Examination of aryl hydrocarbon receptor (AhR), estrogenic and anti-androgenic activities, and levels of polyaromatic compounds (PACs) in tire granulates using in vitro bioassays and chemical analysis

Eriksson, U. Titaley., A, I. Engwall, M & Larsson, M

Location

ScienceDirect

Abstract

Tire granulates recovered from end-of-life tires contain a complex mixture of chemicals, amongst them polyaromatic compounds (PACs), of which many are recognized to be toxic and persistent in the environment. Only a few of these PACs are regularly monitored. In this study a combined approach of chemical analysis and a battery of CALUX® in vitro bioassays was used to determine PAC concentrations and estrogenic, (anti)-androgenic and aryl hydrocarbon receptor (AhR) activities in tire granulates. Tire granulates from a recycling company was analyzed for PAHs, alkyl-PAHs, oxy-PAHs and heterocyclic PACs (NSO-PACs), in total 85 PACs. The concentrations of PACs were between 42 and 144 mg/kg, with major contribution from PAHs (74–88%) followed by alkyl-PAHs (6.6–20%) and NSO-PACs (1.8–7.0%). The sum of eight priority PAHs were between 2.3 and 8.6 mg/kg, contributing with 4.7–8.2% of ∑PACs. Bioassay analysis showed presence of AhR agonists, estrogen receptor (ERα) agonists, and androgen receptor (AR) antagonists in the tire granulate samples. Only 0.8–2.4% of AhR-mediated activities could be explained by the chemical analysis. Benzo[k+j]fluoranthenes, benzo[b]fluoranthene, indeno[1,2,3-cd]pyrene, 2-methylchrysene, and 3-methylchrysene were the major contributors to the AhR-mediated activities. The high contribution (98–99%) of unknown bioactive compounds to the bioassay effects in this study raises concerns and urges for further investigations of toxicants identification and source apportionment.

Let's make the use of biobased and recovered raw materials the new standard.

Let's make the use of biobased and recovered raw materials the new standard.

Let's make the use of biobased and recovered raw materials the new standard.