In the present work, the environmental fate of some chemicals in temperate-zone mountain regions and their sub-lethal effects on no-target organisms have been studied to improve knowledge and propose new approaches that would be useful in the risk assessment procedures. In particular, the potential release of legacy POPs and emerging pollutants from the melting of Italian Alpine glaciers is described with the aim of highlighting the presence of these compounds in a remote high-altitude cold site because of Medium Range Atmospheric Transport (MRAT) processes. Two contrasting processes leading to glaciers contamination have been underlined: on one hand, the results suggest a declining trend of POPs while the accumulation of Emerging Contaminants (ECs) in glaciers has been highlighted. Based on these results, a study of the potential degradation of chlorpyrifos (CPF) in a remote high-altitude cold site was performed. The aim is to describe the role of cryoconite in the accumulation of organic pollutants to include its contribution to the removal of organic pollutants in models predicting the environmental fate of these compounds in cold areas. For this purpose, in situ microcosm experiment was carried out on Forni Glacier by testing the degradation of CPF in light and dark conditions, in abiotic and biotic environments. The results highlight that biodegradation contributes to the removal of CPF from the glacier surface more than photochemical degradation. Therefore, microbial degradation can contrast the accumulation of pollutants transported on glaciers and their possible re-emission. The potential sub-lethal effects induced on aquatic invertebrates by environmental concentrations of widespread ECs were investigated. Indeed, currently the ecotoxicological effects of chemical compounds are evaluated by means of standardised toxicity tests, which overcome many biochemical and physiological processes because they do not allow organisms to cope with contaminants as they do in the field. This should be particularly true at sub-lethal concentrations since these mechanisms are functional, and many of them respond on the scale of days. Especially not lethal effects, including changes in behaviour, could affect fitness and consequently population dynamics. These criticalities are particularly true for the ECs, whose adverse effects towards non-target organisms have been only recently highlighted. Moreover, increasing laboratory evidences show that the exposure to environmental concentrations of different ECs may induce several adverse effects to organisms. Nevertheless, it is largely unknown how the responses to chemical stress are spread through the different levels of the ecological hierarchy. Unveiling this kind of information would be very effective for improving the use of biomarkers as early warning indicators of risk. In order to understand how and if the stress signals measured at a given ecological level are transmitted through the other hierarchical levels and the capability of sub-individual endpoints to predict ecologically relevant effects, Daphnia magna individuals were exposed to environmentally relevant concentrations of CPF and benzoylecgonine (BE). The results show that daphnids exposed to environmental levels of BE and CPF were in a condition of stress. In addition, it was noticed that the activation or non-activation in some enzymes activities can lead to different modifications of the swimming behaviour in D. magna, suggesting the existence of a link between sub- and supra-organismal levels. Eventually, the behavioural responses of daphnids and Diamesa zernyi induced by different dilutions of treated sewage effluents were compared. The results obtained highlight that water samples collected induced significant alteration on different swimming behavioural parameters in both species.

Il progetto ha come scopo generale l’incremento delle conoscenze scientifiche relative al destino ambientale di alcuni contaminati emergenti e tradizionali. Lo studio si è concentrato sulla distribuzione e sugli effetti degli inquinanti a diversi livelli della scala gerarchica ecologica. In particolare è stato studiato il potenziale rilascio dei POP e degli inquinanti emergenti (EC, Emerging Contaminants) dovuto alla fusione dei ghiacciai alpini italiani per evidenziare la presenza di questi composti in un ambiente freddo ad alta quota a seguito dei processi di trasporto atmosferico a scala regionale. L’analisi di campioni di acqua di fusione glaciale raccolti sui ghiacciai alpini ha permesso di notare che la contaminazione degli stessi è dovuta a due processi opposti: da un lato è stata infatti registrata una tendente diminuzione delle concentrazioni dei POP, contrastata però dai processi di accumulo dei EC. Sulla base di questi risultati è stato condotto uno studio sul potenziale di degradazione ad alta quota del clorpirifos (CPF). L'obiettivo è stato quello di descrivere il ruolo della crioconite nell'accumulo di inquinanti organici al fine di includerne il contributo tra i processi di rimozione nei modelli di previsione del destino ambientale di questi composti nelle zone fredde. A tale scopo, è stato condotto un esperimento in situ sul Ghiacciaio dei Forni testando la degradazione del CPF in condizioni di luce e di buio, in ambienti abiotici e biotici. I risultati evidenziano che la biodegradazione contribuisce alla rimozione del CPF dalla superficie del ghiacciaio più significativamente della degradazione fotochimica. Pertanto, la degradazione microbica può contrastare l'accumulo di inquinanti trasportati sui ghiacciai e la loro possibile remissione in ambiente. Sono stati inoltre studiati i potenziali effetti sub-letali indotti sugli invertebrati acquatici dalle concentrazioni ambientali di ECs. Infatti, attualmente gli effetti ecotossicologici dei composti chimici vengono valutati mediante test di tossicità standardizzati, che trascurano molti processi biochimici e fisiologici in quanto non consentono agli organismi di far fronte ai contaminanti come farebbero in ambiente. Ciò è particolarmente vero a concentrazioni sub-letali poiché questi meccanismi sono funzionali e molti di essi rispondono su scala di giorni. Soprattutto gli effetti non letali, compresi i cambiamenti nel comportamento, potrebbero influenzare la fitness individuale e di conseguenza le dinamiche della popolazione. Evidenze di laboratorio mostrano che l'esposizione a concentrazioni ambientali di diversi EC può causare effetti negativi sugli organismi. Tuttavia è in gran parte sconosciuto come le risposte allo stress chimico si diffondano attraverso i diversi livelli della gerarchia ecologica. Ottenere questo tipo di informazioni sarebbe molto utile per promuovere l'uso dei biomarcatori come indicatori di rischio precoce. Al fine di comprendere come e se i segnali di stress vengono trasmessi attraverso i livelli gerarchici e la capacità degli endpoint sub-individuali di predire effetti ecologicamente rilevanti, individui di Daphnia magna sono stati esposti a concentrazioni ambientali di CPF e benzoilecgonina (BE). I risultati mostrano che le dafnie esposte a BE e CPF erano in una condizione di stress. È stato inoltre notato che l'attivazione o la non attivazione di alcune attività enzimatiche può portare a diverse modifiche del comportamento del nuoto in D. magna, suggerendo l'esistenza di un legame tra i livelli sub- e sovra-organismo. Infine, sono state confrontate le risposte comportamentali di dafnia e Diamesa zernyi indotte da diverse diluizioni degli effluenti di depurazione. I risultati ottenuti evidenziano che i campioni di acqua raccolti inducono alterazioni sul comportamento di entrambe le specie.

