Monitoring genotoxicity among gasoline station attendants and traffic enforcers in the City of Manila using the micronucleus assay with exfoliated epithelial cells

Some types of occupations involve high levels of exposure to potentially genotoxic gaseous and particulate substances from internal combustion engines used in motor vehicles. These occupational exposures may contribute to the development of many illnesses, usually through chromosomal change mechanisms that include strand breakage, deletions, sister chromatid exchange and non-disjunction. To determine the effect of occupational exposure in gasoline station attendants and traffic enforcers, the micronucleus test was used. Exfoliated oral mucosa cells from 18 gasoline station attendants, 18 traffic enforcers and 18 control subjects in the City of Manila were examined for micronucleated cell (MNC) frequency. Analysis of buccal cells showed that MNC frequencies in exposed individuals were significantly greater than in control subjects (p < or = 0.05). However, between gasoline station attendants and traffic enforcers, MNC frequencies of the two exposed groups exhibited no significant difference. No relation was also found between MNC frequency and any of the factors such as age, smoking habits, alcohol habits and working period. This was further confirmed in the multiple regression analysis which showed that only occupational exposure was a good predictor of MNC frequency. The results of this study suggest that gasoline station attendants and traffic enforcers, compared to the control individuals, are at a greater risk of chromosomal damage. For the assessment of chromosomal damage, the study, development, and standardization of tests are recommended for public institutions concerned with matters regarding environmental quality and community health.     

Ambient site, home outdoor and home indoor particulate concentrations as proxies of personal exposures

Despite strong longitudinal associations between particle personal exposures and ambient concentrations, previous studies have found considerable inter-personal variability in these associations. Factors contributing to this inter-personal variability are important to identify in order to improve our ability to assess particulate exposures for individuals. This paper examines whether ambient, home outdoor and home indoor particle concentrations can be used as proxies of corresponding personal exposures. We explore the strength of the associations between personal, home indoor, home outdoor and central outdoor monitoring site ("ambient site") concentrations of sulfate, fine particle mass (PM(2.5)) and elemental carbon (EC) by season and subject for 25 individuals living in the Boston, MA, USA area. Ambient sulfate concentrations accounted for approximately 70 to 80% of the variability in personal and indoor sulfate levels. Correlations between ambient and personal sulfate, however, varied by subject (0.1-1.0), with associations between personal and outdoor sulfate concentrations generally mirroring personal-ambient associations (median subject-specific correlations of 0.8 to 0.9). Ambient sulfate concentrations are good indicators of personal exposures for individuals living in the Boston area, even though their levels may differ from actual personal exposures. The strong associations for sulfate indicate that ambient concentrations and housing characteristics are the driving factors determining personal sulfate exposures. Ambient PM(2.5) and EC concentrations were more weakly associated with corresponding personal and indoor levels, as compared to sulfate. For EC and PM(2.5), local traffic, indoor sources and/or personal activities can significantly weaken associations with ambient concentrations. Infiltration was shown to impact the ability of ambient concentrations to reflect exposures with higher exposures to particles from ambient sources during summer. In contrast in the winter, lower infiltration can result in a greater contribution of indoor sources to PM(2.5) and EC exposures. Placing EC monitors closer to participants' homes may reduce exposure error in epidemiological studies of traffic-related particles, but this reduction in exposure error may be greater in winter than summer. It should be noted that approximately 20% of the EC data were below the field limit of detection, making it difficult to determine if the weaker associations with the central site for EC were merely a result of methodological limitations.     

In-vehicle Measurement of Ultrafine Particles on Compressed Natural Gas, Conventional Diesel, and Oxidation-catalyst Diesel Heavy-duty Transit Buses

Many metropolitan transit authorities are considering upgrading transit bus fleets to decrease ambient criteria pollutant levels. Advancements in engine and fuel technology have lead to a generation of lower-emission buses in a variety of fuel types. Dynamometer tests show substantial reductions in particulate mass emissions for younger buses (<10 years) over older models, but particle number reduction has not been verified in the research. Recent studies suggest that particle number is a more important factor than particle mass in determining health effects. In-vehicle particle number concentration measurements on conventional diesel, oxidation-catalyst diesel and compressed natural gas transit buses are compared to estimate relative in-vehicle particulate exposures. Two primary consistencies are observed from the data: the CNG buses have average particle count concentrations near the average concentrations for the oxidation-catalyst diesel buses, and the conventional diesel buses have average particle count concentrations approximately three to four times greater than the CNG buses. Particle number concentrations are also noticeably affected by bus idling behavior and ventilation options, such as, window position and air conditioning.     

