Autism and the Environment (page 2)

By — Autism Society
Updated on Mar 8, 2010

The Need for Chemical Policy Change

Many public health and environmental groups are citing the danger of combined chemicals in requests for federal chemical policy reform. To address this need, refinements to the Toxic Substances Control Act (TSCA - and the newer Kid Safe Chemical Act are now being drafted for consideration in Congress.

To understand the need for chemical policy change, one must understand how chemicals are now tested. Currently, 60,000 manufacturing chemicals are “grandfathered” and exempt from any testing, while others are tested one at a time, with a “safe” level of human exposure established. The “safe” level is the level of human exposure allowed before that exposure becomes toxic. Chemicals are not tested in combination. They are not restricted if they disrupt our bodies’ signals, like hormones or neurotransmitters, at a level lower than the “safe” level. It is these combined and lower level exposures that are suspect and require investigation.

The complexity extends to neurotoxicology testing. At present, there is no requirement to test chemicals for their impact on the extremely sensitive developing nervous system. Of the approximately 3,000 chemicals produced in the largest volumes, only 20-30 have been tested using the EPA’s developmental neurotoxicology protocol. Because of this, we do not have any information regarding the effects on the developing human body and brain from exposure to most chemicals, particularly those in low doses or in combinations.

Other Possible Environmental Causes

The need is apparent for government, scientific, medical and autism communities to probe further into all possible environmental causes of ASD in a fair and thorough way. Findings may help us approach treatment and prevention more effectively. For example, many studies implicate mercury in autism or in problems that are found in autism. Two studies have shown increased autism with increased airborne mercury (from air pollution). Mercury injures the immune system, causes brain inflammation and affects brain development. Several studies have shown that children with autism have elevated porphyrins, which are a sign of excessive mercury exposure. But other chemicals can also have some of these effects, so even though mercury is clearly harmful, it may be hard to prove that it is a central cause of autism.

Some have focused on chemicals in childhood vaccines as suspected agents in the onset of autism. Serious investigation needs to be done on the impact of vaccines and the chemicals in them, in conjunction with other environmental exposures. The research we need includes, but is not limited to, investigating whether thimerosal- containing vaccines (TCVs), the measles-mumps-rubella (MMR) inoculation and/or a combination of the two play any causal or contributory relationship to autism or susceptibility to autism in the population at large or in vulnerable subgroups. It is important for studies to look for ways that these or other exposures may cause or aggravate harm in combination with other factors even if they are not the sole cause. The more we learn about how people can be different from each other in terms of their vulnerabilities, the more we need to consider how some people can be injured by exposures that might be easily tolerated by others.

In the absence of a cure, improving the physical lives of people with autism now relies on largely bolstering weak pathways with nutrition, rest and stress relief, while removing specific irritants in the body or environment that aggravate symptoms. We need to identify pathways and their solutions in a manner that both addresses the heterogeneity of autism and identifies common workable solutions. Science, participatory research and regulatory reform have much to contribute to this effort in the coming years.

For more information, see Autism and the Environment 101:

For more information on participatory research, see Treatment Guided Research Initiative:

1.  Claudio, L, Kwa, W.C., Russell, A.L., & Wallinga, D. (2000). Testing methods for developmental neurotoxicity of environmental chemicals. Toxicol Appl Pharmacol, 164(1):1-14.

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