Presence of polycyclic aromatic compounds in river sediment and surrounding soil: Possible impact from shale gas wastewater.

Shale gas has been extensively extracted in the Sichuan Basin in China in recent years. To gain insight into the potential impact of shale gas wastewater (SGW) discharge, sediment in a small river receiving treated SGW, as well as cultivated soil and paddy soil irrigated by the river water were collected. The occurrence and distribution of polycyclic aromatic compounds (PACs), including polycyclic aromatic hydrocarbons (PAHs) and their alkylated/oxygenated derivatives (APAHs/OPAHs), and thiophenes were investigated, the resultant potential ecological risks were assessed subsequently. The total concentration of PACs varied in the range of 1299.9-9286.4, 2069.4-11,512.3, and 475.7-2927.9 ng/g in sediment, cultivated soil and paddy soil, respectively, with thiophenes followed by APAHs being the abundant components in all the studied samples, demonstrating the potential impact of SGW discharge on sediment and surrounding soil environment. Based on the measured concentrations, potential ecological risks posed by PAHs and APAHs were calculated, and moderate to high ecological risks were observed in partial sampling sites, which mainly caused by 3-4 rings PAHs and APAHs.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier B.V. All rights reserved.)