Environmental laboratories are facing increasing demands to detect toxic compounds, which now extend beyond traditional industrial sources to include emerging contaminants associated with everyday infrastructure. This article, which summarizes insights from the recent PFAS and Emerging Environmental Contaminants Symposium hosted by Separation Science, highlights contributions from Arielle Cocozza of United Chemical Technologies. Cocozza’s discussion focuses on the toxicity and analytical significance of tire wear particles and their transformation products, offering guidance on why these compounds warrant analytical attention and how laboratories can reliably begin measuring them.
Cocozza centers her presentation on 6PPD-quinone (6PPDQ), a degradation product of the tire antiozonant 6PPD. “Tire manufacturers have relied on 6PPD for decades to protect against ozone damage,” she advises, “But once it enters the environment, it oxidizes into 6PPD-quinone, which is far more mobile and toxic.” Tire manufacturers rely on 6PPD to protect rubber from ozone-induced cracking, but once released into the environment, the compound oxidizes into 6PPDQ. Stormwater runoff transports this transformation product from road surfaces into streams, where it accumulates in urban waterways and exposes aquatic organisms.
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Why Tire-Derived Contaminants Matter
Cocozza explains that concern around 6PPDQ has escalated after researchers linked it to urban runoff mortality syndrome in coho salmon. “For years, scientists observed large-scale coho salmon die-offs without a clear cause,” she explains. “The identification of 6PPD-quinone finally connected those losses to stormwater runoff from urban roads.” Affected fish exhibit lethargy, disorientation, and premature death before spawning. Toxicity studies report lethal effects at sub-nanogram-per-gram concentrations, placing extraordinary pressure on analytical methods to deliver clean extracts and confident detection at trace levels.
Despite the ecological and cultural importance of salmon, Cocozza notes that most analytical methods focus on water matrices. Fish tissue, especially salmon, poses a greater challenge due to its high lipid content and complex co-extractives. Without effective cleanup, matrix interference can overwhelm low-level signals and compromise both sensitivity and instrument performance.
From Research Insight to Routine Laboratory Workflows
Cocozza positions her work as a response to this analytical gap. “Most existing methods focus on water,” she notes. “But if we want to understand exposure and risk, we need reliable ways to measure these compounds directly in tissue.” Building on Environmental Protection Agency (EPA) Draft Method 1634, originally developed for stormwater, she adapts the approach to salmon tissue while maintaining routine laboratory workflows. Her goal remains clear: enable environmental labs to detect PPD quinones at toxicologically relevant levels without introducing excessive complexity, downtime, or specialized instrumentation.
She outlines a workflow that balances speed, robustness, and selectivity while remaining compatible with routine environmental testing. The approach adapts both chromatography and sample preparation to address the challenges of high-fat fish tissue. Instead of traditional gel permeation chromatography or solvent-intensive cleanup, the method uses a targeted extraction followed by a push-through cleanup configuration that selectively removes lipids and endogenous pigments while allowing PPD quinones to pass through.
Cocozza emphasizes that cleanup chemistry plays a central role in method performance, reducing matrix load prior to analysis and preserving instrument stability. “Salmon is an extremely challenging matrix,” she asserts. “If you don’t control lipids and pigments early, you lose sensitivity and put unnecessary strain on the instrument.” The workflow integrates directly into existing LC–MS/MS platforms without requiring new columns, specialized hardware, or extensive retraining, making it suitable for laboratories under pressure to adopt emerging contaminant methods quickly.
Analytical Performance With Regulatory Relevance
Data presented during the session demonstrate why this approach matters. Cocozza shows that the method detects PPD quinones at concentrations below the reported median lethal dose (LD50) for juvenile coho salmon, achieving sub‑0.1 ng/g sensitivity in tissue while maintaining clear signal separation at the lowest calibration levels. Recovery studies confirm consistent extraction efficiency across low and mid‑level spikes, reinforcing the method’s suitability for trace analysis in a high‑fat, interference‑prone matrix.
She notes that cleaner extracts directly translate to reduced matrix interference, improved method robustness, and longer instrument uptime—critical factors for laboratories running high sample volumes alongside other regulated analyses. “We’re able to detect these compounds at concentrations below known toxic thresholds, even in a very lipid-rich tissue,” explains Cocozza.
She also highlights the broader implications. As regulatory agencies and research groups intensify efforts to understand and manage tire-derived contaminants, laboratories need practical tools that move emerging science into routine monitoring. Methods that work only under ideal research conditions fail to meet that need.
What This Means For Environmental Laboratories
Cocozza’s presentation reinforces a central message: emerging contaminants demand methods that are both analytically rigorous and operationally realistic. “This has to work in real laboratories,” she notes. “If a method is too complex or disruptive, it won’t be adopted—no matter how good the science looks on paper.” As tire-derived contaminants move from academic concern to regulatory focus, laboratories need workflows that can withstand routine use, complex matrices, and increasing scrutiny.
The on-demand presentation expands on method development decisions, cleanup chemistry selection, and validation outcomes that underpin the results summarized here. “As regulators and researchers pay closer attention to tire-derived contaminants, laboratories need methods that are ready now, not years from now.” For analytical scientists evaluating whether this approach is suitable for their laboratory, the full session provides the technical context needed to assess performance, adaptability, and long-term practicality in real-world environmental testing.
