Biological monitoring of exposure: trends and key developments

Rapid determination of hippuric acid as an exposure biomarker of toluene using a colorimetric assay and comparison with high-performance liquid chromatography

Occupational exposure to toluene is associated with health risks that require reliable monitoring methods. Hippuric acid (HA), a urinary metabolite of toluene, serves as a valuable biomarker for such exposure. Colorimetric methods for the quantitative determination of HA have gained prominence due to their simplicity, cost-effectiveness, and suitability for field application. In the present study, a simple colorimetric technique was optimized for the determination of HA in the urine sample, and compared with a usual HPLC technique. The central composite design (CCD) was applied to examine the effective parameters on the colorimetric determination of HA. The calibration curve for HA was established within the concentration range of 6 to 100 mg L-1 with R2 = 0.97. The detection limit (LOD) and quantification limit (LOQ) were determined to be 1.8 mg L-1 and 6 mg L-1 respectively. The relative standard deviation (RSD%) was less than 5%, and the recovery% (R%) was 90.5-100.1. The overall results showed good agreement between the colorimetric and HPLC results. There was a significant relationship between the results obtained from HPLC and colorimetric methods especially for higher concentration levels of HA (≥ 500 mg/g creatinine). In conclusion, our optimized colorimetric method is a simple, cost-effective, and rapid method for determination of HA in occupational exposure, which is comparable with the HPLC technique.

False positives and false negatives in benzene biological monitoring

Benzene is a commonly used industrial chemical that is a significant environmental pollutant. Occupational health specialists and industrial toxicologists are concerned with determining the exact amount of exposure to chemicals in the workplace. There are two main approaches to assess chemical exposure; air monitoring and biological monitoring. Air monitoring has limitations, which biological monitoring overcomes and could be used as a supplement to it. However, there are several factors that influence biological monitoring results. It would be possible to assess exposure more accurately if these factors were taken into account. This study aimed to review published papers for recognizing and discussing parameters that could affect benzene biological monitoring. Two types of effects can be distinguished: positive and negative effects. Factors causing positive effects will increase the metabolite concentration in urine more than expected. Furthermore, the parameters that decrease the urinary metabolite level were referred to as false negatives. From the papers, sixteen influential factors were extracted that might affect benzene biological monitoring results. Identified factors were clarified in terms of their nature and mechanism of action. It is also important to note that some factors influence the quantity and quality of the influence of other factors. As a result of this study, a decision-making protocol was developed for interpreting the final results of benzene biological monitoring.

Biomonitoring and risk assessment of human exposure to triazole fungicides

Risk assessment and biomarkers were evaluated in volunteers exposed to triazole fungicides in southern Minas Gerais, Brazil. Volunteers were divided into two groups: occupationally and environmentally exposed to pesticides (n = 140) and those unexposed (n = 50) from urban areas. Urine samples were analyzed by GC-MS for triazoles, and samples from men and women in the exposed group were quantified. Groups were further stratified by sex to evaluate the biomarkers results. Oxidative stress was indicated by biomarker analysis for occupationally exposed men with elevated malondialdehyde levels and reduced superoxide dismutase and catalase activity (p < 0.0001). Bile acid levels were also elevated in the exposed group (p < 0.0001). Biomarkers in this study suggest recent, reversible changes due to pesticide exposure. Liver enzyme levels showed no significant differences. The highest Estimated Daily Intake for epoxiconazole ranged from 0.534 to 6.31 μg/kg-bw/day for men and 0.657-8.77 μg/kg-bw/day for women in the exposed group. Considering the highest detected urinary triazole value, the calculated Hazard Quotient for epoxiconazole was 0.789 for men and 1.1 for women. Results indicate a health risk associated with environmental triazole exposure, highlighting the importance of biomonitoring in risk assessment to prevent intoxication and assist in mitigating adverse health effects from chronic pesticide exposure.

Assessment of cellular damage with cytome assay among environmental/occupational triazole

The use of triazole fungicides is common in Minas Gerais, Brazil. However, the risk arising from excessive and often unprotected exposure can be harmful to farmers. Therefore, we evaluated volunteers, exposed to triazole fungicides for cellular damage caused by this pesticide. In the buccal micronucleus cytome assay (BMCyt), cells were analyzed. Urinary triazoles were analyzed by the Liquid-Liquid Extraction coupled with Gas-chromatography/mass-spectrometry (LLE-GC/MS). Statistical differences were found for all cell types evaluated in residents of rural areas (n = 145). Analysis of variance showed statistical difference in kariolytic and pyknotic cells, between the groups of men and women living in rural areas, with higher incidence in the male group. Likewise, higher concentrations triazoles in urine samples in the male group were observed. Greater cellular damage suggests increases in DNA damage, chromossomal instability and cell deaths. The results showed the urgency of the public management with the implementation of measures to minimize the pesticides exposure.

