Trace elements determination in lichens and in the airborne particular matter for the evaluation of the atmospheric pollution in a region of northern Italy

Lichens as biomonitors and neutron activation analysis as analytical technique have been employed to study the distribution of trace elements (TE) in a mountain region of north Italy (Biella) characterized by settlements of wool industry. Samples of airborne particulate matter collected onto filters, different species of lichens and samples of soils have been analyzed for the calculation of the enrichment factors (EFs) of more than 25 TE. By comparison of the corresponding EFs, the most suitable lichen species (Parmelia caperata) was selected as specific TE biomonitor of the area investigated. Samples of this lichen were collected and analyzed for the evaluation of the TE distribution in four different locations. The results obtained from the analysis of the lichens gave information about the predominant direction of pollutants transportation, while those related to the concentrations found in the air particulate allowed the evaluation of the degree of the local TE atmospheric pollution.     

Investigation of the complexation of metal-ions by strong ligands in fresh and marine water

SCOPE: The detection and investigation of metal ions bound in strong complexes in natural waters is a difficult task, due to low concentration of the metal ions themselves, and also of the strong ligands, which, moreover, are often not of a well-defined composition. Here, a method is proposed for the investigation of the speciation of metal ions in natural waters. OBJECTIVE AND METHOD: It is based on the sorption of metal ions on strongly sorbing ion exchange resins, i.e. complexing resins. For this reason the method is called Resin Titration. It has been shown in previous investigations that the concentration of metal ion totally sorbed by a particular resin, and its reaction coefficient in the solution phase in the presence of the resin, can be determined from the sorption data using a simple relationship. Here, a data treatment (the Ruzic linearization method) is proposed for also determining the concentration of the ligands responsible for the complex in equilibrium with the resin. RESULTS: The method was applied to data obtained by Resin Titration of a freshwater and a seawater. Copper(II) and aluminium(III) were considered, using Chelex 100 as a titrant, due to its strong sorbing properties towards these metal ions. The results were: the total metal concentration in equilibrium with the resin, the side reaction coefficients, and the concentration of ligands. In all these cases the ligands forming very strong complexes were found to be at concentration lower than that of the metals. CONCLUSION: The Ruzic linearization method allows the determination of the concentration of the ligands forming very strong complexes in equilibrium with Chelex 100. The reaction coefficient was better determined by the calculation method previously proposed for RT. The ligands responsible for the strong complexes were found to be at low concentration, often lower than that of the metal ions considered. The metal in the original sample is partly bound to these ligands, since the complexes are very strong. Only a part of the metal is linked to weaker ligands, or free.     

Determination of metallic cobalt in the atmosphere

Due to the fact that, among the different chemical species, metallic cobalt is characterized by the highest toxicity, in this paper is proposed a procedure for its determination in the atmospheric paniculate. The air is filtered on a cellulose or glass fiber membrane, to collect the paniculate containing among the other species, metallic cobalt: the determination is based on a selective dissolution of the metallic cobalt possibly present followed by its determination by atomic absorption spectroscopy. The typical interferences that can be present in the matrix are discussed and suggestions for their minimisation are proposed. By the following procedure is also possible to determine separately the sum of the insoluble and water soluble cobalt compounds.     

Sunlight-induced degradation of soil-adsorbed veterinary antimicrobials Marbofloxacin and Enrofloxacin

Marbofloxacin (MAR) and Enrofloxacin (ENR), two largely employed veterinary Fluoroquinolones (FQs), were found to be present at the micrograms per kilogram level in agricultural soils of South Lombardy (Italy) several months after manuring. Distribution coefficients (K_d) from sorption experiments indicated a strong binding to the soil. Soil samples fortified with environmentally significant FQs amounts (0.5 mg kg⁻¹) were exposed to solar light that promoted extensive degradation (80%) of both drugs in 60-150 h. Thus, photochemistry could be considered a significant depollution path in the soil, although it was two orders of magnitudes slower than in aqueous solution and a fraction of the drug (ca. 20%) remained unaffected. For MAR the photoprocess was the same as in solution, and involved cleavage of the tetrahydrooxadiazine ring. On the contrary, with ENR only some of the photoproducts determined in water (those arising from a stepwise oxidation of the piperazine side chain) were observed. Substitution of the 6-fluoro by a hydroxyl group and reduction did not occur in the soil, supporting the previous contention that such processes required polar solvation of FQs. Consistently with this rationalization, the irradiation of thin layers of solid drugs led to essentially the same products distribution as in the soil. From the environmental point of view it is important to notice that photodegradation mainly affects the side-chains, while the fluoroquinolone ring, to which the biological effect is associated, is conserved up to the later stages of the degradation.     

Determination of trace elements and evaluation of their enrichment factors in Himalayan lichens

Within the framework of the Ev-K2-CNR research program of the Italian National Research Council a specific task project has been initiated for the identification of trace elements in lichens in remote high altitude areas. This is to evaluate the possibility of using lichens as biomonitors of trace elements of atmospheric pollution. In this preliminary study, more than 20 elements have been determined in some species of lichens collected at different altitudes (from 1300 to 5000 m) in the region of the Sagarmatha National Park (Nepal). Samples of superficial soils were also collected and analyzed to calculate the trace element enrichment factors (EF) using scandium as a normalizing element. Most of the trace elements were determined by instrumental neutron activation analysis (INAA), while lead and cadmium measurements were carried out with electrothermal atomic absorption spectroscopy (ET-AAS). The EF values as well as the elemental concentrations are reported and discussed.     

Trace elements fingerprint of feathers differs between breeding and non-breeding areas in an Afro-Palearctic migratory bird,the barn swallow (Hirundo rustica)

Environmental Science and Pollution Research - Trace elements are widespread contaminants that can potentially threaten ecosystems and human health. Considering their distribution and toxicity,...     

Environmental photochemistry of fluoroquinolones in soil and in aqueous soil suspensions under solar light

The photodegradation fate of widely used fluoroquinolone (FQ) drugs has been studied both at the water–soil interface and in soil at actual concentrations (500 ng g^?1) under natural solar light. Both human and veterinary drugs have been examined, namely ciprofloxacin, danofloxacin, enrofloxacin, levofloxacin, marbofloxacin and moxifloxacin. After spiking and irradiation, samples were submitted to microwave-assisted extraction and analyzed by high-performance liquid chromatography coupled to fluorescence detection (HPLC–FD). FQs degradation was faster in aqueous soil suspension than in neat soil (but lower than in “clean” water). A number of byproducts were identified by HPLC electrospray ionization tandem mass spectrometry after a post-extraction cleanup based on a molecularly imprinted polymer phase, for a more accurate detection. The distribution in the suspension was intermediate between those observed in soils and in aqueous solutions.     

Determination of baseline element composition of lichens using samples from high elevations

The results of a survey aimed at providing baseline element composition of lichens from unpolluted or very low polluted areas are reported. Lichen samples collected at high elevation areas in Himalayas (Nepal), Mt. Kenya (Kenya) and the Alps (Italy) were analyzed for their trace element content, mostly by INAA, allowing for a multi-element analysis. The elemental composition of lichen samples was essentially influenced by natural occurrence, mainly airborne soil dust. However, also anthropogenic input determined by long-distance atmospheric transport of pollutants was involved for some highly volatile elements such as Br, Cd and Sb. To avoid the influence of soil contamination and air pollution, and obtain baseline concentrations to be used as reference (the "natural" elemental composition of lichens), the average of the lowest concentrations is suggested.