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.
| Original language | English |
|---|---|
| Pages (from-to) | 1419-1426 |
| Number of pages | 8 |
| Journal | Science of the Total Environment |
| Volume | 579 |
| DOIs | |
| Publication status | Published - 2017 Feb 1 |
| Externally published | Yes |
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Keywords
- Enzyme activity
- Fracturing fluids
- Metal mobility
- Microbial toxicity
- Soil interaction
ASJC Scopus subject areas
- Environmental Engineering
- Environmental Chemistry
- Waste Management and Disposal
- Pollution
Cite this
Potential impact of flowback water from hydraulic fracturing on agricultural soil quality : Metal/metalloid bioaccessibility, Microtox bioassay, and enzyme activities. / Chen, Season S.; Sun, Yuqing; Tsang, Daniel C.W.; Graham, Nigel J.D.; Ok, Yong Sik; Feng, Yujie; Li, Xiang Dong.
In: Science of the Total Environment, Vol. 579, 01.02.2017, p. 1419-1426.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Potential impact of flowback water from hydraulic fracturing on agricultural soil quality
T2 - Metal/metalloid bioaccessibility, Microtox bioassay, and enzyme activities
AU - Chen, Season S.
AU - Sun, Yuqing
AU - Tsang, Daniel C.W.
AU - Graham, Nigel J.D.
AU - Ok, Yong Sik
AU - Feng, Yujie
AU - Li, Xiang Dong
PY - 2017/2/1
Y1 - 2017/2/1
N2 - 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.
AB - 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.
KW - Enzyme activity
KW - Fracturing fluids
KW - Metal mobility
KW - Microbial toxicity
KW - Soil interaction
UR - http://www.scopus.com/inward/record.url?scp=85007312025&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85007312025&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2016.11.141
DO - 10.1016/j.scitotenv.2016.11.141
M3 - Article
C2 - 27913018
AN - SCOPUS:85007312025
VL - 579
SP - 1419
EP - 1426
JO - Science of the Total Environment
JF - Science of the Total Environment
SN - 0048-9697
ER -