Plastic particles in soil: state of the knowledge on sources, occurrence and distribution, analytical methods and ecological impacts.

Increased production and use of plastics has resulted in growth in the amount of plastic debris accumulating in the environment, potentially fragmenting into smaller pieces. Fragments <5 mm are typically defined as microplastics, while fragments <0.1 μm are defined as nanoplastics. Over the past decade, an increasing number of studies have reported the occurrence and potential hazards of plastic particles in the aquatic environment. However, less is understood about plastic particles in the terrestrial environment and specifically how much plastic accumulates in soils, the possible sources, potential ecological impacts, interaction of plastic particles with the soil environment, and appropriate extraction and analytical techniques for assessing the above. In this review, a comprehensive overview and a critical perspective on the current state of knowledge on plastic pollution in the soil environment is provided: detailing known sources, occurrence and distribution, analytical techniques used for identification and quantification and the ecological impacts of particles on soil. In addition, knowledge gaps are identified along with suggestions for future research.