Quantifying anthropogenic microparticle contamination in cave sediments: spatial heterogeneity matters.

Area of Science:

• Environmental Science
• Geology
• Ecotoxicology

Background:

• Anthropogenic microparticle pollution is widespread, impacting even remote ecosystems like natural caves.
• Data on microparticle concentration in caves are scarce, often lacking sufficient spatial replication.
• Fragile cave ecosystems may be vulnerable to microparticle contamination impacts.

Purpose of the Study:

• To investigate spatial variation patterns of microparticle contamination in cave surface sediments.
• To quantify microparticle concentration and types in two caves in NE Italy.
• To identify the scales of spatial variation contributing most to microparticle contamination.

Main Methods:

• Implemented a hierarchical sampling design across large, medium, local, and small scales.
• Analyzed surface sediment samples from two caves in the Classical Karst region.
• Quantified microparticle concentration, type (microplastics, cellulose), and relative abundance.

Main Results:

• Anthropogenic microparticles, predominantly microplastics (PP, PET, PE), were found in all samples (avg. 90.9 items/kg).
• Microparticle abundance and type varied significantly at the subarea scale within caves.
• Small and medium scales (subareas and replicates) were the primary contributors to total variability.

Conclusions:

• Cave microparticle contamination exhibits significant small- and medium-scale spatial heterogeneity.
• Existing sampling strategies may underestimate microparticle contamination due to scale-dependent variability.
• More structured sampling designs are needed for reliable microparticle contamination assessment in cave environments.