Tree bark as a bioindicator of the presence of scandium, yttrium and lanthanum in urban environments.

Although rare earth elements (REEs) are important in modern industry, few processes use them, so the possibility of these elements being dispersed in the environment is small. For this reason, there are few studies on their presence in urban environments. REEs exhibit similar chemical properties, and Group 3 elements may be used as indicators of the presence of other REEs in the environment. Tree bark is a suitable collector of airborne trace elements and has been successfully used as a bioindicator. In this study, samples of holm oak bark were collected from three sampling sites subjected to different anthropic pressures (one area is far from human influence, while the other two sites are urban areas characterized by different types of human impact). The reference area is significantly different from urban areas where the concentrations measured are up to 5 times higher (Y) than the reference area. The differences between the two urban areas are also significant. The presence of industrial activities causes a 50% higher exposition of the population with respect to an urban area where only residential activities are present. In the case of La, there is no significant difference between the reference and the residential areas, while the industries are responsible for higher La concentrations (0.9 µg g-1vs. 0.4-0.6 µg g-1). The availability of samples, due to the wide distribution of trees in urban environments, makes possible the production of maps indicating the sources of these elements and highlighting areas which are critical for certain atmospheric pollutants.

Iron overload detection in rats by means of a susceptometer operating at room temperature.

Biosusceptometry is a non-invasive procedure for determination of iron overload in a human body; it is essentially an assessment of the diamagnetic (water) and paramagnetic (iron) properties of tissues. We measured in vivo iron overload in the liver region of 12 rats by a room temperature susceptometer. The rats had been injected with sub-toxic doses of iron dextran. A quantitative relationship has been observed between the measurements and the number of treatments. The assessment of iron overload requires evaluating the magnetic signal corresponding to the same rat ideally without the overload. This background value was extrapolated on the basis of the signal measured in control rats versus body weight (R(2) = 0.73). The mean iron overload values for the treated rats, obtained after each iron injection, were significantly different from the means of the corresponding control rats (p < 0.01). The in vivo measurements have been complemented by chemical analysis on excised livers and other organs (R(2) = 0.89). The magnetic moment of iron atoms in liver tissues was measured to be 3.6 Bohr magneton. Evaluation of the background signal is the limit to the measure; the error corresponds to about 30 mg (1 SD) of iron while the instrument sensitivity is more than a factor of 10 better.

Distribution of trace elements in organs of six species of cetaceans from the Ligurian Sea (Mediterranean), and the relationship with stable carbon and nitrogen ratios.

Mercury (total and organic), cadmium, lead, copper, iron, manganese, selenium and zinc concentrations were measured in different organs of 6 different cetacean species stranded in an area of extraordinary ecological interest (Cetaceans' Sanctuary of the Mediterranean Sea) along the coast of the Ligurian Sea (North-West Mediterranean). Stable-isotopes ratios of carbon ((13)C/(12)C) and nitrogen ((15)N/(14)N) were also measured in the muscle. A significant relationship exists between (15)N/(14)N, mercury concentration and the trophic level. The distribution of essential and non-essential trace elements was studied on several organs, and a significant relationship between selenium and mercury, with a molar ratio close to 1, was found in the cetaceans' kidney, liver and spleen, regardless of their species. High selenium concentrations are generally associated with a low organic to total mercury ratio. While narrow ranges of concentrations were observed for essential elements in most organs, mercury and selenium concentrations are characterised by a wide range of variation. Bio-accumulation and bio-amplification processes in cetaceans can be better understood by comparing trace element concentrations with the stable-isotopes data.

Solubilization and methylation of HgS, PbS, and SnS by iodomethane, a model experiment for the aquatic environment.

Iodomethane is produced in the marine environment by algae and plankton. Model experiments have shown that iodomethane can dissolve a series of metal sulphides, in agreement with some of the results mentioned in the relative literature. While no dissolution of SnS was observed, PbS and HgS were dissolved proportionally with the iodomethane concentration. The two forms of HgS (cinnabar and metacinnabar) behaved differently, with metacinnabar being more soluble than cinnabar. Moreover, iodomethane can methylate lead and tin and mercury can be methylated when methyllead and methyltin compounds are present in the model system. The methylated species were identified using gas chromatography, and there is evidence that lead and tin undergo the same methylation mechanism. Preliminary experiments with natural sediments were performed, but no dissolution of Pb, Sn or Hg was observed. CAPSULE: Iodomethane can solubilize Pb and Hg sulphides, and methylate Pb and Sn, and (indirectly) Hg.

Lichen and moss bags as monitoring devices in urban areas. Part II: trace element content in living and dead biomonitors and comparison with synthetic materials.

Lobes of the lichen Pseudevernia furfuracea (L.) Zopf and shoots of the moss Hypnum cupressiforme Hedw. were subjected to different treatments (water washing, oven drying, HNO3 washing, NH4-oxalate extraction) to assess the influence of vitality on accumulation efficiency, during a 6-week exposure in bags in two Italian cities, Trieste and Naples. No trend emerged between treatments, in terms of accumulation ability, for major and trace elements. Only water-washed lichens showed an increased C and N content after exposure in both cities. Element concentrations generally reached higher values in mosses than in lichens, especially for Al, Fe, and Zn (both cities), and for Cu, Mg and Na (Naples). Surface development strongly influenced accumulation capacity of the biomonitors. Quartzose and cation exchange filters revealed, on a weight basis, a poor performance. In urban environments, surface interception of atmospheric particulate seems to play a major role in accumulation, irrespective of organism vitality.

