MICROFIBERS AT THE NEGRO RIVER, PATAGONIA ARGENTINA

FERNANDEZ MARISOL; ANA L. OLIVA; RONDA ANA CAROLINA; MARÍA CLARA MENÉNDEZ; M. CINTIA PICCOLO; ALEJANDRO J. VITALE; ANDRÉS H. ARIAS

Conferencia; MICRO 2022 Plastic Pollution from Micro to Nano; 2022

Riverine inputs to the ocean has been pointed as a major source of plastics to the ocean;beside this, information on river plastic loads is scarce and patchily distributed around theworld. In this work, we aimed to assess the average amount of microfibers (MFs) transportedin the Negro River (NR, Argentinean Patagonia) water which reaches its estuary and theAtlantic coast along cold (July) and warm (December) seasons. Then, surface water wascollected at six locations along the Negro River estuary (El Condor, El Pescadero, La Baliza,NR mouth, Water Facilities, Patagones City) using a 350 µm pore floating net fitted witha mechanical flowmeter. The samples were subsequently digested with 30% H2O2 at 40 ◦Cfor 72 h, filtered with GF/F filters and finally counted under binocular stereoscopic loupe.The results obtained showed that MF particles were found in 100% of the samples witha global average of 0.65 MFs.m-3. While lower counts were found in winter (0.42±0.21MFs.m-3), concentrations in summer almost doubled the winter values (0.79±0.72 MFs.m3) probably due to the higher outdoor activities along the river. The northern and muchless urbanized area of the river estuary (La Baliza) showed the minimum microfiber valuesindependently of the sampling season. In regards to microfiber size distribution and colour,there was a homogeneous pattern along the year which showed higher counts in the mediumand small microplastic range (> 1 um up to 3 mm). The average colour distribution wasblack (41%)}> transparent (20%)> blue (12%)> white (11%)> red (9%)> green (7%).This work provides evidence of the impact of plastic in riverine waters reaching the AtlanticOcean, providing a scientific baseline and raising a concern in regard to the need to mitigateeach possible source of MFs to the water course.