Title of Example

Example

Introduction

The implementation of an experimental network of biosensors to monitor air quality in Porto Marghera has been established by two permit decrees (dated 19.1.1999 and 7.9.1999), issued by the Italian Industry Ministry, respectively for the thermoelectric plants located in this industrial area and managed by two energy production companies (Enel Production and Edison thermoelectric).

What is bio-monitoring

Biological monitoring, or bio-monitoring, uses the response(s) of sensitive species called indicators to assess changes in the environment. Natural phenomena, human activity or a combination of the two can cause these changes. Bio-monitoring is a valuable assessment tool that is receiving increased use in air quality monitoring programs.

It uses some vegetal species like air quality sensors (biosensors).

These species can be classified in function of their presence in the area to be monitored:

- passive biosensors: sensitive species present spontaneously in the interested territory;

- active biosensors: sensitive species introduced intentionally in the interested territory;

- bio-indicators: sensitive species that present specific symptoms (for example spots on leaves) or that modifies their biological community characteristics (biodiversity) depending on some air pollutant concentrations;

- bio-accumulators: sensitive species that accumulate substances transported by air (for example trace elements) within their tissues and on external surfaces.

Monitoring and results characteristics in the Venetian area

Monitoring has started in the 2000; for the year 2004 a little change in the points location within the network is foreseen.

Three types of passive biosensors have been used:

- lichens (used as bio-indicators),

- lichens (used as bio-accumulators),

- tree leaves (used as bio-accumulators),

together with two types of active biosensors:

- grass in pots (used as bio-accumulators),

- moss-bags (used as bio-accumulators).

These biosensors have been sampled and analysed to determine a number of chemical substances. Data have been used to calculate an air quality index linked to the complex of anthropogenic and natural sources of atmospheric emissions present in this territory. The network is made up of different sampling points, distributed on a regular basis, on a 400 km² surface area, as underlined in Figure 1.

Figure 1 – Bio-monitoring network in Mestre - Marghera

Table 1 - Number of monitoring stations (biosensors).

South of Mestre lichens biodiversity shows a decrease during the years, probably due to the presence of a higher concentration of nitrogen and sulphur oxides than the other interested areas. In any case, compared to 2000, south of Marghera there is an improved air quality situation.

As regards data on bioaccumulation in lime leaves, stations directly influenced by industrial and road traffic air pollution (light-duty and heavy-duty traffic) show Cr, Mn and V concentrations quite higher.

The investigation of active bio-accumulators (Lolium Sp. and moss bags) exposure cycles during the 3 year-experiment, has shown that the most interesting monitoring stations are located:

- inside and in the surroundings of Porto Marghera industrial area;

- in the sites more affected by road traffic emissions.

This situation confirms, in general, what has already been noticed through lichens. Furthermore, also these biosensors show Cr and Mn concentrations rather higher than the ones located in the industrial area.

As to biosensors, the group of stations sited in the South area do not present regular “attention situations” in time and it shows, in most cases, that trace elements concentration values are not particularly relevant.

High concentrations episodes seem referable to local emission sources, both for the distribution and the distance from industrial area.

Conclusions

The more populated areas (Porto Marghera industrial complex, the harbour and the main traffic arteries) differ much more, in terms of air quality, from the rest of the territory.

Bio-monitoring studies have been carried out in many cities in Europe and in Italy.

In the 90s, the Veneto Region has carried out on its territory a wide research on air quality, using on lichens as bio-indicators and bio-accumulators.

Anyway, data referred to 2002 underline an improvement compared to the past. That is why it is important to go on with these studies and to improve the information linking the bio-monitoring network with the atmospheric deposition one (the so-called “depobulk” system). These networks combine (but do not replace) the conventional air quality monitoring network established by the EC and national legislation.

Last Updated

13th January 2005