Arbuscular mycorrhizae increase the arsenic translocation factor in the As hyperaccumulating fern Pteris vittata L.

Phytoremediation techniques are receiving more attention as decontaminating strategies. Phytoextraction makes use of plants to transfer contaminants from soil to the aboveground biomass. This research is devoted to study the effects of arbuscular mycorrhizae (AM) on growth and As hyperaccumulation in the Chinese brake fern Pteris vittata. We grew for 45 days P. vittata sporophytes, infected or not infected with the AM fungi Glomus mosseae or Gigaspora margarita, in a hydroponic system on quartz sand. As-treated plants were weekly fed with 25 ppm As. The As treatment produced a dramatic increase of As concentration in pinnae and a much lower increase in roots of both mycorrhizal and control plants. Mycorrhization increased pinnae dry weight (DW) (G. margarita = G. mosseae) and leaf area (G. margarita > G. mosseae), strongly reduced root As concentration (G. mosseae > G. margarita), and increased the As translocation factor (G. mosseae > G. margarita). The concentration of phosphorus in pinnae and roots was enhanced by both fungi (G. margarita > G. mosseae). The quantitatively different effects of the two AM fungi on plant growth as well as on As and P distribution in the fern suggest that the As hyperaccumulation in P. vittata can be optimized by a careful choice of the symbiont.

Bioaccumulation of vanadium in the epiphytic lichen Parmelia caperata from Liguria (north-west Italy).

The concentration of vanadium was measured in 35 samples of the epiphytic lichen Parmelia caperata collected along the coast of the Ligurian Sea (Italy), in order to detect the possible bioaccumulation of vanadium due to a huge crude oil burning occurred in that area in 1991. The cartographic elaboration of data shows a pattern of distribution of vanadium concentrations according to different degrees of deviation from background condition, showing that 8 years later memory of the accident is still detectable in foliose lichen thalli.

Inhibitory properties of triethylphosphine goldlupinylsulfide in adjuvant-induced arthritis in rats.

A new gold coordination compound (triethylphosphine goldlupinylsulfide: TP-Au-LS) was tested in adjuvant-induced arthritis in the rat, by oral administration at doses of 5, 10 and 20 mg/kg/day of gold for 17 consecutive days, in comparison with auranofin and betamethasone. TP-Au-LS produced a dose dependent reduction of both the injected and uninjected hind paw volume. Gold levels in serum (measured on day 18 by inductively coupled plasma atomic emission spectrometry) were also found to be dose related. At the dose of 10 mg/kg, TP-Au-LS and auranofin induced superimposable reductions of the injected paw volume; however the first drug produced higher serum gold concentrations than those achieved with the latter.

The presence of inorganic and organic mercury and selenium in Nephrops norvegicus from the Ligurian Sea.

Samples of Nephrops norvegicus from the Ligurian Sea were analysed for contents of organic mercury, total mercury and selenium. Results for 37 specimens are reported. Total mercury concentrations increase with size of the specimens. Percentage of organic mercury ranges from 31 to 88% with an average of 58%. Selenium does not correlate with size and the average content is 0.88 micrograms g-1 fresh weight (range 0.30-1.74 micrograms g-1 fresh weight).

Total mercury, organic mercury, copper, manganese, selenium, and zinc in Sarda sarda from the Gulf of Genoa.

The total mercury content of the Atlantic bonito (Sarda sarda) increases with increasing size of the specimen, as shown by other authors for other marine organisms (Renzoni et al., 1973; Buffoni et al., 1982; Bernhard and Andreae, 1984; Thibaud, 1986). Organic mercury content also increases with the size of the specimen, whereas inorganic mercury remains constant, which is in agreement with the prediction made on another species of Sgombridae (Bernhard, 1985). This kind of mercury partitioning has not, to our knowledge, been reported for other species of fish. It is interesting to note that the mercury concentration in the gonads also increases with the size of the specimen. A very small difference between the total mercury content of white and dark muscle was observed, while for selenium, zinc, copper, and manganese the concentrations are lower in white muscle than in dark muscle.

The presence of mercury (total and organic) and selenium in human placentae.

The concentrations of mercury (total and organic) and selenium in samples of human placentae obtained after normal births from 22 women living in Genova (Italy), were determined by atomic absorption spectrometry. The concentration of total mercury was between less than 0.005 and 0.230 microgram Hg/g dry weight, and the average value was 0.076 microgram Hg/g dry weight. For the same samples, the average percentage of organic mercury as mercury was 65%, with a maximum of 95%. Smaller variations were observed for selenium, i.e. concentrations ranging between 0.38 and 1.03 microgram Se/g dry weight, with an average value of 0.77 microgram Se/g dry weight. The ratio between wet weight and dry weight was determined for each sample and the average value found was 6.32. The placental selenium concentration did not correlate with total and organic mercury content, which is in accordance with the results of other researchers.

Extraction of chlorinated hydrocarbons from fish with sulphuric acid.

A method is described for extraction of chlorinated hydrocarbons (DDTs and PCBs) from fish samples with sulphuric acid of various concentrations. The results are better than those obtained by an official method using Soxhiet extraction with n-hexane, especially with 9.5-13M sulphuric acid. The relative standard deviation is about 12% for analysis of portions of a homogenized single sample taken from the dorsal flesh of the same fish. Drawbacks and advantages in comparison with other methods are discussed.