Ichthyofauna revealed a sink of organochlorine compounds in central andes: a preliminary assessment

POMA, GIULIA; CIOCCO, NESTOR F.; RUGGERI, M.FLORENCIA; COVACI, ADRIAN; RÍOS, JUAN MANUEL; MALARVANNAN, G.; ALTAMIRANO, JORGELINA C.

Birmingham

Conferencia; XI Network POPs Conference, University of Birmingham, UK; 2018

Given the importance of mountain regions as freshwater reservoir, the presence of pollutants such as organochlorine compounds (OCs), is a subject of growing concern in recent years. Central Andes is a relevant region because it has the highest peaks in South America, Aconcagua, and its wealth in glaciers. These and other environmental characteristics (climate, temperature) of the region promote a high vine industry as well petrol exploitation. In order to find tools potentially useful for monitoring pollution in this region, OC levels (DDTs, chlordanes, HCB, HCHs; and polychlorinated biphenyls: PCBs) were determined in two fish species: rainbow trout (Onchorrynchus mykiss) and argentinian silverside (Odontesthes bonariensis). The levels of OCs in fish muscle and liver were compared to explore selective accumulation. Fish-to-sediment ratios were used to compare OCs accumulation ability between species, and p,p´-DDE/DDT ratio were used as an indicator of the DDT input time. Results showed clear differences in geographic distribution patterns of total organochlorine pesticide levels. Among the studied species, argentinian silverside from Carrizal dam showed the highest p,p´-DDT, and p,p´-DDE loads. Carrizal dam is located downstream of Tunuyan river, which runs through Uco Valley, the main fruit-horticultural area of central Andes and potentially receives the waste stream from vineyards. Further, surrounding the dam there has historically been recreational activities since 1965. The p,p´-DDE/DDT ratios were > 0.6 in all cases, suggesting that DDT residues in central Andes fish derive from old DDT input. Fish-to-sediment ratios of p,p´-DDT found, suggests that rainbow trout and silverside, both, have relatively high and comparable abilities to accumulate DDTs. Regarding PCBs, no clear spatial distribution patterns were found among sites; and no intraspecific relationships between fish body condition and OC levels were found. Overall, results suggest that rainbow trout and silverside could be useful as organochlorine bioindicators in the central Andes ecosystems.