[Characteristics, use and toxicity of fluorochemicals: review of the literature]. / Caratteristiche, uso e tossicità dei fluorurati: revisione della letteratura.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are perfluorinated surfactants used to produce polymers and telomers whose carbon chain can be differently long. Polytetrafluoroethylene (PTFE), namely Teflon, is the chief fluoropolymer and it has been widely utilised over the last decades and all over the world. Indeed, its particular physical and chemical properties make it difficult to replace this substance in several industries (textile, paper, chemical, fire-fighting foam industry). Perfluoroalkyl-compounds may be considered ubiquitous and, in particular, it has been shown that PFOS may be concentrated in the food chain. Concerns about possible toxic effects of these chemicals date back to seventies, but only in 2000 the Environmental Protection Agency (EPA) stated PFOA and PFOS withdrawal to avoid environmental pollution. In 2002 the Organisation for Economic Co-operation and Development reported that these substances are bio-persistent, tend to accumulate in different tissues of living organisms and are toxic to mammalians. In 2006 EPA established that every PFOA emission will be eliminated not later than 2015. Actually, health effects of perfluoroalkyl-compounds on humans remain controversial, in spite of a number of experimental and epidemiological studies. Research focuses on possible endocrine disruption, thyroid and liver carcinogenicity, and development alteration. Our article reviews the main studies concerning PFOS and PFOA industrial and environmental toxicology.

Saliva as an analytical tool to measure occupational exposure to toluene.

OBJECTIVE: To describe a sensitive and rapid method for the determination of toluene in saliva. Biomonitoring of toluene exposure is commonly performed by determination of urinary hippuric acid, o-cresol or toluene itself. The analysis of blood toluene has been verified as another method for biomonitoring. However, drawing blood is invasive and can often not be performed at the workplace for hygienic reasons. Sampling of saliva may be non-invasive, easy to perform and a viable alternative for biomonitoring in the workplace. METHODS: We measured the solvent concentration in saliva specimens of 5 healthy volunteers studied in the laboratory and a group of 36 workers exposed to toluene in the synthetic leather industry. Saliva was collected into Salivette (Sarstedt, Germany) devices by sterile cotton rolls placed in the mouth and then squeezed into pre-weighted vials. Environmental toluene was collected for the duration of a work-shift by Radiello (FSM, Italy) passive samplers. Toluene in urine and saliva (head space analysis) and in environmental samples was measured by GC-MS. RESULTS: Environmental toluene levels ranged from 0.22 to 57.20 mg/m(3), while the concentrations of the solvent in saliva and urine ranged from 0.12 to 18.30 microg/L, and from 0.47 to 26.64 microg/L, respectively. The correlation coefficients (r) between biological and environmental levels of toluene were 0.77 and 0.93, respectively, for saliva and urine samples. CONCLUSION: This preliminary study suggests that saliva may offer many advantages over 'classical' biological fluids such as blood as it is readily accessible and collectible: therefore saliva toluene may be considered as a possible biomarker of exposure to toluene.

[Recent prevention strategies and occupational risk analysis: Control Banding and Sobane]. / Recenti strategie per la prevenzione e l'analisi dei rischi in ambito occupazionale: Control banding e Sobane.

