Environmental factors affecting the urinary excretion of inorganic arsenic in the general population.

OBJECTIVE: To assess the critical issues concerning the use of urinary inorganic arsenic (iAs), including As3, As5, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), as biomarker of internal dose in order to monitor environmental and occupational exposure to inorganic As, considering the influence of diet and drinking water on excretion of iAs. METHODS: The design protocol stipulated collection of weekly urine samples from 6 male subjects for 5 consecutive months. In all the urine samples, iAs was determined by Hydride Generation-Atomic Absorption Spectrophotometry (HG-AAS). In the subjects with iAs higher than 35 microg/L, Biological Exposure Index (BEI) proposed by the American Conference of Governmental Industrial Hygienists (ACGIH), urinary arsenic speciation was performed by HPLC-ICP-MS. Exposure to airborne As was evaluated monthly using personal environmental samplers worn for 8 hours. Throughout the study, the participants filled out a daily food diary, also detailing types of water drunk. RESULT: Exposure to airborne As was invariably below the limit of detection, equal to 1 ng/m3. A total of 77 urine samples were collected. iAs was always detectable and was higher in 7 urine samples, obtained from 5 of the 6 subjects examined, than the BEI. Among foods with a high As content, the intake of seafood and fish within 72 hours before providing the sample seems to be the principal source of the iAs concentrations, while the intake of rice or drinking water showed no influence on this biological marker. Instead, drinking wine within 24 hours before urine sample collection can cause a significant increase in the excretion of iAs. CONCLUSIONS: In populations that eat large amounts of fish and seafood, the use of iAs to monitor occupational and environmental exposure to inorganic As seems to present some problems, and urinary As speciation may be essential at least in cases with As measurements above the biological limit values. In any case, a diet sheet reporting all foods eaten within 3 days of urine collection seems to be an indispensable tool to ensure a correct interpretation of the results.

Immune effects of polychlorinated biphenyls, smoking and alcohol.

Polychlorinated biphenyls (PCB) have been shown to exert some immune effects. Here we analysed their effects also on immune parameters not previously studied such as TCR alpha-beta, TCR gamma-delta and regulatory T cells (Treg), taking into account the specific and cumulative interference of smoking and alcohol. The study subjects consisted of 26 male workers in a steel works factory, employed in the electrical maintenance sector, with previous exposure to a mixture of PCB (exposed subjects), and 30 male workers with no occupational exposure to PCB (controls). All subjects were given a questionnaire and peripheral venous blood samples were taken to determine serum PCB (33 congeners), total cholesterol and triglycerides, leukocytes, total lymphocytes and the T lymphocyte subpopulations (TCR alpha-beta, TCRgamma-delta, CD4+ and Treg lymphocytes). PCB, even though at a very low concentration, were significantly higher in exposed subjects than controls, and were significantly correlated with age. Monocytes% and CD4+ were significantly reduced in the exposed subjects as compared to the controls. The serum concentration of PCB positively correlated with TCR alpha-beta, and negatively with TCRgamma-delta. Treg lymphocytes showed a positive dependence on tobacco smoking, while the monocytes percentage and CD4+ showed a negative and positive dependence, respectively, on alcohol intake. Our results seem to show some effects of slight exposure to PCB in particular reducing the relative concentration of TCRgamma-delta. This effect can favour indirectly the increase in Treg induced by smoking, the anti-inflammatory or proinflammatory/fibrogenetic/angiogenetic effect of which, exerted by produced cytokines, particularly TGF-beta, deserves further clarification.

[Lesser validity of urinary benzene than S-phenylmercapturic acid for measuring occupational and environmental exposure to very low concentrations of benzene]. / Minore validità del benzene urinario rispetto all'acido S-fenilmercapturico nel rilevare l'esposizione occupazionale ed ambientale a concentrazioni molto basse di benzene.

