Diversity, abundance and distribution of microplastics in the St. Lawrence River

Session: 46. - Plastics in the Great Lakes: Characterizing the Problem and Finding Solutions

Alex Crew, McGill University / Group for Interuniversity Research in Limnology and Aquatic Environment (GRIL), [email protected]
Irene Gregory-Eaves, McGill University, [email protected]
Anthony Ricciardi, McGill University, [email protected]

Abstract

Microplastics are important emerging pollutants in freshwaters, but their presence and fate in riverine environments are still poorly documented. Previous research has demonstrated that sediments in the St. Lawrence River are a significant sink for polyethylene microbeads (Castañeda et al. 2014). Here, we extend previous work by quantifying the abundance and diversity of a broad range of microplastics in the sediments, including above and below wastewater treatment outflows, to identify areas of the river that have high concentrations and diversity of microplastics and to relate these metrics to environmental variables. We sampled 23 sites spanning a land-use gradient as well as 12 wastewater effluent sites, along the fluvial corridor between Montreal and Quebec City, from July to August 2017. Environmental variables were collected at each site along with variables collected through laboratory analysis. Microplastics were extracted from sediments using an oil extraction protocol and enumerated using fluorescent microscopy and Nile red staining. We tested the predictions that water flow, organic matter, sediment composition and land-use type affect microplastic concentrations in the river. 

1. Keyword
microplastics

2. Keyword
St. Lawrence River

3. Keyword
sediments

4. Additional Keyword
environmental contaminants

5. Additional Keyword
pollutants