es6b05179_si_001.pdf (227.55 kB)
Sublethal and Reproductive Effects of Acute and Chronic Exposure to Flowback and Produced Water from Hydraulic Fracturing on the Water Flea Daphnia magna
journal contribution
posted on 2017-01-31, 00:00 authored by Tamzin A. Blewett, Perrine L. M. Delompré, Yuhe He, Erik J. Folkerts, Shannon L. Flynn, Daniel S. Alessi, Greg G. GossHydraulic fracturing is an industrial
process allowing for the
extraction of gas or oil. To fracture the rocks, a proprietary mix
of chemicals is injected under high pressure, which later returns
to the surface as flowback and produced water (FPW). FPW is a complex
chemical mixture consisting of trace metals, organic compounds, and
often, high levels of salts. FPW toxicity to the model freshwater
crustacean Daphnia magna was characterized utilizing
acute (48 h median lethal concentrations; LC50) and chronic
(21 day) exposures. A decrease in reproduction was observed, with
a mean value of 18.5 neonates produced per replicate over a 21 day
chronic exposure to 0.04% FPW, which was a significant decrease from
the average of 64 neonates produced in the controls. The time to first
brood was delayed in the highest FPW (0.04%) treatment. Neonates exhibited
an LC50 of 0.19% of full-strength FPW, making them more
sensitive than adults, which displayed an LC50 value of
0.75%. Quantitative PCR highlighted significant changes in expression
of genes encoding xenobiotic metabolism (cyp4) and
moulting (cut). This study is the first to characterize
chronic FPW toxicity and will help with the development of environmental
monitoring and risk assessment of FPW spills.