Programma della conferenza

In 2013 the scientific opinion “Addressing the New Challenges for Risk Assessment” published by three scientific committees of the European Commission, DG SANCO (SCHER, SCHENIR, SCCS) identified the need for improving the ecological realism in both exposure and effect assessment. For example, it highlighted the necessity to further define bioaccumulation behavior and mechanisms for the variety of plant species, considering also emerging contaminants. Plants can accumulate organic contaminants from air and soil through leaves and roots thanks to several processes, and this represents the first step for the entrance of these compounds in the food webs from herbivore and detritivore organisms. To describe chemical concentration ratios between the plant compartment of interest (e.g., leaves) and the exposure medium (e.g., air), bioconcentration factors (BCF) also known as leaf-air partition coefficient (K_LA) are used. Several authors tried to review and compare some of the available K_LA measured and predicted data in order to assess the comparability of the approaches and suggest preliminary guidance for planning future bioaccumulation studies. However, only a few works were considered, and K_LA source of variability was not fully investigated. Moreover, the suitability of the existing approaches (mainly developed for legacy compounds) for the prediction of leaf uptake of emerging contaminants was not verified. In the current work all the available approaches (i.e., more than K_LA 80 equations) were compared and used to predict emerging contaminant bioaccumulation in plants. The results showed that the equations developed for traditional chemicals (e.g., PAHs, PCBs, DDT, etc.) overestimate the bioaccumulation of emerging contaminants (e.g., phthalates, organophosphate ester flame retardants, etc.) in leaves of several orders of magnitude. Therefore, further studies are necessary to better understand the factors that can influence the accumulation of emerging contaminants in leaves of several species and develop new K_LA equations for these types of compounds.

Transitional environments, such as coastal lagoons, can act as coastal filters by retaining pollutants originating from human activities occurring on the mainland. Among the sources of pollution reaching the lagoonal environment, microplastics (MPs) are considered one of the emerging contaminants whose distribution in the abiotic compartment and subsequent transfer to the biotic compartment need to be addressed. Here we assessed the distribution, abundance and composition of MPs in sediment, water and fish community of a semi-enclosed Mediterranean basin (the Stagnone di Marsala, Italy) with the aim to investigate: i) how the environmental factors characterizing the area (hydrodynamics and exposure to the open sea) influence MPs distribution and abundance in the abiotic compartment; ii) how fish trophic niche features (isotopic niche width) influence MP ingestion. MPs were found in all the compartments examined, with concentrations in the sediment being two orders of magnitude higher than in the water column, while MPs were found in 19% of the 106 fish of the five species analysed (three estuarine resident species: Aphanius fasciatus, Atherina boyeri and Syngnathus abaster, and two transient fish species: Diplodus annularis and D. vulgaris). The most abundant polymer analysed by μ-FTIR in fish was rayon (48%), followed by Polypropylen (14%) and acrylic (14%). Pearson correlation analysis revealed a significant positive correlation between the abundance of MPs in the water column and the abundance of MPs ingested by resident fish species, and a negative correlation between hydrodynamics and the MPs ingested by fish. No significant relationship, instead, emerged between fish trophic features and MPs ingestion. These results suggest that environmental condition influence the uptake of MPs by fish communities and highlights the importance of using a multi-target approach to disentangle the effects of MPs pollution in coastal lagoons.

The 'plastisphere is a new ecosystem developping on plastic surfaces that rapidly undergo biofouling in aquatic ecosystems. While numerous studies have investigated the biodiversity of the plastisphere, few have ventured into understanding the impact of these communities on the functionality and metabolism of aquatic ecosystems. We present an experimental study aiming to address this gap by quantifying the broader effects of plastic debris on epiplastic biofilm community development and by assessing the resulting consequences on ecosystem metabolic traits (i.e., net ecosystem production, gross primary production, respiration, and community dark metabolism from 3 rivers, of the Lower Mekong Basin, with contrasting trophic state and water clarity. Over a 30-day period, we incubated four different plastic polymers (polyethylene (PE_30d); polypropylene (PP_30d); polystyrene (PS_30d); polyamide (PA_30d)) and collected additional macroplastics of an unknown submergence time (PE_unk), characterizing the algal biomass, bacterial and algal biodiversity(16S and 18S rRNA), and metabolic traits of the community growing on their surface. Our findings showed limited microalgal biomass and bacterial dominance, with potential pathogens present. The location significantly influenced community composition, highlighting the role of environmental conditions in shaping community development. When assessing the effects on ecosystem productivity, our experiments showed that biofouled plastics led to a significant drop in oxygen concentration within river water, leading to hypoxic/anoxic conditions with subsequent profound impacts on system metabolism and the capability of influencing biogeochemical cycles. Scaling our findings revealed that plastic pollution may exert a more substantial and ecosystem-altering impact than initially assumed, particularly in areas with poorly managed plastic waste. These results highlighted that the plastisphere functions as a habitat for biologically active organisms which play a pivotal role in essential ecosystem processes.

Microplastics (MPs), deriving from the textile sector, are today receiving great attention. Mainly shaped as fibers, these tiny particles are intensely released during many processes, representing an important contributor to freshwater pollution, mainly through wastewater treatment plants (WWTPs). Although conventional WWTPs are not designed to remove MPs, enhanced technologies (e.g., tertiary and quaternary treatments) could remove more the 90% of MPs. However, not all WWPTs are equipped with these highly performing processes. Moreover, in WWTPs a large amount of MPs may end up in sludge, which could contribute to terrestrial and later aquatic ecosystem contamination. The aim of this study is to investigate the pathway of MPs released by the textile industry to surface water. An overview of different fabric treatments will be given to illustrate the processes responsible for MP release and discharge to textile wastewater. Preliminary data, obtained with a quantitative method (Pyrolysis-GC-MS), regarding the release of MPs in selected fabric production steps and in WWTPs will be illustrated to elucidate the range of concentrations and polymer types which can be found. These activities are part of the LIFE CASCADE project which aims at developing analytical procedures and wastewater treatment technologies meant to detect and remove micropollutants including MPs.

Given the unique physical and chemical properties, plastic materials have brought important benefits to our society, becoming essentials in many applicative fields. Among the different plastics types, polypropylene (PP) is one of the most widespread, whose production increased in the last years due to the huge consumption of surgical masks and single-use packaging. However, its global diffusion led to an unchecked build-up and to an indiscriminate environmental dispersion of derived waste. Due to the low degradability, PP could be affected by biotic and abiotic agents, which lead to its fragmentation into micro- and nano-particles (MPs and NPs respectively). These adversely affect both aquatic and terrestrial organisms, in which bioaccumulate inside tissues, thus impairing their physiological responses. In this context, although numerous studies already demonstrated the potential MPs and NPs side effects on several biological processes, the putative impact of PP particles on wound healing and tissue regeneration has never been examined. To shed light on these aspects, the ability of PP-MPs and NPs to interfere with correct wound healing has been assessed in the consolidated freshwater invertebrate model Hirudo verbana. By means of morphological, immunofluorescence, histoenzymatic, and molecular analyses, in the current work it has been demonstrated how PP-MPs and NPs were able to induce fibrotic events, by a stronger activation of the inflammatory response and an abundant production of extracellular matrix components, which in turn inhibits the correct formation of blood vessels and the recruitment of muscle cells precursors.