Potential impact of flowback water from hydraulic fracturing on agricultural soil quality: metal/metalloid bioaccessibility, Microtox bioassay, and enzyme activities
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
Hydraulic fracturing has advanced the development of shale gas extraction, while inadvertent spills of flowback water may pose a risk to the surrounding environment due to its high salt content, metals/metalloids (As, Se, Fe and Sr), and organic additives. This study investigated the potential impact of flowback water on four representative soils from shale gas regions in Northeast China using synthetic flowback solutions. The compositions of the solutions were representative of flowback water arising at different stages after fracturing well establishment. The effects of solution composition of flowback water on soil ecosystem were assessed in terms of metal mobility and bioaccessibility, as well as biological endpoints using Microtox bioassay (Vibrio fischeri) and enzyme activity tests. After one-month artificial aging of the soils with various flowback solutions, the mobility and bioaccessibility of As(V) and Se(VI) decreased as the ionic strength of the flowback solutions increased. The results inferred a stronger binding affinity of As(V) and Se(VI) with the soils. Nevertheless, the soil toxicity to Vibrio fischeri only presented a moderate increase after aging, while dehydrogenase and phosphomonoesterase activities were significantly suppressed with increasing ionic strength of flowback solutions. On the contrary, polyacrylamide in the flowback solutions led to higher dehydrogenase activity. These results indicated that soil enzyme activities were sensitive to the composition of flowback solutions. A preliminary human health risk assessment related to As(V) suggested a low level of cancer risk through exposure via ingestion, while holistic assessment of environmental implications is required.
Date Issued
2016-11-29
Date Acceptance
2016-11-20
Citation
Science of the Total Environment, 2016, 579, pp.1419-1429
ISSN
0048-9697
Publisher
Elsevier
Start Page
1419
End Page
1429
Journal / Book Title
Science of the Total Environment
Volume
579
Copyright Statement
© 2016, Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Identifier
http://www.ncbi.nlm.nih.gov/pubmed/27913018
PII: S0048-9697(16)32594-3
Subjects
Science & Technology
Life Sciences & Biomedicine
Environmental Sciences
Environmental Sciences & Ecology
Fracturing fluids
Metal mobility
Microbial toxicity
Enzyme activity
Soil interaction
SHALE GAS DEVELOPMENT
MARCELLUS SHALE
WASTE-WATER
CONTAMINATED SOIL
VIBRIO-FISCHERI
HEAVY-METALS
EXTRACTION
ADSORPTION
DESORPTION
ARSENATE
MD Multidisciplinary
Publication Status
Published
Coverage Spatial
Netherlands