Is benzene exposure from gasoline carcinogenic?

This article questions the basis for benzene as the carcinogenic surrogate in deriving health risk-based 'clean-up levels' for gasoline-impacted soil and groundwater at leaking underground storage tank properties. The epidemiological evidence suggests that acute myelogenous leukemia (AML) associated with chronic occupational benzene exposure can be best described by sigmoid dose-response relationships. A review of the molecular toxicology and kinetics of benzene points to the existence of threshold mechanisms in the induction of leukemia. The toxicological and epidemiological literature on chronic exposure to unleaded gasoline indicates that the benzene exposures required to induce a measurable carcinogenic response are substantially greater than exposures likely to be encountered from exposure to gasoline at contaminated properties. Thus, assuming that theoretical cancer risks associated with exposure to benzene from gasoline reflect actual health risks associated with such environmental exposures to gasoline and using these theoretical cancer risks and cancer potency factors for benzene to dictate soil and groundwater clean up of gasoline are not scientifically defensible.     

Submicrometer elemental carbon as a selective measure of diesel particulate matter in coal mines

A monitoring method for diesel particulate matter was published as Method 5040 by the National Institute for Occupational Safety and Health (NIOSH). Organic and elemental carbon are determined by the method, but elemental carbon (EC) is a better exposure measure. The US Mine Safety and Health Administration (MSHA) proposed use of NIOSH 5040 for compliance determinations in metal and nonmetal mines. MSHA also published a rulemaking for coal mines, but no exposure standard was provided. A standard based on particulate carbon is not considered practical because of coal dust interference. Interference may not be a problem if an appropriate size-selective sampler and EC exposure standard are employed. Submicrometer dust concentrations found in previous surveys of nondieselized, underground coal mines were relatively low. If a large fraction of the submicrometer dust is organic and mineral matter, submicrometer EC concentrations would be much lower than submicrometer mass concentrations. Laboratory and field results reported herein indicate the amount of EC contributed by submicrometer coal dust is minor. In a laboratory test, a submicrometer EC concentration of 31 microg m(-3) was found when sampling a respirable coal dust concentration over three times the US compliance limit (2 mg m(-3)). Laboratory results are consistent with surveys of nondieselized coal mines, where EC results ranged from below the method limit of detection to 18 microg m(-3) when size-selective samplers were used to collect dust fractions having particle diameters below 1.5 microm-submicrometer EC concentrations were approximate 7 microg m(-3). In dieselized mines, submicrometer EC concentrations are much higher.     

Occupational exposure to fluorinated hydrocarbons during refrigeration repair work

This study describes refrigeration repair workers' occupational exposures to halogenated refrigerants, focusing on difluorochloromethane (HCFC 22), tetrafluoroethane (HFC 134a) and a mixture of tri-, tetra- and pentafluoroethane (R404A) in 30 work operations. Unlike earlier reported studies, the present study includes working procedures involving welding in order to measure possible occupational exposure to decomposition products. The measurements included hydrogen fluoride (HF), hydrogen chloride (HCl), phosgene (COCl2) and volatile organic compounds (VOC). The exposures were assessed during work operations on small-scale cooling installations like refrigerators and freezers. The repair workers' occupational exposures to refrigerants were moderate, and the major part of the exposures were associated with specific working procedures lasting for relatively short periods of time (<20 min). During these exposure events the concentrations were occasionally high (up to 42434 mg m(-3)). Although welding operations lasted only for short periods of time, HF was detected in 9 out of 15 samples when HCFC 22, HFC 134a or R404A had been used. Hydrogen chloride was detected in 3 out of 5 samples in air polluted with HCFC 22. Phosgene was not detected. A large number of VOCs in various concentrations were found during welding. Except for the applied refrigerants, halogenated compounds were only found in one sample.     

