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There are better causes to donate to, in my opinion. Pb is nasty stuff, but the purported risks have been inflated beyond what's actually grounded in solid evidence. The term "Pb poisoning" has two different meanings: traditionally it's referred to blood lead levels above about 50 mcg/dL, at which demonstrable symptoms occur (slowed reaction times, etc). But in recent decades, it's also used to describe much lower levels (>15 mcg/dL, >10 mcg/dL, or even >5 mcg/dL), for which the only evidence of harm comes from observational studies. Observational studies establish correlation, not causation, and there are good reasons to doubt that the observed correlations are due to Pb neurotoxicity. The relationship between Pb exposure and cognitive/behavioral outcomes is intractably complicated, because for most children Pb exposure is primarily from dirt/dust ingestion, which in turn correlates with a child's developmental status, household cleanliness, and subtle aspects of parenting behaviors (in addition of course to more widely appreciated factors like age/condition of the home). Poor nutrition also causes higher BLLs. It's been demonstrated that publication bias in the Pb literature has steadily risen over time, as reported effect sizes have increased. Several studies have found Pb correlations which resemble a U curve, where children with the highest blood lead levels have better cognitive/behavioral outcomes than those with intermediate BLLs (because outside the range of BLLs which are primarily driven by dirt/dust ingestion, "something else is going on", which doesn't correlate as well with cognitive/behavioral outcomes). Dirt/dust ingestion (and therefore, BLLs) drop precipitously around age 2, because this is around the time when children outgrow mouthing behavior - some children a bit earlier, some children a bit later. BLL measurements at this age therefore a metric of developmental status. Or alternatively, this is the age at which "lead causes the most harm". My argument is of course not that you should go paint your child's nursery with chrome yellow. Ingesting paint chips can be enough to put a child into the "actual lead poisoning" BLL range (drinking water from lead pipes generally cannot). But excluding exposure from leaded gasoline (which was formerly the dominant source of exposure, but which has fortunately been banned almost everywhere) and people living near smelting facilities, it's probably not the scary ubiquitous IQ-point larcenist that it's made out to be. |