Involvement of nitro-compounds in the mutagenicity of urban Pm2.5 and Pm10 in Turin.

Fine particles can be active carriers of toxic compounds into the alveoli of the lungs. Among these compounds are numerous mutagens and carcinogens. The direct mutagenicity per unit mass of fine particulate matter (PM) is significantly higher than that of coarse particles, especially in urban areas. In this study, the mutagenic properties of urban PM2.5 and PM10 were evaluated, and the role of nitro-compounds was estimated. PM2.5 and PM10 samplings, and measurements of NOx and some PAHs were performed daily in 2007 in Turin, following a consolidated in vitro test - the Salmonella mutagenicity assay - conducted with organic extracts of PM2.5 and PM10. The mutagenic properties were assessed for each month of sampling with Salmonella typhimurium strain TA98 and TA98-derived strains: a nitroreductase-deficient mutant strain (TA98NR) and an additional nitroreductase-producing plasmid strain (YG1021). The annual measured mean levels of PM2.5 and PM10 were 34±20 and 48±18µg/m(3). The PM2.5/PM10 ratio ranged from 0.36 to 0.89. The Salmonella assay showed higher mutagenicity in autumn/winter (20±15 TA98NR; 54±39 TA98; 173±161 YG1021 net revertants/m(3)) compared with spring/summer (2±2 TA98NR; 7±8 TA98; 24±27 YG1021 net revertants/m(3)) (p<0.01). There are also statistically significant seasonal differences in the gravimetric analysis data. The number of TA98 net revertants per µg of PM2.5 is 6.5 times greater than per µg PM10. Moreover, the bioassay results showed an amplified response in the YG1021 strain and a reduced response in the TA98NR strain. The net revertant ratio TA98NR/YG1021 is 11±4 for organic extracts of PM2.5 and 13±6 for extracts of PM10 (p<0.01). There is a significant correlation between the NOx and PAH concentrations. These findings illustrate the relevant role of nitro compounds, and they underline the priority in improving preventive measures to reduce air pollution by nitrated molecules.

Meteo-climatic conditions influence the contribution of endotoxins to PM10 in an urban polluted environment.

A decrease in inhalable particulate matter (PM10) pollution is a top priority in urban areas of northern Italy. The sources of PM10 are both anthropogenic and natural. The former have been broadly investigated while the latter are less well known. Endotoxins are natural compounds of PM10 and are potentially toxic. Endotoxins are part of the outer membrane of Gram-negative bacteria. Their health effects are linked to environmental exposure. The effects mainly consist of respiratory symptoms, including pulmonary function decline. The occurrence of endotoxins has been proven in several occupational environments where organic materials supply an optimal substrate for bacteria growth. Knowledge about the presence of these contaminants in the environment is limited. The aim of this work is to evaluate the endotoxin levels of PM10 in the urban air of Turin, and to investigate the influence of seasonal and meteo-climatic factors. The sampling was conducted from January to December 2007. Endotoxin determination was performed by an LAL assay after extraction optimization. The PM10 levels ranged from 11.90 to 104.74 microg/m(3) (48.28 +/- 23.09) while the endotoxin levels ranged between 0.09 and 0.94 EU/m(3) (0.42 +/- 0.23). The seasonal trends of PM10 and endotoxin are inversely proportional. There is a statistically significant correlation between endotoxin and temperature (r = 0.532 p < 0.01), as well as between endotoxin and relative humidity (r = -0.457 p < 0.01). However, temperature has a predominant role. We observed that urban endotoxin concentrations are narrow in range and that the contribution of endotoxins to the total PM10 is only two millionths.

Chemical characteristics and mutagenic activity of PM10 in Torino, a northern Italian city.

