Abstract:
The term ‘microplastics’ was first used in 2004 to describe very small fragments of plastic (~ 50 m³) in the water column and in sediments. In 2009, Arthur et al. proposed that microplastics should include all fragments < 5 mm. Over the past decade, microplastic debris in both marine and freshwater systems has become an emerging environmental issue. Although 70 – 95 % of the marine litter, including microplastics, come from land environment, studies of microplastics in freshwater systems are limited respect to those focused on marine habitats. Rivers and inland waters may transport microplastics to marine habitats and may be a novel vector for the downstream transport of organic persistent pollutants suggesting an overlooked and potentially significant component of the global microplastic life cycle. Herein we report results from a monitoring study with the main objective of evaluate the occurrence and concentration of microplastics in an italian urban river and assess the hypotheses that microplastics amount could vary in response to temporal and seasonal trends. In order to monitor the trend of microplastic concentrations, two seasonal sampling campaigns have been planned (February and April 2017).
Superficial waters samples were collected with three surface plankton nets fixed in the middle of the river simultaneously for two different time slot (11:00-13:00 and 13:00-15:00) for a total of six replicates for each campaign. After sample extraction and purification, validation of visually based microplastics identification was achieved using pyrolysis-gas chromatography-mass spectrometry (Pyrolysis GCMS). The composition of microplastic was studied in term of size, shape, color and polymer type. Results from the six replicates are expressed as mean values (± DEV. ST.) of number of particles per cubic meter (p/m³). Microplastics were found in each net sample for a total amount of 22152 items collected, photographed, enumerated and categorized. Sample concentrations ranged from 3.52 to 13.43 p/m³ showing significantly higher abundances during February than April campaign (Mann?Whitney U Test = 18.00; p-value = 0.028). A total of five polymer have been characterized: PE, PP, PS, PVC and TDI-PUR. All samples contained at least three polymer types: PE, PP and PS. PE accounted for 77% of the total particles identified, followed by PS (12%), PP(10%), PVC (0.9%) and PU (0.4%).
Citation:
SETAC Europe 28th Annual Meeting, May 2018
Keywords:
Microplastics, occurrence, concentration, urban river, Italy