Response Letter to Koivisto et al. 'Evaluating the Theoretical Background of STOFFENMANAGER® and the Advanced REACH Tool'.

In this article, we have responded to the key statements in the article by Koivisto et al. (2022) that were incorrect and considered to be a biased critique on a subset of the exposure models used in Europe (i.e. ART and Stoffenmanager®) used for regulatory exposure assessment. We welcome scientific discussions on exposure modelling (as was done during the ISES Europe workshop) and criticism based on scientific evidence to contribute to the advancement of occupational exposure estimation tools. The tiered approach to risk assessment allows various exposure assessment models from screening tools (control/hazard banding) through to higher-tiered approaches. There is a place for every type of model, but we do need to recognize the cost and data requirements of highly bespoke assessments. That is why model developers have taken pragmatic approaches to develop tools for exposure assessments based on imperfect data. We encourage Koivisto et al. to focus on further scientifically robust work to develop mass-balance models and by independent external validations studies, compare these models with alternative model tools such as ART and Stoffenmanager®.

Carbon Nanotubes: Probabilistic Approach for Occupational Risk Assessment.

In this study, the occupational risk assessment of carbon nanotubes (CNTs) was performed by means of a probabilistic approach. Chronic and subchronic inhalation exposure studies were retrieved during the hazard identification phase of the study. These studies were then used to obtain a guidance value (BMCh, expressed as a lognormal distribution with geometric mean ± geometric standard deviation = 10.0 ± 4.2 µg/m3) for occupational inhalation exposure to CNTs. An exposure scenario was selected from the scientific literature: three different work events (WEs) related to the production of conductive films were considered: (WE1) manufacturing of single walled carbon nanotubes films during normal operation using local exhaust ventilation (LEV); (WE2) manufacturing of SWCNT film without LEV; and (WE3) cleaning of one of the reactors. For each WE, a probability distribution function was applied, considering exposure expressed as mass concentration, as derived from three different measurement techniques. The ratio of the exposure and the BMCh distributions (i.e., the risk characterization ratio-RCR) was used to calculate the probability of occurrence of a relevant occupational risk. All the considered WEs indicated the presence of a risk (i.e., RCR distributions ≥ 1); however, only WE2 resulted in a statistically significant level of risk.

Toxic trace metals in size-segregated fine particulate matter: Mass concentration, respiratory deposition, and risk assessment.

To characterise the mass concentration, size-distribution, and respiratory deposition of selected trace metals (Cr, Mn, Fe, Ni, Cu, Zn, Ba, and Pb) in size-segregated PM2.5, a long-term monitoring campaign was undertaken at an urban background site in Como (Northern Italy). 96-h aerosol samples were collected weekly, from May 2015 to March 2016, using a 13-stage low pressure impactor and analysed via laser ablation-inductively coupled plasma-mass spectrometry. Significantly higher levels of trace metals were generally found during the heating season (two to more than four times) compared to the non-heating period at all size ranges, especially for concentrations in PM0.1-1. Distinct distribution profiles characterised the different elements, even though the corresponding heating and non-heating shapes always exhibited similar features, with negligible seasonal shifts in the average mass median aerodynamic diameters. Fe, Ba, and Cu had >70% of their mass in PM1-2.5, whereas Pb, Zn, and Ni showed higher contributions in the accumulation mode (>60%). Finally, broad size-distributions were found for Cr and Mn. The multiple-path particle dosimetry model estimated the overall deposition fractions in human airways varying between 27% (Pb) and 48% (Ba). The greatest deposition variability was always registered in the head region of the respiratory system, with the highest contributions for those metals predominantly accumulated in the PM2.5 coarse modes. In contrast, the deposition in the deepest respiratory tract maintained nearly constant proportions over time, becoming notably important for Pb, Ni, and Zn (∼13%) with respect to their total deposition. The comparison with national limits established for Pb and Ni suggested the absence of significant risks for the local population, as expected, with average concentrations two orders of magnitude lower than the corresponding annual limit and objective value. Similar findings were reported for all the other metals, for which the estimated hazard quotients were always well <1.