Epidemiological studies of particulate matter (PM) have associated PM mass, as well as certain individual components of PM such as secondary particulate with adverse human health effects. For example genotoxic effects attributed to PM may relate to the content of organic compounds but also to the oxidative DNA damage generated by transition metals like iron. However the exact physiochemical mechanism by which PM produces adverse effects is not clear. The aims of this study were to evaluate (1) concentrations of PM10, (2) amounts of bioavailable iron associated with PM10, (3) amounts of secondary particulate expressed as SO4(=) and NO3(-) and (4) the mutagenic activities of PM10 organic extracts. Sampling was carried out in a meteochemical station located in Torino, a northern Italian city with high levels of PM10. The mean PM10 concentration in the considered period was 46.1+/-28.8 microg/m3, the iron mean concentration was 0.83 microg/m3 (+/-0.65 microg/m3) and the bioavailable Fe was 5.7% (+/-4.4%). The data showed that secondary particulate matter (as sum of sulfates and nitrates) constituted about 47% of PM10 total mass. Both iron and secondary species concentrations were positively associated with PM10 levels. Seasonal variations of PM10 concentration, iron level and secondary species amount were significant. Samples were tested for mutagenicity with Salmonella typhimurium strains TA98 and TA100, with and without metabolic activation and a positive response was observed especially for TA98. There were positive statistical associations between mutagenicity and PM10, bioavailable iron, sulfates and nitrates concentrations. Therefore, these results showed the usefulness of this biological approach for monitoring PM10.

Urban air quality and carboxyhemoglobin levels in a group of traffic policemen.

Toxicological potential of carbon monoxide (CO) on humans is well known. Nevertheless, CO is still considered as a useful marker to detect some environmental and occupational human risk factors typical of cities. The role played by traffic pollution, indoor air quality in offices and tobacco smoke on the expression of carboxyhemoglobin (COHb%) levels was investigated in a large group of traffic policemen in Torino city (North-Western Italy). At the end of the working shift, 228 policemen responded to a questionnaire, weight and height recorded, urine spot samples collected to measure cotinine as biomarker of tobacco smoke exposure, and an arterial blood sample was taken to measure COHb levels. Data of outdoor urban air-CO were collected and to each subject a "CO outdoor air measurement" was related to his/her COHb level. Considering the annual trend of air-CO pollution from 2002 to 2004, one can assume that a general improvement of air quality in Torino was evident. Taking into account the environments where policemen work (urban outdoor and indoor), and analyzing their COHb% content, the traffic-congested areas, and, in general, the outdoor urban environment were equally risky as offices. Furthermore, if compared to CO arising from traffic-congested areas or other outdoor environments, the traffic policemen in Torino city demonstrate COHb% levels largely due to smoking habits.

The mutagenic hazards of environmental PM2.5 in Turin.

Owing to the large number of natural and anthropogenic sources, particulate matter (PM) may present several physical and chemical patterns in different areas. The finer PM2.5 fraction, which is now widely but not routinely measured in Europe, is considered to be the alveolar fraction of the ambient particles. Annual and winter mean concentrations of PM2.5 substantially vary in Europe, with higher concentrations in the South. The aims of this work were to (a) measure the PM2.5 levels in Turin over a long period, (b) evaluate mutagenic activities of organic extracts containing this collected complex mixture using the Ames test and (c) determine the level of polycyclic aromatic hydrocarbons (PAHs) in order to identify important mutagens in ambient air. Sampling was carried out from November 2001 to December 2004. The monthly mean of PM2.5 was 48.76+/-24.12 microg/m3. From the beginning to the end of the sample period there was a decrease in gravimetric levels, with annual means of 54.10+/-29.77 microg/m3 in 2002; 42.48+/-15.73 microg/m3 in 2003 and 45.89+/-24.92 microg/m3 in 2004. Samples were tested for mutagenicity using Salmonella typhimurium strains TA98 and TA100, with and without S9 mix metabolic activation. A positive genotoxic response was observed for TA98, with and without metabolic activation. The measured PAHs monthly mean level was 8.24+/-6.30 ng/m3, with values ranging from 0.20 to 21.38 ng/m3 Seasonal variation of gravimetric, mutagenic and PAH values was significant. The Salmonella assay results statistically correlated to PM2.5 and PAHs levels, but sometimes the mutagenic potencies were rather different despite an equal concentration of pollutant. The results confirm the usefulness of this biological approach to detect genotoxic properties of sampled PM2.5 and they show the variability of the mutagenic properties of the airborne mixture over time.

Airborne particulate matter: Ionic species role in different Italian sites.