Metabolomics for exposure assessment and toxicity effects of occupational pollutants: current status and future perspectives

INTRODUCTION

Work-related exposures to harmful agents or factors are associated with an increase in incidence of occupational diseases. These exposures often represent a complex mixture of different stressors, challenging the ability to delineate the mechanisms and risk factors underlying exposure-disease relationships. The use of omics measurement approaches that enable characterization of biological marker patterns provide internal indicators of molecular alterations, which could be used to identify bioeffects following exposure to a toxicant. Metabolomics is the comprehensive analysis of small molecule present in biological samples, and allows identification of potential modes of action and altered pathways by systematic measurement of metabolites.

OBJECTIVES

The aim of this study is to review the application of metabolomics studies for use in occupational health, with a focus on applying metabolomics for exposure monitoring and its relationship to occupational diseases.

METHODS

PubMed, Web of Science, Embase and Scopus electronic databases were systematically searched for relevant studies published up to 2021.

RESULTS

Most of reviewed studies included worker populations exposed to heavy metals such as As, Cd, Pb, Cr, Ni, Mn and organic compounds such as tetrachlorodibenzo-p-dioxin, trichloroethylene, polyfluoroalkyl, acrylamide, polyvinyl chloride. Occupational exposures were associated with changes in metabolites and pathways, and provided novel insight into the relationship between exposure and disease outcomes. The reviewed studies demonstrate that metabolomics provides a powerful ability to identify metabolic phenotypes and bioeffect of occupational exposures.

CONCLUSION

Continued application to worker populations has the potential to enable characterization of thousands of chemical signals in biological samples, which could lead to discovery of new biomarkers of exposure for chemicals, identify possible toxicological mechanisms, and improved understanding of biological effects increasing disease risk associated with occupational exposure.

Differential immunomodulatory effects of six pesticides of different chemical classes on human monocyte-derived macrophage functions

Exposure to pesticides through eyes, skin, ingestion and inhalation may affects human health by interfering with immune cells, such as macrophages. We evaluated, in vitro, the effect of six pesticides widely used in apple arboriculture on the functions of human monocyte-derived macrophages (hMDMs). hMDMs were cultured for 4 or 24 h with or without pesticides (0.01, 0.1, 1, 10 μmol.L^-1). We showed that chlorpyrifos, thiacloprid, thiophanate, boscalid, and captan had little toxic effect at the tested concentrations, while dithianon had low-cytotoxicity at 10 μmol.L^-1. While boscalid showed no effect on hMDMs function, thiophanate (0.01 μmol.L^-1) stimulated with TPA and thiacloprid (1, 10 μmol.L^-1) stimulated with zymosan activated ROS production. Chlorpyrifos, dithianon, and captan inhibited ROS production and TNF-α, IL-1β pro-inflammatory cytokines. We established that dithianon (0.01-1 μmol.L^-1) and captan (0.1, 1 μmol.L^-1) induced mRNA expression of NQO1 and HMOX1 antioxidant enzymes. Dithianon also induced the mRNA expression of catalase, superoxide dismutase-2 at 10 μmol.L^-1. Together, these results show that exposure to chlorpyrifos, dithianon, and captan induce immunomodulatory effects that may influence the disease fighting properties of monocytes/macrophages while pesticides such as thiacloprid, thiophanate and boscalid have little influence.

Occupational Exposure to Manganese Among Welders: Association Between Airborne Manganese Concentration and Blood Manganese Levels

Background: Manganese (Mn) is an essential element for the human body, but it can cause adverse effects on the Central Nervous System at high doses. Exposure to manganese fumes during welding can harm welders' health. Objectives: The current study aimed to measure manganese produced by shielded metal arc welding (SMAW) in the breathing zone air and blood of welders and investigate the relationship between manganese concentrations in air and blood. Methods: In this descriptive-analytical cross-sectional study, 35 welders were enrolled as the exposed group and 40 office workers as the control group. Manganese concentration in air was measured according to NIOSH method 7301. Air and blood sample analyses were carried out by ICP-OES. Statistical analysis was performed with MINITAB 17. Data were analyzed using Pearson correlation coefficient, one-sample t-test, paired t-test, and logistic regression. The significance level was set at P < 0.05. Result: The mean concentration of welding respirable particles and manganese fumes were 9.56 ± 1.67 and 0.45 ± 0.08 mg/m3, three and 22 times the exposure limit recommended by ACGIH, respectively. Average manganese was significantly higher in the welders’ blood (0.16 ± 0.02 µg/mL) than in the controls’ blood (0.04 ± 0.002 µg/mL). There were strong and significant correlations between the welding respirable particles and manganese concentration in welders’ breathing zone and blood manganese levels. Also, with each year of work experience, the manganese concentration in the welders’ blood increased by 1.5%. Conclusions: Welders are at risk of contamination with manganese. Manganese exposure reduction through more efficient ventilation systems, reducing welder’s exposure time, staff training, and appropriate respiratory protection equipment should be applied to reduce manganese exposure among welders and prevent health complications.

