Increasing levels of PBDEs, PCBs and organochlorine pesticides in fish following a mega-flooding episode in the Negro River basin, Argentinean Patagonia

ONDARZA P.M.; GONZALEZ M.; FILLMANN G.; MIGLIORANZA K.S.B.

Berlín

Congreso; 6th SETAC World Congress/SETAC Europe 22nd Annual Meeting; 2012

Society of Environmental Toxicology and Chemistry (SETAC) Europe Office

A mega-flooding event in the Negro River basin, Argentinean Patagonia, caused a significant outflow of contaminants from the surrounding soils. Agriculture, hydroelectric centrals and industrial-urban conglomerates are the most important activities in the basin. This study evaluates the effects of flooding event on polybrominated diphenyl ethers (PBDEs), endosulfans, DDTs and polychlorinated biphenyls (PCBs) levels in females of silverside (Odontesthes hatcheri) tissues. Muscle, liver, gills, gonads and stomach content were analyzed by GC-MS. Levels in water, suspended particulate matter (SMP) and sediments (SS) were also measured. Post- and pre-flood fish showed the following pattern: DDTs > PCBs > endosulfans ≥ PBDEs. Post-flood fish showed the highest contaminants levels (ng/g lipid), at expenses of PBDEs and PCBs. PBDEs showed the greatest difference between post- and pre-flood fish (up more than 240 times). BDE-47 was the predominant congener in all tissues; however BDE-100 and BDE-99 showed the highest increase in post-flood liver (up to 400 times). The dominance of BDEs 47, 99 and 100 was consistent with the general pattern found in abiotic samples and fish of the same area, as well as denote the use of technical mixtures of penta-PBDEs. PCBs levels in post-flood fish increase until 23 times (from 63.2 to 1,478.6 ng/g lipid in liver), which were dominated by penta- (PCB-110, 118) and hexa- (PCB-153, 138) congeners. These results could have stemmed from historical usage of Arochlor 1254 and 1260 in Argentina. In post- and pre-flood fish, endosulfan sulfate presented the highest levels suggesting metabolic activity in addition to direct metabolite uptake, while an a-/b- ratio >1 similar to the technical mixture which is widely used in the region. In post-flood muscle, DDTs levels increased 5-fold than pre-flood. The metabolite p,p-DDE represented about 80% of DDTs. This pattern would be a result of the intensive use of this insecticide during long time on agricultural practices. Contaminant profiles observed in pre- and post-flood silverside were according to water, SPM and SS, showing that this specie is a good biomonitor of aquatic pollution of Negro River.The presence of pollutants in this river was modified and enhanced by the flooding, increasing their bioavailability to fish. Additionally, pollutant occurrence deserves more attention, and monitoring programs are recommended in order to diminish their incorporation to aquatic ecosystem.