Urinary 1-Hydroxypyrene and t, t-Muconic ACID as Biomarkers of Exposure to Environmental Pollutants in Two Areas in Italy (Epic-Florence and Ragusa)

Reference values of urinary trans,trans-muconic acid: Italian Multicentric Study

This article reports the results of a study, conducted in the framework of the scientific activities of the Italian Society for Reference Values, aimed at defining reference values of urinary trans,trans-muconic acid (t,t-MA) in the general population not occupationally exposed to benzene. t,t-MA concentrations detected in 376 subjects of the resident population in three areas of Italy, two in central (Florence and southern Tuscany) and one in northern Italy (Padua), by three laboratories, compared by repeated interlaboratory controls, showed an interval of 14.4-225.0 microg/L (5th-95th percentile) and a geometric mean of 52.5 microg/L. The concentrations measured were influenced by tobacco smoking in a statistically significant way: Geometric mean concentrations were 44.8 microg/L and 76.1 microg/Ll in nonsmokers (264 subjects) and smokers (112 subjects), respectively. In the nonsmoking population, a significant influence of gender was found when concentrations were corrected for urinary creatinine, geometric mean concentrations being 36.7 microg/g creatinine in males (128 subjects) and 44.7 microg/g creatinine in females (136 subjects). The place of residence of subjects did not seem to influence urinary excretion of the metabolite, although personal inhalation exposure to benzene over a 24-h period showed slightly higher concentrations in Padua and Florence (geometric means of 6.5 microg/m(3) and 6.6 microg/m(3), respectively) than in southern Tuscany (geometric mean of 3.9 microg/m(3)). Concentration of t,t-MA in urine samples collected at the end of personal air sampling showed little relationship to personal inhalation exposure to benzene, confirming the importance of other factors in determining excretion of t,t-MA when concentrations in personal air samples are very low.

Effects of air pollutants on childhood asthma

Epidemiologic studies have suggested the association between environmental exposure to volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) and the increased risk of incurring asthma. Yet there is little data regarding the relationship between personal exposure to air pollution and the incidence of asthma in children. This study was designed to evaluate the effect of exposure to air pollution on children with asthma by using exposure biomarkers. We assessed the exposure level to VOCs by measuring urinary concentrations of hippuric acid and muconic acid, and PAHs by 1-OH pyrene and 2-naphthol in 30 children with asthma and 30 children without asthma (control). The mean level of hippuric acid was 0.158 +/- 0.169 micromol/mol creatinine in the asthma group and 0.148 +/- 0.249 micromol/mol creatinine in the control group, with no statistical significance noted (p=0.30). The mean concentration of muconic acid was higher in the asthma group than in the control group (7.630 +/- 8.915 micromol/mol creatinine vs. 3.390 +/- 4.526 micromol/mol creatinine p=0.01). The mean level of urinary 1-OHP was higher in the asthma group (0.430 +/- 0.343 micromol/mol creatinine) than the control group (0.239 +/- 0.175 micromol/mol creatinine), which was statistically significant (p=0.03). There was no difference in the mean concentration of 2-NAP between the two groups (9.864 +/- 10.037 micromol/mol in the asthma group vs. 9.157 +/- 9.640 micromol/mol in the control group, p=0.96). In conclusion, this study suggests that VOCs and PAHs have some role in asthma.

Twenty-four-hour urinary excretion of ten pesticide metabolites in healthy adults in two different areas of Italy (Florence and Ragusa)

The determination of pesticide metabolites in human biological fluids represents an important biomarker of exposure in the general population and exposed workers. In the frame of a prospective study, we measured the 24-h urinary excretion of 10 pesticide metabolites to evaluate non-occupational exposure to pesticides in the general population in two different areas in Italy. We collected 24-h urine samples from 69 healthy adults residing in Florence (Central Italy, n = 51) and Ragusa (Southern Italy, n = 18). The volunteers (25 males, 44 females; mean age 56 years) did not report any occupational exposure. We measured: six alkylphosphates, aspecific metabolites of organophosphorus pesticides [dimethylphosfate (DMP), dimethylthiophosfate (DMTP), dimethyldithiophosfate (DMDTP), diethylphosfate (DEP), diethylthiophosfate (DEDP), and diethyldithiophosfate (DEDTP)]; 3,5,6-trichloro-2-pyridinol (TCP), the main metabolite of chlorpyrifos; 3-phenoxybenzoic acid (3-PBA), a metabolite of pyrethroid insecticides; ethylenethiourea (ETU) a metabolite of ethylenebisdithiocarbamates; methamidophos (METH), an organophosphorus insecticide. We also measured PABA excretion as compliance marker (mean recovery 95%). Dimethylphosphates were found in detectable concentrations in the majority of samples (89.9%, 82.6% and 60.9% for DMP, DMTP and DMDTP, respectively). Urinary diethylphosphates (DEP, DETP, DEDTP) concentrations were above the detection limit in 80.9%, 61.8% and 27.5% of samples, respectively. TCP, 3-PBA and ETU were detected in 78.3%, 53.6% and 21.7% of samples, respectively. Methamidophos was detected in two samples (2.8%). The median number of metabolites detected in the same urine sample was 6 (range 0-9). Excretion levels were highest for alkylphosphates, particularly for DMTP (median: 142.6 nmol/day). Multivariate analysis showed statistically significant differences between these two groups of adults, with higher mean values of urinary excretion of alkylphosphates, TCP and ETU in Florence in comparison to Ragusa. Overall, a very high percentage of 24-h urine samples positive for several pesticide metabolites emerged, with higher levels of urinary daily excretion in subjects residing in the more urbanised area. Our results suggest that food monitoring programs should be supported by general campaigns aimed to reduce the use of pesticides in agriculture.