How does lead in water affect health?
Young children are more sensitive to the effects of lead because they are still developing and able to absorb ingested lead more easily than adults. Long-term exposure to lead above the standards may increase the risk of subtle impairment of learning capacity and intellectual development. Pregnant women need to limit their lead intake as much as possible to protect the fetus.
In the abstract portion of the article the authors noted that "These cases underscore that there are multiple causes of autism and the importance of environmental influences in some cases."
Both of these children emerged from their autism diagnoses (1 autism disorder, 1 PDD-NOS) with the passage of time but with no specialized treatment. Lidsky and Schneider concluded that:
The two case histories presented here, as well as the reports of autistic symptoms in children with disorders that produce brain lesions or encephalopa- thy, indicate that there are multiple causes of autism. Further, the ability of brain infections and lead poisoning to produce such symptoms highlights the importance of environmental factors in the etiology of *autism*.
The ability of *lead* *poisoning* to induce symptoms of *autism* is also relevant to cases of preexisting pervasive developmental disorders irrespective of etiology. Such individuals have a greater propensity to engage in pica and, as a result, are more likely to become *lead* poisoned.
In such cases, *lead* poisoning can be expected not only to negatively impact neurocognitive functioning, but also to potentially exacerbate the preexisting symptoms of *autism*. Indeed, one case report describes a decrease in hyperactivity and stereotypies in an autistic child with a blood *lead* of 42 µg/dL once this level was reduced by chelation with succimer.
No one can credibly claim that autism is purely genetic or purely environmental. The unified autism theory seems to suggest that both types of factors are involved in the development of genetic mutations giving rise to autism. There is much research to be done, and much being done, on all sides in the search to understand what causes autism. We know there are major toxic substances, including mercury and lead, polluting our environment. It would be foolish to ignore them as possible causes of autism. It would also be foolish to pretend that the research on these issues is complete and that any of these toxic substances can be ruled out as causes of autism.