Employers are responsible for the prevention of risks and must provide for the safety and health of their workers. They are obliged to apply the general principles of prevention: to avoid, where possible, any risk; to characterize and hence to estimate residual risks; to eliminate risks at the source; to adjust jobs to the needs of workers and not workers to the jobs. When we pass to the practical performance of these shared principles we introduce many problems: problems concerning terminology; problems in estimating the nature of the risks that are faced; coordination problems between the subjects that preside over prevention; problems arising from the different typology of the companies investigated In order to answer these questions the "Industrial Hygienists" have long since created various strategies for the prevention and control of risks. Among different models the methods Control Banding and Sobane-Deparis are undoubtedly the most promising. Control Banding is designed to assist especially Small and Medium Enterprises in complying with the chemical safety regulations, the scheme uses the R phrases that in Europe must be assigned to potentially harmful chemicals by the manufacturer of the chemical. R phrases describe the most important harmful effects of a chemical and have been adopted in many non European countries also. The combination of the hazard classification of the chemical and assessment of the exposure potential will allow understanding of the level of risk thus leading the person carrying out the assessment to an appropriate control method. Occupational hygienists with experience of assessing occupational exposure to chemicals agreed parameters that could be used to give reasonable indications of exposure potential. One of them is quantity being used and three categories--small, medium and large--are defined. The likelihood of the chemical becoming airborne has been addressed by defining solids according to levels of dustiness and liquids according to volatility. A simple graph that uses the boiling point of the chemical and the process operating temperature assigns the chemical a high, medium or low volatility rating. The user now has enough information to identify the control approach required to adequately reduce exposures to the chemical Occupational hygienists agreed on three broad control approaches: General Ventilation; Engineering Control; Containment. However it is recognised that in some cases specialist advice will be needed. The user takes the hazard group, quantity and level of dustiness/volatility and matches them to a control approach using a simple table. The controls are described in control guidance sheets, which comprise both general information and, for commonly performed tasks, more specific advice. The second section of the document describes a risk-prevention strategy, called SOBANE, in four levels. These four levels are: screening, where the risk factors are detected by the workers and their management, and obvious solutions are implemented; observation, where the remaining problems are studied in more detail, one by one, and the reasons and the solutions are discussed in detail; analysis, where, when necessary, an occupational health (OH) practitioner is called upon to carry out appropriate measurements to develop specific solutions; expertise, where, in very sophisticated and rare cases, the assistance of an expert is called upon to solve a particular problem. The method for the participatory screening of the risks, Deparis, is proposed for the first level screening of the SOBANE strategy. The aim of Sobane strategy is to make risk prevention faster, more cost effective, and more effective in coordinating the contributions of the workers themselves, their management, the internal and external OH practitioners and the experts.

[Indoor air quality in an Italian military submarine]. / Qualità dell'aria in una nave sommergibile della marina militare Italiana in condizioni operative.

In recent years there has been increasing interest on studies concerning indoor air quality and focusing on risk factors for exposed subjects. Particularly, airborne chemicals, whose adverse effects are well known, have been identified and determined in means of transport as in other indoor places. As concerns chemical air concentrations in submarines, only a limited number of studies have been published. This paper reports measured concentration data for organic compounds (total volatile organic compounds, substances with a chemical bond S-O, nitrogen compounds, carbon monoxide, carbon dioxide, and different organic solvents) in the air sampled during an 8-h period in an Italian Military submarine, under routine operations. We observed that a periodicalfresh-air intake operation (snorkel) might cause temporary increase of contaminants levels in indoor air. Moreover, we could find that pollutants sometimes reach notable peak concentrations being potentially able to induce adverse health effects in crewmembers. Our data highlight the need to promote further investigations.

[The significance of enviromental and biological monitoring in workers employed in service stations after the elimitation of tetraethyl lead from gasoline]. / Il significato del monitoraggio ambientale e biologico nei lavoratori addetti alle stazioni di servizio dopo la eliminazione del piombo tetraetile dalle benzine.

The chemical risk in service stations may be due to toxic compounds present in fuel (particularly benzene and additives) and to the emission of exhausts and fine particulate from vehicles. Owing to the elimination of lead (Pb) from fuel and to the necessity of lowering CO emission, several oxygenated additives have been added to fuel, in particular methyl-tert-butyl-ether (MTBE), whose toxic properties are at present under investigation. The introduction of reformulated gasoline (RFG) and the use of catalytic converters (with possible release of platinum (Pt) in the environment) may have modified the risks for workers employed in service stations. The paper shows data collected from 26 subjects (divided into three specific tasks, namely: fuel dispenser, "self-service" attendant and controller, and cashier) to estimate the actual chemical risk and to compare it with the previous data taken from literature. For this purpose, besides performing the usual medical surveillance, we measured the environmental concentrations of benzene, MTBE and formaldehyde, the urinary levels of benzene metabolites S-phenylmercapturic acid (S-PMA) and t,t-muconic acid (MA) and of unmodified MTBE, and the blood concentrations of Pb and Pt for each subject. Mean values of these compounds were, respectively: 38.81 microg/m3; 174.04 microg/m3; 10.38 microg/m3; 2.36 microg/g creatinine; 96.57 microg/g creatinine; 1.41 microg/L; 7.00 microg/100 mL; 0.0738 ng/ml. The above values were much lower than the corresponding limit values reported by ACGIH and DFG. In particular, after the introduction of vapour recycle systems and the widespread use of "self-service" systems, airborne benzene concentration dropped from 300/400 microg/m3 to lower than 100 microg/m3, without noticeable increasing of exposure to formaldehyde. The disappearing of Pb from gasoline leads to a progressive lowering of its blood levels, while the possible risks due to the very low amounts of Pt released from catalytic converters have still to be defined exactly. Taken all in all, our results seem to indicate that, after the elimination of tetraethyl lead, the chemical risk for workers employed in service stations is now lower than in the past.

