Water is used in petroleum oil refineries in significant volumes for cooling, steam generation and processing of raw materials. Effective water management is required at refineries to ensure their efficient and responsible operation with respect to the water environment. However, ascertaining the potential environmental risks associated with discharge of refinery effluents to receiving waters is challenging because of their compositional complexity. Recent European research and regulatory initiatives propose a more holistic approach including biological effect methods to assess complex effluents and surface water quality. The study presented here investigated potential effects of effluent composition, particularly hydrocarbons, on aquatic toxicity and was a component of a larger study assessing contaminant removal during refinery wastewater treatment (Hjort et al 2021). The evaluation of effects utilised a novel combination of mechanistic toxicity modelling based on the exposure composition, measured bioavailable hydrocarbons using biomimetic solid phase microextraction (BE-SPME), and bioassays. The results indicate that in the refinery effluent assessments measured bioavailable hydrocarbons using BE-SPME was correlated with the responses in standard bioassays. It confirms that bioassays are providing relevant data and that BE-SPME measurement, combined with knowledge of other known non-hydrocarbon toxic constituents, provide key tools for toxicity identification. Overall, the results indicate that oil refinery effluents treated in accordance to the EU Industrial Emissions Directive requirements have low to negligible toxicity to aquatic organisms and their receiving environments. Low-cost, animal-free BE-SPME represents a compelling tool for rapid effluent characterization.
Bibliographical noteFunding Information:
The authors declare no conflicts of interests. The costs of undertaking and reporting this research were funded by Concawe. We want to acknowledge the participating refineries and all the people who provided information on the wastewater treatment process and the collection of the samples, as the study would not have been possible without their cooperation. We acknowledge in particular Mike Spence (Concawe) for setting up the refinery contacts, preparation of the questionnaire used in sample collection, and discussions on the projects. We would like to thank Eleni Vaiopoulou (Concawe) for her critical review and comments as well as the members of Concawe STF32 and Concawe STF34 for the stimulating discussions, support and information. We also like to acknowledge Jacco Koekkoek, Martin van Velzen, Gerda Hopman, and Peter Cenijn of VU Amsterdam who performed the chemical and zebrafish analysis. Rineke Keijzers from Ecofide is acknowledged for the toxicity testing.
© 2021 The Authors
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- Effect based methods
- Petroleum hydrocarbons