Per- and polyfluoroalkyl substances (PFAS) are persistent “novel entities” that increasingly accumulate in coastal food webs, making apex predators critical sentinels for long-term exposure and risk. However, organ-resolved data that capture both legacy PFAS and emerging alternatives in cetaceans—especially across life stages—remain scarce for many rapidly developing subtropical bays, limiting mixture-aware assessment in the substitution era. Here, we quantified 37 PFAS in multi-organ tissues from four stranded cetaceans collected from the Beibu Gulf (a juvenile Omura's whale and three Indo-Pacific humpback dolphins, including a calf), and evaluated congener profiles, tissue-to-muscle ratios (TMR), and screening-level hazard quotients (HQ). ΣPFAS concentrations were pervasive and strongly tissue dependent, spanning 37.4–2322.3 ng g −1 dry weight (dw), with pronounced hotspots in kidney, gut, and lung and the highest burdens observed in the calf dolphin. Across individuals, mixtures retained a stable legacy “backbone” dominated by PFOS and long-chain PFCAs, yet life stage and organ type reshaped internal fingerprints (e.g., kidney PFOS reaching 1564 ng g −1 dw in the calf). Notably, multiple substitutes were consistently detected and displayed tissue-selective behavior, contributing up to 41.4% (kidney) and 38.1% (muscle) of ΣPFAS in the juvenile Omura's whale and up to 43.8% in adult female muscle, while TMR patterns indicated PFOS/long-chain PFCA enrichment in metabolically active and reproductive tissues but distinct redistribution for several alternatives (e.g., HFPO-DA, PFO4DA, 6:2 Cl-PFESA). Although HQs for both legacy PFAS and alternatives remained below unity, several substitutes approached legacy hazard signals, highlighting the need for substitute-inclusive surveillance. Together, these findings provide a rare multi-organ, life-stage-resolved tissue dataset for cetaceans from the Beibu Gulf and show that substitution-era PFAS mixtures and early-life signals cannot be inferred from a single tissue, supporting substitute-inclusive, conservation-relevant biomonitoring and prioritization under ongoing chemical replacement. • Rare multi-organ, life-stage PFAS data from stranded Beibu Gulf cetaceans. • ΣPFAS spans 37.4–2322.3 ng g −1 dw, with kidney, gut and lung as hotspots. • PFOS and long-chain PFCAs dominate; substitutes are ubiquitous and tissue-selective. • The calf shows elevated PFOS, highlighting early-life conservation concern.
Xing et al. (Sun,) studied this question.