'Safe' lead levels harm children 现行铅含量标准对儿童不“安
文章来源:未知 文章作者:meng 发布时间:2009-09-18 06:07 字体: [ ]  进入论坛
(单词翻译:双击或拖选)

Young children's exposure to lead in the environment is harming their intellectual and emotional development, according to UK researchers.

英国科学家警告,环境中的铅元素会损害幼童的智力和情感的发育。

 

Lead is linked to a number of health problems
Lead is linked to a number of health problems

The researchers say the toxic1 effects(毒性作用) of lead on the central nervous system are obvious even below the current so-called safe level of lead in the blood.

They are recommending the threshold(门槛,入口) should be halved2.

A spokesman for the Health Protection Agency said levels of exposure should be kept to the minimum.

Lead has been removed from paint and petrol by law in the UK, but it is still widespread in the environment.

The study from the University of Bristol Centre for Child and Adolescent Health set out to see if there was any effect on the behaviour and intellectual development of children who had ingested(摄取) just below the so-called safe level of 10 microgrammes per decilitre (or tenth of a litre) of blood.

The study is published in the journal, Archives of Diseases in Childhood.

Lead levels

The Bristol researchers took blood samples from 582 children at the age of 30 months.

They found 27% of the children had lead levels above five microgrammes per decilitre.

They followed the children's progress at regular intervals3(每隔一定时间) and then assessed their academic performance and behavioural patterns when they were seven to eight years old.

After taking account of factors likely to influence the results, they found that blood lead levels at 30 months showed significant associations with educational achievement, antisocial behaviour and hyperactivity scores five years later.

With lead levels up to five microgrammes per decilitre, there was no obvious effect.

But lead levels between five and 10 microgrammes per decilitre were associated with significantly poorer scores for reading ( 49% lower) and writing (51% lower).

A doubling in lead blood levels to 10 microgrammes per decilitre was associated with a drop of a third of a grade in their Scholastic4 Assessment5 Tests (SATs).

And above 10 microgrammes per decilitre children were almost three times as likely to display antisocial behaviour patterns and be hyperactive(极度活跃的) than the children with the lower levels of lead in their blood.

Adverse6 effects

The effects of lead toxicity7 in children were first described in 1892 in Brisbane, Australia.

Since then acceptable levels of lead in the blood have fallen sharply.

In 1991, the US Centres for Disease Control and Prevention, revised their level of concern for blood levels down to ten microgrammes per declitre.

The World Health Organisation8 estimates that globally half of the urban children under the age of five have blood levels exceeding this limit.

Professor Alan Emond, who led this study, said a third of the children in his study had levels only half of this but were still exhibiting(展现,呈现) adverse effects(不良反应,副作用).

He said: "Lead in the body is one of many factors that impacts on education, but this is a reminder9 that environmental factors are important and paediatricians(儿科医生) must test more children with behavioural problems for lead."

"We did our blood survey when the children were about two and a half years old.

"We think this is quite close to the peak age for lead ingestion(吸收,咽下) when the children are putting everything in their mouths as they explore their environment.

"This is a normal phase that we grow out of, but for children who have developmental problems, like autism(孤独症,自闭症), it may go on for a longer time so they may be particularly vulnerable. "

A Health Protection Agency spokesman said: "The Agency's advice is that exposures to lead should be kept to the minimum that is reasonably practical.

"This has been the policy in the UK and of health agencies throughout the world for many years.

"Measurements have shown that levels of lead in children and adults have decreased markedly over the last two decades or more, primarily because of these policies."

Lead is linked to a number of health problems
Lead is linked to a number of health problems


点击收听单词发音收听单词发音  

1 toxic inSwc     
adj.有毒的,因中毒引起的
参考例句:
  • The factory had accidentally released a quantity of toxic waste into the sea.这家工厂意外泄漏大量有毒废物到海中。
  • There is a risk that toxic chemicals might be blasted into the atmosphere.爆炸后有毒化学物质可能会进入大气层。
2 halved e23e4ddc1c29e5a63536d2c9bb621fbc     
v.把…分成两半( halve的过去式和过去分词 );把…减半;对分;平摊
参考例句:
  • The shares have halved in value . 股价已经跌了一半。
  • Overall operating profits halved to $24 million. 总的营业利润减少了一半,降至2,400 万元。 来自《简明英汉词典》
3 intervals f46c9d8b430e8c86dea610ec56b7cbef     
n.[军事]间隔( interval的名词复数 );间隔时间;[数学]区间;(戏剧、电影或音乐会的)幕间休息
参考例句:
  • The forecast said there would be sunny intervals and showers. 预报间晴,有阵雨。
  • Meetings take place at fortnightly intervals. 每两周开一次会。
4 scholastic 3DLzs     
adj.学校的,学院的,学术上的
参考例句:
  • There was a careful avoidance of the sensitive topic in the scholastic circles.学术界小心地避开那个敏感的话题。
  • This would do harm to students' scholastic performance in the long run.这将对学生未来的学习成绩有害。
5 assessment vO7yu     
n.评价;评估;对财产的估价,被估定的金额
参考例句:
  • This is a very perceptive assessment of the situation.这是一个对该情况的极富洞察力的评价。
  • What is your assessment of the situation?你对时局的看法如何?
6 adverse 5xBzs     
adj.不利的;有害的;敌对的,不友好的
参考例句:
  • He is adverse to going abroad.他反对出国。
  • The improper use of medicine could lead to severe adverse reactions.用药不当会产生严重的不良反应。
7 toxicity InYwc     
n.毒性,毒力
参考例句:
  • The hoarse grunt or squeal is characteristic of toxicity.嘶哑的哼声和叫声是中毒的特征。
  • Dieldrin is related to aldrin,and its toxicity to earthworms is similar.狄氏剂与艾氏剂有关,对蚯蚓的毒性是相似的。
8 organisation organisation     
n.组织,安排,团体,有机休
参考例句:
  • The method of his organisation work is worth commending.他的组织工作的方法值得称道。
  • His application for membership of the organisation was rejected.他想要加入该组织的申请遭到了拒绝。
9 reminder WkzzTb     
n.提醒物,纪念品;暗示,提示
参考例句:
  • I have had another reminder from the library.我又收到图书馆的催还单。
  • It always took a final reminder to get her to pay her share of the rent.总是得发给她一份最后催缴通知,她才付应该交的房租。
TAG标签: children safe harm lead
发表评论
请自觉遵守互联网相关的政策法规,严禁发布色情、暴力、反动的言论。
评价:
表情:
验证码:点击我更换图片