Indicadores biológicos para la valoración de la exposición humana a compuestos químicos industriales : Plaguicidas carbamatados

Traducción de la obra en inglés \"Biological indicators for the assessment of human exposure to industrial chemicals\" (EUR 11478 EN) publicada por la Oficina para las Publicaciones Oficiales de las Comunidades Europeas. Contiene: plaguicidas carbamatos, efectos en humanos, aldicarb, propoxur, carbofurano, clorprofam y benomilo.

Risk assessment and management of occupational exposure to pesticides in agriculture.

Nearly 50% of the world labour force is employed in agriculture. Over the last 50 years, agriculture has deeply changed with a massive utilisation of pesticides and fertilisers to enhance crop protection and production, food quality and food preservation. Pesticides are also increasingly employed for public health purposes and for domestic use. Pesticide are unique chemicals as they are intrinsically toxic for several biological targets, are deliberately spread into the environment, and their toxicity has a limited species selectivity. Pesticide toxicity depends on the compound family and is generally greater for the older compounds; in humans, they are responsible for acute poisonings as well as for long term health effects, including cancer and adverse effects on reproduction. Due to their intrinsic toxicity, in most countries a specific and complex legislation prescribes a thorough risk assessment process for pesticides prior to their entrance to the market (pre-marketing risk assessment). The post-marketing risk assessment takes place during the use of pesticides and aims at assessing the risk for exposed operators. The results of the risk assessment are the base for the health surveillance of exposed workers. Occupational exposure to pesticides in agriculture concerns product distributors, mixers and loaders, applicators, bystanders, and rural workers re-entering the fields shortly after treatment. Assessing and managing the occupational health risks posed by the use of pesticides in agriculture is a complex but essential task for occupational health specialists and toxicologists. In spite of the economic and social importance of agriculture, the health protection of agricultural workforce has been overlooked for too many years, causing an heavy tribute paid in terms of avoidable diseases, human sufferance, and economic losses. Particularly in the developing countries, where agricultural work is one of the predominant job, a sustainable model of development calls for more attention to occupational risks in agriculture. The experience of many countries has shown that prevention of health risk caused by pesticides is technically feasible and economically rewarding for the individuals and the whole community. A proper risk assessment and management of pesticide use is an essential component of this preventative

Low level exposure to chemicals and immune system.

Industrialized countries are facing an increase of diseases attributable to an alteration of the immune system function, and concern is growing that this trend could be at least partially attributable to new and modified patterns of exposure to chemicals. Among chemicals matter of concern, pesticides can be included. The Authors have reviewed the existing evidence of pesticide immunotoxicity in humans, showing that existing data are inadequate to raise conclusions on the immunotoxic risk related to these compounds. The limits of existing studies are: poor knowledge on exposure levels, heterogeneity of the approach, and difficulty in giving a prognostic significance to the slight changes often observed. To overcome these limits, the Authors have proposed a tier approach, based on three steps: the first, addressed at pointing out a possible immunomodulation; the second, at refining the results and the third one, when needed, to finalize the study and to point out concordance with previous results. Studies should preferably be carried out through comparison of pre- and post-exposure findings in the same groups of subjects to be examined immediately after the end of the exposure. A simplification of the first step approach can be used by the occupational health physician and the occupational toxicologist. Conclusions on the prognostic significance of the slight changes often observed will be reached only by validating the hypothesis generated by field studies with an epidemiological approach. In this field, the most useful option is represented by longitudinal perspective studies.

[Indoor air quality and occupational health, past and present]. / Qualità dell'aria indoor e medicina del lavoro, ieri e oggi.

