FIRST RECORDS OF MICROPLASTICS IN CRASOSSTREA GIGAS AND IN THE WATER COLUMN OF THE BAHÍA BLANCA ESTUARY (SOUTHWESTERN ATLANTIC)

SOL, BUZZI NATALIA; FERNÁNDEZ SEVERINI MELISA DAIANA; CHATELAIN SARTOR GABRIELA; VILLAGRAN DIANA MARIEL

San Luis

Congreso; VII Congreso Argentino de la Sociedad de Toxicología y Química Ambiental; 2018

SETAC y SETAC Argentina

Small plastic debris, called "microplastics" (MP), consist of heterogeneous particles of various shapes and colors suspended in the water column with a maximum size of 5 mm. They are widely distributed pollutants in all the marine ecosystems of the world and can be involuntary ingested by any organism representing a potential risk. They include manufactured plastics of microscopic size, such as industrial scrubbers and pellets that serve as precursors for the plastics industry (primary sources), or fragments or fibers of plastics derived from the decomposition of larger plastic products (secondary sources). In the Bahía Blanca Estuary (EBB) the first records of MP were in samples collected with zooplankton net (200 μm) in 2004, when it was detected the presence of MP in its majority primary pellets and some fibers. The present work corresponds to the first records of MP in the water column in the EBB and in adjacent coastal ecosystems. Samples were taken at different sites along the estuary and at different periods of time with van Dorn bottles and zooplankton nets of 60 and 200 µm. Water samples were filtered with 0,22 µm filters and also net samples were analyzed under stereoscopic microscope (Nikon SMZ 1500) and microscope (Nikon Eclipse 80i). Several types of microplastics, such as filaments, have been detected in the water column as well as some beads. The fibers were the most abundant item (90%) with 100% presence in the samples and a mean density from 13.3 to 782.2 fiber item/L. Also, analysis of stomach content in Crassostrea gigas oysters (17 individuals) with two types of digestions one with 65% HNO3 20 ml of 22.5 M nitric acid and digested overnight at room temperature, followed by 30 min of boiling (100ºC). The resulting mixture was then diluted 1:10 with warm deionized water, before filtration and microscopical observation. The other digestion was based on H2O2 30% at 55ºC for seven days. In both protocols microplastics such as fibers (4.2 and 3 fibers item/ind. respectively) and beads have been detected (1.5 and 0.5 bead item/ind. respectively). The presence of the microplastics in the EBB would be negatively affecting some organisms that inhabit the estuary with potential toxic effects throughout the entire marine trophic chain