Overview of particulate exposures in the US trucking industry

As part of a large epidemiologic study of lung cancer, 55,000 subjects, we have conducted a nation-wide survey of particulate exposures in the US trucking industry. The goal is to differentiate the risks from various types of particulate exposures, such as traffic emissions and general air pollution. We hypothesize that exposures defined by job and work site characteristics can be linked with subjects using their personal job histories. This report covers exposures at 36 randomly chosen large truck freight terminals in the US. Measurements were made of PM2.5, elemental carbon (EC), and organic carbon (OC) upwind of the terminal (background) and in work areas, and by personal samples. Significant differences in exposure intensity, microg m(-3), were found for work locations and jobs relative to background levels (GM[GSD]) at terminal sites: PM2.5 9.8[2.34], EC 0.5[3.24], and OC 5.0[1.76]. Using EC as a marker for diesel particles, work locations varied significantly: office 0.3[3.7], dock area 0.7[2.89] and shop area 1.5[3.52]), as did job titles (non-smokers): clerk 0.1[9.98], dock worker 0.8[2.13], and mechanic 2.0[3.82]. Cigarette smoking contributed substantially to personal exposures, approximately doubling PM2.5 and OC, but having less of an effect on EC. Large differences were seen across the terminal sites due to differences in local regional air pollution levels from traffic and other sources. We conclude that it will be possible to estimate current exposures of the cohort using an exposure assignment matrix based on job title, work location, and terminal site. This distribution overlaps substantially with the general public's exposure to these sources.     

Naphthalene and its biomarkers as measures of occupational exposure to polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAH) include compounds with two or more fused benzene rings, many of which are carcinogens. Industrial sources produce hundreds of PAH, notably in the coke- and aluminium-producing industries. Because PAH are distributed at varying levels between gaseous and particulate phases, exposure assessment has been problematic. Here, we recommend that occupational exposures to naphthalene be considered as a potential surrogate for occupational PAH exposure for three reasons. Naphthalene is usually the most abundant PAH in a given workplace; naphthalene is present almost entirely in the gaseous phase and is, therefore, easily measured; and naphthalene offers several useful biomarkers, including the urinary metabolites 1- and 2-hydroxynaphthalene. These biomarkers can be used to evaluate total-body exposure to PAH, in much the same way that 1-hydroxypyrene has been applied. Using data from published sources, we show that log-transformed airborne levels of naphthalene are highly correlated with those of total PAH (minus naphthalene) in several industries (creosote impregnation: Pearson r= 0.815, coke production: r= 0.917, iron foundry: r= 0.854, aluminium production: r= 0.933). Furthermore, the slopes of the log-log regressions are close to one indicating that naphthalene levels are proportional to those of total PAH in those industries. We also demonstrate that log-transformed urinary levels of the hydroxynaphthalenes are highly correlated with those of 1-hydroxypyrene among coke oven workers and controls (r= 0.857 and 0.876), again with slopes of log-log regressions close to one. These results support the conjecture that naphthalene is a useful metric for occupational PAH exposure. Since naphthalene has also been shown to be a respiratory carcinogen in several animal studies, it is also argued that naphthalene exposures should be monitored per se in industries with high levels of PAH.     

Simultaneous measurement of ventilation using tracer gas techniques and VOC concentrations in homes, garages and vehicles

Air exchange rates and interzonal flows are critical ventilation parameters that affect thermal comfort, air migration, and contaminant exposure in buildings and other environments. This paper presents the development of an updated approach to measure these parameters using perfluorocarbon tracer (PFT) gases, the constant injection rate method, and adsorbent-based sampling of PFT concentrations. The design of miniature PFT sources using hexafluorotoluene and octafluorobenzene tracers, and the development and validation of an analytical GC/MS method for these tracers are described. We show that simultaneous deployment of sources and passive samplers, which is logistically advantageous, will not cause significant errors over multiday measurement periods in building, or over shorter periods in rapidly ventilated spaces like vehicle cabins. Measurement of the tracers over periods of hours to a week may be accomplished using active or passive samplers, and low method detection limits (<0.025 microg m(-3)) and high precisions (<10%) are easily achieved. The method obtains the effective air exchange rate (AER), which is relevant to characterizing long-term exposures, especially when ventilation rates are time-varying. In addition to measuring the PFT tracers, concentrations of other volatile organic compounds (VOCs) are simultaneously determined. Pilot tests in three environments (residence, garage, and vehicle cabin) demonstrate the utility of the method. The 4 day effective AER in the house was 0.20 h(-1), the 4 day AER in the attached garage was 0.80 h(-1), and 16% of the ventilation in the house migrated from the garage. The 5 h AER in a vehicle traveling at 100 km h(-1) under a low-to-medium vent condition was 92 h(-1), and this represents the highest speed test found in the literature. The method is attractive in that it simultaneously determines AERs, interzonal flows, and VOC concentrations over long and representative test periods. These measurements are practical, cost-effective, and helpful in indoor air quality and other investigations.     

