Jonathan Thorn

Emerging Contaminants in Florida's Coastal Landscape: Laboratory Perspectives on Microplastics and 6-PPD-Quinone

Jonathan Thorn, Technical Director and PFAS Practice Leader, Eurofins Environment Testing (USA)

Florida's coastal ecosystems — coral reefs, seagrass beds, mangrove shorelines, and the species that depend on them — are increasingly the subject of emerging contaminant research that the remediation community is only beginning to engage with. Two contaminant classes drawing growing scientific attention are microplastics and 6-PPD-quinone (6-PPD-Q), a tire rubber antiozonant transformation product mobilized through stormwater runoff. For remediation professionals working at urban and peri-urban sites with discharge to Florida's coastal and estuarine receiving waters, understanding what environmental laboratories can realistically measure for these contaminants is a practical and timely question.  Microplastics have been documented in Florida Keys seagrass beds, sand flats, and coral reef tissues, with microfibers as the dominant morphology — a finding that connects directly to stormwater and wastewater pathways relevant to remediation site characterization. This presentation surveys current laboratory methods for microplastic analysis, including visual identification, micro-FTIR, and Py-GC/MS, with a candid look at their respective tradeoffs in sensitivity, throughput, cost, and data defensibility in the absence of approved EPA methods.  For 6-PPD-Q, the discussion covers targeted LC-MS/MS analytical capabilities and achievable detection limits relative to toxicity thresholds established through studies of sensitive fish species. Research to date has documented acute toxicity in several salmonids — including coho salmon, brook trout, rainbow trout, and coastal cutthroat trout — at environmentally relevant concentrations, while other closely related species show little to no response, underscoring the highly species-specific nature of 6-PPD-Q sensitivity. Florida's ecologically and recreationally significant fish species have not yet been evaluated in this context, representing an area where site investigators would benefit from awareness as the science continues to develop.  Attendees will leave with a practical framework for engaging laboratory partners, evaluating analytical proposals, and designing investigations that account for data quality limitations in the evolving landscape of pre-regulatory contaminants.  

Jonathan Thorn joined the Eurofins team as the Technical Director and PFAS Practice Leader in January 2024. Jon has worked in the field of environmental analytical chemistry for over 31 years. For the last 12 years, his primary focus has been the analysis of PFAS in environmental samples, focusing on development and implementation of analytical methods in difficult matrices, including ground water, wastewater, landfill leachate, sediment, soil, biosolids, environmental tissues, agricultural products, animal blood, and consumer products. He received his B.S. in chemistry from Bridgewater State University in 1996.