Assessing on-site plastics fragmentation: Linking macroplastics litter to microplastics pollution in vegetable fields

Area of Science:

• Environmental Science
• Agricultural Science
• Pollution Studies

Background:

• Microplastic pollution is a growing environmental concern, particularly in agricultural soils.
• Understanding the sources of microplastics (on-farm mismanagement vs. external pollution) is crucial for effective mitigation.

Purpose of the Study:

• To develop and apply a novel, accessible method for distinguishing between on-farm and external microplastic pollution sources in agricultural soils.
• To assess the contribution of farmers' macroplastic mismanagement to soil microplastic contamination.

Main Methods:

• A case-study approach was used on 37 vegetable farms in central Chile.
• Linear transects and soil samples were employed to quantify and classify microplastics.
• Kendall correlation analysis compared macro- and microplastic colors to differentiate pollution origins.

Main Results:

• Soil microplastic counts were lower than previously reported (3.68 ± 3.28 u/kg).
• A median color correlation of 0.43 between macro- and microplastics indicated external pollution is often dominant.
• On-site plastic fragmentation predominated in only 25% of the studied fields.

Conclusions:

• Farmers are not the primary source of soil microplastics; external pollution is a more significant factor.
• The proposed methodology is simple, requires no specialized equipment, and can aid environmental monitoring and pollution prevention in agriculture.