Alarming Levels of Mercury in the North West & Possible Link to Autism
October 17, 2016
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An article in EcoWatch by Robert F. Kennedy Jr. and Lyn Redwood, reveals a team of scientists led by the U.S Geological Survey (USGS) released a comprehensive report showing widespread mercury contamination across western North America. The report, based on decades of mercury data and research, found alarming levels of mercury and methylmercury in the forests, fishes, wildlife, plants and waterways of America’s western landscapes.
Among the many disturbing findings are shocking accumulations of mercury in densely forested areas such as those found along the Pacific mountain ranges of California and Oregon. The scientific team showed that these critical ecosystems collect dangerous mercury loads because they receive high amounts of precipitation. Rainfall washes mercury from the atmosphere onto wet forested regions where it binds to the vegetation and accumulates in the soils and surface waters. From these vectors it can bioaccumulate in fish, including salmon.
An earlier study in 2002 reported that industrial emissions in Asia are a major source of mercury in rainwater falling along the California coast. The new USGS study describes the precise atmospheric transport mechanisms that carry massive mercury contamination from Asia and deposit the potent neurotoxin in the water, soils and biota across America’s West Coast.
The USGS study sheds light on earlier research with human health implications. A 2008 study reported children living in areas of high precipitation may be more likely to have autism. Those investigators looked at rainfall in California, Washington and Oregon. That team obtained autism prevalence rates for children born in those three states between 1987 and 1999 and calculated average annual precipitation by county from 1987 to 2001. The researchers also computed the autism rates in relation to the average annual precipitation in the counties when the children were younger than 3 years old.
Those scientists found that counties that received relatively large amounts of precipitation had a relatively high rate of autism. More specifically, counties in Oregon and Washington west of the Cascades receive four times as much precipitation as counties east of the Cascades, and had an autism rate that was twice as high. These are the same states that were identified in the USGS’s comprehensive report demonstrating the relationship between mercury deposition and precipitation.
“Women who were exposed to the highest levels of diesel or mercury in the air were twice as likely to have a child with autism than women who lived in the cleanest parts of the sample,” according to the study author Andrea Roberts, a research associate with the Harvard School of Public Health.