Environmental and lifestyle factors affect benzene uptake biomonitoring of residents near a petrochemical plant.

BACKGROUND: We monitored urinary benzene excretion to examine factors affecting benzene uptake in a sample of the general population living near a petrochemical plant. METHODS: Our study population included 143 subjects: 33 petrochemical plant workers (W) with low level occupational benzene exposure; 30 residents in a small town 2 km from the plant (2kmR); 26 residents in a second small town located 2 to 4 km from the plant (4kmR); and 54 urban residents 25km from the plant (25kmR). Exposure to benzene was evaluated by personal air sampling during one work-shift for the W group, and from 8.00 to 20:00 for general population subgroups, and by urinary benzene (BEN-U). RESULTS: Median airborne benzene exposure was 25, 9, 7 and 6 µg/m(3) benzene among the W, 2kmR, 4kmR, and 25kmR subgroups, respectively; the highest level was found among the workers, while there was no significant difference among the other groups. Median BEN-U was 2 to 14-fold higher in smokers compared to non-smokers; among non-smokers BEN-U was the highest in W (median 236 ng/L), and lower in the 2kmR (48 ng/L) and 4kmR (63 ng/L) subgroups than in the 25kmR (120 ng/L) subgroup. A multiple linear regression analysis, explaining up to 73% of BEN-U variability, confirmed that active smoking and airborne benzene most strongly affected BEN-U. Among the non-smoking, non-occupationally exposed study subjects, a positive association was found between BEN-U and the distance of residence from the plant. This association was explained by increased exposure to urban traffic emissions in the study group residing at a greater distance from the plant. Environmental tobacco smoke had a marginally positive role. CONCLUSION: Among factors affecting benzene uptake in non-occupationally exposed individuals, urban residence contributes to benzene exposure more than residing in close proximity to a petrochemical plant.

[Urinary benzene in biological monitoring of environmental exposure to low benzene concentrations]. / Il benzene urinario nel monitoraggio biologico dell'esposizione a bassi livelli ambientali.

INTRODUCTION: Conflicting opinions exist about urinary benzene (UB) as a reliable biomarker of exposure. Objective of our study is to evaluate the effect of low-level environmental exposure on UB levels. METHODS: We monitored UB excretion in 74 non-smoking non- occupationally exposed subjects; a questionnaire interview gathered information on relevant exposures during the day of monitoring. RESULTS: UB excretion was related (p < 0.05) to gender, sampling time, residence, and reported vehicular traffic, but not to passive smoking and body mass index. CONCLUSION: Our findings support the use of unmetabolized UB as a specific and sensitive biomarker of low-level exposure to benzene.

Causes of death among lead smelters in relation to the glucose-6-phosphate dehydrogenase polymorphism.

OBJECTIVE: To assess, by updating a follow-up mortality study of a lead smelters cohort in Sardinia, Italy, the adverse health effects following occupational lead exposure in relation to the glucose-6-phosphate dehydrogenase (G6PD) polymorphism. METHOD: The 1973-2003 mortality of 1017 male lead smelters were followed-up, divided into two subcohorts according to the G6PD phenotype: whether G6PD deficient (G6PD-) or wild-type (wtG6PD). Deaths observed in the overall cohort and the two subcohorts were compared with those expected, on the basis of the age-, sex- and calendar year-specific mortality in the general male population of the island. Directly standardised mortality rates (sr) in the two subcohorts were also compared. RESULTS: Cardiovascular mortality was strongly reduced among production and maintenance workers, which is most related to the healthy worker effect. However, the sr for cardiovascular diseases was substantially lower among the G6PD- subcohort (5.0x10(-4)) than among the wtG6PD subcohort (33.6x10(-4); chi2 = 1.10; p = NS). Neoplasms of the haemopoietic system exceeded the expectation in the G6PD- subcohort (SMR = 388; 95% CI 111 to 1108). No other cancer sites showed any excess in the overall cohort or in the two subcohorts. No death from haemolytic anaemia occurred in the G6PD- subcohort. CONCLUSION: With due consideration of the limited statistical power of our study, previous results suggesting that in workplaces where exposure is under careful control, expressing the G6PD- phenotype does not convey increased susceptibility to lead toxicity are confirmed. The observed excess risk of haematopoietic malignancies seems to have most likely resulted from chance.

