Trace elements: critical insights from 15 years of monitoring in the Venice Lagoon catchment basin (Italy).

The study focused on selected trace elements (As, Cd, Cr, Hg, Ni, Pb) monitored in surface waters of the Venice Lagoon catchment basin (North East Italy) over the period 2000-2015. The monitoring was undertaken to verify the achievement of the quality objectives set by the European and national legislations. The available results have been analyzed to evaluate the chemical status of water bodies. The limit of quantification (LOQ) of the applied analytic techniques appears critical for the adequate water monitoring; for some parameters, the percentage of not visible values due to non-satisfactory LOQ was higher in the beginning of the period; the subsequent improvement of LOQ allowed assessing the respect of environmental quality standards (EQSs). The study analyzes time trends in single stations and the differences between detected concentrations in the considered stations. Moreover, maximum concentrations and water flows have been considered to understand the potential correlation. Cumulated frequency curves for the most critical parameters have been built to identify situation of potential overtaking of the EQSs in force. The most polluted sampling stations of the drainage basin for the six trace elements were found in Cuori and Fiumazzo rivers. Although LOQs changed over time, the recorded trends show a quality improvement and a good compliance with respect to EQSs set by European legislation, while considering EQSs set by local special legislation, the objectives are not yet satisfied. Arsenic is ubiquitous; thus, it can be supposed to be originated as a background environmental concentration, while nickel appears of industrial origin according to its point and local presence.

Assessing the fluvial system resilience of the river Bacchiglione to point sources of pollution in Northeast Italy: a novel Water Resilience Index (WRI) approach.

Modelling and evaluating the resilience of environmental systems has recently raised significant interest among both practitioners and researchers. However, it has not yet been used to measure the absorption and recovery capacities of a river subject to varying levels of pollution due to natural and anthropic sources of contamination within the basin. Fast worldwide population growth and climate change are contributing to an increased degradation status in surface water bodies and to a decreased efficiency of their natural self-purification processes. Decision-makers are, therefore, more and more encouraged to implement alternative management strategies focussed on improving the system resilience to current and future perturbations. To this end, a novel Water Resilience Index (WRI), based on different quality parameters, was developed, and it is here proposed to estimate the ability of the river Bacchiglione, located in Northeast Italy, absorb continuous and unpredictable changes due to potential effects of point sources of pollution, that is, urban and industrial wastewater, and still maintain its vital functions. This new index is integrated in a mathematical model, which represents the river as an influence diagram where the nodes are the gauged stations and the arcs are the fluvial reaches among the stations, to identify the river reaches in need of resilience improvement. In addition, in order to simplify the analytical procedure and lower the costs and times of the monitoring activities, a principal component analysis is also used, as it is able to reduce the number of the water quality parameters to be collected from the sampling stations, distributed along the main river, and thus to calculate a minimum WRI. The good agreement between the results obtained by both the original and minimum WRI shows the effectiveness of the proposed methodology. This approach could be applied to all basins with the same issues, and not just in the Italian case study here analysed, as it might be a valid tool to plan interventions and mitigation actions, protecting the resource from pollution risks and achieving environmental quality and Sustainable Development Goals both in the water bodies and their surrounding territories. In addition, this strategy could be integrated in the existing models supporting local decision-makers and administrators, aiming at increasing the resilience of urban and rural areas to pollution phenomena and facilitating the development of effective policies to reduce the impacts of global change on water quality.

Financial liability for environmental damage: insurance market in Italy, focus on Veneto region experience.

Making good environmental damage caused by industrial accidents and restoring impaired ecosystems may be associated with high costs. The European Environmental Liability Directive requires that environmental damage is prevented or remediated and confers financial liability on operators responsible for the activities that caused the damage. The directive encourages adoption of financial risk instruments for environmental liability, ensuring that operators stand up for their responsibilities. We analyse the risk financing instruments for environmental liability in Italy, with emphasis on waste treatment and disposal plant management in Venice Metropolitan City, where financial guarantees and environmental insurance are mandatory. The regional legislation obliges operators of waste treatment plants to seek financial protection through financial guarantees and environmental insurance. We have conducted online survey and in-depth interviews with both suppliers and users of financial protection instruments. On national level, the relatively high environmental consciousness is countered by a low perception of risk and subsequently very low penetration of financial security instruments. Among the identified barriers, we have singled out a limited knowledge of cumulative and long-lasting impacts of industrial activities on environment and ecosystems. Financial and insurance are well developed, but a deep support for specific risk identification and coverage lacks. A closer cooperation between public and private sector can be an opportunity to foster the adoption of these instruments and to improve the coverage of public costs for environmental restoration, due to unattended liability.

Assessment of Pressure Sources and Water Body Resilience: An Integrated Approach for Action Planning in a Polluted River Basin.

