Urinary metal and polycyclic aromatic hydrocarbon biomarkers in boilermakers exposed to metal fume and residual oil fly ash

Effects of vanadium (sodium metavanadate) and aflatoxin-B1 on cytochrome p450 activities, DNA damage and DNA methylation in human liver cell lines

Vanadium is considered as "possibly carcinogenic to humans" (V₂O₅, IARC Group 2B), yet uncertainties persist related to the toxicity mechanisms of the multiple forms of vanadium. Exposure to vanadium often co-occurs with other metals or with organic compounds that can be transformed by cytochrome p450 (CYP) enzymes into DNA-reactive carcinogens. Therefore, effects of a soluble form of vanadium (sodium metavanadate, NaVO₃) and aflatoxin-B1 (AFB1) were tested separately and together, for induction of CYP activities, DNA damage (γH2AX and DNA alkaline unwinding assays), and DNA methylation changes (global genome and DNA repeats) in HepaRG or HepG2 liver cell lines. NaVO₃ (≥ 2.3 μM) reduced CYP1A1 and CYP3A4 activities and induced DNA damage, butcaused important cell proliferation only in HepaRG cells. As a binary mixture, NaVO₃ did not modify the effects of AFB1. There was no reproducible effect of NaVO₃ (<21 μM) on DNA methylation in AluYb8, satellite-α, satellite-2, and by the luminometric methylation assay, but DNA methylation flow-cytometry signals in HepG2 cells (25-50 μM) increased at the G1 and G2 cell cycle phases. In conclusion, cell lines responded differently to NaVO₃ supporting the importance of investigating more than one cell line, and a carcinogenic role of NaVO₃ might reside at low concentrations by stimulating the proliferation of tumorigenic cells.

Health Implications of Occupational Exposure of Butchers to Emissions from Burning Tyres

BACKGROUND

Flames from burning scrap tyres are used in de-furring animals for human consumption in most parts of Nigeria. Emissions from tyres are known to contain a myriad of toxic mixtures especially particulate matter (PM), volatile organic compounds, hazardous air pollutants, and inspirable metals, some of which are known human carcinogens. This cross-sectional study investigated the deleterious health effects of these emissions in occupationally-exposed workers at the Dei-Dei Abattoir, Abuja, Nigeria.

METHODS

A total of 156 respondents were divided into two groups. Group 1 (124 butchers) and group 2 [32 administrative staff (AS)]. Data from digital spirometry were used to determine the association between chronic exposure to tyre emissions and lung function. Urinary 1-Hydroxypyrene concentration, phenolic compounds levels and heavy metal concentrations were determined. Also ambient PM and polycyclic aromatic hydrocarbons (PAHs) concentrations at 3 delineated points in the abattoir were measured.

FINDINGS

Spirometry results showed significant deterioration of lung function in the butchers. The concentration of 1-Hydroxypyrene (μg/molCret) in the post-shift urine samples of the butchers was significantly higher (P < 0.05) in butchers relative to the AS (0.52 ± 0.13 Vs 0.20 ± 0.07, respectively). Similarly the concentrations of zinc and nickel (mg/l) were significantly higher in the butchers compared to the AS (zinc: 0.91 ± 0.19 Vs 0.31 ± 0.28, respectively; nickel: 0.11 ± 0.06 Vs 0.06 ± 0.02, respectively). Anthracene, fluoranthene, pyrene, benzo-a- pyrene, and PM concentrations were significantly higher at the de-furring point when compared to the wash bay and the administrative building, especially between 8.00 and 8.30 am.

CONCLUSION

Occupational exposure to scrap tyre emissions resulted in significant adverse health effects. The existing laws banning the use of burning tyres in meat processing should be enforced while the use of personal protective equipment should be encouraged in abattoirs.

Assessment of 1H NMR-based metabolomics analysis for normalization of urinary metals against creatinine

BACKGROUND

Proton nuclear magnetic resonance (¹H NMR, or NMR) spectroscopy and inductively coupled plasma-mass spectrometry (ICP-MS) are commonly used for metabolomics and metal analysis in urine samples. However, creatinine quantification by NMR for the purpose of normalization of urinary metals has not been validated. We assessed the validity of using NMR analysis for creatinine quantification in human urine samples in order to allow normalization of urinary metal concentrations.

