Carlo Gaggi

BIOCONCENTRATION OF ORGANIC CHEMICAL VAPOURS IN PLANT LEAVES : THE AZALEA MODEL

Abstract Experimental data on the accumulation and release kinetics of azalea leaves exposed to constant vapour levels of alachlor, dieldrin and 3,4,3′,4′-tetrachlorobiphenyl are reported. Calculated leaf/air bioconcentration factors for these and other 11 organic chemical vapours are used to improve a correlation with the 1- octanol water and air/water equilibrium partition coefficients.

Chlorinated hydrocarbons in plant foliage: an indication of the tropospheric contamination level

Abstract Levels of some chlorinated hydrocarbons in foliage from the Italian peninsula and other countries of the world are reported. The use of plant leaves in monitoring and for the prediction of potential environmental distribution of persistent hydrophobic pollutants is discussed.

Chlorinated dioxins: volatilization from soils and bioconcentration in plant leaves.

Polychlorinated dibenzodioxins (PCDDs) are a group of xenobiotics of extreme environmental interest, by virtue of their high toxic potential, coupled with high bioaffinity and resistance to degradation. One in particular (2,3,7,8tetrachloro dibenzo-p-dioxin, 2,3,7,8-TCDD), is probably the most poisonous substance ever introduced into the environment. PCDDs are not intentionally produced, but mainly arise from combustion processes and certain industrial activities; all the sources of these substances are not yet completely known (Hutzinger and Fiedler 1989). However, loads to the environment are certainly significant as PCDD residues may be found in many different environmental matrices (Jones and Bennet 1989).

Polychlorinated biphenyls in plant foliage: Translocation or volatilization from contaminated soils?

Physical properties such as water solubility, vapor pressure, and Henrys law constant suggest that polychlorinated biphenyls (PCBs) can easily reach the troposphere as vapor. The potential of plant foliar tissues to take up PCBs as vapor has probably been underrated in some of the previous works. Nevertheless recently it was reported that the level of PCBs found in the foliage is mainly due to vapor transport from the soil, rather than to translocation through the plant. This research has been planned to assess the influence of translocation on the concentration of PCBs in the foliage of different plant species.

Geothermal power plants at Mt. Amiata (Tuscany–Italy): mercury and hydrogen sulphide deposition revealed by vegetation

At Mt. Amiata (Italy) geothermal energy is used, since 1969, to generate electricity in five plants with a nominal capacity of 88 MW. Anomalous levels of mercury characterise geothermal fluids of Mt. Amiata, an area renowned for its vast cinnabar deposits and for the mercury production carried out in the past. Mercury emission rates range from 300 to 400 g/h, or 3-4 g/h per MW electrical installed capacity. These emissions are coupled with a release of 7-8 kg/(h MW) of hydrogen sulphide (H2S). Mercury is discharged as Hg0 gaseous species and reaches the atmosphere with the non-condensable gas fraction. In this fraction, CO, is the major component (94-98%), H2S is around 1% and mercury concentration is as high as 1-10 mg/Nm3. Leaves of a spontaneous grass (Avena sterilis), at the end of the vegetative cycle, were used as mercury bioconcentrators to map deposition near geothermal power plants and to calculate the corresponding average levels of Hg0 in the air. Direct measurements of mercury and hydrogen sulphide vapours in the air reached by power plant emissions showed a ratio of about 1-2000. This ratio was applied to calculate average levels of hydrogen sulphide starting from mercury deposition mapping: typical concentrations of mercury and hydrogen sulphide were of the order of 10-20 ng/m3 and 20-40 microg/m3, respectively.