The expression "indoor pollution" of residential, office and public buildings appeared for the first time in western societies toward the end of the '60s to indicate a complex phenomenon as important to public health as that of the "outdoor air pollution" or even more so. The demonstration of the toxic effects of passive smoking, radon, and other chemical and biological pollutants present in office and residential environments has prompted a wide spectrum of research into health risks, has led to position-taking by national and international authorities, and has given rise to a new scientific multi-disciplinary field of research, with respective international associations, scientific journals, and international conferences attended by thousands of participants. In Italy, since 1988, several scientific conferences have been organised and these have led to institutional initiatives such as the Commission set up in 1990 by the Italian Environment Ministry and the Commission set up in 1998 by the Italian Ministry of Health. The latter produced a Prevention Plan for Health Protection and Promotion in Indoor Environments which, for the first time, tackles indoor air pollution in a systematic way and provides an overall picture of the health and economic impact of the main illnesses related to indoor pollution on society. Decree 626/94 has also been affected, in some way, by these new scientific findings and in art. 33 has produced an update of the old art. 9 of the Decree 303/56. The attention to the subject of indoor air quality, in addition to that of offices and commercial buildings, has turned in more recent years to special environments such as schools and hospitals, resulting in the production of important publications. The modern frontier of research on indoor and outdoor air hazards is represented by fine air particulate matter. A large number of worldwide epidemiological studies have revealed that the daily variation in fine and ultra-fine particle air concentration in urban areas is associated with the simultaneous daily variation in the morbidity and mortality of the general population. The particle-linked increase in mortality has been attributed to respiratory and cardiovascular toxic effects, but the mechanisms by which urban air particles (indoor and outdoor) induce worsening of respiratory and cardio-vascular diseases are so far unknown and are the subject of intense investigation. Workers employed in the tertiary sector (offices, trade, banking, hospitals, schools, etc.) now account for 80% of the Italian labour force and the occupational physician is increasingly requested to assess the risk and monitor the health status of tertiary sector workers. These working environments are believed to be healthy and lacking in specific health risk factors, but such a belief is often only the result of the limited knowledge that employers, workers and the physicians themselves have about these environments and the results of international research studies over the last forty years. This issue is surely at the centre of the interest of our discipline and of public health throughout the developed western world and represents an ongoing challenge for the occupational physician, with new research topics and new problems to deal with. Recent issues include SARS and the defence of buildings and the air of working environments against terrorism attacks, such as the use of anthrax dust.

[Biological monitoring and risk assessment]. / Monitoraggio biologico e valutazione del rischio.

Risk assessment in occupational medicine is the part of risk analysis where physicians also contribute. A risk is the probability of an adverse health effect and derives from the hazard posed by a given chemical and from exposure characteristics. Due to the complexity of this process, models are used in occupational medicine, where risk factors are identified and exposure estimated, combined with an understanding of the severity of possible effects. Theoretically, the advantages of biological monitoring are obvious. However, the paucity of available data on biological monitoring limits its uses. Moreover, the utilization of data on biological monitoring requires evaluation of their significance. Examples are discussed to highlight advantages and limitations of biological monitoring data in both hazard and risk assessments. They include exposure to polycyclic aromatic hydrocarbons, benzene, other carcinogens, paraquat and polychlorinated biphenyls.

[Definition of acceptable operator exposure levels (AOELs) to pesticides]. / La definizione di livelli accettabili di esposizione ad antiparassitari per l'operatore (AOELs).

A guidance document entitled "Recommended method for the establishment of Acceptable Operator Exposure Levels" has been prepared within the EU 5th Framework program. The paper describes the main outcomes of the project and the issues that apply particularly to agricultural workers and bystanders and the difficulties in developing an agreed uniform approach. The scientific basis of the process is discussed, to be used by the European Commission and Member States when making decision about the inclusion of an active substance in Annex 1 of Directive 91/414/EEC.

[Epidemiologic research on asbestos related disease in ENEL SpA electricity production plant maintenance]. / Indagine epidemiologica sulle patologie asbesto correlate nei lavoratori addetti ad attività di manutenzione nelle centrali di produzione di ENEL SpA.

