Phototransformation of <Emphasis Type="SmallCaps">l</Emphasis>-tryptophan and formation of humic substances in water

Humic substances are poorly known, though they represent a major pool of non-biotic organic carbon on earth. In particular, there is little knowledge on the formation of humic substances by irradiation of organic matter dissolved in waters. Specifically, it is known that humic substances can be formed from proteins by photochemical processes in surface waters, but the role of single amino acids and their transformation pathways are not yet known. Therefore, here we studied the phototransformation of aqueous l-tryptophan under simulated sunlight. Irradiated l-tryptophan solutions were analyzed by absorption, fluorescence, nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopies, chromatography, potentiometry and mass spectrometry (MS). The solutions appeared turbid after irradiation; therefore, nephelometry and dynamic laser light scattering were used to characterize the suspended particles. Results show that about 95% of l-tryptophan was degraded in 8-h irradiation, undergoing deamination and decarboxylation of the amino acidic moieties to release ammonium and formate. The MS signal at m/z 146 suggests the formation of 3-ethylindole, while pH-metric and NMR data revealed the presence of hydroxylated compounds. The phototransformation intermediates of l-tryptophan had fluorescence and absorption spectra similar to those of humic substances, they were able to produce ^·OH upon irradiation and tended to aggregate by both ionic and hydrophobic interactions. Overall, our findings reveal for the first time the nature of products formed upon phototransformation of l-tryptophan. Interestingly, the transformation of l-tryptophan is quite different from that of the previously studied l-tyrosine, although both compounds produce humic-like materials under irradiation.     

Rapid analysis of neonicotinoid insecticides in guttation drops of corn seedlings obtained from coated seeds

Regarding the hypothesis that neonicotinoid insecticides used for seed coating of agricultural crops - mainly corn, sunflower and seed rape - are related to the extensive death of honey bees, the phenomenon of corn seedling guttation has been recently considered as a possible route of exposure of bees to these systemic insecticides. In the present study, guttation drops of corn plants obtained from commercial seeds coated with thiamethoxam, clothianidin, imidacloprid and fipronil have been analyzed by an optimized fast UHPLC-DAD procedure showing excellent detection limits and accuracy, both adequate for the purpose. The young plants grown both in pots - in greenhouse - and in open field from coated seeds, produced guttation solutions containing high levels of the neonicotinoid insecticides (up to 346 mg L(-1) for imidacloprid, 102 mg L(-1) for clothianidin and 146 mg L(-1) for thiamethoxam). These concentration levels may represent lethal doses for bees that use guttation drops as a source of water. The neonicotinoid concentrations in guttation drops progressively decrease during the first 10-15 days after the emergence of the plant from the soil. Otherwise fipronil, which is a non-systemic phenylpyrazole insecticide, was never detected into guttation drops. Current results confirm that the physiological fluids of the corn plant can effectively transfer neonicotinoid insecticides from the seed onto the surface of the leaves, where guttation drops may expose bees and other insects to elevated doses of neurotoxic insecticides.     

Database-driven models of the world's Large Marine Ecosystems

We present a new methodology for database-driven ecosystem model generation and apply the methodology to the world's 66 currently defined Large Marine Ecosystems. The method relies on a large number of spatial and temporal databases, including FishBase, SeaLifeBase, as well as several other databases developed notably as part of the Sea Around Us project. The models are formulated using the freely available Ecopath with Ecosim (EwE) modeling approach and software. We tune the models by fitting to available time series data, but recognize that the models represent only a first-generation of database-driven ecosystem models. We use the models to obtain a first estimate of fish biomass in the world's LMEs. The biggest hurdles at present to further model development and validation are insufficient time series trend information, and data on spatial fishing effort.     

Saharan dust particles in snow samples of Alps and Apennines during an exceptional event of transboundary air pollution

Southern European countries are often affected in summer by transboundary air pollution from Saharan dust. However, very few studies deal with Saharan dust pollution at high altitudes in winter. In Italy, the exceptional event occurred on February 19, 2014, colored in red the entire mountain range (Alps and Apennines) and allowed to characterize the particulate matter deposited on snow from a morphological and chemical point of view. Snow samples were collected after this event in four areas in the Alps and one in the Apennines. The particulate matter of the melted snow samples was analyzed by scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDS) and by inductively coupled plasma mass spectrometry (ICP-MS). These analyses confirmed the presence of Saharan dust particle components in all areas with similar percentages, supported also by the positive correlations between Mg-Ca, Al-Ca, Al-Mg, and Al-K in all samples.     