Gases and organic solvents in urine as biomarkers of occupational exposure: a review.

A brief review of urine analysis in studies of occupational exposure to volatile organic compounds and gases is provided. Analysis of exhaled breath for volatile compounds does not have a long history in occupational medicine. A number of studies has been undertaken since the 1980s, and the methods are well enough accepted to be put forward as biological equivalents of threshold limit values (TLVs) for some volatile organic compounds (VOCs) such as acetone; methanol; methyl ethyl ketone (MEK); methyl isobutyl ketone (MIBK); tetrahydrofurane; dichloromethane. In the last 20 years many scientific articles have shown that the urinary concentrations of unchanged solvents are correlated with environmental exposure and could be used for biological monitoring. The use of urine analysis of unchanged solvents in occupational applications is not yet widespread. Nonetheless, in the short time since its application, a number of important discoveries has been made, and the future appears bright for this branch of analysis. In this paper, the basic concepts and methodology of urine analysis are briefly presented with a critical revision of the literature on this matter. The excretion mechanisms of organic solvents in urine are discussed, with regard to biological variability, and the future directions of research are described.

[New biomarkers of exposure]. / Nuovi indicatori di esposizione.

In this paper we have defined the new biomarkers of exposure (NBE) as those biomarkers discovered in the last five years and, among previously validated biomarkers, also those applied in different ranges of doses or those determined in biological matrices which differ from matrices originally considered. We examined the results from the surveys carried out by the main Italian research units involved in biological monitoring, i.e. those from the Universities of Brescia, Milan, Naples, Padua, Parma, Pavia, Turin and Verona. The data were collected using a standardized model and included the following: type of element or organic compound, type of biomarker, analytical technique and method, their relationship with environmental monitoring data, their relationship with effect indicators or effects in general, improvement with respect to old biomarkers, reference values. Twenty two NBEs were identified: 14 elements and chemical compounds as such or as metabolites, 4 examples of mixtures, 3 of new matrices, one of speciation. Among the others, aspects such as interest in requiring NBE, quality assurance, availability, cost-benefit ratio were discussed. We conclude that development of this specific field of research appears to be a crucial point for future improvement in risk assessment and health surveillance procedures.

[Excretion kinetics of phenylhydroxyethyl mercapturic acids (PHEMAs), ethanol consumption, and chronic exposure to styrene: preliminary data on humans]. / Cinetica di escrezione degli acidi fenilidrossietilmercapturici (PHEMAs), consumo di etanolo ed esposizione cronica a stirene: dati preliminari sull'uomo.

Styrene (S) is a widely used aromatic hydrocarbon, responsible for several adverse effects. In humans, the metabolism of S is well characterized: besides the major metabolites (mandelic and phenylglyoxylic acid), a minor metabolic pathway leads to phenylhydroxyethyl mercapturic acids (PHEMAs) [N-acetyl-S-(1-phenyl-2-hydroxyethyl)-L-cysteine (M1) and N-acetyl-S-(2-phenyl-2-hydroxyethyl)-L-cysteine (M2)], that are potentially useful for biomonitoring purposes. A pilot study on a volunteer exposed under controlled conditions to S, with or without ethanol administration, allowed us to characterize the excretion profile of PHEMAs and the ethanol-induced interference on PHEMAs metabolic pathway. We further considered a group of 9 workers exposed to S during the working week to determine the confounding role of chronic exposure. Our results confirm the wide interindividual variability of both the biotransformation rate of S into PHEMAs and of the excretion rate of these metabolites. Moreover, both the above parameters changed during the working week, suggesting the existence of a large intraindividual variability as a consequence of the exposure to S and to other solvents. As a practical rule, the data indicate that it is necessary to collect samples at the beginning of the working week when studies on the correlation between genotype and phenotype are carried out. Finally, the results emphasise the importance of excluding an even extemporary ethanol assumption when practicing a biological monitoring programme based on the determination of urinary PHEMAs.