AIM: To study the validity of urinary benzene as a biomarker of low and very low exposure to this toxicant, as compared with t,t-muconic acid (t,t-MA) and S-phenylmercapturic acid (SPMA), also taking into account the influence of cigarette smoking and co-exposure to toluene on the urinary excretion of benzene. MATERIALS AND METHODS: The results obtained in two different studies were compared: in the first, workers occupationally exposed to low concentrations of benzene (18 fuel tanker drivers and 23 filling station attendants) were compared with 31 controls and in the second, workers exposed to very low concentrations of benzene (the same 23 filling station attendants) were compared with the 31 controls. Exposure to airborne benzene and toluene was monitored with passive personal samplers (Radiello). Then the urine collected at the end of the work shift was analyzed for t,t-MA, SPMA and urinary benzene. All participants also filled out a questionnaire about their lifestyle habits. RESULTS: There were no differences among the three groups in terms of age and smoking habit. Occupational exposure to benzene and toluene and the urinary concentrations of t,t-MA, SPMA and urinary benzene were higher in the fuel tanker drivers than the filling station attendants and higher in the latter than in the controls. Cigarette smoking was found to be associated with urinary excretion of t,t-MA, SPMA and urinary benzene at both low and very low exposure to benzene. The biomarkers t,t-MA, SPMA and urinary benzene were almost always correlated, for both low and very low exposure to benzene. Notably, for low exposure to benzene a dependency relation was found with the levels of t,t-MA, SPMA and urinary benzene on both cigarette smoking and airborne benzene, whereas for very low exposure to benzene there was a dependency relation of SPMA on cigarette smoking and airborne benzene, of urinary benzene only on cigarette smoking and of t,t-MA on none of the variables considered. CONCLUSIONS: For occupational exposure to low concentrations of benzene, urinary benzene and SPMA showed a comparable validity, while for exposure to very low concentrations of this toxicant the validity of SPMA was confirmed while urinary benzene was found to be less useful. Cigarette smoking was the main factor conditioning the excretion of all the biomarkers of benzene in conditions of both low and very low exposure to the toxicant, so for the analysis of occupational exposure to benzene it is best to recommend abstention from smoking at least in the hours immediately before urine collection.

Applicability of urinary benzene to biological monitoring of occupational and environmental exposure to very low benzene concentrations.

OBJECTIVE: To verify whether urinary benzene is an applicable biomarker of occupational exposure to very low concentrations of benzene, considering the influence of cigarette smoke and benzene-toluene co-exposure. MATERIALS AND METHODS: 23 filling station attendants with occupational exposure to benzene and 31 controls were analyzed. Occupational and environmental exposure was monitored and t,t-muconic acid (t,t-MA), S-phenylmercapturic acid (SPMA), urinary benzene and creatinine in the urine samples were tested. RESULTS: Occupational exposure to benzene and toluene was significantly higher in the filling station attendants than in the controls, whereas t,t-MA, SPMA and urinary benzene were not different in the two groups. Instead, the smoker group showed significantly higher values for the above biomarkers than the non-smoker group, each of which included both exposed workers and controls. SPMA was dependent on airborne benzene and cigarette smoking, and urinary benzene only on cigarette smoking, while t,t-MA was not dependent on either of these variables. CONCLUSIONS: At very low concentrations of occupational exposure to benzene, urinary benzene is less valid than SPMA as a biomarker, even if both are strongly influenced by smoking habit. Abstention from smoking should therefore be recommended for at least two hours before urine collection.

[Sleep disorders in cement workers]. / I disturbi del sonno nei lavoratori dell'industria del cemento.

Obstructive Sleep Apnea Syndrome (OSAS) and Excessive Daytime Sleepiness (EDS) are sleep disorders which can increase cardiovascular risk. An health survey was performed on the cement workers to estimate the prevalence of sleep disorders and to investigate occupational, personal and health risk factors that could influence it. A total of 761 male workers, employed at 10 different cement plants of South Italy and Sicily, were examined. All subjects gave informed consent to take part in the survey. The following questionnaires were administered: Berlin Questionnaire to estimate the high risk of OSAS, Epworth Sleepiness Scale for EDS, a questionnaire posing questions about working conditions, personal characteristic, lifestyle, past history of disease and present illness. Statistical analysis was performed with the statistical package SPSS. The prevalence of high risk of OSAS and of EDS resulted respectively in 24.2% and 3.4% of workers. Sleep disorders detected with the two questionnaires were significantly associated. A positive and significant association between OSAS and respectively age, time of employment, BMI, ex-smoker status, neck, waist or hip circumferences, chronic fatigue and arterial hypertension was observed. Subjective variables regarding working conditions (job interest, evaluation oforganization of work and job satisfaction) and alcohol consumption were not associated with the high risk of OSAS. Shift work (2 and 3 shifts) was not associated with the high risk of OSAS. An healthy worker effect was observed for workers who changed from shift work (2 or 3 shifts) to fixed daytime work. For them, this change to fixed daytime work was conditioned by chronic disease like hypertension and obesity. EDS was not dependent, associated or correlated with any of the occupational, personal or pathologic variables investigated in the study. In conclusion the research showed no relationship between working conditions, particularly shift work, and the high risk of OSAS, and the influence of obesity in determining the high risk of OSAS, itself a potential cardiovascular risk factor. The interest of occupational physician has been focused on introducing in health surveillance also measures of health promotion regarding sleep disorders with the aim of preserving health condition in workers.