The present study develops an integrated methodology combining the results of the water-quality classification, according to the Water Framework Directive 2000/60/EC-WFD, with those of a mathematical integrity model. It is able to analyse the potential anthropogenic impacts on the receiving water body and to help municipal decision-makers when selecting short/medium/long-term strategic mitigation actions to be performed in a territory. Among the most important causes of water-quality degradation in a river, the focus is placed on pollutants from urban wastewater. In particular, the proposed approach evaluates the efficiency and the accurate localisation of treatment plants in a basin, as well as the capacity of its river to bear the residual pollution loads after the treatment phase. The methodology is applied to a sample catchment area, located in northern Italy, where water quality is strongly affected by high population density and by the presence of agricultural and industrial activities. Nearly 10 years of water-quality data collected through official monitoring are considered for the implementation of the system. The sample basin shows different real and potential pollution conditions, according to the resilience of the river and surroundings, together with the point and diffuse pressure sources acting on the receiving body.

Modelling as decision support for the localisation of submarine urban wastewater outfall: Venice lagoon (Italy) as a case study.

Microbiological impact is critical in coastal areas where tourism is particularly important for both the local and regional economy. Submarine outfalls are commonly used to enhance the dispersion of treated sewage thus avoiding pollution along the coast. The Venice lagoon (North Italy) has a very sensitive ecosystem, due to the morphological and natural characteristics of the basin and the co-existence of human activities. To preserve the lagoon, the discharge from the treatment plant for urban wastewater collected from the Venezia-Mestre agglomeration, neighbouring areas and local industries (total of 400,000 population equivalent-PE) has been moved from the lagoon to the open Adriatic Sea since November 2013 by means of an approximately 20-km pipeline. Microbiological pollution inside the lagoon can affect shellfish breeding areas instead, along the coast it affects the quality of bathing waters. In this study, and for the first time, a 3D hydrodynamic SHYFEM model (shallow water finite element model) with high spatial resolution coupled with a microbiological module has been applied to the lagoon and to the Adriatic Sea, to evaluate the effectiveness of the location of the submarine outfall. Microbiological data have been produced by the control Authority according to official analytic methods and by the plant operator. The module of survival of free Escherichia coli follows a variable rate in dependence of UV radiation, temperature and salinity in the water. Two scenarios were modelled: final discharge into the lagoon before November 2013 and after into the open sea. In the latter case, two situations have been considered, one with "Bora" and the other with "Scirocco" winds. Our results indicate that the model correctly simulates microbiological decay and dispersion. The transferral of the final discharge point far from the shoreline improves pollution dispersion, thus preserving the lagoon without evidence of impacts on the bathing waters in all meteorological conditions.

Biologic impact on the coastal belt of the province of Venice (Italy, Northern Adriatic Sea): preliminary analysis for the characterization of the bathing water profile.

BACKGROUND, AIM AND SCOPE: This paper presents a preliminary study of the water profile with reference to microbiological parameters, required by Directive 2006/07/EC (European Community 2006) concerning the management of bathing water quality, in the coastal belt of the Province of Venice (Italy, Northern Adriatic Sea). A historical database has been implemented with monitoring data for the period 2000-2006 (data on rivers, bathing and marine coastal waters and on the characterization of Wastewater Treatment Plant (WWTP) discharges) from the institutional activity of Veneto Regional Environmental Prevention and Protection Agency (ARPAV). An integrated areal analysis for the microbiological investigation of homogeneous stretches along the coast of the Province of Venice was performed for a preliminary characterization of the bathing water profile considering water quality status and existing pressure sources. MATERIALS AND METHODS: ARPAV is the institutional body responsible for environmental monitoring and control activities. Data were produced from monitoring and controls made available by the Regional Environmental Informative System and extracted and elaborated for the period of interest (2000-2006). Sampling and analysis of microbiological parameters were executed following the official Italian methods in accordance with international procedures (APHA et al. 1998). For the purpose of this study, the coast was divided into eight stretches, which were considered to be homogeneous according to their physical and geographical characteristics. An ANOVA statistical assessment has been performed on stretches I, V and VIII. RESULTS AND DISCUSSION: From the integrated areal analysis of microbiological parameters in the homogeneous stretches along the coast of all the investigated matrices, high mean levels of faecal contamination were found in some cases. The most critical situation amongst the stretches evaluated is to be found in stretch VIII-Ca' Roman, Sottomarina and Isola Verde shores (Southern part of the Province). These results can be widely attributed to pressure sources from the Brenta and Adige rivers, rather than to local contributions. Stretches VI and VII, which correspond to the area from Punta Sabbioni (Cavallino shore N-E) to the Pellestrina shore (S-W), present the best conditions for faecal contamination parameters (low pollution levels). These situations can probably be explained given that WWTPs 7 and 8 have two submarine outfalls at a distance of about 4 km from the coastline and therefore a discharge point which is distant from the bathing and marine coastal monitoring stations; there are also no river mouths in these two stretches. Due to lack of data, it was not possible to implement seasonal assessments. CONCLUSIONS: This study aimed to develop an integrated areal analysis for biological parameters along the coast over the period 2000-2006 for the identified homogeneous stretches in order to develop a preliminary approach for the characterization of the water profile, as requested by directive 2006/7/EC. From the integrated analysis of the stretches, it is evident that in some cases there are high levels of faecal contamination along the coast which can be caused by river flows which heavily condition the quality of coastal waters as verified with the statistical assessment. RECOMMENDATIONS AND PERSPECTIVES: From the preliminary analysis, the submarine outfalls seem to be the best solution to guarantee good bathing water quality on the coast. Nevertheless, it must be observed that this solution cannot overlook the possible impact of the discharges on seawaters intended for a specific use, such as mussel farms with reference to coastal hydrodynamics. Therefore, a sound wastewater dispersion analysis on the discharges of the WWTPs for the identification of the interested area and the level of contamination must be performed; a modelling study on pollution dispersion is complementary to this study (Scroccaro et al. 2009). This analysis highlights the critical stretches as being numbers II and, above all, VIII with particular correlation with the main river mouths. Thus, it is evident that the issue of microbiological impact must be studied following a river basin approach according to the influence of river loads on coastal areas.

