1,720,975 research outputs found
Influence of climate change on the environmental behavior and distribution of persistent organic pollutants (POPs)
No full textThe climate temporal reconstruction shows how the Earth’s climate is in continuous change. Evidence of climate change has been observed at both the global and regional scales. The environmental contamination caused by Persistent Organic Pollutants (POPs) is also a global concerning issue. This Ph.D. thesis aims at investigating which effects climate change would exert on the environmental distribution of POPs, priority pollutants which behavior is affected by climate variables.
First, the concepts about climate change and POPs are introduced, the methods which will be used in the applicative part are described, and a review on the consequences of climate change on POPs behavior and on POPs-related activities (i.e. monitoring, modeling and regulation) is presented.
In the application section, multimedia fate and transport models are applied in order to investigate the climate change effect on POPs environmental behavior through the development of two case studies. The first model exercise aims at understanding which factors are more effective in determining POPs environmental behavior under a climate change scenario through the application of a global fate and transport model (BETR Global) to two climate scenarios, a present climate scenario and the A2 climate change scenario, a reference climate change scenario defined by the Intergovernmental Panel on Climate Change (IPCC). The second case study consists on the creation of a level III fugacity model for the Adriatic Sea, and is evaluated and then is parameterized following the A1B climate change scenario as it is defined by the IPCC in order to investigate which is the effect of climate change on POPs environmental distribution and concentration.Ricostruzioni temporali dell’andamento climatico dimostrano come esso sia in continuo cambiamento. Sono numerose le osservazioni sperimentali a scala regionale e globale a favore della teoria del cambiamento climatico. Anche i microinquinanti organici (POP, Persistent Organic Pollutants) costituiscono una questione di interesse sopranazionale. Questa tesi di dottorato ha l’obiettivo di studiare in quale modo il cambiamento climatico possa influenzare il comportamento ambientale dei POP, sostanze prioritarie il cui comportamento ambientale dipende anche dalle variabili climatiche.
Nella prima parte della tesi saranno introdotte le tematiche di cambiamento climatico, POP e la metodologia che sarà poi sviluppata nella sezione applicativa seguente, ed è presentata una analisi delle conseguenze che il cambiamento climatico può avere sui vari aspetti connessi ai POP (in particolare sul monitoraggio, sulle attività modellistiche e sulle applicazioni legislative).
Nella seconda sezione saranno applicati modelli di fugacità per sviluppare le considerazioni di cui sopra attraverso due casi di studio. Il primo esercizio modellistico consiste nell’applicazione di un modello esistente a scala globale adattato a due scenari climatici, di cui uno presente a rappresentare lo stato attuale, ed uno scenario di cambiamento climatico A2 come definito dal Pannello Intergovernativo sul cambiamento climatico (IPCC). Il secondo consiste nella costruzione di un modello di fugacità di III livello a scala regionale i cui risultati sono confrontati con valori provenienti da osservazioni sperimentali, e poi è parametrizzato in modo da rappresentare lo senario A1B come definito dall’IPCC in modo da valutare quali fattori influenzino significativamente la distribuzione ambientale dei composti organici considerati
Investigating the environmental fate of active pharmaceutical compounds in a coastal lagoon using a multimedia level III fugacity model
No full textThe use of active pharmaceutical ingredients (APIs) has enhanced life quality and longevity but poses significant environmental risks to ecosystems and human health. Evidence-based risk assessments are essential for addressing these issues, requiring detailed data on API presence, behavior, and effects in the environment. In particular, predictive exposure models offer a cost-effective tool to support such investigations. This study focuses on the application of a multimedia level III fugacity model to estimate the predicted environmental concentrations (PECs) and to simulate transport, distribution, and persistence of nine APIs in the Venice Lagoon (Italy), a transitional environment subjected to multiple anthropogenic stressors. Concentrations of the studied APIs in water were estimated within one order of magnitude of measured data, while the model underestimated the concentration of azithromycin and 17-β-estradiol in the sediments due to water half-life overestimation and lack of