Vincenzo Minganti

Evaluation of different derivatization methods for the multi-element detection of Hg, Pb and Sn compounds by gas chromatography-microwave induced plasma-atomic emission spectrometry in environmental samples

A multi-element, element-specific detector for gas chromatography (GC) based on atomic emission spectroscopy (AES) with a microwave induced plasma (MIP) source was tested on some environmental samples. As derivatization procedure, direct aqueous phase ethylation and chelation/extraction followed by Grignard reaction were tested on the following ions: methylmercury, ethylmercury, phenylmercury, mercury(II), trimethyllead, dimethyllead, lead(II), trimethyltin, dimethyltin, triethyltin, tripropyltin, tributyltin, dibutyltin, butyltin, and tin(IV). For mercury species a direct aqueous phase phenylation was successfully tested. The different methods of derivatization are compared, and the performance (sensitivity, linearity) of the GC-MIP-AES system is discussed. Some examples of application to environmental samples (biological tissues) are given.

Study of trace elements in organs and tissues of striped dolphins (Stenella coeruleoalba) found dead along the Ligurian coasts (Italy)

Abstract Concentrations of copper, iron, manganese, zinc, selenium and mercury (total and organic) were measured in muscle tissue, brain, heart, lung, kidney, spleen, and liver of 18 dead striped dolphins ( Stenella coeruleoalba ) found stranded on the beaches of the Ligurian Sea. Distribution of the trace elements among the tissues and bioaccumulation are discussed. High levels of mercury were observed in all tissues analysed, with concentrations reaching 260 μg g −1 dry weight (dry wt.) in the muscle, 448 μg g −1 dry wt. in the lung, 1316 μg g −1 dry wt. in the spleen, and 2993 μg g −1 dry wt. in the liver. Mercury present in the organic form was, on average, approximately 30% of the total for all tissues with the exception of the heart, which showed higher values (mean 63%), and liver, where organic mercury was very low (mean 12%). In muscle tissue the organic mercury fraction decreased with increasing total mercury concentration. The liver accumulated trace elements to a greater extent than the other organs studied, with the exception of iron. Principal component analysis (PCA) revealed a grouping of the specimens on the basis of their estimated age. A strong positive correlation between the concentration of inorganic mercury and selenium was found for all the tissues analysed. In the liver the selenium to inorganic mercury molar ratio was very close to 1, confirming results of previous authors.

Trace elements in farmed and wild gilthead seabream, Sparus aurata.

In the present study, we sought to determine the concentration of several trace elements (total and organic mercury, selenium, cadmium, lead, arsenic, copper, chromium, iron, manganese, molybdenum, vanadium and zinc) in muscle tissue of gilthead seabream (Sparus aurata), an edible finfish species that is widely cultured in the Mediterranean area. The phenomenon of bioaccumulation and bioamplification (especially of mercury) was investigated by comparing farmed fish with wild specimens of the same species. Farmed specimens showed mercury and arsenic concentrations significantly lower than wild specimens, and no relationship was found between mercury concentration and body size. The lower level of methylmercury in farmed fish has important implications for consumer health.

Microcolumn preconcentration and gas chromatography-microwave induced plasma-atomic emission spectrometry (GC-MIP-AES) for mercury speciation in waters

A novel method for the direct determination of mercury species at the ng l−1 level in natural waters is described. Methyl-, ethyl- and inorganic mercury are preconcentrated on a sulphhydryl cotton microcolumn incorporated in a flow injection system. Retained mercury species are then eluted with hydrochloric acid solution (3 mol/l) and subjected to phenylation before determination by gas chromatography-microwave induced plasma-atomic emission spectrometry. Limits of detection for mercury species are 10 ng l−1 for methyl- and ethyl-mercury and 16 ng l−1 for inorganic mercury based on processing 200 ml of sample. Application of the methodology to waters of the Manchester Ship Canal revealed elevated levels of methylmercury and inorganic mercury.

Biomonitoring of Trace Metals by Different species of Lichens (Parmelia) in North-West Italy

The concentrations of Cd, Cu, Mn, Ni, Pb, V, and Zn were measured in four different species of lichens (Parmelia caperata, P. pastillifera, P. saxatilis, P. sulcata) sampled in North-West Italy, in order to obtain maps showing metal distribution and the degree of deviation from background (natural) conditions. Significant differences among the species were found for Zn, Mn, Pb and V, suggesting that the combined use of mixed species in biomonitoring surveys can affect the interpretation of results. Results obtained for Parmelia caperata samples have been compared with background (natural) levels, and maps showing the distribution of each metal expressed as deviation from background levels have been obtained. Overall such maps show a medium to high alteration degree in the study area.

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.

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.

Total and organic mercury in North Atlantic fin whales: distribution pattern and biological related changes

Abstract Total and organic mercury concentrations were determined in muscle, liver and kidney of thirty-six fin whales ( Balaenoptera physalus ) of the Northeast Atlantic. Age, sex and length relationships for both forms of metal were examined. Tissue concentrations were lower than those of toothed whales and seals. A slight increase with age was observed for total mercury concentrations in muscle and liver and organic mercury concentrations in liver, which suggests a low rate of excretion for the metal, even at low concentrations. No differences between sexes were found regarding mercury concentrations, nor to their accumulation pattern.

Total and organic mercury concentrations in offshore crustaceans of the Ligurian Sea and their relations to the trophic levels

Abstract Total mercury and organic mercury were measured in five crustaceans representative of an offshore pelagic food web in the Gulf of Genoa, Italy: Meganycthiphanes norvegica, Gennadas elegans, Pasiphaea sivado, Pasiphaea multidentata and Aristeus antennatus . According to their predator-prey relationships, they represent three trophic levels in the Ligurian Sea. The concentrations of total and organic mercury increase with the trophic levels and with the weight of the specimens (except in G. elegans and in females of A. antennatus ). However, at higher trophic levels the specimens are also larger. Only in P. sivado , do levels of inorganic mercury increase significantly ( P = 0.001) with the size of the specimens. The ratio between organic mercury and total mercury did not increase with the trophic level.

Temporal trends (1981-2007) of trace and rare earth elements in the lichen Cetraria islandica (L.) Ach. from Italian herbaria.

Twenty-four herbarium specimens of Cetraria islandica collected in Italy from 1981 to 2007 were used for retrospective analysis. Cd, Ce, Cu, Fe, Gd, La, Mn, Ni, Pb, Sb, V, Y, and Zn concentrations were measured. Pb showed a negative temporal trend, linked to the ban of leaded fuel for vehicles. Pb showed a negative correlation with the distance of the sampling sites from a highway in the years before 1995 and no relationship after that year, corresponding to the Pb content reduction in gasoline. A significant trend towards increasing Mn concentrations over time also emerged, which deserves further investigations due to Mn toxicity. Cluster analysis showed a group of elements of anthropogenic origin, while rare earth elements formed a separated cluster of natural origin. Lichens from herbaria proved to be a valuable tool for reconstructing historical trends in trace element deposition, highlighting variations produced by human activities.