High records of mercury in surface waters from Nahuel Huapi National Park, Andean Patagonian Range.

RIZZO, A., ; FAJON, V., ; KOTNIK, J.; DAGA, R.; 1.ARRIBÉRE, M., DIÉGUEZ, M.C., RIBEIRO GUEVARA, S., QUEIMALIÑOS, C. P., FAJON, V., REISSIG, M. AND M. HORVAT; DIÉGUEZ, M.C:; ARCAGNI, M.; HORVAT, M. ; RIBEIRO GUEVARA, S.

Jeju

Congreso; 12th ICMGP; 2015

ICMGP

Lake Nahuel Huapi (41°S-71°W) is an oligotrophic, warm monomictic system, the largest and deepest in Northwest Patagonia. Waters from Brazo Rincón (BR), the northernmost branch situated near Puyehue-Cordón Caulle volcanic system, and its watershed were studied for mercury (Hg) concentrations, given the high Hg levels determined previously in different compartments of this pristine aquatic system. BR has a surface of 11 km2 and a maximum depth of 100 m, with a catchment of 235 km2, 73% covered by dense Andean?Patagonian Nothofagus forest; annual precipitation ~2,500 mm. Total Hg (THg), methyl-Hg (MeHg) and dissolved gaseous Hg (DGM) concentrations were measured on unfiltered water samples taken from the 100 m deep water column of BR, seven streams and a small water body. THg was also determined in suspended load >0.2 μm, collected simultaneously but following independent procedures (water sampler, preservation and transport procedures, and sample conditioning). Rainfall was also collected and analyzed. THg concentrations in waters from streams and the small water body were particularly high, ranging from 20 to 363 ng.L-1, whereas MeHg ranged from