Door Te bruinen van Leslee Dru | Hoe beïnvloeden de kwikemissies zwangere moeders, ongeboren en toddlers? het niveau van het autismetarieven van het emissieseffect? Is het van belang of een kwik-uitzendende bron 10 mijlen vanaf families tegenover 20 mijlen is? Is het risico groter van autisme voor kinderen die dichter aan de verontreinigingsbron leven?

Een onlangs gepubliceerde studie van de gegevens van het de schooldistrict van Texas en industriële kwik-versie gegevens, die door onderzoekers bij de Universiteit van het Centrum van de Wetenschap van de Gezondheid van Texas bij San Antonio wordt uitgevoerd, toont inderdaad een statistisch significant verband tussen ponden van industriële versie van kwik en verhoogde autismetarieven. Het toont - voor het eerst in wetenschappelijke literatuur - ook een statistisch significante vereniging tussen autisme risico en afstand uit de kwikbron.

„Dit is een definitieve studie, maar geen enkel meer één die de vereniging tussen milieukwik en autisme,“ bovengenoemde hoofdauteur Raymond F. bevordert. Palmer, Ph.D., verwante professor van familie en communautaire geneeskunde op het Centrum San Antonio van de Wetenschap van de Gezondheid UT. Het artikel is in het dagboek Gezondheid & Plaats.

Dr. Palmer, Stephen Blanchard, Ph.D., van Onze Dame van de Universiteit van het Meer in San Antonio en Robert Wood van het Centrum van de Wetenschap van de Gezondheid UT vond dat het communautaire autismeoverwicht door 1 percent aan 2 percenten met elke 10 mijlen van afstand van wordt verminderd verontreiniging bron.

„Deze studie werd niet ontworpen om te begrijpen welke individuen in de bevolking toe te schrijven aan kwikblootstelling,“ Dr. in gevaar zijn. Bovengenoemde Palmer. „Nochtans, over het algemeen stelt het voor dat er groter autismerisico dichter voor de verontreinigende bron.“ is

De studie zou verdere onderzoeken moeten aanmoedigen die worden ontworpen om de veelvoudige routes van kwikblootstelling te bepalen. De „gevolgen van blijvende, laag-dosisblootstelling aan kwik verontreiniging, naast visconsumptie, verdien aandacht,“ Dr. Bovengenoemde Palmer. “Ultimately, we will want to know who in the general population is at greatest risk based on genetic susceptibilities such as subtle deficits in the ability to detoxify heavy metals.”

The new study findings are consistent with a host of other studies that confirm higher amounts of mercury in plants, animals and humans the closer they are to the pollution source. The price on children may be the highest.

“We suspect low-dose exposures to various environmental toxicants, including mercury, that occur during critical windows of neural development among genetically susceptible children may increase the risk for developmental disorders such as autism,” the authors wrote.

Study highlights

* Mercury-release data examined were from 39 coal-fired power plants and 56 industrial facilities in Texas.

* Autism rates examined were from 1,040 Texas school districts.

* For every 1,000 pounds of mercury released by all industrial sources in Texas into the environment in 1998, there was a corresponding 2.6 percent increase in autism rates in the Texas school districts in 2002.

* For every 1,000 pounds of mercury released by Texas power plants in 1998, there was a corresponding 3.7 percent increase in autism rates in Texas school districts in 2002.

* Autism prevalence diminished 1 percent to 2 percent for every 10 miles from the source.

* Mercury exposure through fish consumption is well documented, but very little is known about exposure routes through air and ground water.

* There is evidence that children and other developing organisms are more susceptible to neurobiological effects of mercury.

Implications

“We need to be concerned about global mercury emissions since a substantial proportion of mercury releases are spread around the world by long-range air and ocean currents,” Dr. Palmer said. “Steps for controlling and eliminating mercury pollution on a worldwide basis may be advantageous. This entails greener, non-mercury-polluting technologies.” The U.S. Environmental Protection Agency (EPA) estimated environmental mercury releases at 158 million tons annually nationwide in the late 1990s, the time period studied by the Texas team. Most exposures were said to come from coal-fired utility plants (33 percent of exposures), municipal/medical waste incinerators (29 percent) and commercial/industrial boilers (18 percent). Cement plants also release mercury.

With the enactment of clean air legislation and other measures, mercury deposition into the environment is decreasing slightly.

Limitations

Dr. Palmer and his colleagues pointed out the study did not reflect the true community prevalence rates of autism because children younger than school age are not counted in the Texas Education Agency data system. The 1:500 autism rates in the study are lower than the 1:150 autism rates in recent reports of the U.S. Centers for Disease Control and Prevention.

Furthermore, the authors note that distance was not calculated from individual homes to the pollution source but from central points in school districts that varied widely in area.

Data sources

Data for environmentally released mercury were from the United States Environmental Protection Agency Toxics Release Inventory. Data for releases by coal-fired power plants came from the same inventory and from the Texas Commission for Environmental Quality. Data for school district autism came from the Texas Education Agency.

Journal Reference and Source:

Palmer, R.F., et al., Proximity to point sources of environmental mercury release as a predictor of autism prevalence. Health & Place (2008), doi:10.1016/j.healthplace.2008.02.001.

The University of Texas Health Science Center at San Antonio (2008, April 25) ((http://www.newswise.com/articles/view/5…)

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