Assessment of occupational exposure to diesel fumes--parameter optimization of the thermal coulometric measurement method for carbon

'Elemental' carbon (EC) is used as a surrogate to assess occupational exposure to diesel soot. EC thermal analysis needs complete desorption of organic compounds from the soot particles prior to analysis in order to minimize positive interferences and artefacts. The desorption of the organic compounds can be considered as the major step which influences the reliability of the EC determination. A systematic study was carried out to investigate the different parameters of influence such as desorption temperature, desorption duration, heating rate and type of the sample on the desorption efficiency. It was found that temperature and duration are the major parameters of influence on the desorption efficiency. The influence of the sample load can be seen as a measure of the pyrolysis susceptibility of the sample. An optimized temperature program is proposed.     

Concentration gradient patterns of aerosol particles near interstate highways in the Greater Cincinnati airshed

The objective of this study was to determine if there is an exposure gradient in particulate matter concentrations for people living near interstate highways, and to determine how far from the highway the gradient extends. Air samples were collected in a residential area of Greater Cincinnati in the vicinity of two major highways. The measurements were conducted at different distances from the highways by using ultrafine particle counters (measurement range: 0.02-1 microm), optical particle counters (0.3-20 microm), and PM2.5 Harvard Impactors (0.02-2.5 microm). The collected PM2.5 samples were analyzed for mass concentration, for elemental and organic carbon, and for elemental concentrations. The results show that the aerosol concentration gradient was most clearly seen in the particle number concentration measured by the ultrafine particle counters. The concentration of ultrafine particles decreased to half between the sampling points located at 50 m and 150 m downwind from the highway. Additionally, elemental analysis revealed a gradient in sulfur concentrations up to 400 m from the highway in a residential area that does not have major nearby industrial sources. This gradient was qualitatively attributed to the sulfate particle emissions from diesel engine exhausts, and was supported by the concentration data on several key elements indicative of traffic sources (road dust and diesel exhaust). As different particulate components gave different profiles of the diesel exposure gradient, these results indicate that no single element or component of diesel exhaust can be used as a surrogate for diesel exposure, but more comprehensive signature analysis is needed. This characterization is crucial especially when the exposure data are to be used in epidemiological studies.     

Non-invasive measurement of carbon monoxide burden in Guatemalan children and adults following wood-fired temazcal (sauna-bath) use

The use of wood-fired steam baths, or temazcales, is a potentially dangerous source of CO exposure in Guatemalan Highland communities where adults and children use them regularly for bathing, relaxation, and healing purposes. Physical characteristics of children predispose them to absorb CO faster than adults, placing them at greater exposure and health risks. Efforts to quantify temazcal exposures across all age groups, however, have been hampered by the limitations in exposure measurement methods. In this pilot study we measured COHb levels in children and adults following use of the temazcal using three field-based, non-invasive CO measurement methods: CO-oximetry, exhaled breath, and by estimation of COHb using micro-environmental concentrations and time diaries. We then performed a brief comparison of methods. Average CO concentrations measured during temazcal use were 661 ± 503 ppm, approximately 10 times the 15 min WHO guideline. Average COHb levels for all participants ranged from 12-14% (max of 30%, min 2%), depending on the method. COHb levels measured in children were not significantly different from adults despite the fact that they spent 66% less time exposed. COHb measured by CO-oximetry and exhaled breath had good agreement, but precision of the former was affected substantially by random instrument error. The version of the field CO-oximeter device used in this pilot could be useful in screening for acute CO exposure events in children but may lack the precision for monitoring the burden from less extreme, but more day-to-day CO exposures (e.g. indoor solid fuel use). In urban settings, health effects in children and adults have been associated with chronic exposure to ambient CO concentrations much lower than measured in this study. Future research should focus on reducing exposure from temazcales through culturally appropriate modifications to their design and practices, and targeted efforts to educate communities on the health risks they pose and actions they can take to reduce this risk.     

