Two professors studying the presence and impact of two toxic chemicals found in and around Onondaga Lake say more testing needs to be done to determine the concentrations on Murphy’s Island, where the county plans to extend a recreation trail. So far, research indicates a relatively low risk if the contaminants are beneath the surface.
The chemicals called PXE and PTE were first discovered almost accidentally in the 1990’s. SUNY ESF Chemistry Professor John Hassett says they found the unidentified compounds had the same carbon backbone as DDT, had never been produced commercially. Then a hypothesis hit them. Could it be a byproduct of Solvay Process from the late 1800’s?
"Where they were coking coal and using it to get chemical byproducts. One of these was called coal tar light oil. In the processing and refining that light oil, they catalyzed a reaction that formed these compounds."
But Hassett says they knew nothing about the chemical’s toxicology. Enter Syracuse University biology and neuroscience professor Kate Lewis, who found exposing zebra fish eggs to the chemicals made them susceptible to seizures as adults. Associate Professor Jim Hewett performed similar tests in utero on mice, with comparable results into adulthood.
"Everything was fine with them. They didn't show any signs of toxicity. But when we tested their response to a convulsive agent as a model to mimic seizures associated with epilepsy, we found these animals were much more susceptible to convulsions."
Hewett says neuroscientists are keenly interested in the consequences of early exposure to compounds and effects on disease susceptibility later in life…something that’s hard to prove.
So what might this all mean for extending the loop the lake trail on Murphy’s Island? Both professors say more testing is needed because levels of contamination are not entirely clear. Hassett at ESF says the chemicals can’t be within reach.
"If it's fairly light and it's not close to the surface, then fencing it off, 'stay on the trail' notices might be OK. If you had stuff that's at or near the surface that could potentially vaporize, or if someone got their shoes in it, then you might have a problem."
Hewett at SU agrees exposure and risk should be low if people stay on the trail. But his main concern lies with the fish…
"Even though there is very low detectable chemicals in the water, fish accumulate the toxin. By order of magnitude, hundreds of thousands of times higher levels of contaminants are found in the tissue of fish than in the lake itself."
The state department of health and the county say women of childbearing age and children under 15 should not eat fish caught in Onondaga Lake.