Microplastic induces soil water repellency and limits capillary flow

Soils are considered the largest sink of microplastic (MP) in terrestrial ecosystems. However, little is known about implications MP on soil physical properties. We hypothesize that low wettability induces water repellency, depending content and size particles. quantified mixtures sand. The sessile drop method (SDM) was applied to measure static contact angle (CA) glass beads at contents ranging from 0 100% (w/w). results extrapolated varying combinations particle sizes based specific surface area. Capillary rise imaged with neutron radiography quantifying effect dynamic CA, imbibition, saturation distribution At 5% (w/w) content, CA exhibited a steep increase 80.2° for 20–75 μm 59.7° 75–125 μm. Dynamic CAs were approximately 40% lower than CAs. experiments showed reduced imbibition into sand columns (700–1,200 μm), average 40.3° 0.35% 51.8° 1.05%. Decreased increased tortuosity flow paths observed during peaking 3.5% local content. conclude, regions high infiltration thus transport hindered. Local induced by expected limit impede capillary rise.