Assessment of diesel particulate matter exposure in the workplace: freight terminals

A large study has been undertaken to assess the exposure to diesel exhaust within diesel trucking terminals. A critical component of this assessment is an analysis of the variation in carbonaceous particulate matter (PM) across trucking terminal locations; consistency in the primary sources can be effectively tracked by analyzing trends in elemental carbon (EC) and organic molecular marker concentrations. Ambient samples were collected at yard, dock and repair shop work stations in 7 terminals in the USA and 1 in Mexico. Concentrations of EC ranged from 0.2 to 12 microg m(-3) among the terminals, which corresponds to the range seen in the concentration of summed hopanes (0.5 to 20.5 ng m(-3)). However, when chemical mass balance (CMB) source apportionment results were presented as percent contribution to organic carbon (OC) concentrations, the contribution of mobile sources to OC are similar among the terminals in different cities. The average mobile source percent contribution to OC was 75.3 +/- 17.1% for truck repair shops, 65.4 +/- 20.4% for the docks and 38.4 +/- 9.5% for the terminal yard samples. A relatively consistent mobile source impact was present at all the terminals only when considering percentage of total OC concentrations, not in terms of absolute concentrations.     

Air pollution exposure monitoring and estimation. Part V. Traffic exposure in adults

In Oslo, traffic has been one of the dominating sources of air pollution in the last decade. In one part of the city where most traffic collects, two tunnels were built. A series of before and after studies was carried out in connection with the tunnels in use. Dispersion models were used as a basis for estimating exposure to nitrogen dioxide and particulate matter in two fractions. Exposure estimates were based on the results of the dispersion model providing estimates of outdoor pollutant concentrations on an hourly basis. The estimates represent concentrations in receptor points and in a square kilometre grid. The estimates were used to assess development of air pollution load in the area, compliance with air quality guidelines, and to provide a basis for quantifying exposure-effect relationships in epidemiological studies. After both tunnels were taken in use, the pollution levels in the study area were lower than when the traffic was on the surface (a drop from 50 to 40 micrograms m-3). Compliance with air quality guidelines and other prescribed values has improved, even if high exposures still exist. The most important residential areas are now much less exposed, while areas around tunnel openings can be in periods exposed to high pollutant concentrations. The daily pattern of exposure shows smaller differences between peak and minimum concentrations than prior to the traffic changes. Exposures at home (in the investigation area) were reduced most, while exposures in other locations than at home showed only a small decrease. Highest hourly exposures are encountered in traffic.     

Bromine and iodine in 1997 UK total diet study samples

Concentrations of bromine and iodine were analysed in samples from the 1997 UK Total Diet Study (TDS) using ICP-MS. The data has been used to estimate dietary exposures of UK consumers to these elements from the typical UK diet. Samples for the 20 TDS food groups were obtained from 20 towns in the UK in 1997 and analysed in 1998/99 for total bromine and total iodine concentrations. These samples were also analysed for 12 other elements. The UK regulatory authority had considered iodine recently, but had not considered bromine before. This survey provides up-to-data baseline data for those two elements. Iodine concentrations are similar to those found in recent surveys. Levels of bromine were consistent with previous data where available. Dietary exposures to bromine and iodine were calculated to see if there were any risks to health from the levels of these elements found in the UK diet. The estimated population average exposure to iodine was 0.25 mg d-1, which is within the range of previous estimates (1995, 0.21 mg d-1; 1991, 0.17 mg d-1; 1985, 0.28 mg d-1). The estimated population average exposure to bromine was 3.6 mg d-1.     