Since many years research programs have been set up to study the relationship between asbestos occupational exposure and development of asbestos-related lung diseases in electricity production plants workers. In the year 2000 a new study of asbestos-related lung abnormalities prevalence in italian geothermal and idrothermal power plant maintenance workers was planned. The cohort comprised 3891 subjects. To meet the criteria, only workers in service for at least six months before 1990 and still in service at power plants in May 2000 were included in the study; chest X-rays were taken and made anonymous. Independent reading of X-rays was made by two groups of specialists, and a third reading of selected discordant readings X-rays was made by another group of specialists. A further diagnostic protocol (including HRCT) was planned when two out of three readings showed the presence of asbestos related lung abnormalities. The analysis was made on 3063 subjects (78.7% of the cohort). The number of asbestos-related abnormalities in two out of three X-ray readings was 122 (4%). The further diagnostic protocol, that included occupational and pathological anamnesis and HRCT, confirmed an asbestos-related occupational lung abnormalities in 41 cases (1.3% out of 3063 subjects). The prevalence of asbestos-related lung abnormalities among 3063 power plant maintenance workers was 1.3%. If all the cases of lung abnormalities so far detected (data are still provisional) had developed only in the power plant environment, and not in previous working activities, the prevalence of lung abnormalities would be extremely low. These data support the evidence of limited exposure levels to asbestos in this working environment And bears witness to the success of preventive measures to control this specific risk.

Neurobehavioral effects of pesticides: state of the art.

The authors have reviewed the literature on neurobehavioral toxicity of pesticides to assess the status of knowledge on this matter. Some data suggest that exposure to DDT and fumigants may be associated with permanent decline in neurobehavioral functioning and increase in psychiatric symptoms, but, due to the limited number of studies available and the scarce knowledge on exposure levels, no firm conclusion can be drawn. Data on subjects acutely poisoned with organophosphorous compounds suggest that an impairment in neurobehavioral performance and, in some cases, emotional status may be observed as a long-term sequela, but the possibility still remains that these effects were only an aspecific expression of damage and not of direct neurotoxicity. Studies carried out on subjects chronically exposed to organophosphates, but never acutely poisoned, do not provide univocal results but the slight changes consistently observed in sheep dippers suggest the need of focusing on activities characterized by relatively higher exposure levels. In general, the main limits of existing knowledge are the variability of the testing methods used, which makes it difficult to compare the results of single studies, and the scarce knowledge on exposure levels. A promising approach may be the conduction of prospective longitudinal or cohort studies, where exposure and dose assessment can be more easily controlled, or the evaluation of cohorts of workers a priori selected for the availability of environmental and biological monitoring data. The follow up of the populations under study may give an answer at the problem of the prognostic significance of the observed changes. Also the protocols used to assess neurobehavioral functioning need to be standardized.

[From industrial hygiene and toxicology to environmental hygiene and toxicology: problems and prospects]. / Dall'igiene e tossicologia industriale all'igiene e tossicologia ambientale: problemi e prospettive.

BACKGROUND: Low-dose exposures to mixtures of substances have received increasing interest and they involve many different occupational and environmental situations. The presence in the population (working and general) of groups of susceptible individuals is an important public health issue that poses new challenges to science and society. OBJECTIVES: To discuss the evolution from traditional occupational hygiene and toxicology to the new environmental (general and occupational) hygiene and toxicology. RESULTS: Environmental hygiene and toxicology have remarkably improved analytical tools available to solve most of the analytical issues posed by the present exposure scenario. Biomarkers of low-dose exposure, early effects and individual susceptibility are being intensively investigated. CONCLUSIONS: The challenge in this field for the coming years appears to be not the analytical but the medical and ethical implications.

[Occupational exposure to fungicides in floriculture in Ecuador]. / Esposizione professionale a fungicidi in floricoltori dell'Ecuador.

