Commercially important aquatic organisms as indicators of contamination, ecosystem health and human risks in one of the largest rivers of the Brazilian Equatorial Margin (Jaguaribe river, Ceará, Brazil).

Pollution is a major environmental stressor that threatens aquatic ecosystem integrity and the health of aquatic organisms. This study assessed contamination patterns, ecosystem health and human health risks linked to chronic contamination and bioaccumulation in the Jaguaribe River, Ceará, Brazil. Target compounds included PCBs, OCPs, PBDEs, and PPs, analyzed in sediments and in biota, crustaceans (Ucides cordatus), fish (Genidens barbus, Mugil curema, Lutjanus synagris) and mollusks (Crassostrea rhizophorae). Risk to human health was evaluated using HQ, THQ, and CR indices per USEPA guidelines. Fish showed the highest PCB concentrations (up to 42 ng/g, mainly PCB52 - reflecting contributions from diffuse urban sources and regional atmospheric deposition), while mollusks accumulated DDT metabolites (>20 ng/g). Crustaceans contained OCPs and pyrethroids (cypermethrin, deltamethrin). Sediments held heavier PCBs and residual pesticides like heptachlor and α-chlordane. All HQ and THQ values were below 1, and CR values remained within the USEPA "insignificant to acceptable" range (<10-4), indicating no significant human health risk under the assessed exposure scenarios. Nevertheless, the widespread detection of legacy POPs and current-use pesticides highlights persistent, low-level exposure and ongoing contamination, underscoring the need for continuous monitoring, particularly for frequent consumers and vulnerable populations. Fish and crabs exhibited generally stable physiological condition, with minor variations likely associated with environmental stressors.