Short- and medium-chain chlorinated paraffins in fish from an anthropized south-western Atlantic estuary, Bahia Blanca, Argentina

Chlorinated paraffins (CPs) are synthetic organic compounds of growing environmental and social concern. Short-chain chlorinated paraffins (SCCPs) were listed under the Stockholm Convention on Persistent Organic Pollutants (POPs) in 2017. Further, in 2021, medium-chain chlorinated paraffins (MCCPs) were proposed to be listed as POPs. We investigated SCCP and MCCP amounts and homolog profiles in four wild fish species from Bahia Blanca Estuary, a South Atlantic Ocean coastal habitat in Argentina. SCCPs and MCCPs were detected in 41% and 36% of the samples, respectively. SCCP amounts ranged from <12 to 29 ng g-1 wet weight and <750-5887 ng g-1 lipid weight, whereas MCCP amounts ranged from <7 to 19 ng g-1 wet weight and <440-2848 ng g-1 lipid weight. Amounts were equivalent to those found in fish from the Arctic and Antarctic Oceans and from some North American and Tibetan Plateau lakes. We performed a human health risk assessment and found no direct risks to human health for SCCP or MCCP ingestion, according to present knowledge. Regarding their environmental behavior, no significant differences were observed among SCCP amounts, sam-pling locations, species, sizes, lipid content, and age of the specimens. However, there were significant differ-ences in MCCP amounts across species, which could be attributed to fish size and feeding habits. Homolog profiles in all fish were dominated by the medium-chlorinated (Cl6 and Cl7) CPs and shorter chain length CPs were the most abundant, with C10Cl6 (12.8%) and C11Cl6 (10.1%) being the predominant SCCPs and C14Cl6 (19.2%) and C14Cl7 (12.4%) the predominant MCCPs. To the best of our knowledge, this is the first study on the presence of CPs in the environment in Argentina and the South Atlantic Ocean. CP occurrence in the environ-ment, particularly in the food chain, promotes the need for further research on their occurrence and behavior, and the impact of CPs in marine ecosystems in Argentina.

Automated summary

This study investigated the presence and profiles of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in four wild fish species from Bahia Blanca Estuary, Argentina. SCCPs and MCCPs were detected in 41% and 36% of the samples, respectively. The study highlights the need for further research on the occurrence, behavior, and impact of chlorinated paraffins in the marine ecosystems of Argentina.