PA Environment Digest

The Academy of Natural Sciences in Philadelphia is calling for a comprehensive research plan that would result in guidelines and an assessment tool for regulators and managers in order to minimize the environmental impact of Marcellus Shale gas drilling.

"At this time, there is very little information available as to the impacts of long-term exposure of a watershed to Marcellus Shale drilling activities," said Dr. David Velinsky, vice president of the Academy's Patrick Center for Environmental Research. "Nor do we know if there is a cumulative impact of drilling activity on the ecosystem services of a small watershed."

Preliminary research by Academy scientists and a University of Pennsylvania graduate student shows the environmental impact of drilling may be directly related to the amount of drilling in a specific area, referred to as the "density" of drilling.

"The question that needs to be addressed is whether there is a threshold point past which a certain amount of drilling activity has an impact on the ecological health and services of the watershed -- regardless of how carefully drilling is conducted," Velinsky said.

In the preliminary research conducted this summer, scientists examined small watersheds in northeastern Pennsylvania -- three in which there had been no drilling, three with some drilling and three with a high density of drilling. At each site, they tested the water, abundance of certain sensitive insects, and abundance of salamanders. The presence of salamanders is particularly important because amphibians are especially vulnerable to changes in the environment.

For each of the measures, there was a significant difference between high-density drilling locations and locations with no drilling or less drilling. The studies showed that water conductivity (which indicates the level of contamination) was almost twice as high in the high density sites as the other sites, and the number of both sensitive insects and salamanders were reduced by 25 percent.

"This suggests there is indeed a threshold at which drilling -- regardless of how it is practiced -- will have a significant impact on an ecosystem," Velinsky said. "Conversely, it also suggests there may be lower densities of drilling at which ecological impact cannot be detected."

Velinsky stressed that the data is preliminary and that a larger, more comprehensive study must be done before definitive conclusions can be drawn. The Academy has applied to the Department of Environmental Protection to fund such a study.

Visit the Academy's Marcellus Shale webpage for more information.

NewsClips: Academy Of Natural Sciences: Drilling Threatens Streams

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