Multivariate Optimization of an SPME Technique for GC-MS Analysis of Urinary BTX

Volatile organic compounds (VOCs), such as benzene, toluene and xylenes (BTX), are recognized as environmental contaminants due to their acute and chronic toxic effects, and toluene is a substance contained in products used in inhalants. In this way, methods able to determine these substances in non-invasive matrices offer great applicability for assessing acute exposure. In this study, a functionalized polymer, chloropropyltrimethoxysilane/polydimethylsiloxane, was evaluated as a potential material to be used in solid-phase microextraction for the quantification of BTX in urine by gas chromatography coupled to mass spectrometry (GC-MS). The method optimization was performed by using fractional factorial planning 2 (4-1) and the Doehlert's experiment. Desorption time and salinity were the most important factors that impact the sensitivity of the method. Spectroscopic and thermogravimetric characterization demonstrated the functionalization of the material and its thermal stability up to 390°C. This allowed it to be used for ~60 analytical cycles without loss of efficiency. The proposed method demonstrated a satisfactory analytical performance to determine the VOCs studied. The protocol agrees with the principles of green analytical chemistry since the procedure reduced the reagents consumed and wastes generated. It represents a promising tool for acute exposure assessment to BTX since urine tests demonstrated its applicability.

Concentrations and temporal trends in pesticide biomarkers in urine of Swedish adolescents, 2000-2017

Agricultural pesticides are extensively used for weed- and pest control, resulting in residues of these compounds in food. The general population is mainly exposed through dietary intake. Exposure to certain pesticides has been associated with adverse human health outcomes. Our aim was to assess urinary concentrations and temporal trends in the biomarkers of commonly used pesticides. Samples were collected from adolescents (n = 1060) in Scania, Sweden, from 2000 to 2017. Concentrations of 14 pesticide biomarkers were analyzed in urine using LC-MS/MS. Temporal trends in biomarker concentrations (ln-transformed) were evaluated using linear regression. Biomarkers of pyrethroids (3-PBA and DCCA), chlorpyrifos (TCPy), chlormequat (CCC), thiabendazole (OH-TBZ), and mancozeb (ETU) were detected in >90% of the population all sampling years. The biomarkers CCC and TCPy had the highest median concentrations (>0.8 µg/L), whereas the biomarkers of cyfluthrin (4F-3-PBA) and two pyrethroids (CFCA) had the lowest median concentrations (<0.02 µg/L). Increasing temporal trends were found for the biomarkers 3-PBA (3.7%/year), TCPy (1.7%/year) and biomarkers of pyrimethanil (11.9%/year) and tebuconazole (12.2%/year). Decreasing trends were found for CCC (-5.5%/year), OH-TBZ (-5.5%/year), and ETU (-3.9%/year). Our results suggest that Swedish adolescents are commonly exposed to pesticides in low concentrations (median concentrations <3.88 µg/L).

A dual-emitting Tb(iii)&Yb(iii)-functionalized coordination polymer: a "turn-on" sensor for N-methylformamide in urine and a "turn-off" sensor for methylglyoxal in serum

Fluorescent materials with lanthanide cations encapsulated in MOFs are currently used in numerous applications, especially in biosensors. Therefore, herein, two novel composites were designed and developed based on a Tb(iii)&Yb(iii)-functionalized Cu(ii)-coordination polymer, possessing higher thermal and water stability and fascinating fluorescence properties. The first bimetallic composite Tb@Cu-Hcbpp demonstrated broad ligand-centered emission and weak typical Tb³⁺ ion emission; moreover, it was used as an excellent ratiometric fluorescent sensor for the metabolic product NMF of DMF in the human body (LOD = 0.02 μM). In addition, the Yb³⁺ ions were doped into Tb@Cu-Hcbpp to improve the fluorescence performance of the green Tb³⁺ ion emission. Among the series of Tb_1-xYb_x@Cu-Hcbpp samples (x = 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35 and 0.40), Tb_0.85Yb_0.15@Cu-Hcbpp showed maximum enhanced fluorescence intensity (almost 9.6 times that of the pure terbium system), but exhibited high fluorescence quenching efficiency for methylglyoxal (MGO), which could be used for the sensitive detection of MGO (LOD = 0.25 μM). Furthermore, the developed biosensors were successfully applied for the detection of NMF and MGO in urine and serum samples, and satisfactory results were obtained, showing good potential of these biosensors in practical applications such as in disease diagnosis and biochemical research.

Feasibility of Biological Effective Monitoring of Chrome Electroplaters to Chromium through Analysis of Serum Malondialdehyde

BACKGROUND

Great concern about occupational exposure to chromium (Cr [VI]) has been reported due to escalated risk of lung cancer in exposed workers. Consequences of occupational exposure to Cr (VI) have been reported as oxidative stress and lung tissue damage.

OBJECTIVE

To investigate the feasibility of biological effect monitoring of chrome electroplaters through analysis of serum malondialdehyde (MDA).

METHODS

90 workers directly involved in chrome electroplating---categorized into three equal groups based on their job as near bath workers, degreaser, and washers---and 30 workers without exposure to Cr (VI), served as the control group, were studied. Personal samples were collected and analyzed according to NIOSH method 7600. Serum MDA level was measured by HPLC using a UV detector.

RESULTS

Median Cr (VI) exposure level was 0.38 mg/m(3) in near bath workers, 0.20 mg/m(3) in degreasers, and 0.05 mg/m(3) in washers. The median serum MDA level of three exposed groups (2.76 μmol/L) was significantly (p<0.001) higher than that in the control group (2.00 μmol/L). There was a positive correlation between electroplaters' level of exposure to Cr (VI) and their serum MDA level (Spearman's ρ 0.806, p<0.001).

