Fracking fluids were released into Acorn Fork, KY, a designated Outstanding
State Resource Water, and habitat for the threatened Chrosomus cumberlandensis (Blackside
Dace). As a result, stream pH dropped to 5.6 and stream conductivity increased to
35,000 μS/cm, and aquatic invertebrates and fish were killed or distressed. The objective
of this study was to describe post-fracking water quality in Acorn Fork and evaluate if the
changes in water quality could have extirpated Blackside Dace populations. Semotilus
atromaculatus (Creek Chub) and Lepomis cyanellus (Green Sunfish) were collected from
Acorn Fork a month after fracking in lieu of unavailable Blackside Dace. Tissues were histologically
analyzed for indicators of stress and percent of fish with lesions. Fish exposed
to affected Acorn Fork waters showed general signs of stress and had a higher incidence of
gill lesions than unexposed reference fish. Gill lesions observed were consistent with exposure
to low pH and toxic concentrations of heavy metals. Gill uptake of aluminum and iron
was demonstrated at sites with correspondingly high concentrations of these metals. The
abrupt and persistent changes in post-fracking water quality resulted in toxic conditions
that could have been deleterious to Blackside Dace health and survival.
