CIB study: Burton Island coal ash offers minimal threat
Scientists say effects on sea life should be monitored
A recently released report shows sea life near an Indian River coal ash disposal site has acceptable levels of potentially toxic metals.
“We were pleasantly surprised when the results came in,” said Bart Wilson, scientist with the CIB.
The CIB paid a Smithsonian scientist $15,000 to analyze small fish and mussels to determine the concentration of metals including mercury, arsenic and selenium found in mussels and small fish called mummichugs that live near the Burton Island coal ash disposal site. The commissioned report followed a study of potential metal contamination in the area that did not include studying how the metals affect the food chain.
“There was a gap. We were responding to citizen concern,” Wilson said.
The CIB study tested 10 sites – five on Island Creek, a tributary that flows along the south shore of Burton Island and enters Indian River near its mouth at Indian River Bay. Five other sites along Pepper Creek served as comparison sites.
In addition to mercury, arsenic and selenium, the study tested for cadmium, copper, chromium, nickel, lead, thallium and zinc.
The results of the analyses suggested no difference in concentration between the two sampling areas for most of the elements in the study, Wilson said.
In the mussels sampled, there was a difference in levels between the two sites for both arsenic and selenium; in the mummichugs, only selenium had a significant difference in concentrations, Wilson said.
While selenium and arsenic levels near Burton Island were higher than along the Pepper Creek site, Wilson said, the levels were still below what the CIB had expected and below minimum allowable levels set by the Food and Drug Administration.
Other studies of Delaware waters have had similar results.
Bivalves tested for metals at other Delaware locations were statistically the same as the Burton Island results, according to a study by the National Oceanic and Atmospheric Administration.
Likewise, in a previous Department of Natural Resources and Environmental Control study that researched the effects of selenium to aquatic life living near Burton Island, scientist Rick Greene notes the concentrations of selenium in mummichugs and mussels are “well below the ecological risk threshold for selenium exposure and well below a concentration expected to cause reproductive effects in these species.”
In summary, Wilson said the latest study found selenium concentrations in upper Indian River, including along Burton Island, pose no significant ecological or human health risk. The higher levels of arsenic in the ribbed mussel samples of Island Creek are results that should be monitored in the future, he said, but at this time are well below the Food and Drug Administration action level for total arsenic in clams, oysters, and mussels.
Still, the study offers a benchmark for the CIB or other groups to use when evaluating the effects of toxins on aquatic life in the future. Sea level rise or changes in the rate of groundwater movement could change conditions near the Burton Island coal ash disposal site, Wilson said.
“It is recommended that tissue and sediment samples are periodically analyzed to evaluate changes in the prevalence and concentration of elements,” he said.
for full article click here