CONCLUSION

Serum MDA level is a good biomarker for the level of occupational exposure to Cr (VI) in electroplaters.

Exploring a new method for the biological monitoring of plastic workers exposed to the vinyl chloride monomer

Vinyl chloride monomer (VCM) is widely used in the production of polyvinyl chloride (PVC) plastics. VCM is recognized as a confirmed human and animal carcinogenic compound. Recent studies have reported poor health of plastic workers, even having exposure at concentrations below the permissible limit to VCM. There has not been any study regarding exposed workers to VCM in Iran. Similarly, no information exists as to the biological monitoring of such workers. The main purpose of this study was to conduct a thorough occupational and biological monitoring of Iranian plastic workers exposed to VCM.A total of 100 workers from two plastic manufacturing plants (A and B) in Tehran along with 25 unexposed workers as controls were studied. The personal monitoring of all nonsmoking workers exposed to VCM at two plastic manufacturing plants (A and B) was performed in the morning shift (8 a.m. to 4 p.m.) according to the National Institute For Occupational Safety And Health method no. 1007.Biological monitoring of workers was carried out through collection of exhaled breath of all exposed and control workers in Tedlar bags and with a subsequent analysis using gas chromatography-flame ionization detector.Not only the mean occupational exposure of workers to VCM at plant A was higher than the respective threshold limit value but also the statistical significance was higher than workers at plant B. Similarly, VCM concentration in exhaled breath of workers at plant A was also statistically significantly higher than at plant B. Correlation of occupational exposure of all workers to vinyl chloride with its concentration in exhaled breath was statistically significant.This is the first study on biological monitoring for exposed plastic workers to VCM using exhaled breath. On the basis of the results in this study, a novel method of biological monitoring of plastic workers was proposed.

Policy recommendations and cost implications for a more sustainable framework for European human biomonitoring surveys

The potential of Human Biomonitoring (HBM) in exposure characterisation and risk assessment is well established in the scientific HBM community and regulatory arena by many publications. The European Environment and Health Strategy as well as the Environment and Health Action Plan 2004-2010 of the European Commission recognised the value of HBM and the relevance and importance of coordination of HBM programmes in Europe. Based on existing and planned HBM projects and programmes of work and capabilities in Europe the Seventh Framework Programme (FP 7) funded COPHES (COnsortium to Perform Human Biomonitoring on a European Scale) to advance and improve comparability of HBM data across Europe. The pilot study protocol was tested in 17 European countries in the DEMOCOPHES feasibility study (DEMOnstration of a study to COordinate and Perform Human biomonitoring on a European Scale) cofunded (50%) under the LIFE+ programme of the European Commission. The potential of HBM in supporting and evaluating policy making (including e.g. REACH) and in awareness raising on environmental health, should significantly advance the process towards a fully operational, continuous, sustainable and scientifically based EU HBM programme. From a number of stakeholder activities during the past 10 years and the national engagement, a framework for sustainable HBM structure in Europe is recommended involving national institutions within environment, health and food as well as European institutions such as ECHA, EEA, and EFSA. An economic frame with shared cost implications for national and European institutions is suggested benefitting from the capacity building set up by COPHES/DEMOCOPHES.

Factors and Trends Affecting the Identification of a Reliable Biomarker for Diesel Exhaust Exposure

The monitoring of human exposures to diesel exhaust continues to be a vexing problem for specialists seeking information on the potential health effects of this ubiquitous combustion product. Exposure biomarkers have yielded a potential solution to this problem by providing a direct measure of an individual's contact with key components in the exhaust stream. Spurred by the advent of new, highly sensitive, analytical methods capable of detecting substances at very low levels, there have been numerous attempts at identifying a stable and specific biomarker. Despite these new techniques, there is currently no foolproof method for unambiguously separating diesel exhaust exposures from those arising from other combustion sources. Diesel exhaust is a highly complex mixture of solid, liquid, and gaseous components whose exact composition can be affected by many variables, including engine technology, fuel composition, operating conditions, and photochemical aging. These factors together with those related to exposure methodology, epidemiological necessity, and regulatory reform can have a decided impact on the success or failure of future research aimed at identifying a suitable biomarker of exposure. The objective of this review is to examine existing information on exposure biomarkers for diesel exhaust and to identify those factors and trends that have had an impact on the successful identification of metrics for both occupational and community settings. The information will provide interested parties with a template for more thoroughly understanding those factors affecting diesel exhaust emissions and for identifying those substances and research approaches holding the greatest promise for future success.

The use of PowerPrep and HRGC/HRMS for biological monitoring of exposure to PCDD, PCDF and dl-PCB in Poland

PURPOSE

The aim of this study was to design the optimized laboratory protocol as a tool for human biomonitoring of selected Persistent Organic Pollutants (POPs) in Poland. In this study, we present the method developed for the determination of 29 congeners of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs), as well as individual results of the measurements in 40 human breast milk samples collected in central Poland in 2008-2010.

