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Does Kevin Drum's article Raw Data: Lead Poisoning of Kids in Flint describes the lead levels in Flint accurately?

What you see is very steady and impressive progress from 1998 to 2013, with the number of children showing elevated blood lead levels (above 5 micrograms per deciliter) declining from approximately 50 percent to 3.6 percent.

Then Flint stopped using Detroit water and switched to Flint River water, which corroded the scale on their lead pipes and allowed lead to leach into the water. The number of children with elevated lead levels rose to 5.1 percent and then 6.4 percent.

Are the numbers Kevin Drum cites accurate and in line with the numbers the critics cite?

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From 1976-1980, 86% of US children 6 months to 5 years old had lead levels over 10 micrograms per dL. cdc.gov/nchs/data/ad/ad079acc.pdf – DavePhD Mar 8 at 20:32
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When talking about lead poisoning, you need to make sure you're comparing apples to apples. The threshold defined as "lead poisoning" has been lowered repeatedly over the years, so the only valid comparison is actual blood lead levels -- "percent of individuals with lead poisoning" will give invalid results. – Mark Mar 8 at 20:49
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The huge drop from @DavePhD's business as usual numbers from 40 years ago to the current crisis level in Flint show how well the phasing out leaded gasoline (which started in the mid 1970s with the final ban for on road vehicles in 1996) and leaded paint (1978) have had a huge impact. – Dan Neely Mar 8 at 21:16
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It's also worth noting that lead poisoning is only one of many widespread health problems that have been identified in Flint and blamed on the contaminated water. It's the one everyone's focusing on, but by no means the only one. – Mason Wheeler Mar 8 at 22:16
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@nocomprende It doesn't appear to me that the goalposts have been moved. The expectation wasn't a certain rate of lead poisoning, but rather that that rate continues to decrease, that the problem should be getting fixed. Now it's increasing instead, and even though it's lower than it was at some arbitrary point in the past, it's still trending in the wrong direction, getting worse rather than better. – Mason Wheeler Mar 9 at 11:55
up vote 24 down vote accepted

His data are approximately correct. He gives all the sources and assumptions at the bottom of the article as well as a spread sheet with all the data.

Compare his data to Preliminary state data shows drop in rate of elevated lead levels in Flint

In the third quarter of 2010, 8.3 percent of Flint children 6 and younger showed elevated blood lead levels.

The figure decreased to 4.1 percent in the third quarter of 2013.

During the same months in 2014, the figure increased to 7.5 percent and decreased to 6.4 percent in the third quarter of 2015.

3 percent of children children younger than 6 years old and tested since Oct. 1 have had blood lead levels above the federal threshold for lead.

where "elevated" means above 5 micrograms/dL

and to Elevated Blood Lead Levels (EBLL) in Michigan 1998 - 2008 Children less than Six Years of Age, which only shows higher concentration levels.

So in 1998 9.7% of Michigan children under 6 had at least 10 micrograms/dL of lead, whereas at the worst quarter of the current lead problem 7.5% of Flint children had at least 5 micrograms/dL of lead.

Also, in 2005, 16.2% of Flint children under 6 had lead levels over 5 micrograms/dL according to the Michigan Childhood Lead Poisoning Prevention Program 2005 Data Report at page 55 , so even just one decade ago lead levels were more than double that of the peak of the recent lead-level spike in Flint.

Edit: A really good source is Table 1. Incidence of elevated blood lead levels (≥ 5 mcg/dL) among children less than 6 years of age, 2010 – 2016 which includes annual data for each year 2010-2015 for Michigan, Genessee county and specifically for Flint.

The Flint Blood Lead Level data are:

2010: 6.3%

2011: 5.8%

2012: 4.1%

2013: 3.1%

2014: 3.9%

2015: 3.3%

So 2013 was the only year that had a lower level (nominally without considering uncertainty) than the "crisis" year(s).

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Perhaps this is veering out of scope of the question asked here, but I think it's within the spirit: is there a reason that the only data presented are for 6 years and under? While the chart does specify the age group, it is not mentioned anywhere in the prose. – Josh Caswell Mar 8 at 20:50
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@JoshCaswell "Children under the age of 6 are especially vulnerable to lead poisoning" mayoclinic.org/diseases-conditions/lead-poisoning/basics/… – DavePhD Mar 8 at 20:55
    
I see, so those are the people who are most affected and thus under discussion? It's part of the context of the conversation. – Josh Caswell Mar 8 at 20:57
    
@JoshCaswell: Those are probably also the people who we have data for ... I believe doctors perform blood tests for lead on children 6 and other as a part of their regular checkups, but not on older children. – Peter Shor Mar 14 at 2:30
    
@PeterShor here is an older study on 203,554 people ranging from age 6 months to 74 years. cdc.gov/nchs/data/ad/ad079acc.pdf The ones under age 6 years have a higher blood lead level than the other ages (my guess from eating paint chips). But I agree, now it is mostly young children who are tested, because they are the most vulnerable. – DavePhD Mar 14 at 10:36

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