Soil quality and vulnerability in a Mediterranean natural ecosystem of Central Italy.

Wet and dry atmospheric depositions and soil chemical and microbiological properties were determined in a Mediterranean natural ecosystem of Central Italy near Rome (Castelporziano Estate). The monitoring of depositions permitted us to quantify the exceedances of S and N compounds (expressed as eqH(+)ha(-1)year(-1)) over the critical loads of acidity. Critical loads, i.e. the quantity of a substance which a part of the environment can tolerate without adverse effects occurring, were determined adopting the level 0 methodology following the UN/ECE Convention on Long-range Transboundary Air Pollution. Deposition data were available for the period 1992-1997, and acidity exceedances were referred to the main vegetation types present in the area. Results showed that most part of the Estate has a medium degree of vulnerability to acidification, and the corresponding risk of acidification deriving from the exceedances of atmospheric deposition was rather low. The study of soil chemical and microbiological properties included mainly total soil organic carbon (SOC), microbial biomass-C, biomass-C/SOC, soil respiration, and metabolic quotient (qCO2). Soil organic C metabolism has been discussed on the basis of the results from eight sampling sites.

Application of an integrated environmental monitoring system to an incineration plant.

An integrated environmental monitoring system is an innovative approach which allows remarkable understanding of impacts due to a contamination source. Here we report results from environmental monitoring near a typical Italian incinerator plant. By means of mathematical dispersion models, zones of maximum pollutant depositions were determined; according to these simulations, a defined monitoring network was established. Heavy metals, chosen as environmental indicators, showed a wide flux range in gas emissions from the incinerator, over different sampling years. In particular, emissions in the year 2000 were marked by high Pb and Cd concentrations. Correspondingly, soil samples also exhibited a greater concentration of the same metals in 2000, than in previous years. Principal component analysis allowed a better visualisation of these similarities, also showing an interesting correlation between heavy metals observed both in gas emissions and in soil samples. Soil distant from the incinerator was found to be less affected by heavy metal contamination. Also atmospheric wet and dry depositions indicated a significant dependence on distance from incinerator, though extremely variable metal fluxes were registered during different months. Finally, vegetation samples, seasonal or evergreen, did not provide evidence of a significant heavy metal enrichment, apart from an apparent dependence on contamination source distance.

Long-term atmospheric deposition wet-dry fluxes. Critical loads exceedences in an urban area.

The present work provides an overview of the most relevant results concerning a five years monitoring programme of wet and dry deposition (1995-1999) in the city of Bologna. The aim of this research is to get an overall picture of atmospheric pollutants deposition inventory in an urban territory and to allow an assessment of the vulnerability of the area by comparing actual fluxes of acidity and nutrient nitrogen with the respective "critical loads" associated to the territory, in the framework of the UNECE LRTAP (Long Range Transboundary Air Pollution Convention). This comparison, for the Bologna monitoring station, shows "exceedance classes" from 4 to 6 for acidity and from 1 to 5 for nutrient nitrogen, reflecting an urban-industrial context, though a trend in reducing occurs from 1995 to 1999. A water layer surface sampler (DAS-MTX sampler) was employed for "surrogate" dry deposition collection. The contribute of dry fraction to the total deposition fluxes appears to prevail on wet fraction for many pollutants (up to more than 90% for total calcium and alkalinity). A comparison with long term monitoring results from some stations in Italian territory, shows that the differences among chemical species deposition fluxes may be ascribed both to the long distance aerial transport of pollutants and to site characteristics.

Methodological approach for an integrated environmental monitoring system relative to heavy metals from an incineration plant.

The use of an Integrated Environmental Monitoring System is an innovative and very important approach for the determination of environmental impacts due to a contamination source. In the present work, the methodological approach is described and applied to the case study of a MSW incineration plant. Heavy metals were chosen as Environmental Indicators. Gaseous emissions were measured and correlated to wet and dry depositions, soil and vegetation samples. Results show a good correlation between stack emissions and atmospheric depositions; less with soil and vegetation, but these results are important in order to design a standard procedure for an Integrated Monitoring System.