Environmental factors affecting streambed microplastics in a non-perennial river catchment

Area of Science:

• Environmental Science
• River Ecology
• Pollution Studies

Background:

• Microplastics (MPs) pose a significant threat to river ecosystems.
• MP transport and accumulation are influenced by environmental factors, particularly hydrology.
• The impact of flow intermittence on MPs remains largely unknown.

Purpose of the Study:

• To compare MP abundance and characteristics in intermittent versus perennial river reaches.
• To investigate the influence of flow intermittence and other environmental variables on MPs.
• To understand MP pollution dynamics in riverine environments.

Main Methods:

• Collected MPs from sedimentation zones in intermittent and perennial river sections.
• Analyzed MP abundance (normalized by TOC) and characteristics (size, polymer type).
• Assessed environmental factors: land cover, sediment grain size, distance to roads and water sources.

Main Results:

• MP abundance correlated negatively with distance to roads; MP size correlated positively.
• Illegal dumps near roads created localized MP pollution hotspots.
• Flow intermittence negatively correlated with median MP size, but did not affect abundance or polymer diversity.

Conclusions:

• Flow intermittence influences MP size distribution in riverbeds.
• Road proximity and associated illegal dumping are significant sources of riverine MPs.
• This research provides crucial insights into MP behavior under varying hydrological conditions.