METHODS

NMR and ICP-MS techniques were used to measure metabolite and metal concentrations in urine samples from 10 healthy subjects. For metabolite analysis, two magnetic field strengths (600 and 700MHz) were utilized. In addition, creatinine concentrations were determined by using the Jaffe method.

RESULTS

Creatinine levels were strongly correlated (R²=0.99) between NMR and Jaffe methods. The NMR spectra were deconvoluted with a target database containing 151 metabolites that are present in urine. A total of 50 metabolites showed good correlation (R²=0.7-1.0) at 600 and 700MHz. Metal concentrations determined after NMR-measured creatinine normalization were comparable to previous reports.

CONCLUSIONS

NMR analysis provided robust urinary creatinine quantification, and was sufficient for normalization of urinary metal concentrations. We found that NMR-measured creatinine-normalized urinary metal concentrations in our control subjects were similar to general population levels in Canada and the United Kingdom.

The distance-to-source trend in vanadium and arsenic exposures for residents living near a petrochemical complex

Biological monitoring of vanadium (V) and arsenic (As) for residents living near a big petrochemical complex has not been previously studied. This study aims to investigate distance-to-source trends in urinary levels and dispersion-estimated concentrations of V and As in areas surrounding a petrochemical complex in central Taiwan. Our study subjects were 1424 residents living in the townships up to ~40 km from the petrochemical complex, and categorized as near (Zone A), further (Zone B) and furthest (Zone C) from the complex. Urinary and ambient V and As levels were analyzed by inductively coupled plasma mass spectrometry. Two-stage dispersion model was used to estimate V and As concentrations at each study subject's address. Multiple linear regression models were used to study the effects of distance-to-source and estimated air concentrations of V and As on the urinary V and As levels of study subjects. Area-wide levels of both V and As showed a high-to-low trend in urinary levels (μg/g-creatinine) from Zone A (V with 2.86±2.30 and As with 104.6±147.9) to Zone C (V with 0.73±0.72 and As with 73.8±90.8). For study subjects, urinary V and As levels were decreased by 0.09 and 1.17 μg/g-creatinine, respectively, with 1 km away from the emission source of the petrochemical complex, and urinary V levels were significantly elevated by 0.38 μg/g-creatinine with a 1 ng/m(3) increase in estimated ambient V concentrations at their addresses. Our study concludes a distance-to-source gradient in V and As exposures exists for residents living near a petrochemical complex with oil refineries and coal-fired power plants and two-stage dispersion model can predict such a trend for V when inhalation is the major exposure route, but not for As that exposure may be from multiple sources and exposure routes.

Vanadium release in whole blood, serum and urine of patients implanted with a titanium alloy hip prosthesis

INTRODUCTION

Vanadium (V) is a minor constituent of the Titanium-Aluminum-Vanadium (TiAlV) alloy currently used in cementless hip prostheses. Present study aimed at verifying the correlation of vanadium levels among different matrices and assessing reference levels of the ion in a population of patients wearing a well-functioning hip prosthesis.

METHODS

Vanadium was measured using Inductive Coupled Plasma Mass Spectrometry (ICP-MS) in whole blood, serum and urine of 129 patients implanted with a TiAlV-alloy hip prosthesis.

RESULTS

The values in the serum were above the upper limit of the reference values in 42% of patients (29% in urine and 13% in whole blood). A good correlation among matrices was observed (p < 0.001). The cohort of patients (N = 32) complaining of pain or in which a loosening or damage to the prosthesis was assessed showed a significantly higher excretion of vanadium in urine as compared with the remaining asymptomatic patients (p = 0.001). The 95th percentile distribution of vanadium in the cohort of patients with a well-functioning prosthesis was 0.3 μg/L in whole blood, 0.5 μg/L in serum and 2.8 μg/L in urine, higher that in the unexposed population, especially for urine.