Mitochondrial Ca2+ as a key regulator of cell life and death.

Mitochondrial Ca(2+) homeostasis is today at the center of wide interest in the scientific community because of its role both in the modulation of numerous physiological responses and because of its involvement in cell death. In this review, we briefly summarize a few basic features of mitochondrial Ca(2+) handling in vitro and within living cells, and its involvement in the modulation of Ca(2+)-dependent signaling. We then discuss the role of mitochondrial Ca(2+) in the control of apoptotic death, focusing in particular on the effects of pro- and anti-apoptotic proteins of the Bcl-2 family. Finally, the potential involvement of Ca(2+) and mitochondria in the development of two diseases, Ullrich muscular dystrophy and familial Alzheimer's disease, is briefly discussed.

[Significance and limitation of creatinine adjustment for urinary chromium and arsenic in biological monitoring of occupational exposure to these metallic elements]. / Significato e limiti della correzione per creatinina del cromo e dell'arsenico urinari nel monitoraggio biologico dell'esposizione professionale ai due elementi metallici.

Creatinine adjustment has been used to remove the influence of the effect of urine dilution on exposure biomarkers measured in spot samples. This research aimed to determine the reliability of creatinine adjustment for urinary chromium and arsenic in subjects from general population considering interferences able to influence creatinine excretion. 444 male subjects were examined and each participant was administered an anamnestic questionnaire. Chromium and arsenic were determined on second morning void urine samples by atomic absorption spectrophotometry and creatinine by Jaffè method. Urinary creatinine showed a significant negative decrease with age increasing (p < 0.001). Chromium concentrations resulted higher in subjects with renal disease, particularly after creatinine adjustment (p = 0.014). Age was negatively correlated with urinary creatinine (rho = -0.23; p < 0.001), and positively with chromium (rho = 0.13; p = 0.007) and arsenic (rho = 0.17; p = 0.004), only after creatinine adjustment. A positive correlation was also found between unadjusted chromium and arsenic (rho = 0.10; p = 0.039) and between urinary creatinine and both unadjusted chromium (rho = 0.32; p < 0.001) and arsenic (rho = 0.18; p < 0.001). An high coefficient of correlation was observed between unadjusted chromium (rho = 0.88; p < 0.001) and arsenic (rho = 0.90; p < 0.001) and the respective adjusted values. Multiple regression showed a dependence of urinary creatinine and adjusted chromium and arsenic concentrations on age. In conclusion, although chromium and arsenic seem to have a renal kinetics of excretion comparable to the creatinine one, the influence of age on creatinine elimination suggests that the expression of urinary values of these metallic elements as microg/L is more reliable.

[Influence of cigarette smoking on the excretion of urinary benzene in filling-station attendants]. / Influenza del fumo di sigaretta sulla concentrazione di benzene urinario negli addetti alla distribuzione di carburante.

The influence of cigarette smoking on concentrations of urinary benzene, a sensitive and specific biomarker proposed for biological monitoring of exposure to very low doses of benzene, was investigated in 24 filling-station attendants and 31 workers non occupationally exposed to benzene. Environmental monitoring was performed by personal passive samplers "Radiello", and a spot urine sample was collected at the end of the work shift, from all subjects, for the determination of urinary benzene. Exposure to benzene resulted significantly higher in filling-station attendants (mean 23.3 +/- 17.0 microg/m3; range 4.5-66.3 microg/m3) than in controls (mean 4.6 +/- 2.6 microg/m3; range < 3-11.5 microg/m3), while concentrations of urinary benzene did not show any significant difference between the two groups. Considering all subjects as a single group, it was observed that urinary benzene concentrations were positively correlated with the number of cigarettes smoked during the sampling time (rho = 0.38; p = 0.047) and with airborne benzene levels (rho = 0.32; p = 0.019), and negatively correlated with the time elapsed between the last smoked cigarette and urine collecting (rho = -0.40; p = 0.045). Multiple regression analysis confirmed the influence of cigarette smoking on urinary benzene concentrations. In conclusion, our study showed the validity of urinary benzene as a biomarker for biological monitoring of exposure to very low doses of benzene, although cigarette smoking determined a prevalent etiological role at the low environmental benzene concentrations observed.

