Tuesday, April 21, 2009

The CDC needs to get the lead out

The CDC needs to do learn to do their job better, at least according to story that appeared on salon.com earlier this month entitled "Health agency covered up lead harm". The controversy this time has to do with how the CDC investigated and reported on the high lead levels that were found in the water supply of Washington D.C.

In March of 2003 the DC Water and Sewer Authority expanded some of the required lead-in-water testing to homes with lead service pipes that had not been tested before. What they found was that the majority of these tests turned up lead levels that exceeded the EPA's limit of 15 parts per billion (ppb) and in some small number (~3%) of cases the lead concentrations were greater than 300 ppb. So the Water Authority turned to the CDC for assistance.

The CDC studies the problem and releases a report that basically says that there is no problem. The lead in the water might have contributed to a small increase of blood lead levels but the levels seen wouldn't be a problem.

The CDC publishes the results of the report and closes the case. The results of this study are used by other municipalities to justify not responding aggressively to high lead levels in their water.

But of course, there wouldn't be a problem here if that was all there was to the story. Anyone familiar with the autism world should be able to see what comes next.

It appears that the report that the CDC issued had some problems.

First, a large chunk of data from the final study year (2003) was silently dropped from the report. And while the CDC acknowledges that the data is missing they still stand by the conclusions of the study because the large amount of missing data would not have changed the results.

Second, and more importantly, it seems to be that the conclusions of the study were wrong. Outside researchers kept looking at the problem after the initial report and found evidence that contradicted the CDC's finding.

This scrutiny prompted the CDC to take another look at the issue and by 2007 the CDC had completed another study. This new study looked specifically at the blood level of children in Washington D.C. who were exposed to lead from lead service pipes. What was found was a strong relationship between children with lead poisoning ( blood lead level > 10 ug/dL) and living in homes that had lead service pipes.

Or in other words the first report was wrong and the level of lead in the water supply was giving children lead poison

Being a responsible government agency you would think that they would make a big deal about the new findings and get the word out that there was a problem with the earlier results. You would think that they would take aggressive steps to address the problem.

You would be wrong. The CDC basically buried the results of the second study -
CDC scientists and press representatives did not respond to requests for an explanation about why the results were not widely publicized. George Hawkins, director of the District Department of the Environment, in Washington, says he became aware of the 2007 study only on April 2 this year, when Salon showed him an abstract of the study. Scientists from other agencies, including EPA and HUD, also say they were never told about the results. "CDC never told us," says an EPA scientist, "and they never asked our help or any other water expert's help when they did their studies..."
This is the same government agency that plays a leading role in the the autism world. I can only hope that they do a better job in that field.

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