Assessment of trace metal air pollution in Paris using slurry-TXRF analysis on cemetery mosses

Mosses are useful, ubiquitous accumulation biomonitors and as such can be used for biomonitoring surveys. However, the biomonitoring of atmospheric pollution can be compromised in urban contexts if the targeted biomonitors are regularly disturbed, irregularly distributed, or are difficult to access. Here, we test the hypothesis that cemeteries are appropriate moss sampling sites for the evaluation of air pollution in urban areas. We sampled mosses growing on gravestones in 21 urban and peri-urban cemeteries in the Paris metropolitan area. We focused on Grimmia pulvinata (Hedwig) Smith, a species abundantly found in all studied cemeteries and very common in Europe. The concentration of Al, As, Br, Ca, Ce, Cl, Cr, Cu, Fe, K, Mn, Ni, V, P, Pb, Rb, S, Sr, Ti, and Zn was determined by a total reflection X-ray fluorescence technique coupled with a slurry sampling method (slurry-TXRF). This method avoids a digestion step, reduces the risk of sample contamination, and works even at low sample quantities. Elemental markers of road traffic indicated that the highest polluted cemeteries were located near the highly frequented Parisian ring road and under the influence of prevailing winds. The sites with the lowest pollution were found not only in the peri-urban cemeteries, adjoining forest or farming landscapes, but also in the large and relatively wooded cemeteries located in the center of Paris. Our results suggest that (1) slurry-TXRF might be successfully used with moss material, (2) G. pulvinata might be a good biomonitor of trace metals air pollution in urban context, and (3) cemetery moss sampling could be a useful complement for monitoring urban areas.

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Graphical abstract We tested the hypothesis that cemeteries are appropriate moss sampling sites for the evaluation of air pollution in urban areas. We sampled 110 moss cushions (Grimmia pulvinata) growing on gravestones in 21 urban and peri-urban cemeteries in the Paris metropolitan area. The concentration of 20 elements in mosses was determined by a total reflection X-ray fluorescence technique coupled with a slurry sampling method. Statistical analysis revealed that: - Urbanized Parisian areas crossed by traffic roads have the highest polluted cemeteries with a strong influence of main wind direction on the distribution of air pollutants - As expected, small cemeteries with low tree density were heavily polluted - Less obvious, large green spaces such as large cemeteries (Père Lachaise, Montmartre, Montparnasse) in the center of a dense metropolis like Paris present the same level of atmospheric trace metal pollution as cemeteries in less urbanized areas or nearing a very large forest. This suggests that even in densely urbanized areas, there is more spatial variability in pollution distribution than usually assumed and that large urban areas with low traffic and green filters such as trees are likely to intercept air pollutants

     

Evaluation of microbiological air quality and of microclimate in university classrooms

The proliferation of air-diffused microorganisms inside public buildings such as schools, hospitals, and universities, is often indicated as a possible health risk. In this research, we have illustrated the results of an investigation realized to determine the health of the air in some university classrooms, both from a microbiological and a microclimatic viewpoint, during the normal didactic activity of direct lessons. The results obtained have been expressed by means of contamination indices, already used in previous works. Very little contamination was recorded in the different phases of air treatment, which underlines the efficiency of the system and of the maintenance protocols. The Global Index of Microbial Contamination (GIMC per cubic meter) showed a value greater than the mean during the heating period (290), while the highest values (95th percentile 1,138.45) were recorded in the period using air conditioning. The index of mesophilic bacterial contamination, though it did not show any significant differences in the various modes of air treatment, showed a mean value (1.34) and the 95th percentile value (4.14), which was greater in the air-conditioning phase. Finally, the mean value of the amplification index underlined a decrease in the microbial contamination in comparison to the outside, while showing situations of increased microbial amplification during the period of simple ventilation (95th percentile 4.27). The 95th percentile values found for GICM in the three sampling periods, however, permitted us to identify the value of GIMC per cubic meter equal to 1,000 as a guide to provide a means of self-monitoring the quality of the air inside the classrooms. From a microclimatic viewpoint, two periods of the year manifested discomfort situations: during the heating phase (winter) and during the simple ventilation phase (spring). The results obtained indicate, therefore, a need to intervene on the environmental parameters, not being able, in this particular case, to intervene on other aspects that influence the microclimate.     