information about unmonitored emission sources. In detail, the highest levels of APIs in the water were estimated for amoxicillin and clarithromycin, while sediments showed a significant presence of azithromycin and ciprofloxacin. Model results also showed the possibility for sediments to act as sink for azithromycin, ciprofloxacin, erythromycin, estrone, and 17-β-estradiol. For all target APIs, degradation in the water column and adjective outflow were the most important elimination processes, while degradation in the sediments was significant only for erythromycin, ciprofloxacin, and clarithromycin. Monte-Carlo uncertainty and sensitivity analysis showed that degradation in water, affinity to organic matter, and sediment dynamics were the parameters with the strongest influence on model’s results. Overall, this work provided valuable information on the environmental fate and behavior of the investigated APIs in a complex transitional waterbody such as the Venice Lagoon and can be useful to support future environmental risk assessments as well as studies to evaluate the effects of emission control measures (e.g., restriction of use, substitution, or implementation of new technologies for wastewater treatment) on APIs environmental exposure
Fate and transport of ten plant protection products of emerging concern in a coastal lagoon: application and evaluation of a multimedia level III fugacity model
Full text linkMultimedia fugacity models are effective tools for studying the environmental behaviour and occurrence of contaminants of emerging concern (CECs) and assessing associated risks, especially when experimental data is limited. These models describe processes controlling chemical partitioning, transport, and reactions in environmental media using mathematical statements based on the concept of fugacity.
To aid in identifying and prioritizing CECs for future local monitoring, we present here the application of a level III multimedia fugacity model assuming non-equilibrium between compartments and steady-state conditions. This model estimated predicted environmental concentrations (PECs), persistence, distribution, and transport of ten plant protection products (PPPs) in the Venice Lagoon, a complex coastal environment under high anthropogenic pressure.
The model was evaluated through uncertainty and sensitivity analysis using the Monte Carlo approach and by comparing PECs with PPP concentrations measured during four sampling campaigns. Results showed good agreement with field data, with the highest concentrations in water and sediments estimated for glyphosate, followed by imidacloprid, metaflumizone, and triallate. The model indicated accumulation of all investigated PPPs in sediments. For most chemicals, advection outflow and degradation in the water column were the main removal mechanisms, while volatilization was significant only for oxadiazon and triallate.
Sensitivity and uncertainty analysis revealed that degradation rates, organic carbon/water partitioning coefficients (KOC), and parameters describing air-water interactions had the strongest influence on the model’s results, followed by inputs accounting for sediment sinking and resuspension. The lack of data on PPP degradation in brackish waters accounted for most of the uncertainty in model results.
This work shows how a relatively simple multimedia model can offer new insights into the environmental behaviour of PPPs in a complex transitional waterbody such as the Venice lagoon, providing useful data for the identification of the CECs to be prioritised in future local monitoring efforts
Modeling the influence of climate change on the mass balance of polychlorinated biphenyls in the Adriatic Sea
No full textClimate forcing is forecasted to influence the Adriatic Sea region in a variety of ways, including increasing temperature, and affecting wind speeds, marine currents, precipitation and water salinity. The Adriatic Sea is intensively developed with agriculture, industry, and port activities that introduce pollutants to the environment. Here, we developed and applied a Level III fugacity model for the Adriatic Sea to estimate the current mass balance of polychlorinated biphenyls in the Sea, and to examine the effects of a climate change scenario on the distribution of these pollutants. The model's performance was evaluated for three PCB congeners against measured concentrations in the region using environmental parameters estimated from the 20th century climate scenario described in the Special Report on Emission Scenarios (SRES) by the IPCC, and using Monte Carlo uncertainty analysis. We find that modeled fugacities of PCBs in air, water and sediment of the Adriatic are in good agreement with observations. The model indicates that PCBs in the Adriatic Sea are closely coupled with the atmosphere, which acts as a net source to the water column. We used model experiments to assess the influence of changes in temperature, wind speed, precipitation, marine currents, particulate organic carbon and air inflow concentrations forecast in the IPCC A1B climate change scenario on the mass balance of PCBs in the Sea. Assuming an identical PCBs' emission profile (e.g. use pattern, treatment/disposal of stockpiles, mode of entry), modeled fugacities of PCBs in the Adriatic Sea under the A1B climate scenario are higher because higher temperatures reduce the fugacity capacity of air, water and sediments, and because diffusive sources to the air are stronger. © 2012 Elsevier Ltd
