Using chemometrics to discern patterns and spatial distribution of heterocyclic aromatic compounds in Lake Erie fish

Polycyclic aromatic compounds (PACs) are ubiquitous environmental contaminants and while polycyclic aromatic hydrocarbons (PAHs) are well-studied, their heterocyclic counterparts (HPACs) remain poorly understood. We examined the spatial distribution and bioaccumulation of 104 PACs in four fish species [freshwater drum (Aplodinotus grunniens), yellow perch (Perca flavescens), gizzard shad (Dorosoma cepedianum), and walleye (Sander vitreus)] from the three main basins of Lake Erie, North America. Total (∑) PAC concentrations ranged from 0.7 to 43.2 μg/g lipid weight, with the highest levels found in biota from the western basin. Regardless of the basin and species type, HPACs were the most abundant contaminants, representing over 50% of ∑₁₀₄PACs in most samples. New and existing chemometric approaches revealed distinct-basin and species-dependent clustering in PAC profiles. Hierarchical cluster analysis highlighted enrichment of brominated HPACs in the central basin, particularly its western region with smaller levels in top predator walleye, suggesting limited trophic transfer. Overall, the identification of previously unreported HPACs in Great Lakes biota, coupled with advanced chemometric approaches to resolve spatial and species-specific patterns, improves our understanding of PAC bioaccumulation and distribution in freshwater ecosystems and supports ecological risk assessments aimed at protecting the Great Lakes.