How to Adapt Chemical Risk Assessment for Unconventional Hydrocarbon Extraction Related to the Water System

Abstract

We identify uncertainties and knowledge gaps of chemical risk assessment related to unconventional drillings and propose adaptations. We discuss how chemical risk assessment in the context of unconventional oil and gas (UO&G) activities differs from conventional chemical risk assessment and the implications for existing legislation. A UO&G suspect list of 1,386 chemicals that might be expected in the UO&G water samples was prepared which can be used for LC-HRMS suspect screening. We actualize information on reported concentrations in UO&G-related water. Most information relates to shale gas operations, followed by coal-bed methane, while only little is available for tight gas and conventional gas. The limited research on conventional oil and gas recovery hampers comparison whether risks related to unconventional activities are in fact higher than those related to conventional activities. No study analyzed the whole cycle from fracturing fluid, flowback and produced water, and surface water and groundwater. Generally target screening has been used, probably missing contaminants of concern. Almost half of the organic compounds analyzed in surface water and groundwater exceed TTC values, so further risk assessment is needed, and risks cannot be waived. No specific exposure scenarios toward groundwater aquifers exist for UO&G-related activities. Human errors in various stages of the life cycle of UO&G production play an important role in the exposure. Neither at the international level nor at the US federal and the EU levels, specific regulations for UO&G-related activities are in place to protect environmental and human health. UO&G activities are mostly regulated through general environmental, spatial planning, and mining legislation.

The NORMAN Suspect List Exchange (NORMAN-SLE): facilitating European and worldwide collaboration on suspect screening in high resolution mass spectrometry

“…Updates have been suggested for S17 KEMIMARKET [68], S28 EUBIOCIDES [196] with information from ECHA [273], S34 EXPOSOMEXPL [165,166] with new data from [274] plus new microbial metabolites [275,276] and S75 CyanoMetDB [118,119] (next release due early 2023). Suggestions for new contributions include a list of endocrine disruptors within the activities of PARC, the Proposition 65 (Prop-65) list of chemicals from the California EPA [277], Phenol-Explorer [278][279][280], the Database on Migrating and Extractable Food Contact Chemicals (FCCmigex) [281], and finally a shale gas suspect list [282] that has been applied in other studies: [283,284] and will fill a long-identified gap with respect to fracking-related content.…”

Social Vulnerability and Groundwater Vulnerability to Contamination From Unconventional Hydrocarbon Extraction in the Appalachian Basin

“…For every model in the ensemble, we simulated contamination events by releasing particles at UOG source locations (well pads) and tracking the pathways where the contaminants were transported by groundwater flow. The approach focuses on contaminant release mechanisms at well pads as these have been demonstrated to be the most likely pathway for environmental release of UOG contaminants and does not account for possible mechanisms away from well pads that have lower probabilities, such as roadside truck spills (Faber et al., 2019 ; Rozell & Reaven, 2012 ; Shanafield et al., 2019 ). GWV, defined as the likelihood for contaminants from UOG to reach specified locations in the domain, was calculated for each grid cell as the proportion of models in the ensemble where particle tracks intersected that grid cell.…”

An integrative method for identification and prioritization of constituents of concern in produced water from onshore oil and gas extraction

“…Practices that intentionally discharge produced water to the environment have the potential to increase risks to human health and the environment by introducing a new exposure pathway to an understudied wastewater ( Faber et al, 2019 ). To date, the majority of studies on chemical hazards associated with onshore produced water have focused on hydraulic fracturing chemicals used in the stimulation process rather than the produced water generated by it and other development practices ( Colborn et al, 2011 ; Elsner and Hoelzer, 2016 ; Gordalla et al, 2013 ; Rogers et al, 2015 ; Yost et al, 2016a , 2017 ).…”