[audioFiles]2017m5s/audio_ezfj_178_201705[/audioFiles] Tracking Toxic Chemic

游客2024-09-14  9

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答案     Tracking Toxic Chemicals
    The fireproof chemicals used in furniture and clothing / can become toxic pollutants when winding up in the environment. / As they are in the environment all over the world, / tracking the spread of them has been a major challenge. / But it got easier since a new technique has been developed / to measure the presence and concentration of these chemicals in the air by sampling tree bark. / A tree’s bark provides a large surface area that takes in chemicals. / Also, because a layer of bark remains on the tree for years before being shed, / it provides a unique record of the environment over time. /

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