Additives, plasticizers and small microplastics (<100 μm) in wet and dry depositions from an urban area of Venice, Italy

The atmosphere is considered one of the most important pathways for the transport of microplastics (MPs) from urban areas to far and remote places (Evangeliou et al., 2020; Zhang et al., 2019). Atmospheric depositions consist of dry and wet depositions, and it may be a positive driver in atmospheric pathways of MPs, especially for the smallest particles (SMPs &lt; 100 µm), since they are considering the current scavenging mechanisms for aerosol particles. However, there is a lack of knowledge on the amount and relative pathways of these emerging pollutants in atmospheric depositions, including sampling, pretreatments, and analytical techniques for their quantification and chemical identification. Further, additives and plasticizers can be leached from MPs and SMPs in depositions and they can be transported through different environmental compartments contributing to potential toxic effects on different organisms (Beiras et al., 2021). In this study, SMPs, additives, plasticizers, natural and non-plastic synthetic fibers (APFs), and of other components of micro-litter were investigated in wet and dry depositions from an urban area of Mestre (Venice-Italy). A wet and dry deposimeter was used for the sampling procedure with glass decontaminated buckets. A pretreatment method was developed for the quantification and chemical identification of both SMPs and APFs using a MicroFTIR to avoid further degradation/denaturation of these compounds. From the results, the removal efficiency of wet deposition in terms of the total SMPs and APs from the atmosphere is higher than in dry periods due to the scavenging effect. The consequence of this atmospheric removal by precipitation is the main sink for SMPs and APs on the ground with consequences in aquatic and terrestrial compartments. Different sources from the urban area could affect the abundance and distribution of SMPs and APs. Different APs investigated could be a good proxy of SMPs presence in the environment, for instance, road dust resuspension.