Antiproliferative activity of lichen extracts on murine myeloma cells

In the present study we report some preliminary results concerning the evaluation of antiproliferative activity on murine myeloma cells (P3X63-Ag8.653) of crude extracts of two common lichen species, Evernia prunastri and Xanthoria parietina.The results were evaluated by means of the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] test, which is commonly used to assess the activity of living cells through mitochondrial dehydrogenases. They indicated that extracts of E. prunastri had no effect, while those of X. parietina significantly affected murine myeloma cell proliferation, with a reduction down to 75% for methanolic extracts. This opens perspectives for deeper investigations extended also to other mammalian cell lines.

Models, field studies, laboratory experiments: An integrated approach to evaluate the environmental fate of atrazine (s-triazine herbicide)

Abstract A 3-step procedure was applied to the study of the environmental distribution and fate of atrazine. This comprised: (1) physical-mathematical models, following the fugacity approach; (2) field studies of the disappearance of atrazine from treated soil and a contaminated lake; (3) laboratory experiments to evaluate the main routes of disappearance of atrazine from fortified soils and waters. Models were used to evaluate the main trends in the environmental distribution of atrazine and to point out potential reservoirs and sinks. On the basis of these evaluations, field experiments were planned. Laboratory experiments were carried out to analyse the information from the field, by individual study of the main transport and transformation mechanisms. Through water runoff and leaching, atrazine tends to move from treated soils to water compartments. Volatilization from soils and water seems negligible. In water, the bioaccumulation potential of this chemical is poor (BCF c. 10, for fish muscle). The degradation in soil follows pseudo-I-order kinetics, t 1 2 around 50 days; similar kinetics have been found for atrazine degradation in natural lake waters, but with a slower rate ( t 1 2 = 168 days ).

The real water consumption behind drinking water: The case of Italy

The real amount of drinking water available per capita is a topic of great interest for human health and the economic and political management of resources. The global market of bottled drinking water, for instance, has shown exponential growth in the last twenty years, mainly due to reductions in production costs and investment in promotion. This paper aims to evaluate how much freshwater is actually consumed when water is drunk in Italy, which can be considered a mature bottled-water market. A Water Footprint (WF) calculation was used to compare the alternatives: bottled and tap water. Six Italian brands of water sold in PET bottles were inventoried, analysed and compared with the public tap water of the city of Siena, as representative of the Italian context. Results showed that more than 3 L of water were needed to provide consumers with 1.50 L of drinking water. In particular, a volume of 1.50 L of PET-bottled water required an extra virtual volume of 1.93 L of water while an extra 2.13 L was necessary to supply the same volume of tap water. These values had very different composition and origin. The WF of tap water was mainly due to losses of water during pipeline distribution and usage, while WF of bottled water was greatly influenced by the production of plastic materials. When the contribution of cooling water was added to the calculation, the WF of bottled water rose from 3.43 to 6.92 L. Different strategies to reduce total water footprint are discussed.

Mercury vapour accumulation in azalea leaves

Abstract Experimental data on the accumulation and release kinetics of azalea leaves exposed to a constant vapour level of mercury is reported. The accumulation of mercury appears to be irreversible, probably as a consequence of chemical transformation. Potential applications and implications on the biogeochemical cycle of mercury are discussed.

The adaptive response of lichens to mercury exposure involves changes in the photosynthetic machinery.

Lichens are an excellent model to study the bioaccumulation of heavy metals but limited information is available on the molecular mechanisms occurring during bioaccumulation. We investigated the changes of the lichen proteome during exposure to constant concentrations of mercury. We found that most of changes involves proteins of the photosynthetic pathway, such as the chloroplastic photosystem I reaction center subunit II, the oxygen-evolving protein and the chloroplastic ATP synthase β-subunit. This suggests that photosynthesis is a target of the toxic effects of mercury. These findings are also supported by changes in the content of photosynthetic pigments (chlorophyll a and b, and β-carotene). Alterations to the photosynthetic machinery also reflect on the structure of thylakoid membranes of algal cells. Response of lichens to mercury also involves stress-related proteins (such as Hsp70) but not cytoskeletal proteins. Results suggest that lichens adapt to mercury exposure by changing the metabolic production of energy.