METHODS

The protocol of sample preparation and quantitative analysis of PCDD/Fs and dl-PCBs was optimized for the isotopic dilution method with high resolution gas chromatography/high resolution mass spectrometry HRGC/HRMS. Fat content in the extracts was determined gravimetrically. The results were corrected by fat content in the samples.

RESULTS

The average sum of PCDD/F and dl-PCBs in the human milk samples from the urban area was 7.429 WHO-TEQpg/g fat (with the range 0.431-14.27), and in the rural area it was 6.448pg WHO-TEQ/g fat (0.539-12.61).

CONCLUSIONS

The results obtained in this study indicate that the mothers were exposed uniformly to PCDD/Fs and PCBs regardless of location. The significant difference of p<0.1 between the milk samples from the urban and rural mothers in 2,3,7,8-TCDD; 1,2,37,8,9-HxCDD and 2,3,4,6,7-HxCDF were observed. For the other 14 PCDD/F and 12 dl-PCB congeners, the observed differences were not significant. The total WHO-TEQ values are lower in comparison with the average results in Europe from the fourth round of a WHO-coordinated study.

Biological monitoring versus air monitoring strategies in assessing environmental-occupational exposure

Assessment of environmental and occupational exposure to chemicals can be performed with environmental monitoring (EM) and biological monitoring (BM). Biological monitoring was for a long time considered as a method complementary to environmental monitoring. At present this attitude is changing and in certain areas biological monitoring is applied as the method of choice for exposure and health-risk assessment. This paper examines advantages and disadvantages of those two approaches. In occupational settings environmental monitoring of exposure to VOCs seems to be superior to biological monitoring (possibility of simultaneous determination of components of mixtures, simple interpretation, possibility of evaluation of short-term exposure to local irritants). In the case of this group of compounds BM can be useful in selected cases such as evaluation of dermal absorption or efficiency of protective measures. In the case of metals both forms of monitoring can be used depending on the available methods for interpretation of results. BM of exposure may be considered as superior for evaluating the effects of exposure to lead, cadmium and mercury. However, quantitative evaluation of cancer risk after exposure to arsenic or chromium is possible only on the basis of determination in the air and the use of unit risk values. Both environmental and biological monitoring are useful for evaluation of occupational and environmental exposure to polycyclic aromatic hydrocarbons (PAHs). In certain areas such as evaluation of exposure to external tobacco smoking, cytostatic drugs, and pesticides, biological monitoring is the method of choice used for individual exposure assessment or tracing the trends of environmental exposure.

Bioelements and mineral matter in human livers from the highly industrialized region of the Upper Silesia Coal Basin (Poland)

Contents of mineral substance, silica, and a range of bioelements and toxic elements (Mg, Na, K, Ca, Ba, Zn, Cr, P Al, Cd, Mn Cu, Ni, Pb, Sr, Fe) in 38 livers of donors from the Upper Silesia Coal Basin (southern Poland) are presented. Elements were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES) with the exception of silica that was estimated colorimetrically. Concentrations, concentration variability, and correlations between selected liver components determined for the total population are related to donor age, gender, and lesion occurrence. Correlations between particular elements were found using correlation coefficient values and the Fisher transformation. Mineral substance in the livers lies in the range 0.40-5.03 wt%. With increasing donor age, mineral-matter content decreases to a minimum for the 40-60 years of age range. Microbioelement contents show a similar tendency, while microbioelements and toxic elements reach maximum contents in donors aged 60-80 years. All elements show content decreases in livers from the oldest group (>80 years). Silica contents increase with age. Variability of element contents is lowest in the older subpopulations. Livers with lesions show lower element contents and variability. The results are compared to literature data for regions of Poland assumed to be of low pollution and to data from comparable regions in Japan and Hungary. Up to our knowledge, this paper is the first work describing the total contents, as distinct from contents of selected elements, of mineral substance in human livers.

External quality assessment scheme for biological monitoring of occupational exposure to toxic chemicals

Objectives

In this study, we summarized the External Quality Assessment Scheme (EQAS) for the biological monitoring of occupational exposure to toxic chemicals which started in 1995 and continued until a 31^st round robin in the spring of 2010. The program was performed twice per year until 2009, and this was changed to once a year since 2010. The objective of the program is to ensure the reliability of the data related to biological monitoring from analytical laboratories.

Methods

One hundred and eighteen laboratories participated in the 31^st round robin. The program offers 5 items for inorganic analysis: lead in blood, cadmium in blood, manganese in blood, cadmium in urine, and mercury in urine. It also offers 10 items for organic analysis, including hippuric acid, methylhippuric acid, mandelic acid, phenylglyoxylic acid, N-methylformamide, N-methylacetamide, trichloroacetic acid, total trichloro-compounds, trans,trans-muconic acid, and 2,5-hexanedione in urine. Target values were determined by statistical analysis using consensus values. All the data, such as chromatograms and calibration curves, were reviewed by the committee.

Results

The proficiency rate was below 70% prior to the first round robin and improved to over 90% for common items, such as PbB and HA, while those for other items still remained in the range of 60-90% and need to be improved up to 90%.

