Silver incorporation in lacustrine food webs through chironomid larvae uptake: a study case from northern Patagonia

ARRÍBERE, M.A.; RIZZO, A.; RIVEIRO GUEVARA, S.; WILLIAMS, N.; AÑÓN SUÁREZ, D. A.

ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH

SPRINGER HEIDELBERG

Lugar: HEIDELBERG; Año: 2017 p. 1 - 12

0944-1344

Silver (Ag) is a pollutant of high concern in aquaticecosystems, considered among the most toxic metallic ions. Inlacustrine environments, contaminated sediments are a sourceof Ag for the food web. Chironomidae (Insecta: Diptera) arethe most abundant, diverse, and representative insect groups inaquatic ecosystems. Chironomid larvae are closely associated tobenthic substrates and link primary producers and secondaryconsumers. Given their trophic position and their life habits, theselarvae can be considered the entry point for the transference ofAg, from the benthic deposit to the higher trophic levels of thefood web. Previous studies in lakes from Nahuel Huapi NationalPark (Northern Patagonia) showed Ag enrichment over backgroundlevels (0.04?0.1 μg g−1 dry weight) both in biota (bivalvesand fish liver) and sediments from sites near human settlements.The aim of this study was to analyze the role of chironomidsin the transference of Ag from the benthic reservoir ofLake Moreno Oeste to the food web. The concentration of Ag inchironomid larvae tissue ranged from 0.1 to 1.5 μg g−1 dryweight, reaching a bioaccumulation factor up to 17 over substratesand depending on the associated substrate type, feedinghabitats, larval stage, and season. The main Ag transfer to highertrophic levels by chironomids occurs in the littoral zone, mostlyfrom larvae inhabiting submerged vegetation (Myriophyllumquitense) and sediment fromvegetated zones. This study presentsnovel evidence of the doorway role played by chironomid larvaein Ag pathways from the sediments into food webs of freshwaterecosystems.