Submarine wastewater discharges: dispersion modelling in the Northern Adriatic Sea.

BACKGROUND, AIM AND SCOPE: Opposite interests must coexist in coastal areas: the presence of significant cities and urban centres, of touristic and recreational areas, and of extensive shellfish farming. To avoid local pollution caused by treated wastewaters along the Northern Adriatic coast (Friuli Venezia-Giulia and Veneto regions), marine outfall systems have been constructed. In this study, the application of a numerical dispersion model is used to support the traditional monitoring methods in order to link information concerning the hydrodynamic circulation and the microbiological features, to evaluate possible health risks associated with recreational and coastal shellfish farming activities. The study is a preliminary analysis of the environmental impact of wastewater treatment plants (WWTPs) with submarine discharge outfalls. It also could be useful for the water profile definition according to the Directive 2006/7/EC on the quality of bathing water and for the integrated areal analysis (Ostoich et al. 2006), to define the area of influence of each submarine discharge point. MATERIALS AND METHODS: Historical data on discharges of the considered WWTPs were recovered and evaluated. Data on discharges' control for Veneto region (WWTPs of Lido and Cavallino) were produced by the WWTPs' manager Veritas Laboratory service, while data for the WWTPs of Friuli Venezia-Giulia region were produced by the regional environmental protection agency in the institutional control activity following official methods. The hydrodynamic model used in this work is the three-dimensional version of the finite element model SHYFEM, developed at ISMAR-CNR (Marine Science Institute of the Italian National Research Council) in Venice (Umgiesser et al. J Mar Syst 51:123-145, 2008). RESULTS AND DISCUSSION: Numerical simulations have been carried out with the 3D version of the finite element model SHYFEM for 3 months during autumn 2007 to evaluate the bacterial pollution dispersion along the coasts of Veneto and Friuli Venezia-Giulia regions, prescribing meteo-marine forcings and concentration values at the points corresponding to the positions of the submarine outfalls. Model results show that during autumn 2007 the discharges of the submarine outfalls of the Venice province seem to have no impact on the surface water quality, while there are some visible effects in the Gulf of Trieste. This reflects the behaviour of the experimental data collected by ARPAV and ARPA FVG and monitoring campaigns both on water and shellfish quality. Further results have been elaborated to identify the area of influence of each discharge point; scenarios were developed with imposed concentrations. The results seem to highlight that the two discharges of the Veneto region are not noticeable, while the discharges of the Gulf of Trieste (in particular the Servola and Barcola ones) are perceptible. CONCLUSIONS: This study represents a new step towards the study of the microbiological pollution dispersion and impact due to the discharges of the submarine outfalls of the Veneto and Friuli Venezia-Giulia regions (nine considered discharge points). With the 3D version of the finite element model SHYFEM, the information obtained from the hydrodynamic circulation has been linked to the classical methods of analysis, to assess possible risks connected to the microbiological parameter Escherichia coli. RECOMMENDATIONS AND PERSPECTIVES: In future studies the time scale for microbiological parameters' decay could be linked to various environmental parameters such as light climate, temperature, and salinity. Interesting information would come from the study of new scenarios with different configurations of the discharge of the pipelines and/or the treatment plants and in particular from the improvements of the 3D version of the SHYFEM model, to take the stratification process into account which occurs during spring-summer, since the Northern Adriatic Sea is a very complex ecosystem, both as physical and ecological processes.