VOA慢速英语：多种无害化学物混合会致癌

From VOA Learning English, this is the Health &Lifestyle report.

Every day, people come into contact with thousands ofchemicals. These chemicals are said to be harmless tohuman health. In fact, the chemicals are considered sosafe that we wash with them. We put them on ourbodies and even our faces. Other chemical productsare used throughout our homes.

We are surrounded every day by thousands of chemicals. These chemicals have been found to be safe -- on their own. But are they still "safe" if mixed with other chemicals? That's the big question. (FILE PHOTO)

By the time, you walk out your front door you havealready been exposed to thousands of chemicals.

On its own, each chemical seems harmless. But incombination with other chemicals, they may becomedeadly. That is the finding of a two-year study by ahigh-profile task force of scientists. The task forcewas told to investigate the cancer-causing possibility ofchemical mixtures.

Linda Gulliver was one of 174 scientists on the task force. Their job was tostudy the cancer-causing potential of 85 chemicals. All 85 are said to becommon in the environment.

Ms. Gulliver explains that chemicals have the potential, or ability, to formdangerous mixtures. Even simple minerals can become dangerous whenmixed with chemicals found in plastics or beauty products.

“We're talking about everything that could be from basic minerals elementslike copper, nickel to pesticides that are used in things like cosmetics and hairsprays and nail polishes and food wrappers."

Ms. Gulliver is also on the medical faculty of Otago University in Dunedin, NewZealand. While the chemicals are safe on their own, she says, theresearchers found that many chemical compound cause cancer in humancells.

Working in groups, the scientists explored how different chemical mixturescould lead to cancer. Ms. Gulliver’s team looked at the ability of differentcombinations to support the increase of malignant human cells.

She says the big issue – what she calls ‘the $64 million dollar question’ – is, “Which common, every day chemicals do people need to avoid?”

"The $64 million dollar question that everybody wants to ask is, ‘Which ones[chemicals] should we be looking out for?’ And the answer to that is, ‘We don'tknow yet.’ "

She says the current way to identify whether chemicals cause cancer is totest them one at a time. This method leads, she adds, to a long list ofsupposedly "safe" chemicals. She and her team say that approach needs tochange.

"We definitely need certain research … to find out what mixtures of chemicalswould be more harmful than others; what groups of chemicals, when together,would produce more harmful effects. And at the moment, that is not known."

An estimated one in five cancers has been linked to chemical exposure. Itmay turn out that the cancer-causing villain is not a single chemical at all. The villain could be a deadly combination. The increase of risk to cancer couldbe from exposure to many chemical compounds at the same time, orsimultaneously.

The task force published its findings in the journal Carcinogenesis.

And that’s the Health & Lifestyle report. I’m Anna Matteo.

VOA’s Jessica Berman reported on this story. Anna Matteo adapted it for Learning English. George Grow was the editor.

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Words in This Story

expose – v. to cause (someone) to experience something or to be influencedor affected by something : exposure is the noun

potential – n. a chance or possibility that something will happen or exist in thefuture : potential can also be used as an adjective

task force– n. a group of people who deal with a specific problem

villain– n. someone or something that is blamed for a particular problem ordifficulty

simultaneously – adv. happening at the same time: simultaneous is theadjective