COVID-19 Outbreak in Italy: Protecting Worker Health and the Response of the Italian Industrial Hygienists Association.

The number of people infected with severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), i.e. the virus causing coronavirus disease (COVID-19), is dramatically increasing worldwide to the size of a pandemic. At the time of writing Italy is ranking first among countries both in terms of number of COVID-19 confirmed cases and in terms of number of deaths. Such a wide spread of COVID-19 has led to concern among workers who are facing the risk of becoming infected during the execution of their duties. We believe it is useful to remark on the need for professional expertise in the field of Occupational Hygiene in this emergency context, in which the indications provided by national and international bodies, the available scientific literature and the legal provisions are constantly and rapidly evolving. It is of fundamental importance that there is an effective analysis of expert inputs, to provide essential guidance to Health, Safety and Environmental managers and other prevention managers in workplaces. In this regard, not only a constant update of the regulatory framework is needed, but also a development and circulation of operational guidance to all the stakeholders to translate general indications into clear operating procedures and implementation tools to be adopted in the workplaces. We believe that the scientific associations in the field of Occupational Hygiene play a crucial role in guiding and assisting prevention professionals. There is considerable expertise in the occupational hygiene and exposure science communities that can help employers and workers to contain and delay the spread of COVID-19. For this reason, the Italian Association of Industrial Hygienists (AIDII-Associazione Italiana degli Igienisti Industriali) published documents containing operational guidelines to provide correct and constantly updated information for: (i) workers employed in essential activities (with low and medium risk of contagion), (ii) health workers and other workers at high or very high risk of contagion, and (iii) for the correct use and handling of personal protective equipment for workers and for the population in general. It is worth pointing out that the documents produced are not intended to replace those produced by authoritative bodies, but to comply with and complete them by reporting an effective summary and further indications about the measures that should be taken in practice under the light of the Italian legislation. At present, the challenge is to produce scientifically sound knowledge, appropriate tools, and effective methodologies, by coordinating the initiatives of different scientific associations, with the final aim to effectively transfer them to employers and workers.

Indoor gaseous air pollutants determinants in office buildings-The OFFICAIR project.

The aim of this study was to identify determinants of aldehyde and volatile organic compound (VOC) indoor air concentrations in a sample of more than 140 office rooms, in the framework of the European OFFICAIR research project. A large field campaign was performed, which included (a) the air sampling of aldehydes and VOCs in 37 newly built or recently retrofitted office buildings across 8 European countries in summer and winter and (b) the collection of information on building and offices' characteristics using checklists. Linear mixed models for repeated measurements were applied to identify the main factors affecting the measured concentrations of selected indoor air pollutants (IAPs). Several associations between aldehydes and VOCs concentrations and buildings' structural characteristic or occupants' activity patterns were identified. The aldehyde and VOC determinants in office buildings include building and furnishing materials, indoor climate characteristics (room temperature and relative humidity), the use of consumer products (eg, cleaning and personal care products, office equipment), as well as the presence of outdoor sources in the proximity of the buildings (ie, vehicular traffic). Results also showed that determinants of indoor air concentrations varied considerably among different type of pollutants.

In-vehicle airborne fine and ultra-fine particulate matter exposure: The impact of leading vehicle emissions.

