Assessment of microplastic-sorbed contaminant bioavailability through analysis of biomarker gene expression in larval zebrafish.
Microplastics (MPs) are prevalent in marine ecosystems. Because toxicants (termed here "co-contaminants") can sorb to MPs, there is potential for MPs to alter co-contaminant bioavailability. Our objective was to demonstrate sorption of two co-contaminants with different physicochemistries [phenanthrene (Phe), log10Kow=4.57; and 17α-ethinylestradiol (EE2), log10Kow=3.67] to MPs; and assess whether co-contaminant bioavailability was increased after MP settlement. Bioavailability was indicated by gene expression in larval zebrafish. Both Phe and EE2 sorbed to MPs, which reduced bioavailability by a maximum of 33% and 48% respectively. Sorption occurred, but was not consistent with predictions based on co-contaminant physicochemistry (Phe having higher log10Kow was expected to have higher sorption). Contaminated MPs settled to the bottom of the exposures did not lead to increased bioavailability of Phe or EE2. Phe was 48% more bioavailable than predicted by a linear sorption model, organism-based measurements therefore contribute unique insight into MP co-contaminant bioavailability.
['Sleight|Victoria A|VA|', 'Bakir|Adil|A|', 'Thompson|Richard C|RC|', 'Henry|Theodore B|TB|']
D000818:Animals D001682:Biological Availability D015415:Biomarkers D004997:Ethinyl Estradiol D015870:Gene Expression D007814:Larva D010616:Phenanthrenes D010969:Plastics D014874:Water Pollutants, Chemical D015027:Zebrafish
Bioavailability Microplastics Sorption Phenanthrene 17α-ethinylestradiol Danio rerio