Application of high-resolution site characterisation tools and sampling methods for assessing microplastic migration...

Area of Science:

• Environmental Science
• Geology
• Soil Science

Background:

• Rising global plastic production and inadequate waste management exacerbate microplastic (MP) accumulation in municipal solid waste (MSW) dumpsites.
• Limited understanding of MP migration pathways through complex soil strata necessitates robust tracking methodologies.

Purpose of the Study:

• To investigate the accumulation and migration of MPs from MSW dumpsites into deeper soil and groundwater (GW).
• To present an innovative, integrated approach for characterizing MP movement in subsurface environments.

Main Methods:

• Employed advanced site characterization: cone penetration test (CPT) and hydraulic profiling tool (HPT).
• Utilized continuous soil and discrete GW sampling techniques to minimize cross-contamination.
• Integrated geophysical and hydrogeological tools to identify high-permeability zones for targeted sampling.

Main Results:

• Identified distinct MSW layers with high plastic, textile, and metal content.
• MP concentrations were highest at the MSW-soil interface (6600-8800 items/kg), decreasing with depth (300-700 items/kg in saturated zones).
• Smaller MPs (<500 µm) dominated soil samples, while GW contained 26-171 items/L, predominantly fibers (<250 µm).

Conclusions:

• Subsurface soils act as partial barriers to MP migration into groundwater.
• The integrated sampling methodology effectively characterized MP distribution and migration pathways.
• Findings underscore the environmental risk of MP contamination from dumpsites into deeper soil and GW.