Lead (exposure) in the Time of Standardized Tests

by Haifa Haroon on March 2, 2013

You know the drill: Clear your desk. #2 pencils only. Fill in the oval on your Scantron. If you change your answer, erase it completely.*

Just about every school year, students throughout Michigan spend a week taking the Michigan Educational Assessment Program (MEAP) test. The purpose of the test is to gauge how well students and schools are performing in 5 subject areas – reading, writing, math, science & social studies. The school district can use the results to guide curriculum improvements.

In addition to the content, several other factors influence academic success including teaching style, our health, parental education, family income – and early lead exposure.

Courtesy of Mr. Katzoff.org

Research has linked early lead exposure and high blood lead levels (BLL > 5ug/dl) in children with cognitive impairment, behavioral problems, lower IQ scores, hyperactivity and aggressiveness. However, the association between lead exposure and academic achievement has not been as well studied.

A recent study in the American Journal of Public Health reported an inverse relationship between blood lead levels among children under 6 years (1st grade or lower) and MEAP scores. The researchers obtained blood lead surveillance data for children under 6 years in Detroit and matched their identity to MEAP test results for grades 3, 5 and 8. The researchers found a dose-response relationship between the two variables. Increased BLL was associated with “less than proficient” scores even when controlling for factors such as race, gender, grade level, language, maternal education and SES. (Note: The test scores have 4 levels: advanced, proficient, partially proficient and non proficient). BLLs greater than 10ug/dL at age 6 or under was associated with over twice the probability of scoring “less than proficient” on MEAP tests at grade 3,5 and 8 in comparison to individuals with BLLs less than 1ug/dL

The average BLL among this study group was 7.12ug/dL. This is higher than the CDC reference level of 5ug/dL, which was lowered in 2012 from what was referred to as the blood lead “level of concern”, 10ug/dL. This is a small amount-  a microgram (ug) is a millionth of a gram and a deciliter (dL) is almost half a cup.

Detroit has one of the highest prevalences of elevated BLLs in the US –  4.6% in children, compared to the national average of 1.4%. Among large cities, it has the 4th highest number of childhood lead poisoning cases.

No. of children with BLL of 10ug/dL or greater by zipcode
Courtesy of Michigan.gov

Lead-based paint is one of the main sources of lead exposure in Detroit. Although it was banned in 1978, over 50% of the houses in Detroit were built before 1950. As the paint deteriorates, the lead-based chips and dust fall to the ground, increasing access to young children, who may ingest or inhale the particles.

Other sources of lead exposure in Detroit include food/liquids stored in lead glazed containers, water traveling through old lead pipes and soil. Lead in soil is deposited after being released from industrial plants. In Detroit, exposure through soil and lead dust is a concern for individuals that live near these sites.

Although over 1 million children age 6 and under in the US still have blood lead levels at or above the new CDC standard, overall blood lead levels have been decreasing. In the graph below, you can see the BLL decline in Detroit. Additionally, children under 6 that live in the city of Detroit are required by the Detroit Department of Health and Wellness Promotion (DHWP) to get tested yearly for lead. This is important because it identifies children that may be at risk for the negative health effects of long term lead exposure early on.

Courtesy of Michigan.gov

*The test is now offered online, so this may not apply as much. I feel ancient.

Mary Ellen Anderson March 2, 2013 at 5:53 pm

Achievemnet testing is increasingly a part of the school experience. Having worked in grade schools for 26 years, I know well the factors that influence scores. I also recognise that we have become responsible for “teaching the test.” I have not previously been alerted to the possible effect of lead on test scores. Thank you for your interesting input.

Haifa Haroon March 6, 2013 at 1:40 pm

I’m glad you enjoyed it. Thanks for reading!

Angela March 3, 2013 at 6:15 pm

Hi Haifa! Thanks for the post. I really liked that you made the connection between a general and a local (Detroit) issue and showed some of the sources of lead exposure. I think it might help readers if you move the ug/dL explanation further up, when you first use the ratio.

Haifa Haroon March 6, 2013 at 1:43 pm

I see what you mean – I’ll move it up. Thanks!

Liz Borkowski March 4, 2013 at 9:58 am

Thanks for the clear, concise description of this important study (and nice title)! One thing you might want to add at the end is a brief description of what can be done when a child is identified as having an elevated BLL. The best thing to do is to eliminate the source of exposure (usually lead paint, but sometimes toys or candies that contain lead), and steps like wet-cleaning play areas and washing children’s hands frequently can also help.

Haifa Haroon March 6, 2013 at 1:45 pm

That’s a good point. I think I will add that in. Thanks!

Also – I’m glad you liked the title! :)

Melani April 15, 2013 at 12:45 pm

Jody, if you’re into scenery, I’d reecmmond Cabrillo Nat’l Monument. Very cool lighthouse and nice rugged coastline view. I’d also reecmmond Mount Soledad, which I believe is one of the highest points in the San Diego area and offers an incredible view.One of our favorite places is the Joe’s Crab Shack in the Pacific beach area that’s right on the sand, maybe a hundred feet from the water. Grab a seat by a window (on the 2nd floor) and enjoy the scenery. Yeah, Joe’s isn’t the best chow, but the location is fantastic and the blue slushy drink is yummy!You HAVE to try fish tacos when you’re in So Cal! I’ve been hooked ever since I first tried fish tacos about 10 years back in Carlsbad, just a few miles north of SD.I’m kinda jumping all over the place cuz I really dunno what kind of stuff you’d care to see or do. Give us a bit more to go on and maybe some of us can home in on some more pinpointed suggestions.

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