Bushra Khan, project scientist in the Department of Environmental Toxicology at UC Davis and laboratory director of the Granite Canyon Laboratory, told the SPOT Scientific Review Committee that non‑targeted analysis (NTA) can strengthen the program’s ability to find drivers of toxicity and fill gaps in targeted monitoring.

"The idea here is how NTA can add value to our specific management questions and the design that we have," Khan said, describing a workflow that pairs correlation of high‑resolution mass‑spectrometry features with toxicity markers and, separately, a quantitative branch using a purchased standards list.

Why it matters: SPOT is a long‑running statewide sediment monitoring program used to detect chemical trends and prioritize sites for follow‑up. Committee members repeatedly raised concerns about budget constraints and laboratory comparability; Khan and UC Davis collaborators argued that NTA — run consistently and with clear QA/QC — can reveal novel contaminants and provide quantitative data when commercial targeted analyses are not scheduled.

Khan described two primary NTA outputs. The first is a qualitative prioritization that ranks library matches and peak heights, then correlates those features with toxicity markers and land‑use to produce a narrowed list of candidate contaminants for follow‑up. The second is a quantitative branch that uses a preselected list of commercially available standards (about 70 compounds in the pilot) to return concentrations comparable to targeted chemistry for some analytes.

The committee heard pilot results. Anna Furek (UC Davis/Tom Young laboratory) and others applied a prioritization model to 2021–2024 extracts and, in multiple analyses, identified bifenthrin as a major driver of toxicity — a result that mirrors years of targeted data. Khan emphasized that NTA uniquely highlighted chemical fingerprints that differ by region and that adding organisms or endpoints (for example, Chironomus as well as Hyalella toxicity tests) identifies some sites missed by single endpoints.

On quantitative performance, Khan presented site‑level comparisons showing NTA‑derived concentrations for bifenthrin and fipronil that were broadly comparable to targeted results at both high‑ and low‑concentration sites. She acknowledged differences in limits of detection: for example, the SPOT QAPP reports a bifenthrin reporting limit of 0.25 ng/g for targeted analyses and the NTA quantitative LODs used in the pilot were higher (0.5 ng/g for bifenthrin). She also noted cases where targeted labs reported non‑detects while NTA returned quantitative values and said these instances are being investigated under a draft QA/QC protocol.

Committee members pressed on QA/QC and method consistency. "The short answer is I would need to do a 1‑to‑1 comparison of the lab," said Anna Furek when asked about extraction and preparation differences. Several SRC members cautioned that trend analysis requires method and lab consistency over time; UC Davis staff said they are documenting alignment and repeatability steps and working to publish QA/QC guidance for both qualitative and quantitative NTA outputs.

Khan outlined how the two NTA branches would be used operationally: qualitative prioritization to generate candidate contaminant lists for regions or specific management questions (e.g., urban vs. agricultural fingerprints), and the quantitative branch to supply numeric values for key analytes in years when the commercial targeted contract does not cover those compounds. Extracts from NTA runs are archived, Khan said, enabling purchase of a standard later and retroactive quantitation if a compound becomes a priority.

The session closed with several agencies offering collaboration. Anne Cooper Doherty (Safer Consumer Products Program, DTSC) and others said their product‑screening work could help interpret many non‑target matches; Department of Water Quality staff described ongoing PFAS efforts that could be coordinated with NTA outputs.

Khan and UC Davis indicated they will provide draft QA/QC documentation and make the 2021–2024 NTA correlation datasets available for SRC review before the next meeting. The presenters repeatedly stressed that consistent laboratory practice and documented QA/QC are prerequisites for using NTA outputs for trend work or regulatory interpretation.

Ending: UC Davis researchers recommended integrating NTA as a persistent program component — with documented QA/QC and a defined five‑year work plan — so SPOT can detect novel drivers of toxicity and supplement targeted chemistry in gap years.