Evaluation of a temporal trend heavy metals contamination in Posidonia oceanica (L.) Delile, (1813) along the western coastline of Sicily (Italy)

The use of biological species in the monitoring of marine environmental quality allows the evaluation of biologically available levels of contaminants in the ecosystem and the effects of contaminants on living organisms. The seagrass Posidonia oceanica is a useful bioindicator because through the lepidochronology technique it is possible to obtain a historical contamination trend of a given area. This study aims to assess the temporal trend contamination by heavy metal investigations on dead sheaths of 100 samples of P. oceanica collected in the Protected Marine Area of "Plemmirio" (Sicily) and in the Siracusa bay. Important results were obtained because data show a significant negative temporal trend for the metals analysed especially for As, Co, Cr, Hg, Pb, Se, U and V that in the past had higher concentrations, with a stronger contamination in the Plemmirio area, the site much more exposed to the pollution of the nearby petrochemical complex. This study confirms the relevance of the use of P. oceanica as a biological indicator of metal contamination in coastal ecosystems. Thus the usefulness of P. oceanica as a tracer of spatial metal contamination and as a good tool for water quality evaluation is reinforced.     

Determination of particulate polycyclic aromatic hydrocarbons in ambient air by gas chromatography-mass spectrometry after molecularly imprinted polymer extraction

A solid phase extraction procedure (SPE) is described for the quantitative analysis of polycyclic aromatic hydrocarbons (PAHs) in atmospheric particulate matter (PM), as ubiquitous environmental pollutants routinely measured in air quality monitoring. A SPE cartridge was used based on a molecular imprinted polymer (MIP-SPE) properly tailored for selective retention of PAHs with 4 and more benzene fused rings. The performance of the clean-up procedure was evaluated with the specific concern of selective purification towards saturated hydrocarbons, which are the PM components mostly interfering GC analysis of target PAHs. Under optimized operative conditions, the MIP-SPE provided analyte recovery close to 95% for heavier PAHs, from benzo(α)pyrene to benzo(ghi)perylene, and close to 90% for four benzene rings PAHs, with good reproducibility (RSDs: 2.5%-5.9%). Otherwise, C₁₇-C₃₂ n-alkanes were nearly completely removed. The proposed method was critically compared with Solid Phase Micro Extraction (SPME) using a polyacrylate fiber. Both methods were successfully applied to the analysis of ambient PM_2.5 samples collected at an urban polluted site. Between the two procedures, the MIP-SPE provided the highest recovery (R% ≥ 93%) for PAHs with 5 and more benzene rings, but lower for lighter PAHs. In contrast, SPME showed a mean acceptable R% value (∼ 80%) for all the investigated PAHs, except for the heaviest PAHs in the most polluted samples (R%: 110%-138%), suggesting an incomplete purification from the interfering n-hydrocarbons.     

Environmental–sanitary risk analysis procedure applied to artificial turf sports fields

Owing to the extensive use of artificial turfs worldwide, over the past 10 years there has been much discussion about the possible health and environmental problems originating from styrene-butadiene recycled rubber. In this paper, the authors performed a Tier 2 environmental–sanitary risk analysis on five artificial turf sports fields located in the city of Turin (Italy) with the aid of RISC4 software. Two receptors (adult player and child player) and three routes of exposure (direct contact with crumb rubber, contact with rainwater soaking the rubber mat, inhalation of dusts and gases from the artificial turf fields) were considered in the conceptual model. For all the fields and for all the routes, the cumulative carcinogenic risk proved to be lower than 10^?6 and the cumulative non-carcinogenic risk lower than 1. The outdoor inhalation of dusts and gases was the main route of exposure for both carcinogenic and non-carcinogenic substances. The results given by the inhalation pathway were compared with those of a risk assessment carried out on citizens breathing gases and dusts from traffic emissions every day in Turin. For both classes of substances and for both receptors, the inhalation of atmospheric dusts and gases from vehicular traffic gave risk values of one order of magnitude higher than those due to playing soccer on an artificial field.