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

Abstract

This study is the first to investigate the ingestion of microplastics (MPs), plasticizers, additives, and particles of micro-litter &lt;100 μm by larvae of Simuliidae (Diptera) in rivers. Blackflies belong to a small cosmopolitan insect family whose larvae are present alongside river courses, often with a torrential regime, up to their mouths. Specimens of two species of blackfly larvae, Simulium equinum and Simulium ornatum, were collected in two rivers in Central Italy, the Mignone and the Treja. Small microplastics (SMPs, &lt;100 μm), plasticizers, additives, and other micro-litter components, e.g., natural and non-plastic synthetic fibers (APFs) ingested by blackfly larvae were, for the first time, quantified and concurrently identified via MicroFTIR. The pretreatment allowed for simultaneous extraction of the ingested SMPs and APFs. Strong acids or strong oxidizing reagents and the application of temperatures well above the glass transition temperature of polyamide 6 and 6.6 (55–60 °C) were not employed to avoid further denaturation/degradation of polymers and underestimating the quantification. Reagent and procedural blanks did not show any SMPs or APFs. The method’s yield was &gt;90%. Differences in the abundances of the SMPs and APFs ingested by the two species under exam were statistically significant. Additives and plasticizers can be specific to a particular polymer; thus, these compounds can be proxies for the presence of plastic polymers in the environment.

Microplastics, Additives, and Plasticizers in Freshwater Bivalves: Preliminary Research of Biomonitoring

“…Therefore, the distribution of polymers in different rivers was similar as PA-6 is predominant in the SMPs composition. The extraction procedure of SMPs used in this research allowed the researchers to identify polymers with a high accuracy, enabling the detection of PA-6, which can be easily lost due to high temperatures or aggressive treatments [12,13,40,64,65]. PA-6 is very common in fishing nets and fish tackles employed in bivalve and fish farms [66]; a very high concentration was found in T0 (16,742 SMPs/g ww) from the specimens taken directly from the commercial breeding.…”

“…The extraction and purification procedure were employed according to the method developed by [12] which resulted in the minimization of any possible polymer degradation, and the method's yield was >90%. The particles were not further denatured, even polyamide, which can be denatured with temperatures ≥ 55 • C, as is often employed in extraction procedures [12,13,40].…”

“…These ubiquitous pollutants are widespread in freshwater, which can be affected by anthropogenic factors (e.g., proximity of urban centers, low efficiency of wastewater treatments plants (WWTPs), use of sewage debris for fields), while natural factors (e.g., wind, storms, floods) contribute to their dispersion in the aquatic environment [7][8][9]. Aquatic organisms can actively ingest microplastics (MPs < 5 mm) [10][11][12][13] and these particles may exert adverse effects on individual, cellular or molecular levels [14][15][16]. The most common effect of MPs is the reduction in food uptake, which is probably due to false food satiation and particularly observed in combination with other contaminants [17][18][19].…”

Editorial for the Special Issue “Microplastics in Aquatic Environments: Occurrence, Distribution and Effects”

“…The eight selected research papers can be grouped into three main themes: (1) the effects of microplastic exposure to aquatic biota (rotifers, mussels, fish larvae, and microalgae), encompassing 55% of the published papers in this SI [ 9 , 10 , 11 , 12 , 13 , 14 ]; (2) the distribution and seasonal variation of microplastics in aquatic environments [ 15 ]; and (3) the contaminants associated with microplastics in freshwater environments [ 16 ].…”

“…Other organisms that have been found to be capable of ingesting microplastics are blackfly larvae (Simuliidae), as shown by Corami et al (2022) [ 14 ]. Two species of blackfly larvae, Simulium equinum and Simulium ornatum , were sampled from two rivers in Italy and analyzed for microplastics (<100 μm), and natural and non-plastic synthetic fibers.…”