Microplastics in soils: assessment, analytics and risks

Environmental context There is increasing concern from both the general public and the scientific community about microplastic-related pollution. Despite the alarming and well-documented accumulation of plastics in the marine environment, little attention has been paid to the sources, fate and effects of microplastics in terrestrial settings. We overview the prevalence of microplastics in soils, evaluate their impacts, and appraise the current difficulties in their determinations in terms of sampling, isolation and identification. Abstract There has been an increasing interest by both the general public and the scientific community in microplastic-related pollution. Owing to their physical and chemical characteristics, these highly ubiquitous contaminants may be ingested by numerous organisms at the base of food-webs. Furthermore, owing to their tendency to adsorb other chemical substances, such as persistent organic pollutants (POPs), these plastic particles can lead to bioaccumulation and bioamplification phenomena, which significantly increases their potential environmental effects. However, most of the current research available is focussed on the prevalence and effects of these materials in water, and, more precisely, in oceans. Although this is understandable, owing to the alarming accumulation of plastics in this environmental compartment, little attention has been paid to the sources, fate and effects of microplastics (MPs) in terrestrial settings. This is further complicated by the current lack of universally accepted methods for the assessment and identification of MPs, not only in liquid, but also in solid matrices. We overview the most current data regarding the presence and prevalence of MPs in soils and evaluate their recognised impacts and potential consequences. We also appraise the current sampling, isolation and identification methodologies and suggest methods that may contribute to the development of standard operating procedures (SOPs) for the sampling and characterisation of these pervasive pollutants in complex matrices, such as soils.