(2018). Emerging contaminants: distribution, environmental fate and effects at different levels of the ecological hierarchy organization. (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2018).

Emerging contaminants: distribution, environmental fate and effects at different levels of the ecological hierarchy organization

FERRARIO, CLAUDIA
2018

Abstract

In the present work, the environmental fate of some chemicals in temperate-zone mountain regions and their sub-lethal effects on no-target organisms have been studied to improve knowledge and propose new approaches that would be useful in the risk assessment procedures. In particular, the potential release of legacy POPs and emerging pollutants from the melting of Italian Alpine glaciers is described with the aim of highlighting the presence of these compounds in a remote high-altitude cold site because of Medium Range Atmospheric Transport (MRAT) processes. Two contrasting processes leading to glaciers contamination have been underlined: on one hand, the results suggest a declining trend of POPs while the accumulation of Emerging Contaminants (ECs) in glaciers has been highlighted. Based on these results, a study of the potential degradation of chlorpyrifos (CPF) in a remote high-altitude cold site was performed. The aim is to describe the role of cryoconite in the accumulation of organic pollutants to include its contribution to the removal of organic pollutants in models predicting the environmental fate of these compounds in cold areas. For this purpose, in situ microcosm experiment was carried out on Forni Glacier by testing the degradation of CPF in light and dark conditions, in abiotic and biotic environments. The results highlight that biodegradation contributes to the removal of CPF from the glacier surface more than photochemical degradation. Therefore, microbial degradation can contrast the accumulation of pollutants transported on glaciers and their possible re-emission. The potential sub-lethal effects induced on aquatic invertebrates by environmental concentrations of widespread ECs were investigated. Indeed, currently the ecotoxicological effects of chemical compounds are evaluated by means of standardised toxicity tests, which overcome many biochemical and physiological processes because they do not allow organisms to cope with contaminants as they do in the field. This should be particularly true at sub-lethal concentrations since these mechanisms are functional, and many of them respond on the scale of days. Especially not lethal effects, including changes in behaviour, could affect fitness and consequently population dynamics. These criticalities are particularly true for the ECs, whose adverse effects towards non-target organisms have been only recently highlighted. Moreover, increasing laboratory evidences show that the exposure to environmental concentrations of different ECs may induce several adverse effects to organisms. Nevertheless, it is largely unknown how the responses to chemical stress are spread through the different levels of the ecological hierarchy. Unveiling this kind of information would be very effective for improving the use of biomarkers as early warning indicators of risk. In order to understand how and if the stress signals measured at a given ecological level are transmitted through the other hierarchical levels and the capability of sub-individual endpoints to predict ecologically relevant effects, Daphnia magna individuals were exposed to environmentally relevant concentrations of CPF and benzoylecgonine (BE). The results show that daphnids exposed to environmental levels of BE and CPF were in a condition of stress. In addition, it was noticed that the activation or non-activation in some enzymes activities can lead to different modifications of the swimming behaviour in D. magna, suggesting the existence of a link between sub- and supra-organismal levels. Eventually, the behavioural responses of daphnids and Diamesa zernyi induced by different dilutions of treated sewage effluents were compared. The results obtained highlight that water samples collected induced significant alteration on different swimming behavioural parameters in both species.
FINIZIO, ANTONIO
VILLA, SARA
contaminanti; emergenti,; effetti; comportamentali,; ghiacciai
emerging; contaminants,; behavioural; effects,; ghiacciai
BIO/07 - ECOLOGIA
English
5-apr-2018
SCIENZE CHIMICHE, GEOLOGICHE E AMBIENTALI - 94R
30
2016/2017
open
(2018). Emerging contaminants: distribution, environmental fate and effects at different levels of the ecological hierarchy organization. (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2018).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/199127
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