Airborne particulate matter (PM) concentrations inside vehicle cabins are often extremely high compared to background levels. The present study was motivated by the fact that in the last few decades, the implementation of new emission standards has led to the reduction of vehicle particle emissions. This study addresses for the first time the relationship between leading vehicle (LV) emissions and in-cabin PM exposure levels in the immediately following vehicle (henceforth called the study vehicle - SV), with particular emphasis on the role of the LV's emission reduction technologies (e.g., diesel particulate filter-DPF) as an effective risk management measure. The study was performed using an instrumented study vehicle (always to be considered as the following vehicle) on a 26-km fixed route where 10 repeated tests were conducted during 60-minute trips. On-line monitoring of the fine 0.3-1 µm and 1-2.5 µm (PM0.3-1 and PM1-2.5) and ultra-fine particle (UFP) concentrations was performed inside the SV's car cabin with fixed ventilation settings (i.e., windows closed, air conditioning off, and recirculation fan off). Simultaneously, the license plate numbers of the LVs along the route were recorded to retrieve information pertaining to their fuel type and Euro emission standard category. The results clearly showed that the in-cabin PM levels were significantly affected by the LV's Euro emission standard. Regarding petrol-fuelled LVs, the median in-cabin particle exposure levels were statistically lower (e.g., -34% for PM0.3-1) when following vehicles with stricter emission standards (in particular, Euro 6) than when following a low-emission standard vehicle (i.e., Euro 0-2). Concerning diesel-fuelled LVs, a strong and significant decrease in the in-cabin median exposure levels (up to -62%, -44%, and -48% for UFPs, PM0.3-1, and PM1-2.5, respectively) was observed for recent-emission standards LVs (i.e., Euro 5-6) with respect to older-emission standard LVs (i.e., Euro 0-4). A specific analysis revealed that the in-cabin median exposure concentrations of PM were highly and significantly reduced by DPF-equipped LVs. For UFPs, this resulted in a 47% reduction compared to diesel-fuelled (non-DPF) LVs. For PM0.3-1, an approximate 80% reduction was observed compared to both petrol-fuelled and diesel-fuelled (non-DPF) LVs. For PM1-2.5, an approximate 38% reduction was observed compared to petrol-fuelled LVs and a 46% reduction compared to non-DPF LVs.

[Chemical risks in research laboratories]. / I rischi nei laboratori di ricerca: i rischi di tipo chimico.

SUMMARY: Research laboratories represent peculiar employment realities, generally characterized by the use of reduced volumes of several chemicals, often used in mixture, thus defining a potential exposure to multiple chemical agents. Methods. The aim of the study is to provide a brief review of the most widely used methods for assessing chemical risk in laboratories, with particular emphasis on their limits and advantages. Results. The approach most often used for assessing chemical risk in research laboratories involves the use of a qualitative modeling approach for risk assessment or quantitative exposure assessment tools. Conclusions. Chemical risk assessment algorithms represent a useful solution for the purposes of the initial screening for the assessment of chemical risk in research laboratories: their ease of use makes them easily accessible, but on the other hand does not allow to take into proper consideration the particularities of the assessed exposure scenarios. Regarding the exposure estimation models, although these instruments have a wide range of applicability, there is no solid and complete validation, which evaluates the accuracy and reliability for this peculiar type of exposure scenarios.

Probabilistic approach for the risk assessment of nanomaterials: A case study for graphene nanoplatelets.

An experimental probabilistic approach for health risk assessment was applied for graphene nanoplatelets (GNPs). The hazard assessment indicated a low level of toxicity for the GNPs. The benchmark dose method, based on sub-chronic and chronic inhalation exposure studies, was used to quantify a guidance value (BMCh) for occupational inhalation exposure to GNPs, expressed as a lognormal distribution with a geometric mean ±â€¯geometric standard deviation of 0.212 ±â€¯7.79 mg/m3 and 9.37 × 104 ±â€¯7.6 particle/cm3. Exposure scenarios (ES) were defined based on the scientific literature for large-scale production (ES1) and manufacturing (ES2) of GNPs; a third ES, concerning in-lab handling of GNPs (ES3) was based on results of experiments performed for this study. A probability distribution function was then assumed for each ES. The risk magnitude was calculated using a risk characterization ratio (RCR), defined as the ratio of the exposure distributions and the BMCh distribution. All three ES resulted in RCR distributions ≥1 (i.e. risk present); however, none of the ES had a statistically significant level of risk at a 95% confidence interval. A sensitivity analysis indicated that ∼75% of the variation in the RCR distributions was due to uncertainties in the BMCh calculation.

