E. Barbolani

Residual heavy metal (Cu and Cd) removal byIris Pseudacorus

The uptake of Cu and Cd by the roots ofIris pseudacorus and its transport to rhizome and leaves were examined using solutions containing 0.5 and 5.0 mg L−1 of Cu and Cd. Heavy metal accumulation was measured while replacing the metal absorbed by the plants with daily introduction to restore the initial concentrations. The heavy metal accumulation by Iris p. was 1.01 g Cu and 0.69 g Cd kg−1 of fresh plant at the end of the tests for the solutions of 5.0 mg L−1 metal concentration, respectively.

Effects of acid fog and detergents on foliar leaching of cations

Relative rates of nutrient leaching from the epygeous apparatus of Quercus ilex L., Fagus sylvatica L., Acer opalus Mill., Euonymus japonicus L. and Phaseolus vulgaris L. were examined after exposure to simulated acid fog. Copper, Al, Fe, Mn, Ca, Mg, and Pb were preferentially leached at low pH, whereas leaching rates of Na, K, and Cd did not appear to be pH-influenced. Addition of surfactant to the spray solutions showed a slight reduction of leaching for all elements investigated. Except for Mg, foliar nutrient levels were not influenced during our experiments.

Mineral nutrients and trace metals in tree rings ofPinus sp.

SummaryCa, Mg, K, Na, Fe, Mn, Cu, Al, Zn, Pb, Cd, Rb have been determined in the rings of twoPinus sp. trees growing in different sites in Italy. Noticeable behavioral differences exist between nutrients and trace metals.

Elemental leaching from quercus ilex L. in response to simulated acidic fog

Quercus ilex L. seedlings were intermittently exposed to simulated acidic and non-acidic fogs in 6-hr events for 16 times. After a 1-mo break, treatments were carried out again for a 5 day period. Strong acidity neutralization, weak acidity release and cation leaching from foliage and stem were determined. Leaching of Al, Cu, Mn, Fe, Cd, Pb, Ca, Mg, and K increased in response to acid treatment. This effect was less marked for Na. A positive correlation between H− uptake and cation leaching was found. Cationic release and neutralization of strong acidity increased after breaks in acid treatment, but this faculty and the amount of leached cations and neutralized acidity decreased with time. The stem showed a higher cation loss and higher buffer capacity than the leaves.

Potentiometric titration of chlorine and its oxy compounds in water

Abstract Potentiometric titrations at constant current with identical platinum electrodes are applied to mixtures of chlorine, chlorine dioxide and chlorite. The procedure is compared with the common amperometric method. Chlorine can be titrated with phenylarsine oxide at pH 7 even in mixtures with chlorine dioxide and chlorite, and three-component mixtures can be resolved by titrations at pH 2 and 7 with and without iodide addition. The behavior of chlorine and chlorite mixtures can be characterized by appropriate titrations.

Incipient Forest Decline in the Province of Trento (Northern Italy). Preliminary Sem Observations and Consideration of Inorganic Components of Leaves and Roots

Abstract One year old needles of both healthy and damaged silver fir and Norway spruce from the area of Trento (Northern Italy) were observed by SEM. Needles of damaged trees show quite evident structural alterations of epidermis, expecially epicuticular waxes. Roots and needles of both fir and spruce are also tested for their metal content. Evidence is reported of an increasing concentration of Fe, Mg and Ca in roots of plants grown on alkali soil. Ca, and to a lesser extent Fe, Al and Pb, appears to be more present in old needles, whereas K and Mg exhibit higher amounts in young needles. Some indications are found between damage and the content of some metals such as Mg and Mn in needles.

A new approach to experimental data evaluation from tree ring analysis

SummaryA different approach is outlined for the correlation between the element values determined and the annual growth of tree rings in order to assess the total burden. Oxygen flask combustion and ion-chromatographic analysis has been applied to the determination of P, Cl and S in annual growth rings of Pinus pinea L. in Southern Sardinia (Italy). The high sensitivity of the method permits the analysis of individual growth rings using a minimum amount of material for the complete combustion. The preliminary investigation shows that a net increase of S, P and Cl over the last decade is evident both in concentration and in total quantity.

Acid deposition in the tuscan appennines during the dry period 1988-89

Abstract The typical parameters of acid precipitation are evaluated in the forest of Vallombrosa (Tuscan Appennines) during the dry period 1988-89. Individual rain events (dry and wet deposition) were sampled in a clearing of the forest and below the canopy of an evergreen tree as well as a deciduous broadleaf tree. In atmospheric precipitation the pH values usually vary around 4.4, with neutralization in the hot season due to calcareous material from distant sources. Relatively large concentrations of Pb and Cd are found in rain, but only in a small amount in canopy leachate. Aluminium, manganese and iron are more significantly washed off than Pb and Cd.

Comparison between colorimetric and electrometric methods for chlorine and its derivative compounds

A critical comparison of the usual methods for determination of C1 and OC1 compounds, particularly those used as sterilants in potable water plants, showed that theo-tolidine test is neither reproducible nor specific. ClO2 is best determined by Acid Chrome Violet K. The role of amperometric titration in distinguishing between the various sterilants and in examining the reactions involved in water chlorination is discussed.

Variazioni stagionali di nutrienti minerali ed elementi in traccia nelle foglie di Fagus sylvatica L. a Vallombrosa (FI)

Abstract Seasonal variations of mineral nutrients and trace elements in Fagus sylvatica L. leaves at Vallombrosa (FI). - During the vegetative periodo 1987 monthly samples of beech leaves were collected in Vallombrosa forest area to determine the nutritive situation of beech trees by leaves analysis. Among nutrients, potassium appears the worst supplied one. Even copper is present in very low values, under the critical level. Heavy metals as manganese, aluminium, lead, cadmium and also iron show a clear increase during the vegetative season.