Mercury and methylmercury trophodynamics in the food chains of native and introduced fish from a Northwest Patagonia Lake

ARCAGNI, M.; RIZZO, A.; HORVAT, M.; JUNCOS, R.; PAVLIN, M.; CAMPBELL, L.M.; FAJON, V.; ARRIB¨¦RE, M.A.; RIBEIRO GUEVARA, S.

Conferencia; ICMGP 2015 12th Internacional Conference on Mercury as a Global Pollutant; 2015

Total mercury [THg] and methylmercury [MeHg] concentrationswere measured in introduced fish (rainbow trout, brown trout), in native fish(creole perch, big puyen), and in their prey (small fish, macroinvertebratesand plankton) in Lake Nahuel Huapi, the largestultraoligotrophic system in North Patagonia, Argentina.Samples were obtained at three sites (Brazo Rincón-BR, Bahía López-BL, and DinaHuapi-DH) which present different geographic, hydrogeomorphic, and environmentalcharacteristics. [THg] were determined by Instrumental Neutron ActivationAnalysis and by using a Direct Mercury Analyzer and [MeHg] via GC-separation onan automated MeHg analyzer. THg and MeHg trophodynamics in each fish speciesfood chain were assessed using stable nitrogen (d15N) and carbon (d13C) isotopes asindicators of trophic level and carbon source, respectively.Log-transformed [THg] (LogTHg) increased with increasing trophic level (biomagnification) in the food chain of creole perch from thethree sites and big puyen from BR, but decreased with increasing trophic level (biodilution) in the food chains of brown trout and rainbow trout from BR. Log-transformed[MeHg] (LogMeHg) increased with increasing d15N in the food chains ofcreole perch from BL and BR, and decreased with increasing trophic level inbrown trout from BR.LogTHg decreased with increasing d13C values in thefood chains of creole perch and brown trout from BR and LogMeHg decreased with increasing d13C values in the foodchain of brown trout from BR.