Chironomids are the species richest family among macroinvertebrates and are often used as indicators of ecological condition in inland waters. High taxonomic expertise is needed for identification and new species are still described even in the well-known West Palaearctic region. Data were filed in a Microsoft Access relational database and analysed using the R environment. Our database comprises data on Chironomid species collected in rivers and lakes in Italy and some other European countries over a period of about 50 years, often associated with physical-chemical data, but in some cases only benthic macroinvertebrates are available with no associated environmental data. In this case, the possibility of estimating water quality with only species composition available is discussed. Traits summarizing the species response to environmental variables were evaluated, with emphasis on natural and man influenced factors: current velocity, water temperature, conductivity, dissolved oxygen, nutrients. Traits calculations was possible using the subset of database including both environmental data and Chironomid abundances. The relations between sites, species and traits were evaluated using correspondence analysis and other multivariate methods. The response of species showed an interaction among different factors, with the possibility to order species along a single environmental gradient, extending from cold running waters to warm standing waters, with few exceptions. The utility and limits of the use of ecological traits are discussed.

Microplastics are widespread in freshwater environments and could impact these ecosystems. Bivalves are freshwater organisms that are particularly exposed to microplastic contamination. Therefore, in this preliminary study, the accumulation of microplastics, plasticizers, and additives in the freshwater bivalves Anodonta cygnea through active biomonitoring was investigated. Specimens commercially bought were exposed in three rivers in Central Italy for different exposure times: short (1 month) and long (3 months). The gills and the gastrointestinal tract (GIT) were analyzed separately to evaluate the possible uptake and ingestion of particles via Micro-FTIR. For the first time, small microplastics (SMPs, 5-100 µm), plasticizers, additives, and other micro-litter components, e.g., natural and non-plastic synthetic fibers (APFs) were identified in the bivalve A. cygnea. The most abundant polymer in the gills (94.4%), and GITs (66.1%) was polyamide, which had the highest concentration in each river. A decrease in SMPs' abundance was observed over time in the gills in each river, while the abundance in GIT increased. Compared to polymers, a greater variety of APFs was observed in rivers. The APFs changed during the time of exposure and between different rivers more evidently than polymers, allowing a clearer identification of the possible sources. These results highlighted plastic pollution by SMPs using freshwater bivalves as sentinel organisms and the need to investigate further the additives that can be proxies of the presence of microplastics in the environment and biota.