90 When Oil and Water Mix: Understanding the Environmental Impacts of Shale Development I

Monday, 26 September 2016
8:00 AM - 12:00 PM
Mile High Ballroom 2A/3A

UNCONVENTIONAL OIL AND GAS (UOG) WASTEWATER SPILLS: PERSISTENCE OF CONTAMINANTS AND ENVIRONMENTAL HEALTH IMPLICATIONS

Paper number: 90-7
Program: Technical Sessions
Time: 9:55 AM – 10:15 AM

Authors

Abstract

UOG wastewaters that contain toxic and radioactive elements from geologic formations, or chemical additives from production, pose largely unknown impacts to water resources, aquatic ecosystems, and human health. In North Dakota alone, over 8,000 recorded spills from 2008-2015 included over 20-mill gal of waste fluids. As part of a national study of the impacts of UOG activities, USGS researchers are conducting interdisciplinary studies in regions of active UOG development, including the Williston Basin, ND. In Jan. 2015 an estimated 3 mill gal of wastewater brine (TDS 138 g/L) from UOG production spilled into Blacktail Creek, a tributary of the Missouri River.

Water and sediment samples were collected, and in situ bioassays were conducted, along a 44 km reach between the spill and the Missouri River in Feb and June 2015 and June 2016, to assess potential impacts from the spill. Wastewater in the ruptured pipeline contained 16.2 mg/L Ba and > 1,000 mg/L Sr. Samples collected in June 2015, indicate presence of UOG-wastewater markers and biological impacts in the river. These results document the persistence of geochemical alterations six months post spill. Fish bioassays conducted in June, 2015, demonstrated 97.5% mortality at 7.1 km downstream from the spill.

Alterations in sediment microbial communities downstream from the spill were observed in February 2015. Labile Ba and Sr concentrations extracted from sediments collected in June 2015 were higher downstream from the spill site than upstream. Radium concentrations in sediment downstream from the spill site (approx. 10 dpm/g) were up to 5 times the background concentrations. Ra and Sr isotope ratios in sediment downstream from the spill site resemble the radiogenic signatures from the pipeline and support the conclusion that elevated Ra and Sr concentrations reflect input from the spilled wastewater brine.

Experiments with an aquatic model invertebrate, the freshwater snail Lymnaea stagnalis, showed aqueous Ba is bioavailable and thus will bioaccumulate. Ba has deleterious effects on aquatic organisms and humans and a similar reactivity to Ra, providing insight into Ra pathways through the food chain. Partitioning of elements from the wastewater spill onto sediment limits aqueous transport but could provide a long-term source to aquatic ecosystems.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-283704

© Copyright 2016 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.