SSS听说练习第二期：lead pollution

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This is Scientific Americans' 60-Second Science. I'm Cynthia Graber. This will just take a minute.

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Toy companies and parents reacted quickly this year when some toys made in China were found to contain lead.Because lead is known to affect kids' cognitive development.

+ C8 `9 k8 b# x3 j+ IIn 1991, the Centers for Disease Control set a federal standard of 10 micrograms of lead per deciliter of blood.

9 f0 [9 b- E  v2 k* k2 R6 X* zSo the 8% of US kids five and younger who have lead levels between 5 and 10 micrograms are considered safe.

% `: b$ i% [2 ^* `( UBut recent Cornell University research in the journal Environmental Health Perspective supports a stricter standard.

/ ?. I/ b1 f" x; X+ Y0 A6 ~: _The research team had previously followed kids from birth through age 5.

7 @: |- D: V  b/ UThe current study looked again at the children at age 6.
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* u3 u1 n( v2 Z3 I/ C& n: HThe kids were divided into 2 groups,one with blood lead levels between 0 and 5,and the other with 5 to 10.
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Again currently considered ok.

Turned out that those in the 5 to 10 group had IQ scores about 5 points lower than those with the lowest lead levels.
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1 q$ R! o* D% L# Z. Q5 _5 C; {Scientists say this could affect educational performance later in life.
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7 z1 y: z/ [9 N. w6 ]They recommend reconsidering federal standards for lead in consumer products,and reevaluating the acceptable blood lead levels in children.  



Thanks for the minute for Scientific Americans' 60-Second Science. I’m Cynthia Graber.