Transport and Deposition of Microplastics and Mesoplastics along the River Course: A Case Study of a Small River in Central Italy

Abstract

The release of plastics in freshwater is an increasing concern for ecosystem safety worldwide. There is a large knowledge gap on plastic pollution in Mediterranean freshwater, especially regarding surveys along entire river courses, partly due to the absence of guidelines for standardized monitoring of plastics. The present study analyzes the plastic distribution from source to mouth, also according to the River Continuum Concept, of the environmental matrices (water and sediments) and biota (caddisfly cases) of the Mediterranean River Mignone and their cause-effect relationship. The results of the water quality indices (Extended Biotic Index and Fluvial Functionality Index) were compared with the plastic concentrations observed in the water and sediments to explore what relationship there might be and to understand if the indices could be a proxy of the plastic pollution. Our results showed a significant prevalence of blue fibers, the concentration of which in water and sediment is positively associated. Plastic concentration at each site was not accurately detected by the water quality indices. These results may suggest that the factors considered by water quality indices are not able to detect the contamination of plastic pollution. It is mandatory to identify new tools for assessing the plastic impacts on river ecosystems.

Occurrence and Characterization of Small Microplastics (<100 μm), Additives, and Plasticizers in Larvae of Simuliidae

“…Some other studies have dealt with the presence of MPs by riverine insects [ 10 , 11 , 12 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ]. Some of these have dealt with the ingestion of MPs by riverine insects [ 10 , 11 , 12 , 40 , 41 , 42 , 43 ]; however, the insects studied were not Simulidae, and some studies were mainly exposure experiments to few native polymers.…”

“…Some of these have dealt with the ingestion of MPs by riverine insects [ 10 , 11 , 12 , 40 , 41 , 42 , 43 ]; however, the insects studied were not Simulidae, and some studies were mainly exposure experiments to few native polymers. Caddisfly cases (Trichoptera) from the same area of the Mignone River were investigated for the presence of plastics [ 39 ]. Nevertheless, the fragments studied had sizes ( well above those observed for the ingested SMPs by the two species under examination here, and they were analyzed only by a visual exam (microscopical examination); thus, the polymers were not properly identified.…”

Assessing the Ecological Status of European Rivers and Lakes Using Benthic Invertebrate Communities: A Practical Catalogue of Metrics and Methods

“…Improving ESC assessment will therefore require a shift towards modules and metrics based on ecological characteristics of the bioindicator communities as well as calibration of new and better ESCATs targeting the most important stressors [6,61,62]. Indeed, many of the currently used ESCATs were designed to depict impact of organic pollution-which, due to the implementation of the EU Directive on Urban Wastewater Treatment (91/271/EEC) and the WFD, in large areas of Europe no longer is the most pressing stressor-and do not cover emerging or multiple stressors including pollution by microplastics [6,[61][62][63][64]. Naturally, assessment systems need to be adapted to reflect environmental changes brought about by the prevalent stressors.…”

Microplastics Affect the Inflammation Pathway in Human Gingival Fibroblasts: A Study in the Adriatic Sea

“…Artificial polymers have been found in the stomach contents of Mediterranean pelagic predators, deep-sea fish and commercial species [21]. About 1/3 of Mediterranean freshwater discharges flow into the Adriatic Sea, which is a narrow elongated sub-basin with a high land to sea ratio (1.80) surrounded by seven countries (~3.5 million inhabitants in the coastal zone) and many tourist centers (e.g., Venice, Split, Dubrovnik, Corfu) [22,23].…”