Acute Toxicity Testing of the Tire Rubber-Derived Chemical 6PPD-quinone on Atlantic Salmon (Salmo salar) and Brown Trout (Salmo trutta)

Abstract

Recent identification of 6PPD-quinone as the chemical causing acute toxicity in coho salmon has led to substantial concern regarding the toxicity of this contaminant for other aquatic species. Environmental occurrence of 6PPD-quinone is probably high, because it is an oxidation product of a common tire rubber additive. Research on 6PPD-quinone toxicity in fish has revealed a rather unusual pattern, with closely related species exhibiting responses ranging from extreme sensitivity to no effect. Of 11 previously studied fish species, 6PPD-quinone was toxic to four. The species-specific toxicity of 6PPD-quinone complicates urgently needed environmental risk assessment. We investigated the acute toxicity of 6PPD-quinone in Atlantic salmon and brown trout alevins (sac fry). These species have previously not been tested for sensitivity to 6PPD-quinone. The fish were exposed in static conditions in eight treatments with initial concentrations ranging from 0.095 to 12.16 µg/L. Fish were observed for 48 h, and changes in concentrations of 6PPD-quinone were monitored throughout the experiment. No mortalities or substantial changes in behavior were recorded in either Atlantic salmon or brown trout. This provides an important first step in assessing effects of 6PPD-quinone on these economically and culturally highly important species. Environ Toxicol Chem 2022;41:3041-3045. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Keywords: 6PPD-quinone; 6PPDQ; Salmo; aquatic toxicology; contaminants of emerging concern; ecological risk assessment; runoff; toxic effects.

Figure 1

Boxplot of relative concentration of 6PPD‐quinone in relation to initial concentration (y‐axis) sampled during the experiment (hours after start of experiment, x‐axis). The bottom and top of the box indicate the 25th and 75th percentiles (i.e., the boxes include the middle 50% of observations), the whiskers span to the most extreme data point if more than 1.5 times the interquartile range, and the bold horizontal line represents the median value.

Figure 2

Phylogenetic tree of the fish species that have been tested for 6PPD‐quinone toxicity. Presumed toxicity is indicated for three species; *tested with tire wear particle leachate, **tested with urban roadway runoff. Species names of tolerant species are in black and sensitive species in red (phylogeny from timetree.org).