Floriculture represents one of the major sources of income in the Ecuadorian Andean Region that can be carried out either in open fields as in greenhouses by using chemical compounds, growing hormones and xenobiotics. Among pesticides, ethylenbisdithiocarbamate (EBDTCs) fungicides represent the most extensively used. The aim of the study was the assessment of exposure to EBDTCs in Ecuadorian floricultural workers by the determination of the urinary excretion of the main metabolite of these compounds, ethylenethiourea (ETU). For this purpose, thirty-six floriculture workers and 7 unexposed healthy subjects were recruited for the study. Median level of ETU excretion in agricultural workers before the work shift was 3.2 micrograms/g creatinine, ranging from 0.4 to 34.5 micrograms/g creatinine. After pesticide application, urinary ETU increased to 6.2 micrograms/g creatinine (1.5-26.5) microgram/g creatinine. Urinary ETU resulted significantly higher in overall workers, taken as pre- and post-shift samples, when compared to controls (0.7, 0.4-2.1 micrograms/g creatinine, p < 0.01). According to jobs, applicators showed the highest levels of ETU excretion whereas growing, post-harvesting and maintenance workers showed similar levels of exposure. Higher level ETU excretion was observed in greenhouse compared to open field workers.

[Risk profiles in agriculture: activities in the region of Lombardy]. / Profili di rischio in agricoltura: attività in Regione Lombardia.

Agriculture represents a very complex scenario that needs proper tools. To this aim, in the frame of Special Project "La Prevenzione nell'impiego di Antiparassitari in Agricoltura" promoted by the Region of Lombardy, profiles of exposure and/or risk have been identified as valid approach able to define particular conditions of exposure and risk for the operator in particular settings. The evaluation necessarily needs to identify the most important parameters affecting exposure and their extent on magnitude of exposure. Therefore, field studies should be further performed in order to confirm and improve the profile. The identification of profiles of exposure and risk is an activity still in progress that need to be carefully set up and standardised. The team involved in the study identified priorities deserving much attention in Lombardy, and planned a three years programme aimed at define the profile of exposure and risk in viticulture, maize crop, rice growing, nursery gardening, horticulture in greenhouses, maintenance of gardens, and poplar growing.

Periportal fibrosis and other liver ultrasonography findings in vinyl chloride workers.

AIMS: To investigate the presence of liver lesions and their relation with vinyl chloride monomer (VCM) exposure or other personal risk factors, in workers involved in the production of VCM and polyvinyl chloride (PVC). METHODS: A liver ultrasonography examination was conducted in 757 workers, some of whom had long standing service in the production of VCM and PVC. The study involved: assessment of individual past and present VCM exposure of each worker; collection of past personal health history, lifestyle and personal data; routine liver function tests; and liver ultrasonography. RESULTS: No cases of liver malignancies were detected. Angiomas and liver cysts were found with a frequency of occurrence within the expected range of the general population. The main findings consisted of hepatomegaly (34.7%), steatosis (31.8%), and periportal fibrosis (16.0%). A logistic regression analysis indicated that hepatomegaly and steatosis were associated with obesity and lipid metabolism disturbances and not with VCM exposure. Periportal fibrosis, in addition to constitutional or dietary factors, was shown to be associated with VCM exposure, but only when maximum exposure in the subject's history had been at least 200 ppm as a yearly average; no effects were observed at 50 ppm or below. CONCLUSIONS: Workers exposed to 200 ppm VCM for at least one year have a fourfold increased risk of developing periportal liver fibrosis. Liver ultrasonography is a suitable and important diagnostic test for the medical surveillance of vinyl chloride workers.

Ethylenethiourea in urine as an indicator of exposure to mancozeb in vineyard workers.

