Vertical distribution of microplastics in a river water column using an innovative sampling method

Area of Science:

• Environmental Science
• Water Quality Assessment
• Pollution Monitoring

Background:

• Microplastic contamination is a growing environmental concern.
• Subsurface water is often under-sampled, limiting understanding of microplastic distribution.
• Innovative sampling methods are needed to accurately assess microplastic pollution in aquatic environments.

Purpose of the Study:

• To investigate microplastic contamination in surface, subsurface, near-bottom water, and sediments of a freshwater river.
• To evaluate the influence of different weather conditions (stormy, rainy, dry) on microplastic vertical distribution.
• To determine the representativeness of surface water sampling for assessing microplastic contamination in the entire water column.

Main Methods:

• Utilized an innovative sampling method to collect water samples from surface, subsurface, and near-bottom layers.
• Conducted sampling during three distinct weather conditions: stormy, rainy, and dry.
• Analyzed microplastic abundance and polymer types in different aquatic compartments.

Main Results:

• No significant difference in microplastic abundance and types between surface and subsurface water samples.
• A notable decrease in the proportion of low-density polymers (density < 1) from surface/subsurface to near-bottom/sediment samples.
• Rainfall events were found to significantly influence microplastic concentration across all analyzed compartments.

Conclusions:

• Surface water sampling can be representative of microplastic contamination in shallow river water columns.
• Environmental conditions, particularly rainfall, must be considered to avoid erroneous estimations of microplastic concentration and flux.
• Accurate microplastic assessment requires comprehensive sampling strategies that account for vertical stratification and weather patterns.