[Biological monitoring of occupational exposure to desflurane]. / Monitoraggio biologico dell'esposizione occupazionale a desflurane.

In these last years Desflurane (D) has become used, alone or in combination with nitrous oxide, in surgical procedures. Occupational exposed groups include anesthesiologists, other physicians, (e.g. surgeons) and operating room nurses. Desflurane is a halogenated methylethylether which is administered by inhalation. Desflurane is halogenated exclusively with fluorine. The blood/gas partition coefficient of Desflurane is 0.42. Changes in the clinical effects of Desflurane rapidly follow changes in the inspired concentration. Studies in man indicate that Desflurane washes into the body rapidly. It also washes out of the body rapidly, allowing flexibility in adjustment of the depth of anaesthesia. Desflurane is eliminated via the lungs, undergoing only minimal metabolism (0.02%). In order to investigate the role of urinary D as an indicator of occupational exposure to Desflurane (CI, ppm), CI was measured in 21 members of operating room staffs. For the measurement of environmental concentration of Desflurane (CI), the ambient air was sampled using personal passive dosimeters. The analyte was desorbed by a water-methanol mixture and was analysed by means a gas chromatograph--mass spectrometer (GC-MSD) and headspace technique. The biological monitoring of exposed workers was conducted by determining the concentration of Desflurane in urine (Cu, microgram/L). Urine concentrations of Desflurane were determined by headspace analysis using GC-MSD. Significant correlations were found between the environmental Desflurane concentration and the urinary concentrations. The correlation between CI (ppm) and Cu (microgram/L) was: Log D (Cu, microgram/L) = .191 + .922 * LogCI; r = .916 On the basis of the equation it was possible to establish tentatively the biological limit values corresponding to the respective occupational exposure limit values proposed for Desflurane.

Urinary determination of N-acetyl- S-( N-methylcarbamoyl)cysteine and N-methylformamide in workers exposed to N, N-dimethylformamide.

OBJECTIVES: We conducted this biomonitoring study with the aim of evaluating the correlation between the excretion of N-methylformamide (NMF) (mainly from N-hydroxy- N-methylformamide) and N-acetyl- S-( N-methylcarbamoyl)cysteine (AMCC), and levels of exposure to N, N-dimethylformamide (DMF) among occupationally exposed subjects. METHODS: Exposure levels were determined by personal sampling: breathing zone air samples were collected by means of passive samplers. DMF collected by the charcoal in personal samplers was analysed after extraction with methanol by a gas chromatograph. For the purpose of biological monitoring the levels of NMF and AMCC were measured in pre-shift and post-shift samples. Determinations were carried out by, respectively, gas chromatography and high performance liquid chromatography (HPLC). RESULTS AND CONCLUSIONS: The mean time-weighted average (TWA) exposure was approximately half (13.5 mg/m(3)) of the current threshold limit value, the range of the values was from 0.4 to 75.2 mg/m(3). Environmental DMF concentrations exhibited a significant correlation with the specific mercapturic acid (AMCC) collected at the end of the working week (AMCC Friday morning mg/l=1.384xDMF (mg/m(3))+8.708; r(2)=0.47; P<0.008]; hence urinary AMCC represents an index of the average exposure during several preceding working days, making it possible to calculate the approximate relationship between DMF uptake and excretion of this metabolite. A significant correlation was found also between the daily excretion of NMF and the corresponding levels of DMF in air. The equation of the regression line was: NMF (mg/g creatinine)=0.936xDMF (mg/m(3))+7.306; r(2)=0.522 ( P<0.0001).

