Title of Example

Example

Introduction

The area around Venice is a particularly complicated ecosystem within which 1,5 million people live. In this relatively small area you can find a city of art, a somewhat environmentally fragile lagoon area, high population density urban areas and an important industrial area, Porto Marghera.

Porto Marghera is famous for its petrochemical industry based on mainly chlorine chemistry which has caused quite a bit of controversy because of its impact on the environment.

Other production cycles are those related to the production of caprolactam, acetonecyanohydrin, hydrocloroflourinecarbides, hydroflorinecarbides and acrylic fibres. Apart from the petrochemical plants, other industries present in the area are:

- a petrol refinery;

- industrial plants for the production and transformation of non-ferrous metals (aluminium, copper and zinc);

- seven thermoelectric power plants;

- five waste incinerators.

Two years ago, the local authority (Province of Venice, Environmental Policy Dept.) launched a full–scale inquiry into the effects and health hazards caused by industrial emissions.

Within this inquiry, our task was to estimate and evaluate those potentially dangerous industrial emissions released and dispersed over the last 40 years and to examine if these had affected, in any way, the local population.

Targeting exposure and inhalation pathways, the case study began with the process and technological analysis applied in Porto Marghera over the past 40 years. Then, more than 1000 emission points of TSP, SO₂, NO_X, Pb, Cd, Hg, Benzene, Dioxins and other chlorine products were estimated using emission factors and data retrieved from local archives. Finally, pollutant emission dispersion and soil concentration values were modelled using the U.S, EPA, ISC Model. 40 maps were made up to indicate the levels of soil pollution over the past 4 decades and to provide information on the level of population exposure to help the epidemiological survey.

The second step was to compare present emissions and modelled dispersion with the results of air quality control. Using the year 2001 as a reference point, TSP, SO₂, and NO_X emissions were estimated and pollutant emission dispersions along with soil concentration values were modelled using the U.S. EPA, ISC Model. Hence, it was possible to carry out a comparison between modelled and monitored data so as to validate the model and the method of analysis.

Evaluation of Polluting Emissions

This stage of the project focused on rating the quality and quantity of the principal carcinogenic pollutants from 1962 until 2001. In particular, Dioxin and other chlorinated by-products such as: mercury, benzene, cadmium and lead were put under major scrutiny. The study also covered pollutants such as TSP, SO₂, NO_X, generally considered responsible for a number of chronic pathologies.

The analysis started off by using a series of indicators, taken from different sources, to define the point of emission peculiarity (high mass flow rate emissions and others) and emission factors in reference to the type of process and pollution reduction technologies applied.

Ei = A x EFi (1)

Where:

- Ei = mass flow of i – pollutant emitted (kg/year);

- A = activity key parameter, ex: raw material consumes, fuel fired, final product obtained (ton/year);

- EFi = Emission factor for i - pollutant (kg pollutant/ton fuel).

The historical rating of pollutants released over the past 40 years has required both a bibliographical and historical study of industrial process analysis based on documentation registered by the Public Authority on Prevention and Control concerning the main characteristics of industrial plants.

This kind of analysis provided awareness of process layout, modifications spanning the last 40 years, the opening of new production lines and the closing down of old ones and also led to an inquiry into the characteristics of pollutant treatment systems.

Following the same study guidelines carried out in the year 2001, the year taken as reference point to model the monitored air quality data , we were able to compare estimated emission values using emission factors with monitoring data and legally enforced control data along with what was openly declared by the companies which make the Area Evaluation Pact Foreseen for Porto Marghera in accordance with the Chemical Agreement. With these values at hand, the competent authorities can then verify and control all the monitored data with those declared and supplied by the companies while, at the same time, taking into consideration the origins and margins for improvement by applying BATs (Best Available Technologies).

Table 1 - Grid view estimating polluting emissions

Figure. 1 - Estimated air emission values

Exposure to Polluting Emissions

The study, in particular, targeted on exposure and inhalation pathways. To achieve this we began by measuring the concentration of each pollutant in the atmosphere along with the exposure times for each one.

The release of pollutants into the atmosphere and their fall out on soil was simulated through models of different industrial plant technologies from the 60s until today so as to identify those environmental elements and those people exposed to the airborne pollutants.

Evaluation of the atmospheric dispersion of pollutants from 1960 until now has been based on the use of climatic models. For historical analysis in particular, data containing yearly averages were used based on values recorded over a period of 40 years regarding typical weather factors such as wind velocity, frequency and direction, temperature and other factors. For the 2001 study , the data was based on an hourly average measured by automatic pollution control stations managed by Ente Zona and by ENEL Spa. The study of pollutant concentration and fall out was carried out with the ISC (Industrial Source Complex) calculation code and in particular, the release 4.6 ISCAERView mode software developed by Lakes Environmental.

In the end, this was carried out through GIS (Geographic Information System), a digital information representation of the Province of Venice, which highlighted the most critical areas and how the populations living there were affected. The purpose of this step was to simplify the epidemiological study, which will be carried out at the same time as this task.

Results

The results of the study, recorded in a fairly large file, describe the processes and plants of the Porto Marghera industrial areas from 1962 until today. The report also contains mass flow rate values for the examined 10 pollutants released over the last 40 years, how and why this came about and the evolution starting from the introduction of new technologies and techniques along with all the new environmental legislation. The first report also contains the exposure scenarios and the intake cycle of such pollutants.

The case study results have been laid out, coded and mapped onto digital support so as to obtain a practical tool which makes simple and fast reading and will certainly be helpful in the future when and if new projects will have to be devised and drawn up.

Therefore what we have available is:

- an alphanumeric database with more than 1000 entries;

- the trend of polluting emissions subdivided sector by sector along with the major contributors to each single scenario;

- 40 maps indicating pollution fall out onto the soil at different times over the past 40 years;

- pollution concentrations in the soil and, once again, the major contributors to each single scenario;

- the digital representation by GIS of the most exposed areas in the Province of Venice.

Figure 2 - Dioxin fallout map (decade 80 – 90) data in fentogramme mass/m³

A further result consists in simulating the deposition values to the surface for emissions of PTS, NO_X and SO_X in those locations where air and soil monitoring stations had been installed. Comparing data on the typical daily trend obtained through simulation, with data obtained through the monitoring system, the concurrence between the two different values and the effectiveness of the method, as for SO₂ (figure 3) is concerns, proves more than satisfactory. As for NO_X and TSP, the influence of traffic emissions and household heating emissions did not, on the other hand, allow any effective comparison.

Figure 3 - Monitoring station for Malcontenta: comparison between monitored concentrations of SO₂ vs. modelled on daily average in reference to weather data monitored by two meteorological stations known as: 22 and 5

Table 2 - Extract from figure 3: major plants sharing to the pollution concentration in the atmosphere

Acknowledgements

This text has been kindly made available from the Province of Venice Authority.

See the full text document(in Italian language):

Past and Present Environmental Analysis of the Porto Marghera Industrial Area

See the Maps at the website:

http://www.provincia.venezia.it/proveco/area/epidemio/epidemio.htl

Last Updated

13th January 2005