Multi-element analysis of size-segregated fine and ultrafine particulate via Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry.

In this study a novel and reliable Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) measurement protocol for the elemental characterization of size-segregated particulate was developed. Special efforts were made to improve and optimize sample pre-treatment steps and LA operating conditions to avoid some critical drawbacks encountered during analysis and to make the particulate samples suitable for an accurate and reproducible LA-ICP-MS analysis, regardless of the mass loading on each filter. For example, a new approach for dust-fixation on the sample-carrier was developed using a glycerol coverage, which allowed to overcome problematic sample losses during the ablation process. Under the optimum conditions, dust samples, blank filters and standards for calibration were analyzed by multiple rastering of defined spot areas. Quantitative analysis was accomplished with dried micro-droplets of aqueous standard solutions. Derived method detection limits varied between 0.001 and 0.1 ng m-3 and allowed even for the smallest particle fraction quantitative measurements. The accuracy of LA-ICP-MS results was verified by comparison with conventional ICP-MS analysis of selected PM samples after sample mineralization. The proposed LA treatment procedure benefits from a simple and fast sample preparation, thus overcoming the laborious pre-treatment steps required for wet chemical digestion. Moreover, the better sensitivity of the LA-ICP-MS approach provided more complete information about the mass concentration and size-distribution of the investigated elements, thus allowing to deeper investigate the composition of the most dangerous PM fractions in terms of health concern.

Precision and Accuracy of a Direct-Reading Miniaturized Monitor in PM2.5 Exposure Assessment.

The aim of this study was to evaluate the precision, accuracy, practicality, and potential uses of a PM2.5 miniaturized monitor (MM) in exposure assessment. These monitors (AirBeam, HabitatMap) were compared with the widely used direct-reading particulate matter monitors and a gravimetric reference method for PM2.5. Instruments were tested during 20 monitoring sessions that were subdivided in two different seasons to evaluate the performance of sensors across various environmental and meteorological conditions. Measurements were performed at an urban background site in Como, Italy. To evaluate the performance of the instruments, different analyses were conducted on 8-h averaged PM2.5 concentrations for comparison between direct-reading monitors and the gravimetric method, and minute-averaged data for comparison between the direct-reading instruments. A linear regression analysis was performed to evaluate whether the two measurement methods, when compared, could be considered comparable and/or mutually predictive. Further, Bland-Altman plots were used to determine whether the methods were characterized by specific biases. Finally, the correlations between the error associated with the direct-reading instruments and the meteorological parameters acquired at the sampling point were investigated. Principal results show a moderate degree of agreement between MMs and the reference method and a bias that increased with an increase in PM2.5 concentrations.

Miniaturized Monitors for Assessment of Exposure to Air Pollutants: A Review.

Air quality has a huge impact on different aspects of life quality, and for this reason, air quality monitoring is required by national and international regulations. Technical and procedural limitations of traditional fixed-site stations for monitoring or sampling of air pollutants are also well-known. Recently, a different type of miniaturized monitors has been developed. These monitors, due to their characteristics (e.g., low cost, small size, high portability) are becoming increasingly important for individual exposure assessment, especially since this kind of instrument can provide measurements at high spatial and temporal resolution, which is a notable advantage when approaching assessment of exposure to environmental contaminants. The aim of this study is indeed to provide information regarding current knowledge regarding the use of miniaturized air pollutant sensors. A systematic review was performed to identify original articles: a literature search was carried out using an appropriate query for the search of papers across three different databases, and the papers were selected using inclusion/exclusion criteria. The reviewed articles showed that miniaturized sensors are particularly versatile and could be applied in studies with different experimental designs, helping to provide a significant enhancement to exposure assessment, even though studies regarding their performance are still sparse.