Conclusion

The EQAS has taken a primary role in improving the reliability of analytical data. A total quality assurance scheme is suggested, including the validation of technical documentation for the whole analytical procedure.

The use of biomarkers in occupational health research, practice, and policy

Biomarkers are potentially useful tools for occupational health and safety research, practice, and policy. However, the full realization of this potential has not been achieved. In this paper, the progress made in these three usage areas is reviewed to identify what efforts can be taken to realize the full promise of biomarkers. Biomarker uses are described by a diverse taxonomy that builds on the categories of exposure, effect and susceptibility, and the continuum between exposure and disease prognosis. The most significant uses of biomarkers in occupational health have been in biological monitoring of workers. Other important uses have been in enhancing research and assessing mechanisms of action of occupational toxicants at low exposures. Seven critical areas will influence the extent to which the potential of biomarkers in occupational health and safety is realized. These include: (1) adequate investment in validation; (2) obtaining international agreement on exposure guidelines; (3) exploring the utility of biomarkers in regulation; (4) applying biomarkers to critical occupational safety and health questions; (5) developing the exposome; (6) utilizing biomarkers to address emerging occupational health issues; and (7) continuing to address the ethical and social justice issues related to biomarkers. Overall, if biomarkers are to make a major contribution to occupational health and safety then a more holistic approach to bringing them from the laboratory to practice will be needed.

Occupational exposure to antineoplastic drugs in four Italian health care settings

Exposure assessment of health care workers to antineoplastic drugs (ADs) is still an open issue since new, critical, and emerging factors may put pharmacists who prepare hazardous drugs or nurses who administer anti cancer agents to an increased risk of developing adverse health effects. Overall, eight pharmacies and nine patient areas have been surveyed in this study. Wipe and pad samples were experienced during the surveillance program in four Italian health care settings. Urine samples were collected from workers handling ADs. Cyclophosphamide (CP), ifosfamide (IF), and gemcitabine (GEM) were detected in all the work environments by using a LC-MS/MS method-based capable of analysing all the three drugs simultaneously. In total, 54% of wipe samples were positive for at least one drug and 19% of pad samples were shown to be contaminated by cyclophosphamide. Pharmacies were generally more contaminated than patient areas with the exception of one site where a nurse had an acute exposure during the cleaning-up of an hazardous drug solution spill. In total, 22 urine samples collected from pharmacists and 78 urine samples from nurses had no detectable concentrations of any antineoplastic drugs. Despite the adherence to the recommended safety practices residue contamination on surfaces and floors has continued to be assessed in all the investigated sites.

The role of exposure reconstruction in occupational human health risk assessment: current methods and a recommended framework

Exposure reconstruction for substances of interest to human health is a process that has been used, with various levels of sophistication, as far back as the 1930s. The importance of robust and high-quality exposure reconstruction has been recognized by many researchers. It has been noted that misclassification of reconstructed exposures is relatively common and can result in potentially significant effects on the conclusions of a human health risk assessment or epidemiology study. In this analysis, a review of the key exposure reconstruction approaches described in over 400 papers in the peer-reviewed literature is presented. These approaches have been critically evaluated and classified according to quantitative, semiquantitative, and qualitative approaches. Our analysis indicates that much can still be done to improve the overall quality and consistency of exposure reconstructions and that a systematic framework would help to standardize the exposure reconstruction process in the future. The seven recommended steps in the exposure reconstruction process include identifying the goals of the reconstruction, organizing and ranking the available data, identifying key data gaps, selecting the best information sources and methodology for the reconstruction, incorporating probabilistic methods into the reconstruction, conducting an uncertainty analysis, and validating the results of the reconstruction. Influential emerging techniques, such as Bayesian data analysis, are highlighted. Important issues that will likely influence the conduct of exposure reconstruction into the future include improving statistical analysis methods, addressing the issue of chemical mixtures, evaluating aggregate exposures, and ensuring transparency with respect to variability and uncertainty in the reconstruction effort.

DNA damage in workers occupationally exposed to pesticide mixtures

Pesticides are used in agriculture to protect crops but represent at the same time a potential risk to farmers and environment. The aim of this work is the evaluation of 54 subjects occupationally exposed to pesticides and 30 subjects as a control group using the quantification of DNA damage level by means of the alkaline Comet assay and the evaluation of repair processes. Damage index Comet assay (DICA) and damage index repair assay (DIRA) were studied in 27 pesticide applicator workers, 27 non-pesticide applicators and controls. Our results show that both exposed groups revealed significant increase in DICA when compared with controls (P < 0.0001), as well as in DIRA (P < 0.0001). However, the spraying group exhibited a marginally significant difference in DICA (P = 0.05) when years of exposure are considered and a significant difference (P < 0.05) when the personal protective equipment used by individuals was taken as a comparison factor. The influence of confounding factors on the genotoxic effects of occupational exposure to pesticides was investigated and no significant differences were observed considering age, gender, smoking and alcohol consumption in relation to DICA and DIRA. Since DNA damage is an important step in events leading from carcinogen exposure to cancer disease, our study highlights the potential health risk associated with agrochemical exposure in developing countries with vast cultivated areas, such as Argentina.