Climate change effects on POPs’ environmental behaviour: a scientific perspective for future regulatory actions
No full textSince the adoption of the United Nations Framework Convention on Climate Change, international efforts were aimed
at limiting global change, and at managing and reducing its inevitable impacts. The growing concern on climate change
related issues lead to create international agreements such as the Kyoto Protocol, and to establish the
Intergovernmental Panel on Climate Change aimed at studying climate evolution and at defining common actions
through the adoption of joint climate change mitigation and adaptation measures. From the time when international
Task Forces, projects and programs were shared in order to deal with the reduction of environmental exposure to
persistent organic pollutants (POPs), international organisations have also been committed to estimate how climate
change may affect POPs’ environmental behaviour and distribution. In this review paper, we report the track of POPs’
regulation efforts driven towards decreasing POPs’ environmental concentrations through reducing or banning POP
emissions in the environment. We also report scientific studies on climate change related effects on POPs’
environmental behaviour in order to feature how climate change is influencing POPs’ fate and transport. Our final aim
is to identify how POPs–related regulations may take into account climate change in managing current or future POPs
sources. We find in several case studies on this topic that climate change is considered to contribute to enhance POPs’
long–range transport and that remote areas are considered likely to be the most impacted by POPs’ pollution under a
climate change perspective. Our findings also consider that continuous monitoring programs oriented towards the
observation of secondary POP sources and the enhancement of inventories reporting primary and secondary POP
emissions are useful in dealing with POPs’ exposure under climate change scenarios. We also suggest how
communication between science and regulation should be driven towards considering climate change effects into
chemicals’ legislation
Role of Physiologically Based Kinetic modelling in addressing environmental chemical mixtures – A review
No full textThe role of Physiologically Based Kinetic (PBK) modelling in assessing mixture toxicology has been growing for the last three decades. It has been widely used to investigate and address interactions in mixtures. This review describes the current state-of-the-art of PBK models for chemical mixtures and to evaluate the applications of PBK modelling for mixtures with emphasis on their role in chemical risk assessment. A total of 35 mixture PBK models were included after searching web resources (Scopus, PubMed, Web of Science, and Google Scholar), screening for duplicates, and excluding articles based on eligibility criteria. Binary mixtures and volatile organic compounds accounted for two-thirds of the chemical mixtures identified. The most common exposure route and modelled system were found to be inhalation and rats respectively. Twenty two (22) models were for binary mixtures, 5 for ternary mixtures, 3 for quaternary mixtures, and 5 for complex mixtures. Both bottom-up and top-down PBK modelling approaches are described. Whereas bottom-up approaches are based on a series of binary interactions, top-down approaches are based on the lumping of mixture components. Competitive inhibition is the most common type of interaction among the various types of mixtures, and usually becomes a concern at concentrations higher than environmental exposure levels. It leads to reduced biotransformation that either means a decrease in the amount of toxic metabolite formation or an increase in toxic parent chemical accumulation. The consequence is either lower or higher toxicity compared to that estimated for the mixture based on the additivity principle. Therefore, PBK modelling can play a central role in predicting interactions in chemical mixture risk assessment
Introducing an integrated climate change perspective in POPs modelling, monitoring and regulation.