Accuracy Evaluation of Three Modelling Tools for Occupational Exposure Assessment.

OBJECTIVES: The objective of this study is to evaluate the accuracy and robustness of three exposure-modelling tools [STOFFENMANAGER® v.6, European Centre for Ecotoxicology and Toxicology of Chemical Target Risk Assessment v.3.1 (ECETOC TRA v.3.1), and Advanced REACH Tool (ART v.1.5)], by comparing available measured data for exposure to organic solvents and pesticides in occupational exposure scenarios (ESs). METHODS: Model accuracy was evaluated by comparing the predicted and the measured values, expressed as an underestimation or overestimation factor (PRED/EXP), and by regression analysis. Robustness was quantitatively described by the so-called variable 'Uncertainty Factor' (UF), which was attributed to each model's input: a higher UF score indicates greater model uncertainty and poorer robustness. RESULTS: ART was the most accurate model, with median PRED/EXP factors of 1.3 and 0.15 for organic solvent and pesticide ESs, respectively, and a significant correlation (P < 0.05) among estimated and measured data. As expected, Tier 1 model ECETOC TRA demonstrated the worst performance in terms of accuracy, with median PRED/EXP factors of 2.0 for organic solvent ESs and 3545 for pesticide ESs. Simultaneously, STOFFENMANAGER® showed a median UF equal to 2.0, resulting in the most robust model. DISCUSSION: ECETOC TRA was not considered acceptable in terms of accuracy, confirming that this model is not appropriate for the evaluation of the selected ESs for pesticides. Conversely, STOFFENMANAGER® was the best choice, and ART tended to underestimate the exposure to pesticides. For organic solvent ESs, there were no cases of strong underestimation, and all models presented overall acceptable results; for the selected ESs, ART showed the best accuracy. Stoffenmanager was the most robust model overall, indicating that even with a mistake in ES interpretation, predicted values would remain acceptable. CONCLUSION: ART may lead to more accurate results when well-documented ESs are available. In other situations, Stoffenmanager appears to be a safer alternative because of its greater robustness, particularly when entry data uncertainty is difficult to assess. ECETOC TRA cannot be directly compared to higher tiered models because of its simplistic nature: the use of this tool should be limited only to exceptional cases in which a strong conservative and worst-case evaluation is necessary.

Occupational exposure to arsenic and cadmium in thin-film solar cell production.

INTRODUCTION: Workers involved in the production of Cd/As-based photovoltaic modules may be routinely or accidentally exposed to As- or Cd-containing inorganic compounds. METHODS: Workers' exposure to As and Cd was investigated by environmental monitoring following a worst-case approach and biological monitoring from the preparation of the working facility to its decommissioning. Workplace surface contamination was also evaluated through wipe-test sampling. RESULTS: The highest mean airborne concentrations were found during maintenance activities (As = 0.0068 µg m(-3); Cd = 7.66 µg m(-3)) and laboratory simulations (As = 0.0075 µg m(-3); Cd = 11.2 µg m(-3)). These types of operations were conducted for a limited time during a typical work shift and only in specifically suited containment areas, where the highest surface concentrations were also found (laboratory: As = 2.94 µg m(-2), Cd = 167 µg m(-2); powder containment booth: As = 4.35 µg m(-2), Cd = 1500 µg m(-2)). The As and Cd urinary levels (As_u; Cd_u) were not significantly different for exposed (As_u = 6.11±1.74 µg l(-1); Cd_u = 0.24±2.36 µg g(-1) creatinine) and unexposed workers (As_u = 6.11±1.75 µg l(-1); Cd_u = 0.22±2.08 µg g(-1) creatinine). CONCLUSION: Despite airborne arsenic and cadmium exposure well below the threshold limit value (TLV) when the operation is appropriately maintained in line, workers who are involved in various operations (maintenance, laboratory test) could potentially be at risk of significant exposure, well in excess of the TLV. Nevertheless, the biological monitoring data did not show significant occupationally related arsenic and cadmium intake in workers and no significant changes or differences in arsenic and cadmium urinary level among the exposed and unexposed workers were found.