Simultaneous determination of cyclophosphamide, ifosfamide, doxorubicin, epirubicin and daunorubicin in human urine using high-performance liquid chromatography/electrospray ionization tandem mass spectrometry: bioanalytical method validation

A reversed-phase high-performance liquid chromatography (rp-HPLC) system interfaced with an electrospray ionization (ESI) source coupled to tandem mass spectrometry (MS/MS) was developed and validated for the determination of cyclophosphamide (CP), ifosfamide (IF), daunorubicin (DNR), doxorubicin (DXR), and epirubicin (EPI) in human urine. The analysis of samples containing multiple analytes with a dissimilar range of polarities was carried out using a conventional reversed-phase chromatographic BDS Hypersil C8 column. The analytical run was 15 min. The triple quadrupole mass spectrometer was operated in positive ion mode and multiple reaction monitoring (MRM) was used for drug quantification. The method was validated over a concentration range of 0.2 to 4.0 microg.L(-1) for CP, IF, DXR, EPI and 0.15-2.0 microg.L(-1) for DNR in human urine. The lower limit of quantification (LLOQ) was 0.2 microg.L(-1) for CP, IF, EPI and was set at 0.3 and 0.15 microg.L(-1) for DXR and DNR, respectively. The relative standard deviations (RSD%) were <11.2% for inter- and intra-day precisions. The overall accuracy was also within 114.7% for all analytes at the concentrations of the quality control samples. The potential of ionization suppression resulting from the endogenous biological material on the rp-HPLC/MS/MS method was evaluated and measured. The feasibility of the proposed HPLC/ESI-MS/MS procedure was demonstrated by analyzing urine samples from pharmacy technicians and nurses working in hospitals or personnel employed in drug-manufacturing plants.

Long-term biomonitoring of polychlorinated biphenyls and organochlorine pesticides in human milk from mothers living in northern Germany

Polychlorinated biphenyls (PCBs) and organochlorine pesticides are persistent organic pollutants that have a widespread distribution in the environment. Human biomonitoring is a suitable tool to assess the burden of humans with these substances. Over a time span of 8 years, a free analysis of their milk was offered to lactating mothers residing in the state of Lower Saxony, Germany. The human milk was analyzed for a number of organic chemicals including polychlorinated biphenyls (PCBs), 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), hexachlorobenzene (HCB) and beta-hexachlorocyclohexane (beta-HCH). Factors that may influence these levels were investigated using a questionnaire. In total, 4314 samples were collected in the years 1999-2006 and analyzed for their content of these persistent organic pollutants (POPs). A clear downward trend of median total PCB, DDT, beta-HCH and HCB values in all participants and also in different selected subgroups could be observed. The median values of calculated total PCB in the year 2006 including all participants was 0.1825mg/kg lipid, that of DDT 0.0815mg/kg lipid, beta-HCH 0.0116mg/kg lipid and of HCB 0.0229mg/kg lipid. There were reductions between 40.9% and 47.1% compared to the year 1999. Among other influencing factors, median concentrations of total PCB, DDT, beta-HCH and HCB showed a clear rise with increasing age of mothers whereas an increasing number of breastfed infants per mother led to a decrease. The proportions of other measured substances exceeding limits of quantification were as follows: dieldrin 68.6%, alpha-HCH 1.3%, gamma-HCH 60.1%, heptachlor epoxide 41.5%, musk xylene 15.6%, musk ambrette 0.4%. We conclude that the known declining trend of important xenobiotic substances in human milk of German mothers has continued.

Electrochemical sensors for the detection of lead and other toxic heavy metals: the next generation of personal exposure biomonitors

To support the development and implementation of biological monitoring programs, we need quantitative technologies for measuring xenobiotic exposure. Microanalytical based sensors that work with complex biomatrices such as blood, urine, or saliva are being developed and validated and will improve our ability to make definitive associations between chemical exposures and disease. Among toxic metals, lead continues to be one of the most problematic. Despite considerable efforts to identify and eliminate Pb exposure sources, this metal remains a significant health concern, particularly for young children. Ongoing research focuses on the development of portable metal analyzers that have many advantages over current available technologies, thus potentially representing the next generation of toxic metal analyzers. In this article, we highlight the development and validation of two classes of metal analyzers for the voltammetric detection of Pb, including: a) an analyzer based on flow injection analysis and anodic stripping voltammetry at a mercury-film electrode, and b) Hg-free metal analyzers employing adsorptive stripping voltammetry and novel nanostructure materials that include the self-assembled monolayers on mesoporous supports and carbon nanotubes. These sensors have been optimized to detect Pb in urine, blood, and saliva as accurately as the state-of-the-art inductively coupled plasma-mass spectrometry with high reproducibility, and sensitivity allows. These improved and portable analytical sensor platforms will facilitate our ability to conduct biological monitoring programs to understand the relationship between chemical exposure assessment and disease outcomes.

Exposure to mercury vapors in dental workers in Poland

OBJECTIVES

The study aimed at assessing the effect of low-level exposure to mercury (Hg) vapor from amalgam fillings among dental surgery staff in the city of Łódź, Poland.