In the present study, the personal exposure to mancozeb and/or ethilenethiourea (ETU) in 13 Italian vineyard workers and in 13 subjects without occupational exposure to pesticides was investigated. With this aim, the level of ETU in urine and the dermal exposure to mancozeb were determined. Baseline urinary ETU results were lower than the analytical limit of detection for all controls (<0.5 microg/g creatinine) and for ten workers (median <0.5, range <0.5-3.4 microg/g creatinine). In workers, urinary ETU was significantly increased at the end of shift (2.5, <0.5-95.2 microg/g creatinine) compared with baseline levels. End-shift urinary ETU was higher in operators using open tractors (n=7) than in those using closed tractors (n=5) (16.2 vs. 2.4 microg/g creatinine), but the difference was not significant (P=0.073). End-shift urinary ETU was positively correlated with dermal exposure to mancozeb determined both over the clothes and on the skin (Spearman's rho=0.770 and 0.702, P=0.009 and 0.024, respectively). Wine consumption positively influenced the excretion of ETU.

[Adaptation of the TriTEST TM for the investigation of blood samples for a multicenter study taken to a single laboratory]. / Adattamento del TriTEST TM per la raccolta di campioni ematici in studi multicentrici afferenti ad uno stesso laboratorio.

BACKGROUND: Immunotoxicological studies in humans are usually carried out via the determination of some selected immune parameters in subjects occupationally and/or environmentally exposed to immunotoxic substance. One of the most often measured parameters is the determination of lymphocyte subsets, which needs to be carried out in a very short time (a few hours) after blood collection. This is the major problem limiting the determination of lymphocyte subpopulations in field studies, where samples are usually collected directly at the workplace, and very often at the end of the workshift. Unfortunately, these collection modalities significantly prolong the time between collection and analysis. The problem is more evident in multicentric studies, where a further problem is represented by the time needed to send samples to the laboratory. OBJECTIVE: Since an immune evaluation was planned, including the determination of lymphocyte subpopulations CD4 (T-helper), CD8 (T-suppressor cytotoxic) and CD16/CD56 (natural killer) in the project "Assessing health effects in man from exposure to low doses of inorganic mercury in environmental and occupational settings", a method was developed for performing cytofluorimetric analysis in "field studies". METHODS: The method is based on commercially-available kits, and involves in loco treatment. Whole blood is labeled with monoclonal antibodies, and fixed samples immediately after collection. After the treatment, the samples are ready for flow cytometric analysis, which may be performed after a two-day period from sample collection. RESULTS AND CONCLUSION: The method described is adequate for immunotoxicity testing in field studies because it prolongs the maximum latency time from collection and cytofluorimetric analysis up to 48 hours. A second interesting characteristic of the method is the possibility of using whole blood, without any need of either complex manipulations or particular equipment.

Comparative endometrial histology in postmenopausal women with sequential hormone replacement therapy of estradiol and, either chlormadinone acetate or micronized progesterone.

OBJECTIVES: To determine the endometrial response in postmenopausal women treated with a sequential hormone replacement therapy (HRT) of estradiol and, either chlormadinone acetate (CA) or micronized progesterone (MP). METHODS: Three hundred and thirty-six postmenopausal women with a normal endometrium were randomized in the double-blind study. All patients received percutaneous estradiol 1.5 mg/day from day 1 to day 24 and either CA 10 mg/day or oral MP 200 mg/day from day 10 to day 24. The total duration of treatment was 18 months. Endometrial biopsies were performed before treatment and between day 18 and day 24 of the 18th month of HRT. RESULTS: Of the 336 patients selected, 317 had a biopsy at inclusion. Of them, 244 patients (124 in the CA group and 120 in the P group) were suitable for evaluation for analysis at the 18th month. Insufficient sampling occurred in 33.9% in the CA group and 60% in the MP group (probably atrophic). No case of hyperplasia could be reported in both groups. The endometrium was atrophic in 19.5 versus 27.1%, proliferative in 3.7 versus 8.3% and secretory in 76.8 versus 62.5% in CA and MP groups, respectively. It was possible to see histological differences induced by the two progestins. The CA endometria showed fewer glands lined by a cubo-cylindrical epithelium, with an edematous stroma, compared to the MP endometria which had more glands lined by a cylindrical epithelium, stroma being poorly edematous. These figures varied in intensity due to the length of progestative impregnation, predecidualization occurring later in the CA group, with distended capillaries. CONCLUSIONS: These results show that CA 10 mg/day is a powerful progestin compared to MP 200 mg/day, on weakly estradiol-primed endometria, giving a molecule-specific histological aspect with a good endometrial safety.