[Evaluation of the role of occupational and environmental exposure to inorganic arsenic in the urinary excretion of the metal: preliminary data]. / Valutazione del ruolo dell'esposizione professionale e ambientale ad arsenico inorganico (iAs) sull'eliminazione urinaria del metallo: dati preliminari.

INTRODUCTION: Urinary inorganic arsenic is an expression of occupational exposure to the metal, provided that there is no history of ingestion of foods containing high concentrations of inorganic and/or organic arsenic. The present study was conducted to assess the contribution of professional and environmental exposure to inorganic arsenic on urinary excretion of the metal. MATERIALS AND METHODS: We examined 195 workers at a steelfoundry in Taranto, exposed to very low concentrations of inorganic arsenic and two control groups consisting of 105 subjects resident near the factory and 144 subjects resident approximately 20 Km away. All participants were administered a questionnaire enquiring about general characteristics, lifestyle, occupational and extra occupational exposure to arsenic. Urinary arsenic was determined by atomic-absorption spectrophotometry. RESULTS: Exposed and non exposed subjects were similar as regards general characteristics and lifestyle. The environmental concentration of arsenic for the foundryworkers was invariably lower than 0.1 microg/m3. Urinary excretion of arsenic was higher in the subjects in all three groups, examined singly and together, if they had eaten crustaceans and/or shellfish in the three days before urine collection. There was a significant positive correlation with the consumption of shellfish and a significant negative correlation with the number of days since the last crustacean/shellfish meal. Multiple regression analysis showed a dependence of urinary elimination of arsenic on the days since the last crustacean/shellfish meal. DISCUSSION: The absence of occupational exposure to arsenic allowed us to attribute the higher urinary elimination of arsenic to ingestion of crustaceans and/or shellfish in the three days before collection of the urine, both in subjects exposed to inorganic arsenic and in the two groups belonging to the general population. Our results support the hypothesis that inorganic arsenic, determined by atomic-absorption spectrophotometry, may derive from the catabolism of organic arsenic compounds contained in crustaceans and/or shellfish included in the diet.

Assessment of reference values for mercury in urine: the results of an Italian polycentric study.

The results of a polycentric study to assess the reference values of urinary mercury (U-Hg) in four Italian cities are presented. A total of 383 subjects were selected on the basis of standardised criteria by a questionnaire on personal habits, lifestyle, occupational or non-occupational exposure to Hg, medical history, number and area of dental amalgams. U-Hg was determined by hydride generation atomic absorption method (HG-AAS), with a detection limit of 0.5 microg/l and by flow injection (FI) inductively coupled plasma mass spectrometry (ICP-MS), with a detection limit of 0.03 microg/l. The median value of U-Hg, determined by HG-AAS, was 0.78 microg/g creatinine (0.75 for males and 0.83 for females), with 5 degrees and 95 degrees percentiles, respectively, of 0.17 and 3.66 microg/g creatinine. When determined by FI ICP-MS, the median value was 0.79 microg/g creatinine (0.77 for males and 0.79 for females) with 5 degrees and 95 degrees percentiles of, respectively, 0.12 and 5.02 microg/g creatinine. Among the independent variables, city of origin, area of dental amalgams, fish intake and tobacco smoking significantly influenced the U-Hg levels. The U-Hg reference values from this survey are lower than those from other recent investigations, probably due to characteristics and selection of the examined individuals and to the strict control of pre-analytical and analytical factors of variability.

Monocyte-macrophage system and polymorphonuclear leukocytes in workers exposed to low levels of metallic mercury.