Epidemiological studies have provided evidences for an association between exposure to elevated levels of ambient particulate matter (PM) and increased mortality and morbidity. However, the exact physiochemical nature of the responsible component is not clear. Secondary airborne PM formed from gas-phase pollutants contributes significantly to the most severe particulate air quality events. Although chemical formation for ionic species of aerosol have been observed, they have not been well reported for local variation. This work evaluates the amount of secondary particulate ionic species: sulfates (SO(4)(2-)) and nitrates (NO(3)(-)), chlorides (Cl(-)) and the mutagenic activities of PM10 extracts in different Italian sites (one Southern, one Central and three Northern; in one of the latter also PM2.5 has been evaluated). In general, mean secondary species concentration constitutes about 35-45% of PM10 mass in the North sites, 15% in the center site and 20% in the South site and it is positively associated with PM10 levels. There are significant local differences in the mean levels of PM10 ionic constituents: NO(3)(-) are predominant in northern cities, SO(4)(2-) are more equally distributed and coastal southern city is abundant in Cl(-). Samples were also tested for mutagenicity with Salmonella typhimurium strains TA98 and TA100, with and without metabolic activation; mutagenicity did not correlate with PM10 concentrations. The results showed the important roles and the geographical variability of PM secondary species in the total mass PM10 concentrations and the usefulness of this biological approach for monitoring PM to understand hazards from PM.

Application of semipermeable membrane device for assessing toxicity in drinking water.

Semipermeable membrane devices (SPMDs) mimic passive diffusive transport of bioavailable hydrophobic organic compounds through biological membranes and their partitioning between lipids and environmental levels. Our study was developed on a surface water treatment plant based in Turin, Northern Italy. The investigated plant treats Po River surface water and it supplies about 20% of the drinking water required by Turin city (about one million inhabitants). Surface water (input) and drinking water (output) were monitored with SPMDs from October 2001 to January 2004, over a period of 30 days. The contaminant residues, monthly extracted from SPMDs by dialysis in organic solvent, were tested with the Microtox acute toxic test and with the Ames mutagenicity test. Same extracts were also analyzed with gas chromatography--mass spectrometry technique in order to characterise the organic pollutants sampled, especially Polycyclic Aromatic Hydrocarbons (PAHs). Although the PAHs mean concentration is about one hundred times lower in the output samples, the mean toxic units are similar in drinking and surface water. Our data indicate that the SPMD is a suitable tool to assess the possible toxicity in drinking water.

[Augmentation of the biodisposition of simple sugars from sorghum biomass mediated with biotechnologic processes]. / Aumento della disponibilità di zuccheri semplici da biomasse di sorgo zuccherino mediante processi biotecnologici.

The results of the enzymatic hydrolysis of pectin, hemicellulose and cellulose in the biomass of sweet sorghum (Sorghum vulgare var. saccharatum, L.) are reported. Some commercial enzymatic preparations were used: Maxazym CL 2000 (with prevailing cellulase activity), Rapidase C 80 (with prevailing pectinase activity) Rohament PC (mainly with pectinase and cellulase activities) and Rohament O (mainly with pectinase and hemicellulase activities). The treatment with Rohament PC, Rohament O and Rapidase C 80 gives an increase of the glucose content higher than the effect induced by Maxazym CL 2000. On the other hand, the cellulase and pectinase combined treatment (Maxazym CL 2000 + Rapidase C 80 or Maxazym CL 2000 + Rohament O) shows a good synergistic effect in the degradation of the plant cell wall cellulosic material.

[Characterization of the biomass of the stems of sweet sorghum]. / Caratterizzazione della biomassa dei culmi di sorgo zuccherino.

In this study the amount of glucose, sucrose and fructose was determined in the water soluble fraction while cellulose, hemicellulose, pectin and lignin contents were determined in the alcohol insoluble fraction after hydrolysis. Stalks of sweet sorghum (Sorghum vulgare L., var. saccharatum) cv. Vespa, Soave, Roce and MN 1500 at the physiological ripeness stage were used. The results of the analysis of variance with the least significant difference method (LSD, = 0.05) show that cv. Vespa and Roce have a significantly higher total amount of glucose, fructose and sucrose and at the same time, a lower cellulose, pectin, hemicellulose and lignin content then cv. Soave and cv. MN 1500.