Chlormadinone acetate versus micronized progesterone in the sequential combined hormone replacement therapy of the menopause.

OBJECTIVE: The efficacy and safety of chlormadinone acetate (CA) versus micronized progesterone (P) were assessed in non-hysterectomized postmenopausal women. MATERIALS AND METHODS: This was a multicenter, randomized, parallel group study with a 6-month double-blind period followed by a 12-month open period. Patients were randomized to receive every month during 18 months percutaneous 17 beta-estradiol (E(2)) 1.5 mg/day from Day 1 to 24 of treatment cycle, combined from Day 11 to 24 to either CA 10 mg/day (n=167) or P 200 mg/day (n=169). Endometrial biopsy (EB, main analysis criterion) was performed at baseline, and at Day 18-24 of the 6th and 18th cycles. RESULTS: At Month 6, EB did not evidence any hyperplasia. EB were inadequate for assessment in 24.5% and 47.5% of patients in the CA and MP groups, respectively. CA was found to be as protective as P (96.3% and 92.0% of success). However, the hormonal status of the endometrium differed (P<0.001): a secretory endometrium was found in 81.5% of the CA patients, compared to 50.7% in the P group. These transformations resulted in predictable, cyclic bleeding in 94.5% of the CA patients, compared to only 62.3% of the P patients (P=0.0001). Unscheduled bleeding, spotting and/or metrorrhagia, were more frequent under P than under CA (17.9% and 13.7%, respectively). The beneficial effects on hot flushes were more important in the CA group than in the P (P<0.001). At Month 18, the biopsy and clinical results were similar to those obtained at Month 6. The safety profile, particularly the lipid one, was similar in both groups, except for drowsiness and dizziness, which were significantly more frequent under P than under CA. CONCLUSION: The progestative effects of CA on the endometrium and on menopause-related symptoms were at least as good as those of P. Moreover, CA resulted more often than P in secretory effects, and in satisfying bleeding patterns.

Exposición ocupacional a pesticidas en el mundo en desarrollo: efectos sobre la salud y estrategias para su prevención / Occupational exposition to pesticides in the developed word: health effects and strategies for its prevention

A causa de su clima, en la mayoría de los países en desarrollo aumenta el uso de pesticidas y fertilizantes producidos en países industrializados. Sin embargo, la baja cantidad de denuncias sobre intoxicaciones agudas, debido frecuentemente a legislaciones deficientes, hace difícil probar la asociación entre pesticidas y la ocurrencia de efectos crónicos adversos. En los países en desarrollo deben ser desarrolladas nuevas estrategias que apunten a prevenir y reducir el riesgo asociado a la exposición humana a pesticidas. La prevención debería observarse tanto en la pre-comercialización de esos productos químicos como en la pos-comercialización. Un elemento clave en la fase previa es el testeo toxicológico de un producto. En la etapa pos-comercialización es esencial la promoción del manejo adecuado de los riesgos a la salud en el lugar de trabajo. La prevención debe ser complementada con programas nacionales que respondan a las características de cada país...