Our previous research (Soleo L, Vacca A, Vimercati L et al. Occup Environ Med 1997;54:437-442) showed a reduction in tumor necrosis factor-alpha (TNF-alpha) serum levels in workers with prolonged exposure to low doses of inorganic mercury, suggesting an in vivo functional defect of the monocyte-macrophage system. On this basis, here we wondered whether workers exposed to lower doses of metallic mercury displayed possible changes in the monocyte-macrophage system. In this particular cohort of workers, we also sought for the effects of the exposure on the polymorphonuclear leukocytes (PMNL) chemotaxis. The monocyte-macrophage system and the natural killer (NK) cells were examined in 19 exposed workers and in 25 unexposed workers, as the control group (controls). Specifically, the circulating monocyte-macrophage cells and their CD13, CD15 and CD33 subsets, serum cytokines (IL-8, GM-CSF and TNF-alpha) and the NK cells were analyzed. In seven exposed and seven controls randomly chosen workers the PMNL chemotaxis was also assessed. The selected indicator of mercury exposure were the levels of mercury in the urine (U-Hg), that was significantly higher in exposed workers than the controls (9.7 +/- 5.5 microg/l and 2.4 +/- 1.2 microg/l, respectively). None of the exposed workers had shown signs of either acute or chronic inorganic mercury toxicity or any form of hypersensitivity. Several immunological variables tested, monocyte-macrophage cells and their subsets, NK cells and serum cytokines overlapped between the exposed and the control workers. When the workers were considered as a whole (exposed plus controls), no correlation was found between current U-Hg and all immunological parameters. However, when exposed workers were studied separately, an inverse correlation was disclosed between cumulative U-Hg and cells (as percentage) expressing the CD13 (r = -0.599; P = 0.007) and CD15 (r = -0.614; P = 0.005) molecules, and NK cells (r = -0.455; P = 0.05). Moreover, a significant impairment in the PMNL chemotaxis (t = 3.70; P = 0.003) was observed in the exposed workers. The results of our study suggest that the exposure to very low levels of metallic mercury led to subtle impairment of circulating monocyte and NK cells (as percentages) according to the increase in U-Hg levels, as well as of the PMNL chemotactic function in this particular group of workers, even though they remain clinically asymptomatic. Therefore, we suggest that impairment of these parameters provide a sensitive indicator of metallic mercury and other chemical contaminants present in the environment.

[Dental amalgams and urine elimination of mercury in workers exposed to low concentrations of inorganic mercury]. / Amalgami dentari ed eliminazione urinaria di mercurio in lavoratori esposti a basse concentrazioni di mercurio inorganico.

The aim of the research was to assess the contribution of dental amalgams and other non-occupational factors of exposure to inorganic mercury (diet, etc.) to the quantity of mercury excreted with urine in workers exposed to low level concentrations of inorganic mercury. Two groups of workers (Groups I and II) were studied who were exposed to low and different environmental concentrations of inorganic mercury. These two groups were compared with a group of subjects not occupationally exposed to mercury in the same geographical area (Group III). All subjects were administered a questionnaire concerning personal data, lifestyle, recent removal and/or insertion of dental amalgam fillings, presence of nasal obstruction or bruxism and consumption of fish. The number of amalgam-filled teeth was established for each subject. Mean environmental exposure to inorganic mercury was 0.0087 mg/m3 for Group I and 0.0030 mg/m3 for Group II. Urinary excretion in the 3 groups was 4.2 +/- 2.8 micrograms/l for Group I, 3.0 +/- 2.1 micrograms/l for Group II and 1.6 +/- 1.2 micrograms/l for Group III. The results showed that of the factors of exposure to inorganic mercury, only occupational exposure (T = 9.18; p = 0.000) and the number of amalgam-filled teeth (T = 2.03; p = 0.043) were able to influence significantly urinary excretion of mercury; the sources of non-occupational exposure did not appear to play any role. The contribution of each amalgam filling to urinary mercury excretion was calculated to be 0.08 microgram/l. Occupational exposure therefore, even at low level doses, is still the main cause of urinary mercury excretion in workers exposed to inorganic mercury; of the non-occupational exposure factors, a significant role is played by amalgam dental fillings, whose contribution needs to be taken into consideration in order to make a correct interpretation of the results of biological monitoring of exposed workers.

The influence of amalgam fillings on urinary mercury excretion in subjects from Apulia (southern Italy).

The purpose of this study was to assess the role of dental amalgams and diet upon urinary mercury (U-Hg) excretion. 98 subjects (50 men and 48 women) not exposed to inorganic mercury, for either occupational or environmental reasons, and living in coastal and inland districts of Apulia (Southern Italy) were considered. All the subjects were administered a questionnaire with questions concerning life style, medical history, and occupational activity. Dental amalgams were evaluated with respect to their number and their surface areas. Urinary mercury was measured by the cold vapour atomic absorption technique. Expressed in terms of arithmetic mean, U-Hg excretion was found to amount to 1.03 micrograms/g creatinine (5th and 95th percentile: 0.31 and 2.40; range 0.30-3.25). Multiple linear regression analysis showed that, of the several tested independent variables (dental amalgams, age, body mass index, consumption of tuna, bass, swordfish, etc.), only the number of amalgam fillings (T = 5.25; p = 0.025) and the number of restored surfaces (T = 2.33; p = 0.020) were found liable to affect urinary mercury excretion in a significant manner. In conclusion, the results of this study confirm the primary role of amalgam fillings in affecting urinary mercury excretion in those subjects who are not occupationally exposed to inorganic mercury, The resulting urinary mercury levels can no doubt be taken as the reference values for the population of Apulia.