No full textThis paper presents a review on the implications of climate change on the monitoring, modelling and regulation of persistent organic pollutants (POPs). Current research gaps are also identified and discussed. Long-term data sets are essential to identify relationships between climate fluctuations and changes in chemical species distribution. Reconstructing the influence of climatic changes on POPs environmental behaviour is very challenging in some local studies, and some insights can be obtained by the few available dated sediment cores or by studying POPs response to inter-annual climate fluctuations. Knowledge gaps and future projections can be studied by developing and applying various modelling tools, identifying compounds susceptibility to climate change, local and global effects, orienting international policies. Long-term monitoring strategies and modelling exercises taking into account climate change should be considered when devising new regulatory plans in chemicals management. Climate change implications on POPs are addressed here with special attention to monitoring, modelling and regulation issues
Grouping of multi-walled carbon nanotubes to read-across genotoxicity: A case study to evaluate the applicability of regulatory guidance
No full textMulti-walled carbon nanotubes (MWCNTs) consist of multiple layers of graphene sheets in a tubular shape. Depending on the synthesis and purification method, MWCNTs may differ in size, shape, rigidity and other properties. Previous research has shown that physicochemical properties can influence the translocation and toxicity of MWCNTs. Extensive in vitro and in vivo testing may be required to characterise the hazard of various physical forms of MWCNTs. Grouping of MWCNTs to read-across data for toxicological endpoints could efficiently contribute to reduce and focus MWCNT testing. This paper describes a case study to explore and illustrate read-across of genotoxicity data by following the “Recommendations for nanomaterials applicable to the Guidance on QSARs and Grouping”, developed by the European Chemicals Agency (ECHA). The grouping hypothesis was supported by the use of chemoinformatics techniques such as hierarchical clustering and principal components analysis. The uncertainties of the present case study were evaluated using the Read-Across Assessment Framework (RAAF) developed by ECHA. While the aim of this study was not to conduct a hazard assessment, the study data chosen for illustrative purposes suggest that the MWCNTs analogues selected are not genotoxic. No (major) differences between the analogues were observed which could be attributed to differences in physicochemical properties such as length, diameter or rigidity/straightness. Such properties, however, may have an impact on other hazard endpoints such as carcinogenicity. This study shows the practical application of the ECHA framework for grouping of nanomaterials (NMs) as well as use of the ECHA RAAF for NMs, and how this can be supported by chemoinformatics techniques. Some adaptations to the workflow are suggested for a more practical and straightforward narrative in the reporting
Modeling the Global Levels and Distribution of Polychlorinated Biphenyls in Air under a Climate Change Scenario
No full textWe used the multimedia chemical fate model BETR Global to evaluate changes in the global distribution of two polychlorinated biphenyls, PCB 28 and PCB 153, under the influence of climate change. This was achieved by defining two climate scenarios based on results from a general circulation model, one scenario representing the last twenty years of the 20th century (20CE scenario) and another representing the global climate under the assumption of strong future greenhouse gas emissions (A2 scenario), The two climate scenarios are defined by four groups of environmental parameters: (1) temperature in the planetary boundary layer and the free atmosphere, (2) wind speeds and directions in the atmosphere, (3) current velocities and directions in the surface mixed layer of the oceans, and (4) rate and geographical pattern of precipitation. As a fifth parameter in our scenarios, we consider the effect of temperature on primary volatilization emissions of PCBs. Comparison of dynamic model results using environmental parameters from the 20CE scenario against historical long-term monitoring data of concentrations of PCB 28 and PCB 153 in air from 16 different sites shows satisfactory agreement between modeled and measured PCBs concentrations. The 20CE scenario and A2 scenario were compared using steady-state calculations and assuming the same source characteristics of PCBs. Temperature differences between the two scenarios is the dominant factor that determines the difference in PCB concentrations in air. The higher temperatures in the A2 scenario drive increased primary and secondary volatilization emissions of PCBs, and enhance transport from temperate regions to the Arctic. The largest relative increase in concentrations of both PCB congeners in air under the A2 scenario occurs in the high Arctic and the remote Pacific Ocean. Generally, higher wind speeds under the A2 scenario result in more efficient intercontinental transport of PCB 28 and PCB 153 compared to the 20CE scenario. Our modeling indicates that in a future impacted by climate change,we can expect increased volatilization emissions and increased mobility of persistent organic pollutants with properties similar to those of PCBs
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