Microplastics and nanoplastics barely enhance contaminant mobility in agricultural soils

Farmland soils are prone to contamination with micro- and nanoplastics through a variety of agricultural practices. Concerns are recurrently raised that micro- and nanoplastics act as vector for organic contaminants to deeper soil layers and endanger groundwater resources. Whether and to what extent...

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Bibliographic Details
Published in:Communications earth & environment 2021-12, Vol.2 (1), p.1-9, Article 193
Main Authors: Castan, Stephanie, Henkel, Charlotte, Hüffer, Thorsten, Hofmann, Thilo
Format: Article
Language:English
Subjects:
Additives
Agricultural land
Agricultural practices
Agrochemicals
Contaminants
Contamination
Desorption
Diffusion
Groundwater
Hydrophobicity
Microplastics
Mobility
Organic contaminants
Organic soils
Plastic pollution
Pollution transport
Polyethylene
Polyethylenes
Polymers
Preferential flow
Sediment pollution
Soil contamination
Soil layers
Soil pollution
Water resources
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Summary:Farmland soils are prone to contamination with micro- and nanoplastics through a variety of agricultural practices. Concerns are recurrently raised that micro- and nanoplastics act as vector for organic contaminants to deeper soil layers and endanger groundwater resources. Whether and to what extent micro- and nanoplastics facilitate the transport of organic contaminants in soil remains unclear. Here we calculated the ratio between transport and desorption time scales using two diffusion models for micro- and nanoplastics between 100 nm and 1 mm. To identify micro- and nanoplastics bound contaminant transport we evaluated diffusion and partitioning coefficients of prominent agrochemicals and additives and of frequently used polymers e.g., polyethylene and tire material. Our findings suggest that the desorption of most organic contaminants is too fast for micro- and nanoplastics to act as transport facilitators in soil. Contaminant transport enabled by microplastics was found to be relevant only for very hydrophobic contaminants (log K ow >5) under preferential flow conditions. While micro- and nanoplastics might be a source of potentially harmful contaminants in farmland soils this study suggests that they do not considerably enhance contaminant mobility.
ISSN:2662-4435
2662-4435
DOI:10.1038/s43247-021-00267-8