Trichloroethylene in urine as biological exposure index.

Occupational exposure to trichloroethylene (TRI) was studied by analysis of environmental air and urine from 49 workers operating in a special printing house on glass. For the measurement of environmental concentration of TRI (Cenv), the ambient air was sampled using personal passive dosimeters. The activated charcoal was desorbed with carbon disulfide and injected into a gas-cromatograph - mass spectrometer (GC-MSD). The biological monitoring of exposed workers was conducted by determining the concentration of TRI in urine (Curine) Urine concentration of TRI was determined by headspace analysis using GC-MSD. Significant correlation was found between the environmental TRI concentration and urinary TRI concentration. The use of a regression equation between Curine (microg/l) and Cenv (mg/m3) (Curine = 0.081 x Cenv + 4.27) resulted in a value of Curine corresponding to Threshold Limit Value-Time Weighted Average (TLV-TWA) exposure value (269 mg/m3) of 26.0 microg/L.

[Biological monitoring of occupational exposure to sevoflurane]. / Monitoraggio biologico dell'esposizione professionale a sevoflurane.

Sevoflurane has been used in the last few years in brief surgical operations, either alone or in combination with nitrous oxide. Occupationally exposed groups include anesthesiologists, surgeons and operating room nurses. In 1977 the National Institute for Occupational Safety and Health (NIOSH) recommended that occupational exposure to halogenated anesthetic agents (halothane, enflurane, and isoflurane), when used as the sole anesthetic, should be controlled so that no worker would be exposed to time-weighted average concentrations greater than 2 ppm during anesthetic administration. When halogenated anesthetics are associated with nitrous oxide, NIOSH recommends that the limit value should not exceed 0.5 ppm. We think these recommendations can be extended to sevoflurane. Metabolism of sevoflurane is catalyzed by cytochrome P-450; this involves oxidation of the fluoromethyl side chain of the molecule, followed by glucuronidation. Two urinary metabolites of sevoflurane have been identified: inorganic fluoride (which, however, is not specific) and a non-volatile compound that yields hexafluoroisopropanol (HFIP) when digested with the enzyme beta-glucuronidase. In order to investigate the role of urinary HFIP as an indicator of occupational exposure to sevoflurane (CI, ppm), CI was measured in 145 members of 18 operating room staffs. The measurements of the time-weighted average of CI in the breathing zone were made by means of diffusive personal samplers. Each sampler was exposed during the whole working period. Sevoflurane was desorbed with CS2 from charcoal and the concentrations were measured on a gas chromatograph (GC) equipped with a mass selective detector (MSD). The GC was equipped with a 25 meter cross-linked phenylmethylsilicon column (internal diameter 0.2 mm). GC conditions were as follows: injector column temperature = 200 degrees C; column temperature = 30 degrees C; carrier gas = helium; injection technique of samples = splitless. The analytical conditions for the MSD were the following: ion mass monitored = 131 m/e; dwell time = 50 msec; selected ion monitoring window time = 0.1 amu; electromultiplier = 400 V. Urine samples were collected near the end of the shift and were analyzed for HFIP by head-space gas chromatography after glucuronide hydrolysis. 0.5 ml of urine and 1.5 ml of 10 M sulfuric acid were added to 21.8 ml headspace vials. The vials were immediately capped, vortexed, and loaded into the headspace autosampler. Samples were maintained at 100 degrees C for 30 min, after which glucuronide hydrolysis was 99% complete. Analyses were performed on a GC equipped with a MSD. The analytical conditions for urine analysis were as follows: cross-linked 5% phenylmethylsilicon column (internal diameter 0.2 mm, length 25 m); column temperature = 35 degrees C; carrier gas = helium. The analytical conditions for the MSD were: monitored ions = 51.05 and 99; dwell time = 100 ms; selected ion monitoring window time = 0.1 amu; electromultiplier voltage = 2000 Volt. With our analytical procedure, the detection limit of HFIP in urine was 20 micrograms/L. The variation coefficient (CV) for HFIP measurement in urine was 8.7% (on 10 determinations; mean value = 1000 micrograms/L). The median value of CI was 0.77 ppm (Geometric Standard Deviation = 4.08; range = 0.05-27.9 ppm). The correlation between CI and HFIP (Cu, microgram/L) was: Log Cu (microgram/L) = 0.813 x Log CI (ppm) + 2.517 (r = 0.79, n = 145, p < 0.0001). On the basis of the equation it was possible to establish tentatively the biological limit values corresponding to the respective occupational exposure limit values proposed for sevoflurane. According to our experimental results, HFIP values of 488 micrograms/L and 160 micrograms/L correspond to airborne sevoflurane concentrations of 2 and 0.5 ppm respectively.

