Anthropogenically impacted lake catchments in Denmark reveal low microplastic pollution

Area of Science:

• Environmental Science
• Ecotoxicology
• Freshwater Ecology

Background:

• Microplastics are prevalent in global lake environments, with agricultural and populated areas being significant sources.
• Understanding microplastic contamination in freshwater ecosystems is crucial due to potential ecological impacts.

Purpose of the Study:

• To investigate microplastic contamination in five Danish freshwater lakes and their sediments.
• To assess microplastic presence in the zebra mussel (Dreissena polymorpha) within these lakes.
• To correlate microplastic concentrations with catchment characteristics and environmental parameters.

Main Methods:

• Sediment and Dreissena polymorpha samples were collected from five Danish freshwater lakes.
• Microplastic concentrations (50-5000 µm) were quantified in sediments and mussels.
• Data were analyzed to identify relationships between microplastic levels, catchment land use, and environmental factors.

Main Results:

• Microplastic concentrations in lake sediments were low (average 0.028 items/g dry weight).
• Only one microplastic particle was found in the collected zebra mussels.
• No significant relationship was found between microplastic concentrations in sediment and mussels, or with environmental parameters.

Conclusions:

• The studied Danish freshwater lakes exhibited low microplastic contamination.
• Dreissena polymorpha in these lakes were not significantly contaminated by microplastics, suggesting limited interaction at low concentrations.
• Factors such as regional plastic use, species-specific behavior, and reporting biases may influence observed microplastic levels.