Federico Valerio

Monitoring low benzene exposure : comparative evaluation of urinary biomarkers, influence of cigarette smoking and genetic polymorphisms

Benzene is a human carcinogen and an ubiquitous environmental pollutant. Identification of specific and sensitive biological markers is critical for the definition of exposure to low benzene level and the evaluation of the health risk posed by this exposure. This investigation compared urinary trans,trans-muconic acid (t,t-MA), S-phenylmercapturic acid, and benzene (U-benzene) as biomarkers to assess benzene exposure and evaluated the influence of smoking and the genetic polymorphisms CYP2E1 (RsaI and DraI) and NADPH quinone oxidoreductase-1 on these indices. Gas station attendants, urban policemen, bus drivers, and two groups of controls were studied (415 subjects). Median benzene exposure was 61, 22, 21, 9 and 6 μg/m3, respectively, with higher levels in workers than in controls. U-benzene, but not t,t-MA and S-phenylmercapturic acid, showed an exposure-related increase. All the biomarkers were strongly influenced by cigarette smoking, with values up to 8-fold higher in smokers compared with nonsmokers. Significant correlations of the biomarkers with each other and with urinary cotinine were found. A possible influence of genetic polymorphism of CYP2E1 (RsaI and/or DraI) on t,t-MA and U-benzene in subjects with a variant allele was found. Multiple linear regression analysis correlated the urinary markers with exposure, smoking status, and CYP2E1 (RsaI; R2 up to 0.55 for U-benzene). In conclusion, in the range of investigated benzene levels (<478 μg/m3 or <0.15 ppm), smoking may be regarded as the major source of benzene intake; among the study indices, U-benzene is the marker of choice for biomonitoring low-level occupational and environmental benzene exposure.

Cytogenetic biomonitoring in traffic police workers: micronucleus test in peripheral blood lymphocytes.

Atmospheric pollution represents a relevant environmental hazard which has been associated with considerable excess mortality, morbidity, and increased rates of respiratory diseases in humans. To date, more than 3,000 environmental chemical compounds have been identified in the ambient atmosphere, including a variety of mutagenic and/or carcinogenic agents, such as polycyclic aromatic hydrocarbons (PAHs), aromatic amines, and heterocyclic compounds. Positive associations between cytogenetic markers and airborne levels of PAHs have been reported by experimental and human studies. Traffic has been implicated as the major determinant for the concentration of PAHs and, therefore, for the genotoxic activity of urban air. A biomonitoring study has been conducted in 82 Italian traffic police workers exposed to air pollutants and 34 control subjects (matched by age, gender, and smoking habits) not exposed to traffic pollutants. The aim of this study was to assess the cytogenetic effects, such as micronucleus frequency in peripheral blood lymphocytes, and to estimate the association with individual exposure to PAH. Statistical analysis of the frequency of micronuclei in binucleated cells showed higher mean levels in referent subjects (4.03%) than in traffic police officers (3.73%). Smoking showed no effect on the frequency of micronuclei. The study failed to detect any association between micronucleus frequency and individual level of benzo(a)pyrene, considered a marker of exposure to PAHs. These findings indicate that exposure to urban air pollutants does not result in increased levels of micronuclei in peripheral white blood cells. Environ. Mol. Mutagen. 30:396–402, 1997

Polycyclic Aromatic Hydrocarbon Pollution in Native and Caged Mussels

During 1999, a biological monitoring study was conducted at four sites along the Ligurian coast (Cornigliano, Voltri, Vado Ligure and Sanremo). At each site the concentration and composition of polycyclic aromatic hydrocarbons (PAH) were investigated in native and caged mussels. The mussels (Mytilus galloprovincialis), sampled in the Spring and the Autumn, showed different accumulation patterns according to the source of pollution they were exposed to. The PAH concentrations were higher in the native than in the caged mussels. The coastal sites were classified according to PAH concentrations found in mussel tissue samples: Native mussels: Vado Ligure < Voltri < San-remo < = Cornigliano, Caged mussels: Vado Ligure = Voltri = San-remo << Cornigliano. The different classification is explained by the different location of the organisms: native mussels were located near the air-water interface, while caged mussels were situated at -3 m from the water surface. The PAH concentrations in the native and caged mussels showed a similar seasonal variability, and can provide the same information about the sources of PAHs.

Chemical and photochemical degradation of polycyclic aromatic hydrocarbons in the atmosphere

Results of studies on chemical and photochemical transformations of polycyclic aromatic hydrocarbons (PAH) are reviewed. Various parameters may modify the kinetics of these reactions, such as light intensity, concentration of gaseous pollutants (NOx, SOx, O3), chemico-physical characteristics of particulates or substrates into which the PAH are adsorbed. Depending on these variables, the half-life of BaP varies from 10 to 104 300 min. The possibility of artefact formation during sampling is discussed. The necessity of clarifying mechanisms for these phenomena, in order to correctly evaluate the risks for exposed populations, is emphasized.

Principal Component Analysis Application in Polycyclic Aromatic Hydrocarbons "Mussel Watch" Analyses for Source Identification

Abstract This article aims to show how a careful pre-treatment of data can be used to demonstrate various features embedded in a given data set obtained from a “mussel watch” survey, namely site- and source-specific characteristics and weather-related changes, and to provide indications so as to allow comparison with analyses performed on another substrate matrix. Polycyclic aromatic hydrocarbons (PAHs) biomonitored in the aquatic environment by means of caged mussels are compared by site and by season. Moreover, their fingerprints were compared to marine sediments and atmospheric airborne PAHs. The characterization of the sampling stations by means of the multivariate technique called principal component analysis (PCA) allows distinguishing the prevalence of pyrogenic or petrogenic types of pollution and between two kinds of combustibles. This was confirmed by jointly analyzing the percent composition of sea (mussel) and air (filter) samples.