Modeling population exposure to ultrafine particles in a major Italian urban area.

Average daily ultrafine particles (UFP) exposure of adult Milan subpopulations (defined on the basis of gender, and then for age, employment or educational status), in different exposure scenarios (typical working day in summer and winter) were simulated using a microenvironmental stochastic simulation model. The basic concept of this kind of model is that time-weighted average exposure is defined as the sum of partial microenvironmental exposures, which are determined by the product of UFP concentration and time spent in each microenvironment. In this work, environmental concentrations were derived from previous experimental studies that were based on microenvironmental measurements in the city of Milan by means of personal or individual monitoring, while time-activity patterns were derived from the EXPOLIS study. A significant difference was observed between the exposures experienced in winter (W: 28,415 pt/cm3) and summer (S: 19,558 pt/cm3). Furthermore, simulations showed a moderate difference between the total exposures experienced by women (S: 19,363 pt/cm3; W: 27,623 pt/cm3) and men (S: 18,806 pt/cm3; W: 27,897 pt/cm3). In addition, differences were found as a function of (I) age, (II) employment status and (III) educational level; accordingly, the highest total exposures resulted for (I) 55-59 years old people, (II) housewives and students and (III) people with higher educational level (more than 10 years of scholarity). Finally, significant differences were found between microenvironment-specific exposures.

Airborne particulate matter in school classrooms of northern Italy.

Indoor size-fractioned particulate matter (PM) was measured in seven schools in Milan, to characterize their concentration levels in classrooms, compare the measured concentrations with the recommended guideline values, and provide a preliminary assessment of the efficacy of the intervention measures, based on the guidelines developed by the Italian Ministry of Healthand applied to mitigate exposure to undesirable air pollutants. Indoor sampling was performed from Monday morning to Friday afternoon in three classrooms of each school and was repeated in winter 2011-2012 and 2012-2013. Simultaneously, PM2.5 samples were also collected outdoors. Two different photometers were used to collect the PM continuous data, which were corrected a posteriori using simultaneous gravimetric PM2.5 measurements. Furthermore, the concentrations of carbon dioxide (CO2) were monitored and used to determine the Air Exchange Rates in the classrooms. The results revealed poor IAQ in the school environment. In several cases, the PM2.5 and PM10 24 h concentrations exceeded the 24 h guideline values established by the World Health Organization (WHO). In addition, the indoor CO2 levels often surpassed the CO2 ASHRAE Standard. Our findings confirmed that important indoor sources (human movements, personal clouds, cleaning activities) emitted coarse particles, markedly increasing the measured PM during school hours. In general, the mean PM2.5 indoor concentrations were lower than the average outdoor PM2.5 levels, with I/O ratios generally <1. Fine PM was less affected by indoor sources, exerting a major impact on the PM1-2.5 fraction. Over half of the indoor fine particles were estimated to originate from outdoors. To a first approximation, the intervention proposed to reduce indoor particle levels did not seem to significantly influence the indoor fine PM concentrations. Conversely, the frequent opening of doors and windows appeared to significantly contribute to the reduction of the average indoor CO2 levels.

Increased lung cancer risk among bricklayers in an Italian population-based case-control study.

