Il rilascio nell'ambiente di inquinanti organici, classici ed emergenti, è aumentato con la crescita della popolazione, urbanizzazione e modernizzazione. Considerando che un gran numero di contaminanti, derivati dal trattamento delle acque reflue e scarichi industriali, sono persistenti, bioaccumulabili e tossici; l'ambiente acquatico rappresenta un ecosistema estremamente vulnerabile. In questo contesto, il verificarsi dei ritardanti di fiamma (FRs) è stato oggetto di preoccupazione negli ultimi dieci anni. Fin dalla loro introduzione sul mercato, che risale agli anni Settanta, il loro uso è diventato massiccio e incontrollato grazie alle loro proprietà. I FRs sono infatti incorporati in una varietà di prodotti di consumo al fine di renderli più resistenti all’ accensione, ridurre o interrompere il ciclo di combustione e aumentare la sicurezza delle persone. Attualmente queste sostanze sono considerate contaminanti ambientali a causa della loro riscontrata presenza in diverse comparti quali suolo, sedimenti, acqua, aria, biota etc. Alla luce di quanto sopra, il presente progetto mira a focalizzare l'attenzione sull'impatto ambientale dei FRs (HFRs e OPFRs) in tre diversi bacini fluviali europei (Adige, Evrotas e Sava) e di valutare l'esposizione dell'organismo umano e acquatico a queste sostanze nel Fiume Adige attraverso l'uso di un modello matematico. / The release of classic and emerging organic pollutants into the environment has increased with the growing population, urbanization and modernization. Considering that a great number of contaminants derive from wastewater treatment plant and industrial discharges, and are persistent, bioaccumulative and toxic; the aquatic environment is the most vulnerable ecosystem. In this context, the environmental occurrence of flame retardants (FRs) has been a subject of concern for the past decade. Since their introduction on the market, which dates back to the seventies, their use has become massive and uncontrolled thanks their properties. HFRs are extremely used and incorporated in different consumer products in order to render them more resistant to ignition, reduce or stop the combustion cycle and increase the safety of lives. Nowadays, these substances are considered as environmental contaminants due to their presence in different compartments such as soil, sediment, water, air, biota etc. In the light of the above, the present project aim to focus the attention on the environmental impact of FRs (HFRs and OPFRs) in three different European river basins (Adige, Evrotas and Sava) and to assess the exposure of human and aquatic organism to these substances in Adige River through the use of mathematical modelling.

A significant number of consumer goods and building materials act as emission sources of flame retardants (FRs) in the indoor environment. As a result, FRs have become ubiquitous indoors raising concerns about human exposure and possible health implications. Once released indoors, FRs can escape to the outdoors where they can persist, be transported over long distances and present a threat to the environment. Despite the increasing number of studies reporting the occurrence of FRs in the indoor environment, the understanding of i) how and to what extent these chemicals are released from indoor sources, and ii) their subsequent fate indoors remains limited. The overarching objective of this thesis was to improve this understanding by assessing the indoor emissions and fate of FRs using a combination of multimedia modelling strategies and experimental/empirical approaches. Paper I identifies a number of knowledge gaps and limitations regarding indoor emissions and fate of FRs and the available modelling approaches. These include a limited understanding of the key emission mechanisms for low volatility FRs, uncertainties regarding indoor air/surface partitioning, poor characterization of dust and film dynamics and a significant lack of knowledge regarding indoor reaction/degradation processes. In Paper II we highlighted the serious scarcity in physicochemical property data for the alternative FRs and demonstrated the applicability of a simple QSPR technique for selecting reliable property estimates for chemical assessments. A modelling fate assessment indicated a strong partitioning to indoor surfaces and dust for most of the alternative FRs. Indications for POP (persistent organic pollutant)-like persistence and LRT (long-range transport) and bioaccumulative potential in the outdoor environment were also identified for many alternative FRs. Using an inverse modelling approach in Paper III we estimated 2 to 3 orders of magnitude higher emissions of organophosphate FRs (0.52 and 0.32 ng.h-1) than brominated FRs (0.083 μg.h-1 and 0.41 μg.h-1) in Norwegian households. An emission-to-dust signal was also identified for organophosphate FRs suggesting that direct migration to dust may be a key fate process indoors. No evidence of a direct source-to-dust transfer mechanism was seen in Paper IV where the chemical transfer between a product treated with an organophosphate FR and dust in direct contact was experimentally investigated. It was concluded though that direct contact between an FR source and dust can result in contamination hotspots indoors. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.</p>