Environmental and biological monitoring of traffic wardens from the city of Rome.

A molecular epidemiological study on Roman policemen is ongoing. The results of a first assessment of the occupational exposure to aromatic compounds of 66 subjects engaged in traffic control and of 33 office workers are presented in this paper. Passive personal samplers and urinary biomarkers were used to assess exposure to benzene and polycyclic hydrocarbons during work shifts. The results obtained indicate that benzene exposure in outdoor workers is about twice as high as in office workers (geometric mean 7.5 and 3.4 micrograms/m3, respectively). The distribution of individual exposure values was asymmetrical and skewed toward higher values, especially among traffic wardens. Environmental benzene levels recorded by municipal monitoring stations during work shifts (geometric mean 11.2 micrograms/m3) were in the first instance comparable to or greater than individual exposure values. However, several outlier values were observed among personal data that greatly exceeded average environmental benzene concentrations. Among the exposure biomarkers investigated, only blood benzene correlated to some extent with previous exposure to benzene, while a seasonal variation in the excretion of 1-hydroxypyrene and trans-muconic acid was observed in both study groups. In conclusion, these results suggest that outdoor work gives a greater contribution than indoor activities to benzene exposure of Roman citizens. Moreover, relatively high-level exposures can be experienced by outdoor workers, even in the absence of large-scale pollution episodes.

Exposure to benzene in urban workers: environmental and biological monitoring of traffic police in Rome.

OBJECTIVES: To evaluate the contribution of traffic fumes to exposure to benzene in urban workers, an investigation on personal exposure to benzene in traffic police from the city of Rome was carried out. METHODS: The study was performed from December 1998 to June 1999. Diffusive Radiello personal samplers were used to measure external exposures to benzene and alkyl benzenes during the workshift in 139 policemen who controlled medium to high traffic areas and in 63 office police. Moreover, as biomarkers of internal exposure to benzene, blood benzene, and urinary trans, trans-muconic and S-phenyl mercapturic acids were measured at the beginning and at the end of the workshift in 124 traffic police and 58 office police. RESULTS: Time weighted average (TWA) exposure to benzene was consistently higher among traffic police than among indoor workers (geometric mean 6.8 and 3.5 microg/m(3), respectively). Among the traffic police, the distribution of individual exposures was highly asymmetric, skewed toward higher values. Mean ambient benzene concentrations measured by municipal air monitoring stations during workshifts of traffic police were generally higher (geometric mean 12.6 microg/m(3)) and did not correlat with personal exposure values. In particular, no association was found between highest personal exposure scores and environmental benzene concentrations. Among the exposure biomarkers investigated, only blood benzene correlated slightly with on-shift exposure to benzene, but significant increases in both urinary trans, trans-muconic and S-phenylmercapturic acids were found in active smokers compared with non-smokers, irrespective of their job. CONCLUSION: The exposure to traffic fumes during working activities in medium to high traffic areas in Rome may give a relatively greater contribution to personal exposure to benzene than indoor sources present in confined environments. Smoking significantly contributed to internal exposure to benzene in both indoor and outdoor workers.

Metabolic polymorphisms and urinary biomarkers in subjects with low benzene exposure.

