A joint study from the U.S. Geological Survey and the U.S. Fish and Wildlife Service released Wednesday found that a fracking fluid spill in Kentucky in 2007 likely caused the widespread death of several types of fish.
Nami Resources Company, a London, Ky.-based oil and gas exploration company, spilled fracking fluid from four well sites into the Acorn Fork Creek in southeastern Kentucky in May and June 2007. Not long after, nearly all the aquatic life -- including at least two fish from a threatened species -- in the part of the stream near the spill died. Chemicals released during the spill included hydrochloric acid.
After studying samples of the water and bodies of green sunfish and creek chub, government researchers have concluded that the spill acidified the stream and increased concentrations of heavy metals including aluminum and iron. Fish exposed to the water developed gill lesions and showed signs of liver and spleen damage, USGS announced in a press release.
The gill lesions were consistent with "toxic concentrations of heavy metals," the researchers concluded.
The stream is also home to the blackside dace (Chrosomus cumberlandensis), a small fish in the minnow and carp family which has been listed as threatened species since 1987. Papoulias and Velasco said they weren't able to gather any samples of the blackside dace, but they believe the impacts on the other fish suggest the threatened species was also negatively impacted by the spill. Two dead blackside dace were found downstream of Nami's well immediately following the spill.
Fracking fluid, a mixture of water, sand and chemicals, is pumped underground at high pressure to stimulate the release of oil or natural gas through a drilled well. Energy companies have fought against the disclosure of chemicals used during fracking, but several states now require it.
Nami Resources pleaded guilty to charges that it violated the Clean Water and Endangered Species Acts in the spill and paid a $50,000 fine in October 2009, but blamed the incident on "independent contractors" who were not under the company's direct supervision.
"Our study is a precautionary tale of how entire populations could be put at risk even with small-scale fluid spills," said USGS scientist and lead author Diana Papoulias in the release.
"These species use the same water as we do, so it is just as important to keep our waters clean for people and for wildlife," co-author Tony Velasco said. "This is an example of how the smallest creatures can act as a canary in a coal mine."
The study appears in a special 2013 issue of the peer-reviewed journal Southeastern Naturalist.