BACKGROUND: Bricklayers may be at increased risk of lung cancer, although a firm association has not been established. We examined this association within the EAGLE (Environment And Genetics in Lung cancer Etiology) study, a population-based case-control study conducted in Italy between 2002 and 2005. METHODS: For men in selected occupations in the construction sector we calculated smoking-adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs). For bricklayers we estimated the population attributable fraction (PAF) and the attributable community risk (ACR). RESULTS: We found increased lung cancer risk for bricklayers (OR 1.57, 95% CI 1.12-2.21; 147 cases, 81 controls). The PAF was 3.5% (95% CI 0.6-6.3), corresponding to an ACR of 3.6 cases annually per 100,000 men (95% CI 0.6-6.6) [corrected] in the whole community. Among bricklayers, there were increased risks for squamous cell (OR 2.03, 95% CI 1.32-3.13, 56 exposed cases) and small cell carcinomas (OR 2.29, 95% CI 1.29-4.07, 21 exposed cases), while no excess (OR 1.06, 95% CI 0.68-1.65, 41 exposed cases) was found for adenocarcinoma. CONCLUSIONS: Our findings provide additional evidence of increased lung cancer risk in Italian bricklayers. The association is plausible because they are exposed to several carcinogens, notably crystalline silica.

Airborne concentrations of chrysotile asbestos in serpentine quarries and stone processing facilities in Valmalenco, Italy.

Asbestos may be naturally present in rocks and soils. In some cases, there is the possibility of releasing asbestos fibres into the atmosphere from the rock or soil, subsequently exposing workers and the general population, which can lead to an increased risk of developing asbestos-related diseases. In the present study, air contaminated with asbestos fibres released from serpentinites was investigated in occupational settings (quarries and processing factories) and in the environment close to working facilities and at urban sites. The only naturally occurrence of asbestos found in Valmalenco area was chrysotile; amphibole fibres were never detected. An experimental cut-off diameter of 0.25 µm was established for distinguishing between Valmalenco chrysotile and antigorite single fibres using selected area electron diffraction analyses. Air contamination from chrysotile fibres in the examined occupational settings was site-dependent as the degree of asbestos contamination of Valmalenco serpentinites is highly variable from place to place. Block cutting of massive serpentinites with multiple blades or discs and drilling at the quarry sites that had the highest levels of asbestos contamination generated the highest exposures to (i.e. over the occupational exposure limits) asbestos. Conversely, working activities on foliated serpentinites produced airborne chrysotile concentrations comparable with ambient levels. Environmental chrysotile concentrations were always below the Italian limit for life environments (0.002 f ml(-1)), except for one sample collected at a quarry property boundary. The present exposure assessment study should encourage the development of an effective and concordant policy for proper use of asbestos-bearing rocks and soils as well as for the protection of public health.

Urinary methyl tert-butyl ether and benzene as biomarkers of exposure to urban traffic.

Methyl tert-butyl ether (MTBE) and benzene are added to gasoline to improve the combustion process and are found in the urban environment as a consequence of vehicular traffic. Herein we evaluate urinary MTBE (MTBE-U) and benzene (BEN-U) as biomarkers of exposure to urban traffic. Milan urban policemen (130 total) were investigated in May, July, October, and December for a total of 171 work shifts. Personal exposure to airborne benzene and carbon monoxide (CO), and atmospheric data, were measured during the work shift, while personal characteristics were collected by a questionnaire. A time/activity diary was completed by each subject during the work shift. Spot urine samples were obtained for the determination of MTBE-U and BEN-U. Median personal exposure to CO and airborne benzene were 3.3 mg/m(3) and 9.6 µg/m(3), respectively; median urinary levels in end-of-shift (ES) samples were 147 ng/L (MTBE-U) and 207 ng/L (BEN-U). The time spent on traffic duty at crossing was about 40% of work time. Multiple linear regression models, taking into account within-subject correlations, were applied to investigate the role of urban pollution, atmospheric conditions, job variables and personal characteristics on the level of biomarkers. MTBE-U was influenced by the month of sampling and positively correlated to the time spent in traffic guarding, CO exposure and atmospheric pressure, while negatively correlated to wind speed (R(2) for total model 0.63, P<0.001). BEN-U was influenced by the month and smoking habit, and positively correlated to urinary creatinine; moreover, an interaction between CO and smoking was found (R(2)=0.62, P<0.001). These results suggest that MTBE-U is a reliable marker for assessing urban traffic exposure, while BEN-U is determined mainly by personal characteristics.