The effect of some common metabolic polymorphisms on the rate of trans,trans-muconic acid (TMA) and S-phenylmercapturic acid (SPMA) excretion was investigated in 169 policemen exposed to low benzene levels (<10 microg/m3) during the work shift. End-shift urinary concentrations of TMA and SPMA, normalized to unmetabolized blood benzene concentration, were used as indicators of individual metabolic capacity. CYP2E1, NQO1, GSTM1, and CSTT1 polymorphisms were analyzed in all subjects by polymerase chain reaction (PCR) restriction fragment length (RFL). The results obtained show significantly elevated levels of TMA and SPMA in urine of smokers compared to nonsmokers, whereas no correlation with environmental benzene was observed. TMA/blood benzene ratio was partially modulated by glutathione S-transferase (GST) genotypes, with significantly higher values in null individuals (GSTM1 and GSTT1 combined). However, a greater fraction of total variance of TMA/blood benzene in the study population was explained by other independent variables, that is, season of sampling, smoking habits, and gender. Variance in SPMA/blood benzene ratio was only associated with smoking and occupation, whereas no significant role was observed for the metabolic polymorphisms considered. These results suggest that in a population exposed to very low benzene concentrations, urinary TMA and SPMA levels are affected to a limited extent by metabolic polymorphisms, whereas other factors, such as gender, lifestyle, or other confounders, may account for a larger fraction of the interindividual variability of these biomarkers.

[High-pressure liquid chromatography (HPLC) with UV developer for the analysis of N-acetyl-S-(N-methylcarbomoyl)cysteine (AMCC)]. / Uso della cromatografia liquida ad alte prestazioni (HPLC) con rivelatore UV per il dosaggio dell'N-acetil-S-(N-metilcarbamoil) cisteina (AMCC).

N,N-dimethylformamide (DMF) is a solvent widely used to prepare synthetic fibers. Biomonitoring of DMF is usually performed by measuring urinary N-methylformamide, which allows us to estimate exposure during the working day. An alternative biomarker is the mercapturic acid N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) whose excretion accounts for about 13% of the absorbed DMF dose. Owing to its slow excretion (mean half-life = 23 hours) the urinary levels of AMCC at the end of a workweek reflect the cumulative dose of DMF during the whole week. Methods given in literature for measuring AMCC need the derivatization of the molecule before analysis. The paper describes a method for the determination of urinary AMCC by high-performance liquid chromatography (HPLC) with direct UV detection. Samples were purified by solid phase extraction with C18 and ENV+ cartridges, then 10 microliters were directly injected onto an Aminex HPX-87H Ion Exclusion column maintained at a temperature of 37 degrees C. Analyses were performed by isocratic run with 1 mM sulphuric acid delivered at 0.85 mL/min. The detector was set at 196 nm. Under these conditions, AMCC eluted at 11.1 min., and the detection and quantification limits were 1.32 mg/L and 3.96 mg/L, respectively. The performance of the method was evaluated on samples containing 25 mg/L and 400 mg/L of AMCC: each sample was analysed three times. The mean recovery of the extraction procedure was 88.3%. The precision (CV%) and the accuracy (Error%) ranged from 0.8% to 2.9%, and from -1.2% to +3.2%. The calibration curve was linear up to a concentration of 1000 mg/L, the coefficient of correlation was r = 0.9997. AMCC was measured in urine samples from 30 exposed and 20 unexposed (smokers and nonsmokers) subjects. Measurable amounts of AMCC were found in all of the samples from workers exposed to DMF; on the contrary, none of the samples from unexposed subjects contained this metabolite. The proposed method is sufficiently sensitive and specific for the evaluation of occupational exposure to DMF, thus it could be useful for the biological monitoring of workers exposed to this solvent.

Importance of genetic polymorphisms of drug-metabolizing enzymes for the interpretation of biomarkers of exposure to styrene.