Exposición ocupacional a pesticidas en el mundo en desarrollo: efectos sobre la salud y estrategias para su prevención / Occupational exposition to pesticides in the developed word: health effects and strategies for its prevention

A causa de su clima, en la mayoría de los países en desarrollo aumenta el uso de pesticidas y fertilizantes producidos en países industrializados. Sin embargo, la baja cantidad de denuncias sobre intoxicaciones agudas, debido frecuentemente a legislaciones deficientes, hace difícil probar la asociación entre pesticidas y la ocurrencia de efectos crónicos adversos. En los países en desarrollo deben ser desarrolladas nuevas estrategias que apunten a prevenir y reducir el riesgo asociado a la exposición humana a pesticidas. La prevención debería observarse tanto en la pre-comercialización de esos productos químicos como en la pos-comercialización. Un elemento clave en la fase previa es el testeo toxicológico de un producto. En la etapa pos-comercialización es esencial la promoción del manejo adecuado de los riesgos a la salud en el lugar de trabajo. La prevención debe ser complementada con programas nacionales que respondan a las características de cada país...(AU)

Allergens in indoor air: environmental assessment and health effects.

It has been suggested that the increase in morbidity and mortality for asthma and allergies, may also be due to an increase in exposure to allergens in the modern indoor environment. Indoor allergen exposure is recognised as the most important risk factor for asthma in children. House dust mites, pets, insects, plants, moulds and chemical agents in the indoor environment are important causes of allergic diseases. House dust mites and their debris and excrements that contain the allergens are normally found in the home in beds, mattresses, pillows, carpets and furniture stuffing, but they have also been found in office environments. Domestic animals such as cats, dogs, birds and rodents may cause allergic asthma and rhinoconjunctivitis. The exposure usually occurs in homes, but also in schools and kindergartens where domestic animals are kept as pets or for education; moreover, cat and dog owners can bring allergens to public areas in their clothes. Allergy to natural rubber latex has become an important occupational health concern in recent years, particularly among healthcare workers; when powdered gloves are worn or changed, latex particles get into the air and workers are exposed to latex aerosolised antigens. To assess the environmental risk to allergen exposure or to verify if there is a causal relationship between the immunologic findings in a patient and his/her environmental exposure, sampling from the suspected environment may be necessary.

[Evaluation to the exposure to polycyclic aromatic hydrocarbons, benzene, toluene and xylenes in workers in a power plant fueled with heavy oil]. / Valutazione dell'esposizione ad idrocarburi policiclici aromatici ed a benzene, toluene e xileni di lavoratori di una centrale termoelettrica che utilizza olio combustibile denso.

Occupational exposure to polycyclic aromatic hydrocarbons (PAHs) has been demonstrated in many industrial sectors. However, up to date there are few studies in the literature on PAH exposure in thermoelectric power plants. The study was aimed at the evaluation of personal exposure to PAHs in workers of a power plant fueled with heavy oil. Exposure to polycyclic aromatic hydrocarbons (PAHs) and to benzene, toluene and xylenes (BTX) was evaluated on power plant workers exposed to heavy fuel oil; the control group consisted of office workers of the same power plant. Altogether 39 subjects were studied, for a total of 84 days of monitoring. Personal environmental exposure, cutaneous exposure and urinary concentrations of 1-hydroxypyrene (1-OHP), trans,trans-muconic acid (TTMA) and nicotine were measured. Personal environmental exposure to PAHs was very low; only maintenance workers showed exposure to total carcinogenic PAHs significantly higher than controls (median levels 3.05 and 0.88 ng/m3 respectively). All workers showed very low levels of dermal exposure to PAHs (less than 1 ng). The median 1-OHP urinary concentrations were 0.16, 0.11 and 0.08 mumol/mol creatinine in the groups of exposed workers and 0.08 mumol/mol creatinine in the control group. Neither the exposed workers nor the controls showed a significant increase in 1-OHP urinary concentrations across the shift. The regression analysis showed a significant effect of cigarette smoking on urinary 1-OHP, while no association was observed between occupational exposure and diet. Personal environmental exposure levels to BTX were very low. TTMA urinary concentrations of the exposed subjects were similar to those of the controls. No significant increase in the TTMA urinary concentrations was observed across the shift and, as expected, smokers showed higher values than non-smokers. The study did not show a measurable intake of PAHs and BTX in power plant workers that could be ascribed to occupational exposure, thus confirming the efficacy of the protective measures in force.