Spatial and temporal distribution of microplastics in water and sediments of a freshwater system (Antuã River, Portugal)

M O Rodrigues; N Abrantes; F J M Gonçalves; H Nogueira; J C Marques; A M M Gonçalves

doi:10.1016/j.scitotenv.2018.03.233

Spatial and temporal distribution of microplastics in water and sediments of a freshwater system (Antuã River, Portugal)

Sci Total Environ. 2018 Aug 15:633:1549-1559. doi: 10.1016/j.scitotenv.2018.03.233. Epub 2018 Apr 4.

Authors

M O Rodrigues¹, N Abrantes², F J M Gonçalves³, H Nogueira⁴, J C Marques⁵, A M M Gonçalves⁶

Affiliations

¹ Department of Biology, CESAM, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: marianarodrigues@ua.pt.
² Department of Environment, CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
³ Department of Biology, CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
⁴ Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro, Portugal.
⁵ MARE, Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal.
⁶ Department of Biology, CESAM, University of Aveiro, 3810-193 Aveiro, Portugal; MARE, Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal.

PMID: 29758905
DOI: 10.1016/j.scitotenv.2018.03.233

Abstract

Microplastics (particles with a size<5mm), one of the most emerging aquatic pollutants, are of particular concern since they can reach high densities and interact with biotic and abiotic environment. The occurrence of microplastics in freshwater systems is less understood than in marine environment. Hence, the present study aims to provide new insights into microplastics abundances and distribution in Antuã River (Portugal) by applying the isolation method of wet peroxide oxidation with addition of zinc chloride to water and sediment samples collected in March and October 2016, in three sampling sites. The abundance of microplastics in water ranged from 5 to 8.3mgm^-3 or 58-193itemsm^-3 in March and from 5.8-51.7mgm^-3 or 71-1265itemsm^-3 in October. In sediments, the abundance ranged from 13.5-52.7mgkg^-1 or 100-629itemskg^-1 in March and from 2.6-71.4mgkg^-1 or 18-514itemskg^-1 in October. The water and sediment samples with the greatest abundances were from São João da Madeira and Aguincheira, respectively. Spatio-temporal distribution showed different pattern according to methodological approaches, seasonal and hydrodynamic conditions and the proximity to urban/industry areas. Analysis of plastics by Fourier transform infrared spectroscopy underline polyethylene and polypropylene as the most common polymer types identified in this work. The low medium high oxidation ratio was 56:22:22 (%) in March and 61:31:8 (%) in October. Foams and fibers were the most abundant type in São João da Madeira, while fibers and fragments were the most abundant in Aguincheira and Estarreja in water and sediment samples, respectively. This study emphasizes the importance of rivers as carriage systems of microplastics. Further studies should be performed to identify point sources in order to mitigate the microplastics contamination in aquatic systems.

Keywords: Antuã River; Contamination; Microplastics; Sediment; Water.