MATERIALS AND METHODS

The study group was composed of 51 workers (mean age, 39.25+/-11.05 years) employed in dental surgeries; the control group comprised 16 white-collar workers (mean age, 40.05+/-10.57 years) of the Nofer Institute of Occupational Medicine, Łódź, who had no or a few amalgam dental fillings. Total urine mercury (Hg-U) concentration was determined with cold vapor atomic absorption spectrometry (CV-AAS) based on tin (II) chloride mercury reduction after overnight digestion of urine sample with potassium permanganate in sulfuric acid solution. The reliability of mercury determinations was verified by measuring Hg concentration in the reference material and via participation in the external quality assessment scheme.

RESULTS

No statistically significant differences were found in geometric mean of urine Hg concentrations between the study and control groups (GM+/-SD, 0.44+/-0.440 and 0.5+/-0.270 mug/g creatinine, respectively, p = 0.242). Among different factors affecting Hg exposure in dental surgeries, only the duration of dental practice showed a statistically significant influence on total Hg-U (r = 0.3000; p = 0.024). Having divided the subjects into two groups, with and without amalgam fillings, we noted a statistically significant difference in urine Hg concentrations (0.60 +/- 0.720, n = 38; 0.36 +/- 0.650, n = 29; p = 0.004) between these two groups.

CONCLUSIONS

The results of biological monitoring of dental surgery staff did not reveal current exposure to Hg vapors from amalgam fillings. However, these dental workers may have been the subject to such an exposure in the past. The only statistically significant correlation was that between total Hg-U concentrations and the duration of dental practice.

Human biomonitoring activities – Programmes by industry

Biomonitoring of exposure to chemicals has been practiced for over half a century on a regular basis. During the last decade, however, the focus changed from occupational to environmental settings, requiring a different interpretative framework. Under the auspices of the European Centre for Ecology and Ecotoxicology (ECETOC) a framework was developed that allows to assess the relevance of any biomonitoring result to be interpreted reliably. If biomonitoring data is to be used for the evaluation of health risks of a substance, information is required on the analytical integrity of the data, the toxicokinetics of this substance, and its health effects in relation to (low) exposures. In addition, a weight-of-evidence needs to be used. The framework also identifies a number of data-gaps, several of which are addressed through the Long-range Research Initiative (LRI), an initiative of the global chemical industries (EU, USA, and Japan), which aims to help answering important questions in the application of biomonitoring data in human health risk assessment.

Exposure assessment at the workplace: implications of biological variability

Biological monitoring (BM) and biomarkers are widely applied in occupational toxicology. BM is mainly aimed at (i) defining the existence of an occupational exposure; (ii) quantifying the level of internal dose; (iii) verifying that exposure limits (BEI((R)), BAT, BLV) are respected. As compared to ambient monitoring, BM is more expensive and complex. Several biomarkers are available for the same chemical and the meaning of the marker may depend on the sampling time. Therefore, practical issues, including cost and selection of an adequate sampling strategy, should be dealt with when planning a BM program for specific purposes. In addition, several biological and analytical sources of variability may influence biomarker levels, thus making the interpretation of BM data a difficult task. However, we should recognize that the main aim of BM is not to reduce, but to explain biological variance. The decreasing trend in occupational exposure levels highlighted the specificity problems of traditional biomarkers of exposure and prompted the research to the development of new biomarkers, e.g. unchanged volatile compounds in urine, minor metabolites, DNA and protein adducts. Depending on the scope and context (research or routine) different requirements of biomarkers can be envisaged in terms of validation and acceptable variability.

Volatile organohalogen compounds in human urine: the effect of environmental exposure

The paper presents the results of determination of volatile organohalogen compounds (VOX) in urine samples from subjects exposed to these compounds in their workplaces and through consumption of chlorinated tap water. The analytes were isolated and preconcentrated from the complex urine samples using the thin layer headspace (TLHS) technique with autogenous generation of the liquid sorbent. Final gas chromatographic determination was carried out by direct aqueous injection with electron capture detection (DAI-ECD). The results indicate that only a small fraction (<4%) of the VOX input is excreted with urine in the non-metabolized form. A positive correlation was found between the occupational levels of VOX in the workplace and their levels in urine. VOX levels in the urine of subjects not exposed to them in the workplace were significantly lower. Their presence in the organisms was most probably related to consumption of tap water produced by chlorination of surface waters.

Toxic serum factor long after single exposure to organophosphate; a new approach for biomonitoring

One of the major limitations of current methods of biological detection of exposure to hazardous environmental agents is their inability to detect long-term exposures. In the current study we examined the potential of a new bioassay based on the hypothesis that serum of exposed individuals contains a toxic factor(s) produced by an affected cell/tissue. The procedure included exposure of neuronal PC12 cell cultures to sera of rats treated once with the organophosphate chlorpyrifos. Samples taken 4 weeks after chlorpyrifos exposure reduced nerve growth factor (NGF)-induced neurite outgrowth by 40%. This effect lasted 6 weeks after treatment, whereas motor activity and cholinesterase activity returned to normal levels within 1 week. These results demonstrate the potential of the proposed method to detect environmental exposures long after they have occurred.