Aryl hydrocarbon receptor-mediated potencies in field-deployed plastics vary by type of polymer

Christine Schönlau,John P Giesy,Anna Kärrman,Magnus Engwall,Monika M Lam,Chelsea Rochman,Maria Larsson

doi:10.1007/s11356-019-04281-4

Abstract

Plastic is able to sorb environmental pollutants from ambient water and might act as a vector for these pollutants to marine organisms. The potential toxicological effects of plastic-sorbed pollutants in marine organisms have not been thoroughly assessed. In this study, organic extracts from four types of plastic deployed for 9 or 12 months in San Diego Bay, California, were examined for their potential to activate the aryl hydrocarbon receptor (AhR) pathway by use of the H4IIE-luc assay. Polycyclic aromatic hydrocarbons (PAH), including the 16 priority PAHs, were quantified. The AhR-mediated potency in the deployed plastic samples, calculated as bio-TEQ values, ranged from 2.7 pg/g in polyethylene terephthalate (PET) to 277 pg/g in low-density polyethylene (LDPE). Concentrations of the sum of 24 PAHs in the deployed samples ranged from 4.6 to 1068 ng/g. By use of relative potency factors (REP), a potency balance between the biological effect (bio-TEQs) and the targeted PAHs (chem-TEQs) was calculated to 24–170%. The study reports, for the first time, in vitro AhR-mediated potencies for different deployed plastics, of which LDPE elicited the greatest concentration of bio-TEQs followed by polypropylene (PP), PET, and polyvinylchloride (PVC).

Highlights

In the early 1970s, plastic particles were detected in marine systems for the first time (Carpenter and Smith 1972)
Quantification of 42 polycyclic aromatic compounds, including Polycyclic aromatic hydrocarbons (PAH), oxy-PAHs, and azaarenes, was performed by use of an Agilent 7890A gas chromatograph, coupled to a 5975C, low-resolution mass spectrometer (GC/LRMS), which was equipped with a ZB-SemiVolatiles column (30 m × 0.25 mm, 0.25 μm film thickness; Phenomenex)
The results of this study present experimental evidence to corroborate the hypothesis by Rochman et al (2013) that PE plastics might pose a greater toxicological risk compared to PP, polyethylene terephthalate (PET), and PVC

Summary

Introduction

In the early 1970s, plastic particles were detected in marine systems for the first time (Carpenter and Smith 1972). While the mere physical threat such as entanglement, strangulation, and abrasion that plastic can pose to organisms is obvious, it has been hypothesized that plastics hold a toxicological risk due to the transfer of pollutants when the particles are ingested (Teuten et al 2007; Teuten et al 2009). There is mounting evidence for the presence of Environ Sci Pollut Res (2019) 26:9079–9088 plastic particles in higher trophic level organisms (CBD 2016) as well as in commercially important fish and shellfish species (Romeo et al 2015; Van Cauwenberghe and Janssen 2014). Besides a possible bioaccumulation of contaminants due to ingested plastics (Teuten et al 2009), there might be a potential for biomagnification of contaminants throughout the food chain. The TTF is defined as the concentration of contaminant in consumer tissue divided by the concentration of the contaminant in food (Suedel et al 1994)

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