoplastics with a microscope using dual¹ lasers.

Scientists long figured there were lots of these very small plastic pieces. But until researchers at Columbia and Rutgers universities did their calculations, they never knew how many or what kind.

Looking at five samples each of three common bottled water brands, researchers found particle levels ranged from 110,000 to 400,000 per liter. The average was around 240,000, the study said. The research appeared recently in the publication Proceedings² of the National Academy of Sciences.

Nanoparticles are particles that are less than a micron in size. In comparison, a human hair is about 83 microns wide.

Previous studies have looked at slightly bigger microplastics that range from 5 millimeters, which could be seen by human eyes, to one micron. About 10 to 100 times more nanoplastics than microplastics were discovered in bottled water, the study found.

Much of the plastic seems to be coming from the bottle and the filtration system to clean the water itself, said the study's lead writer Naixin Qian of Columbia University.

She would not name the three brands because researchers want more samples and they want to study more brands. Still, she said they were common and bought at a Walmart, a popular store in the U.S.

Researchers still cannot answer the big question: Are those nanoplastic pieces harmful to health?

"That's currently under review. We don't know if it's dangerous or how dangerous," said study co-writer Phoebe Stapleton of Rutgers University. "We do know that they are getting into the tissues (of mammals, including people) ... and the current research is looking at what they're doing in the cells."

The International Bottled Water Association said in a statement: "There currently is both a lack of standardized⁴ (measuring) methods and no scientific" agreement on the possible health effects of nano- and microplastic particles. The statement added, "Therefore, media reports about these particles in drinking water do nothing more than unnecessarily scare consumers."

The American Chemistry Council, which represents plastics manufacturers, declined to immediately comment.

The Associated Press spoke⁵ with four co-writers of the study. All of them said they would cut back on their bottled water use.

Columbia chemist Wei Min said he has reduced his bottled water use by half. Stapleton said she now depends more on filtered water at home in New Jersey⁶.

But study co-author Beizhan Yan, a Columbia environmental chemist who increased his tap water usage, pointed⁷ out that filters themselves can be a problem by introducing plastics.

"There's just no win," Stapleton said.

Outside experts, who praised the study, agreed that there is a general unease about the risks of fine plastic particles. Still, it is too early to say anything certain about the risks.

"The danger of the plastics themselves is still an unanswered question. For me, the additives⁸ are the most concerning," said Jason Somarelli of Duke University in North Carolina. Somarelli was not part of the research. He added, "We and others have shown that these nanoplastics can be internalized into cells, and we know that nanoplastics carry all kinds of chemical additives that could cause cell stress, DNA⁹ damage and change metabolism¹⁰ or cell function."

Somarelli said his own research has found more than 100 "known cancer-causing chemicals in these plastics."

Dual laser microscope

About 15 years ago, Min invented dual laser microscope technology that identifies specific compounds by their chemical properties and how they respond when exposed to lasers. Yan and Qian talked to him about using that technique to find and identify plastics that had been too small for researchers using established methods.

Kara Lavender Law of the Sea Education Association said "the work can be an important advance in the detection of nanoplastics," but she said she'd like to see other chemists use the technique and get the same results.

Yan said he is starting to study water supplies in the U.S. cities of Boston, St. Louis, Los Angeles and elsewhere to see how much plastics are in their tap water. Previous studies looking for microplastics and some early tests suggest there may be less nanoplastic in tap water than in bottled water.

Even with unknowns about human health, Yan said he does have one suggestion: Use reusable bottles instead of single-use plastics.

Words in This Story

sample – n. an amount of something that gives you information about the thing it was taken from

brand -- n. a category of products that are all made by a particular company

review -- v. to look at or examine (something) carefully especially before making a decision or judgment¹¹

standardize³ – v. to change (things) so that they are similar and consistent

tap water – n. water that comes through pipes from the public water system

internalize -- v. to absorb or take in

metabolism -- n. the chemical processes by which a plant or an animal uses food or water to make energy

detect -- v. to discover or notice the presence of something

1 dual   

adj.双的；二重的，二元的

参考例句：

• The people's Republic of China does not recognize dual nationality for any Chinese national.中华人民共和国不承认中国公民具有双重国籍。
• He has dual role as composer and conductor.他兼作曲家及指挥的双重身分。

2 proceedings   

n.进程，过程，议程；诉讼(程序)；公报

参考例句：

• He was released on bail pending committal proceedings. 他交保获释正在候审。
• to initiate legal proceedings against sb 对某人提起诉讼

3 standardize   

v.使符合标准，使标准化

参考例句：

• We will extend and standardize legal services and provide effective legal aid.拓展和规范法律服务，积极开展法律援助。
• There is a drive both to standardise components and to reduce the number of models on offer.正在为实现零部件标准化和减少推出的型号数量而努力。

4 standardized   

adj.标准化的

参考例句：

• We use standardized tests to measure scholastic achievement. 我们用标准化考试来衡量学生的学业成绩。
• The parts of an automobile are standardized. 汽车零件是标准化了的。

5 spoke   

n.（车轮的）辐条；轮辐；破坏某人的计划；阻挠某人的行动 v.讲，谈（speak的过去式）；说；演说；从某种观点来说

参考例句：

• They sourced the spoke nuts from our company.他们的轮辐螺帽是从我们公司获得的。
• The spokes of a wheel are the bars that connect the outer ring to the centre.辐条是轮子上连接外圈与中心的条棒。

6 jersey   

n.运动衫

参考例句：

• He wears a cotton jersey when he plays football.他穿运动衫踢足球。
• They were dressed alike in blue jersey and knickers.他们穿着一致，都是蓝色的运动衫和灯笼短裤。

7 pointed   

adj.尖的，直截了当的

参考例句：

• He gave me a very sharp pointed pencil.他给我一支削得非常尖的铅笔。
• She wished to show Mrs.John Dashwood by this pointed invitation to her brother.她想通过对达茨伍德夫人提出直截了当的邀请向她的哥哥表示出来。

8 additives   

n.添加剂( additive的名词复数 )

参考例句：

• chemical additives in petrol 汽油中的化学添加剂
• It'says on the packet that these crisps contain no additives. 包装上说这些炸薯片不含添加剂。 来自《简明英汉词典》

9 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

10 metabolism   

n.新陈代谢

参考例句：

• After years of dieting,Carol's metabolism was completely out of whack.经过数年的节食，卡罗尔的新陈代谢完全紊乱了。
• All living matter undergoes a process of metabolism.生物都有新陈代谢。

11 judgment   

n.审判；判断力，识别力，看法，意见

参考例句：

• The chairman flatters himself on his judgment of people.主席自认为他审视人比别人高明。
• He's a man of excellent judgment.他眼力过人。