Determining the Temperature Dependency of Biodegradation Kinetics for 34 Hydrocarbons while Avoiding Chemical and Microbial Confounding Factors

Biodegradation kinetics data are keystone for evaluating the environmental persistence and risk of chemicals. Biodegradation kinetics depend highly on the prevailing temperature, which influences microbial community structures, metabolic rates, and chemical availability. There is a lack of high-qual...

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Bibliographic Details
Published in:Environmental science & technology 2021-08, Vol.55 (16), p.11091-11101
Main Authors: Knudsmark Sjøholm, Karina, Birch, Heidi, Hammershøj, Rikke, Saunders, David M. V., Dechesne, Arnaud, Loibner, Andreas P., Mayer, Philipp
Format: Article
Language:English
Subjects:
Availability
Biodegradation
Chemicals
Confounding (Statistics)
Contaminants in Aquatic and Terrestrial Environments
Depletion
Hydrocarbons
Inoculum
Isomers
Kinetics
Metabolic rate
Microorganisms
Rivers
Substrates
Temperature
Temperature dependence
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Summary:Biodegradation kinetics data are keystone for evaluating the environmental persistence and risk of chemicals. Biodegradation kinetics depend highly on the prevailing temperature, which influences microbial community structures, metabolic rates, and chemical availability. There is a lack of high-quality comparative biodegradation kinetics data that are determined at different test temperatures but with the same microbial inoculum and chemical availability. The present study was designed to determine the effect of test temperature on the biodegradation kinetics of hydrocarbons while avoiding confounding factors. We used inocula from a Northern river (2.7 °C) and a Central European river (12.5 °C). Aqueous stock solutions containing 45 individual hydrocarbons were generated by passive dosing and added to river water containing the native microorganisms. Compound-specific biodegradation kinetics were then determined at 2.7, 12, and 20 °C based on substrate depletion. Main findings comprise the following: (1) Degradation half-times (DegT50) of 34 test chemicals were determined at different test temperatures and were largely consistent with the Arrhenius equation (activation energy, 65.4 kJ/mol). (2) Differences in biodegradation kinetics between tested isomers were rather limited. (3) The recent lowering of standard test temperature from 20 to 12 °C results typically in a doubling of DegT50 values and can lead to a stricter persistency assessment.
ISSN:0013-936X
1520-5851
DOI:10.1021/acs.est.1c02773