The objective of this study was to test the infiuence of genetic polymorphisms for metabolic enzymes (CYP2E1, mEH, GSTM1 and GSTT1) implicated in the biotransformation of styrene in humans on the interpretation of urinary biomarkers of exposure. Thirty workers from a fibreglass-reinforced plastics factory took part in the study. Ambient styrene concentration was determined during the whole workshift by passive sampling. Urine was collected at the end of the shift for the determination of mandelic acid (MA) and phenylglyoxylic acid (PGA) (major biotransformation pathway), N-acetyl-S-(1-phenyl-2-hydroxy)ethyl-L-cysteine (M1) and N-acetyl-S-(2-phenyl-2-hydroxy)ethyl-L-cysteine (M2) (minor metabolic pathway) and creatinine. The average airborne styrene concentration of 18.2 ppm (range: 0.9-68.9 ppm) was very close to the current threshold limit value (TLV-TWA) recently adjusted by ACGIH from 50 to 20 ppm. There was a better correlation between external and internal exposure as estimated by urinary MA + PGA (r=0.92; p<0.0001) compared with urinary M1 + M2 (r=0.74; p<0.0001). To investigate to what extent genetic polymorphisms in metabolic enzymes could explain interindividual variations observed in the concentration of urinary biomarkers related to a given external exposure, two 'metabolic indexes' (derived from the ratio between the sum of urinary metabolites for a specific pathway and ambient styrene concentration) were calculated for each worker and compared for different allelic combinations. Monovariate analyses showed that GSTM1 polymorphism was clearly the most significant parameter infiuencing urinary concentrations of mercapturic acids. Based on GSTM1 allelic status, two different biological exposure indexes (BEIs) for M1 + M2 in post-shift urinary samples corresponding to a 20 ppm styrene concentration are proposed (GSTM1null: 1330 µg g(-1) creatinine, GSTM1+: 2878 µg g(-1) creatinine). Multivariate regression analyses were also performed and revealed that the presence of the rare CYP2E1*1B allele linked to TaqI polymorphism (A1/A2) was associated with increased urinary concentrations of metabolites from both pathways. Two previously described polymorphisms for the EPHX gene were also tested but seemed not really relevant for interpretation of biomarkers. In conclusion, while CYP2E1 genotyping, particularly assessment of the CYP2E1*1B allelic status, is useful for a more accurate interpretation of the concentration of urinary biomarkers, GSTM1 genotyping is absolutely necessary when considering a biological monitoring programme based on determination of urinary mercapturic acids.

[Measurement of N-methylformamide in occupational exposure to N,N-dimethylformamide]. / Il dosaggio della N-metilformamide nella esposizione professionale a N,N-dimetilformamide.

N,N-dimethylformamide (DMF) is a solvent that is widely used in industry. The major occupational sources of exposure results from production of synthetic leather. The main metabolite formed in both man and animals is N-hydroxymethyl-N-methylformamide. Demethylation leads to N-methylformamide (NMF) and formamide and also to a small extent to hydroxy-methylformamide. All the metabolites are excreted in urine, as are very small amounts of the unchanged substance. N-acetyl-S-(N-methyl-carbamoyl)-cysteine can be determined in urine as a further metabolite. We conducted this biomonitoring study with the aim of evaluating the correlation between the excretion of N-methylformamide (mainly from N-hydroxymethylformamide) and levels of exposure to N,N-dimethylformamide among occupationally exposed people. The mean time-weighted average (TWA) exposure was about half (13.5 mg/m3) of the current threshold limit value, the range of the values varying from 0.4 to 75.2 mg/m3. A linear equation existed between urinary NMF concentration and DMF concentration in the environment. The findings show that the urinary NMF concentration can be used as an appropriate biological exposure index. The authors suggest for occupationally exposed subjects, a urinary NMF concentration corresponding to the time-weighted average of the threshold limit value of 39.9 mg/l (37.2 mg/g creatinine) and a 95% lower confidence limit (biological threshold) of 23.4 mg/l (22.2 mg/g creatinine).

[The use of Internet in occupational medicine and industrial hygiene]. / L'utilizzo di Internet in Medicina del Lavoro ed Igiene Industriale.

The internet as we know is today includes an array of tools that make information exchange easier than ever before. The best known Internet tools are the World Wide Web and the electronic mail. In the present job we identify those that are the home pages that better can help Industrial Hygienists and Doctors to acquire useful information for the profession. From the detailed examination of the possibilities offered from Internet (web documents acquisition, reading on line of scientific papers, use of mailing lists and e-mail) we can wait in future that the this new instrument will play an important role by offering extensive knowledge and information in the field of occupational and environmental health.