CONCLUSIONS

The presence of a prosthesis, even though well-functioning, may cause a possible release of vanadium into the blood and a significant urinary excretion. The reference values of vanadium of the asymptomatic patients with titanium alloy hip prostheses supplied information regarding the background exposure level of the ions and their lower and upper limits.

Cardiac autonomic dysfunction from occupational exposure to polycyclic aromatic hydrocarbons

OBJECTIVES

Exposure to polycyclic aromatic hydrocarbons (PAHs) has been associated with cardiopulmonary mortality and cardiovascular events. This study investigated the association between a biological marker of PAH exposure, assessed by urinary 1-hydroxypyrene (1-OHP), and heart-rate variability in an occupational cohort of boilermakers.

METHODS

Continuous 24 h monitoring of the ambulatory electrocardiogram (ECG) and pre- and postshift urinary 1-OHP were repeated over extended periods of the work week. Mixed-effects models were fitted for the 5 min SD of normal-to-normal intervals (SDNN) in relation to urinary 1-OHP levels pre- and postworkshift on the day they wore the monitor, controlling for potential confounders.

RESULTS

The authors found a significant decrease in 5 min SDNN during work of -13.6% (95% CI -17.2% to -9.8%) per SD (0.53 μg/g creatinine) increase in the next-morning preshift 1-OHP levels. The magnitude of reduction in 5 min SDNN was largest during the late night period after work and increased with each SD (0.46 μg/g creatinine) increase in postshift 1-OHP levels.

CONCLUSION

This is the first report providing evidence that occupational exposure to PAHs is associated with altered cardiac autonomic function. Acute exposure to PAHs may be an important predictor of cardiovascular disease risk in the work environment.

A review of effects of particulate matter-associated nickel and vanadium species on cardiovascular and respiratory systems

Many epidemiological investigations indicate that excess risks of mortality and morbidity may vary among specific PM(2.5) components. Nickel (Ni) and vanadium (V) particulate metal species may potentially be related to increasing respiratory and cardiovascular mortality and morbidity. This review focuses on exposure concentrations of these two species in various settings, their health effects based on epidemiological and toxicological studies and the underlying mechanisms. The evidence shows that environmental exposure concentrations of Ni and V in general setting are lower than the World Health Organization standard (V, 1 microg/m(3)/day) in 2000, or the European Environment Agency standard (Ni, 1 microg/m(3)/day) in 2003, but their associations with cardiopulmonary diseases can still be found. The toxicological mechanism can be explained by laboratory-based studies. Updated safe guidelines on environmental and human exposure of Ni and V are necessary in order to clarify the associations between them and cardiopulmonary diseases and provide environmental intervention policies.

Reference values for cobalt, copper, manganese, and nickel in urine among women of the general population in Japan

OBJECTIVE

The present study was initiated to establish the reference levels of Co, Cu, Mn, and Ni in urine of women in the general Japanese population.

METHODS

Stored urine samples were subjected to the analysis. The samples were collected from 1,000 adult women all over Japan, who had no occupational exposure to these elements. Co, Cu, Mn, and Ni in urine were analyzed by graphite furnace atomic absorption spectrometry. The concentrations were distributed log-normally, and were presented in terms of geometric mean (GM) and geometric standard deviation, as observed or after correction for creatinine concentration or a specific gravity of urine of 1.016.

RESULTS

The GM values of observed levels (i.e., with no correction for urine density) and of the levels after correction for creatinine (cr) concentration (values in parenthesis) were 0.68 g/l (0.60 microg/g cr) for Co, 13.4 g/l (11.8 g/g cr) for Cu, 0.14 microg/l (0.12 g/g cr) for Mn and 2.1 g/l (1.8 g/g cr) for Ni. There was a life-long age-dependent increase in Cu. Mn levels reached the maximum at 60 to 69 years of ages. In contrast, age-dependency was not substantial in Co and Ni.

CONCLUSIONS

Comparison with values reported in literatures for other areas showed that Co and Ni levels in urine of Japanese women are higher than, Cu level is comparable with, and Mn level is lower than others. The reasons for high Co and Ni levels deserve further study.