Sister chromatid exchange induction in peripheral blood lymphocytes of traffic police workers.

Traffic police workers, as a population exposed to urban atmosphere, were compared with a control population exposed to indoor air pollution levels. Sister chromatid exchanges (SCEs) as a biomarker of effect were measured in peripheral blood lymphocytes of 54 exposed subjects and 35 controls, and environmental concentration of polynuclear aromatic hydrocarbon (PAH) tracer compounds was detected by personal air samplers. The mean exposure level to benzo[a]pyrene in our group of traffic policemen (3.4 mg/m3) was in the range that has been estimated in urban areas in Europe during the last 10 years. No difference in SCE levels was found between exposed workers (7.36, SD 1.35) and controls (7.47, SD 1.28). No correlation was observed between SCE/cell and airborne PAH concentration in the traffic worker population. A positive regression of SCE on exposure estimate was found only in the non-smoking group of police workers. Our findings suggest that exposure to urban air pollution does not induce relevant cytogenetic effects.

Is the smokers exposure to environmental tobacco smoke negligible

BackgroundVery few studies have evaluated the adverse effect of passive smoking exposure among active smokers, probably due to the unproven assumption that the dose of toxic compounds that a smoker inhales by passive smoke is negligible compared to the dose inhaled by active smoke.MethodsIn a controlled situation of indoor active smoking, we compared daily benzo(a)pyrene (BaP) dose, estimated to be inhaled by smokers due to the mainstream (MS) of cigarettes they have smoked, to the measured environmental tobacco smoke (ETS) they inhaled in an indoor environment. For this aim, we re-examined our previous study on daily personal exposure to BaP of thirty newsagents, according to their smoking habits.ResultsDaily BaP dose due to indoor environmental contamination measured inside newsstands (traffic emission and ETS produced by smoker newsagents) was linearly correlated (p = 0.001 R2 = 0.62) with estimated BaP dose from MS of daily smoked cigarettes. In smoker subjects, the percentage of BaP daily dose due to ETS, in comparison to mainstream dose due to smoked cigarettes, was estimated with 95% confidence interval, between 14.6% and 23% for full flavour cigarettes and between 21% and 34% for full flavour light cigarettes.ConclusionsDuring indoor smoking, ETS contribution to total BaP dose of the same smoker, may be not negligible. Therefore both active and passive smoking exposures should be considered in studies about health of active smokers.

Sources and atmospheric concentrations of polycyclic aromatic hydrocarbons and heavy metals in two Italian towns (Genoa and La Spezia)

The same sampling and analytical methods were used to compare atmospheric pollution due to polycyclic aromatic hydrocarbons (PAHs) and heavy metals (Tl, Pb, Mn, Fe, Cr, V, Zr, Ni Cd) in two towns in Italy, Genoa and La Spezia, whose populations are 746, 785 and 112,602 respectively. Knowledge of the organic and inorganic composition of airborne particulates permits a reliable identification of the main sources of pollution which is required in order to identify populations at risk. In the urban area of Genoa and in La Spezia, traffic appears to provide a diffuse source of carcinogenic and toxic compounds in the atmosphere producing high and constant exposures to PAHs and lead along busy streets. In Genoa approximately 70,00 people (10% of residents) are considered to be exposed to the highest concentrations of toxic and cancerogenic pollutants emitted from this source. The highest daily PAH concentrations were found in the industrial areas; in Genoa, coke ovens were identified as the main localised sources of these compounds. According to meteorlogical and orographic characteristics for this area, for approximately 25,00 people (3% of the general population) may be exposed to pollutants emitted from this source over a maximum period equivalent to approximately 3 months each year. The highest individual doses of PAHs due to urban pollution inhaled by the population of Genoa and La Spezia were comparable to those produced by high exposure to passive smoke; the exposure to carcinogenic metals (Cr, NI, Cd) was relatively low. The mean concentrations of the analysed pollutants appeared to depend strictly on urban characteristics; no correlations were found with the size of the town.

Decomposition of benzo (a) pyrene deposited on glass fiber filters and exposed to sunlight

Measurements of Benzo (a) Pyrene deposited on glass fiber filters exposed to solar radiation indicate a time dependent exponential decrease. Possible impli cations of this phenomenon in the measurements of B(a)P in particulate samples are discussed.

Preliminary evaluation, using passive tubes, of carbon monoxide concentrations in outdoor and indoor air at street level shops in Genoa (Italy)

Abstract Preliminary information on carbon monoxide (CO) concentrations (exposure time: 8 h) both inside and outside 38 randomly selected shops situated on four heavy traffic streets of Genoa was obtained using passive diffusion tubes. Reproducibility and accuracy of this analytical method were tested in real outdoor urban conditions and found within 25%; the detection limit was 1 mgm−3 of CO. The highest mean CO concentrations (15.8 ± 2.2 mgm−3) were found inside shops on Balbi street, a narrow “canyon street”. Only in two small shops and two bars (both with many smokers) and in a delicatessen, were indoor CO concentrations significantly higher than outdoor values. The mean outdoor CO concentrations (mgm−3) along the four streets considered (XX Settembre, Balbi, Rolando, Fillak) were 7.4 ± 2.2; 14.5 ± 8.7; 5.8 ± 0.4; 10.5 ± 3.7, respectively. No statistical difference was found, comparing the mean indoor CO concentration with the mean CO outdoor value, measured simultaneously along the sidewalks of each street. CO concentrations in 10 shops without smokers and the nearest outdoor measurements were linearly correlated (r = 0.99; p