Withdrawal syndrome from gamma-hydroxybutyric acid (GHB) and 1,4-butanediol (1,4-BD) in Sardinian alcohol-preferring rats.

Gamma-hydroxybutyric acid (GHB) and its precursors, 1,4-butanediol (1,4-BD) and gamma-butyrolactone (GBL), are recreational drugs widely abused in the US, Europe and Australasia. A severe withdrawal syndrome from GHB, 1,4-BD and GBL has been increasingly documented over the last years, necessitating the development of a reliable animal model for investigations of potential therapeutic approaches. The present study describes the induction and occurrence of audiogenic seizures as a sign of withdrawal from GHB and 1,4-BD in selectively bred Sardinian alcohol-preferring (sP) rats, treated with escalating doses of GHB (1.5-3.5 g/kg, twice daily; i.g.) or 1,4-BD (500-1000 mg/kg, twice daily; i.g.) for 9 consecutive days. Acute administration of the selective GABA(B) receptor antagonist, SCH 50911, dramatically increased seizure occurrence. We propose that the inherent sensitivity of sP rats to different GHB-associated responses may have contributed to the unraveling of a phenomenon which was otherwise not recognizable in other rat strains.

Urinary 6-sulfatoxymelatonin excretion in humans during domestic exposure to 50 hertz electromagnetic fields.

OBJECTIVES: Exposure to extremely low frequency electromagnetic fields (ELF-EMF) has been suggested to suppress melatonin secretion, which might result in higher cancer risks because of its missing oncostatic action. We investigated the effects of residential exposure to ELF-EMF on the excretion of urinary 6-sulfatoxymelatonin (6-OHMS), the major melatonin metabolite, as an indicator of nocturnal melatonin secretion. METHODS: 6-OHMS was measured in two spot urine samples, collected at 22.00 h and 08.00 h, in 29 men and 22 women. Spot ELF-EMF measurements were conducted at the centre and the four angles of the living room, the bedroom, and the kitchen of study subjects at low current configuration (all lights and appliances turned off), and they were repeated immediately at high current configuration (all lights and appliances turned on). RESULTS: Risk of a reduced 6-OMHS nocturnal secretion was elevated for daily alcohol intake (OR = 6.4; 95%C.I. 1.4,33.1), and body mass index (BMI) above the median (OR = 2.2; 95%C.I. 0.5,9.6). Risk of disrupted rhythm of 6-OHMS excretion was moderately elevated for domestic ELF-EMF exposure above the upper tertile at low current configuration (OR = 2.6; 95%C.I. 0.4,15.7). CONCLUSION: Alcohol consumption, BMI, and gender seem to affect nocturnal melatonin secretion, while an effect of residential exposure to ELF-EMF is uncertain. Future studies should properly account for the effect of such variables, when addressing the hypothesis of disturbances in melatonin secretion as a plausible explanation for the reported excess risk of several tumoral diseases associated with low level ELF-EMF exposure.

Reproductive outcomes in DDT applicators.

OBJECTIVES: To explore reproductive outcomes in relation to occupational exposure to DDT. METHODS: We inquired into the reproductive history, including total number of children, sex distribution in the offspring, time-to-pregnancy, and number of spontaneous abortions and stillbirths, of the spouses of 105 men first exposed to DDT in a 1946-1950 anti-malarial campaign in Sardinia, Italy. The time-to-pregnancy in months at the first successful conception was estimated from population Registrars. Cumulative DDT exposure during the anti-malarial campaign was retrospectively estimated. RESULTS: The stillbirth rate was elevated and the male/female ratio in the offspring was reversed among DDT-exposed workers, and particularly among DDT applicators, compared to the unexposed subjects. Among DDT applicators, the stillbirth rate increased and the male/female ratio decreased by the tertile of cumulative DDT exposure. The fecundity ratio among spouses of DDT applicators was 0.72 (95% CI, 0.41,1.21) compared to the unexposed. The average number of children and abortion rate were unaffected by DDT exposure. CONCLUSIONS: The low statistical power of our study does not allow definitive conclusions. However, the results prompt further in-depth research into adverse reproductive outcomes and reduced fertility among men heavily exposed to DDT.