Burnt Plastic\n(Pyroplastic) from the M/V <i>X‑Press\nPearl</i> Ship Fire and Plastic Spill Contain Compounds That\nActivate Endocrine and Metabolism-Related Human and Fish Transcription\nFactors

In\nMay 2021, the M/V <i>X-Press Pearl</i> ship\nfire disaster\nled to the largest maritime spill of resin pellets (nurdles) and burnt\nplastic (pyroplastic). Field samples collected from beaches in Sri\nLanka nearest to the ship comprised nurdles and pieces of pyroplastic.\nThree years later, the toxicity of the spilled material remains unresolved.\nTo begin understanding its potential toxicity, solvent extracts of\nthe nurdles and pyroplastic were screened for their bioactivity by\nseveral Attagene FACTORIAL bioassays (TF, NR, and AquaTox), which\nmeasured the activity of a combined 70 human transcription factor\nresponse elements and nuclear receptors and 6 to 7 nuclear receptors\nfor each of three phylogenetically distinct fish species. Extracts\nof the pyroplastics robustly activated end points for the human aryl\nhydrocarbon receptor (AhR), estrogen receptor (ER), pregnane X receptor\n(PXR), peroxisome proliferator-activated receptor (PPAR), retinoid\nX receptor (RXR), and oxidative stress (NRF2) and had the potential\nfor activation of several others. The bioactivity profile of the pyroplastics\nwas most similar (similarity score = 0.96) to that of probable human\ncarcinogens benzo[<i>b</i>]fluoranthene and benzo[<i>k</i>]fluoranthene despite the extracts being a complex mixture\nof thousands of compounds. The activity diminished only slightly for\nextracts of pyroplastic collected eight months after the spill. The\nAquaTox FACTORIAL bioassay measured the activation of ERα, ERβ,\nandrogen receptor (AR), PPARα, PPARγ, and RXRβ for\nhuman, zebrafish (Danio rerio), Japanese\nmedaka (Oryzias latipes), and rainbow\ntrout (Oncorhynchus mykiss), revealing\nspecies-specific sensitivities to the chemicals associated with the\npyroplastics. These findings provide needed information to guide long-term\nmonitoring efforts, make hazard assessments of the spilled material,\nand direct further research on pyroplastic, an emerging global contaminant.