Risk ranking of multiple-POPs in detritivorous fish from the Río de la Plata

To evaluate the bioaccumulation and the risk associated to consumption of lipid-rich detritivorous fish, a comprehensive set of organic pollutants (n = 213) including polychlorinated biphenyls (PCBs), dioxin like PCBs (dlPCBs), chlorinated pesticides (CHLPs), chlorobenzenes (CBzs), polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo dioxins and furans (PCDD/F), resolved (ALI) and unresolved aliphatic hydrocarbons (UCM) and linear alkyl benzenes (LABs) were analyzed in Sábalo fish (Prochilodus lineatus) collected in the polluted Metropolitan Buenos Aires coast and in migrating specimens. Fatty fish muscles (lipids: 74 ± 9.3% dry weight) contained homogeneous (24–51% variability) and very high-concentrations of organic pollutants ranging from 60 to 1300 μg g−1 fresh weight (fw) ALI + UCM; 10–40 μg g−1 fw LABs and PCBs; 0.1–1 μg g−1 fw dlPCBs, DDTs, chlordanes, CBzs and PBDEs; 0.01–0.1 μg g−1 fw mirex, endosulfans, aldrin, dieldrin, endrin and 0.07–0.2 ng g−1 PCDD/F. Total toxicity equivalents (TEQs) ranged from 60 to 395 pg g−1 fw (34 ± 17 and 213 ± 124 pg g−1 TEQs for PCDD/F and dlPCBs respectively). These are among the highest concentrations reported for fish and point out the remarkable ability of Sábalo to feed on anthropogenic organic-enriched particles and tolerate a high pollutant load. Contaminant signatures show partial alteration with still abundant lower molecular weight components indicating that fish feeds directly in the outfalls. Consumption limits based on reference doses ranged from 0.1 (PCBs) to >12 000 g d−1 (endosulfan) allowing a comprehensive risk-based ranking of contaminants in this long-range migrating, detritivorous fish.

► The diet energy optimization of detritus feeding fish leads to efficient bioaccumulation of POPs.
► Risk ranking of multiple POPs was evaluated based on reference doses and fish concentrations.
► PCBs, PCDD/Fs showed the higher risks and Chlorobenzenes and chlorinated pesticides the lowest.
► Contaminant signatures show incipient alteration indicating direct feeding in the outfalls.