Exposure of garbage truck drivers and maintenance personnel at a waste handling centre to polycyclic aromatic hydrocarbons derived from diesel exhaust

Exposure to diesel exhaust was evaluated in summer and winter by measuring vapour and particle phase polycyclic aromatic hydrocarbons (PAHs). Fifteen PAHs were simultaneously determined from the air samples obtained from truck drivers collecting household waste and maintenance personnel at a waste handling centre. The major compounds analysed from the personal air samples of exposed workers were naphthalene, phenanthrene and fluorene. The total PAH exposure (sum of 15 PAHs) of garbage truck drivers ranged from 71 to 2,660 ng m(-3) and from 68 to 900 ng m-3 in the maintenance work. The exposure of garbage truck drivers to benzo[a]pyrene (B[a]P) ranged from the mean of 0.03 to 0.3 ng m(-3) whereas no B[a]P in control samples or in those collected from maintenance workers was detected. A statistically significant difference in diesel-derived PAH exposure between the garbage truck drivers and the control group in both seasons (in summer p = 0.0022, degrees of freedom (df) 70.5; and in winter p < 0.0001, df = 80.4) was observed. Also, a significant difference in PAH exposure between the garbage truck drivers and the maintenance workers (in summer p < 0.0001, df = 50.1; and in winter p < 0.0001, df = 44.2) was obtained.     

Intercomparison of five PM10 monitoring devices and the implications for exposure measurement in epidemiological research

Five different instruments for the determination of the mass concentration of PM10 in air were compared side-by-side for up to 33 days in an undisturbed indoor environment: a tripod mounted BGI Inc. PQ100 gravimetric sampler with a US EPA certified Graseby Andersen PM10 inlet; an Airmetrics Minivol static gravimetric sampler; a Casella cyclone gravimetric personal sampler; an Institute of Occupational Medicine gravimetric PM10 personal sampler; and two TSI Inc. Dustrak real-time optical scattering personal samplers. For 24 h sampling of ambient PM10 concentrations around 10 microg m(-3), the estimated measurement uncertainty for the two gravimetric personal samplers was larger (approximately +/- 20%) compared with estimated measurement uncertainty for the PQ100/Graseby Andersen sampler (< +/- 5%). Measurement uncertainty for the Dustraks was lower (approximately +/- 15% on average) but calibration of the optical response against a reference PM10 method is essential since the Dustraks systematically over-read PM10 determined gravimetrically by a factor approximately 2.2. However, once calibrated, the Dustrak devices demonstrated excellent functionality in terms of ease of portability and real-time data acquisition. Estimated measurement uncertainty for PM10 concentrations determined with the Minivol were +/- 5%. The Minivol data correlated well with PQ100/Graseby Andersen data (r= 0.97, n = 18) but were, on average, 23% greater. The reason for the systematic discrepancy could not be traced. Intercomparison experiments such as these are essential for assessing measurement error and revealing systematic bias. Application of two Dustraks demonstrated the spatial and temporal variability of exposure to PM10 in different walking and transport microenvironments in the city of Edinburgh, UK. For example, very large exposures to PM10 were identified for the lower deck of a double-decker tour bus compared with the open upper deck of the same vehicle. The variability observed emphasises the need to determine truly personal exposure profiles of PM10 for quantifying exposure response relationships for epidemiological studies.     

Oxidative stress in Nile tilapia (Oreochromis niloticus) and armored catfish (Pterygoplichthys anisitsi) exposed to diesel oil

Considering that diesel oil is one of the most common aquatic contaminants, we compare the oxidative stress between two species of fish with different habitats (Pterygoplichthys anisitsi, benthic and Oreochromis niloticus, nektonic) exposed to diesel oil. Malondialdehyde concentrations (MDA) and the activities of ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase were all analyzed in the fishes' livers and gills after 2 and 7 days of exposure to different concentrations of diesel (0.1 and 0.5 mL/L). In the tilapia, MDA levels and the activities of EROD and GST activity in the liver, as well as MDA levels and the activities of GST and SOD in the gill had statistically significant differences between the treatments and between the times of exposure. For the catfish, the same occurred in the case of MDA, EROD, and SOD in the liver and in CAT and SOD in the gills. There were significant differences in the enzyme activity and lipid peroxidation between the species. Although the activity of most enzymes seemed to be more expressive and responsive to diesel in O. niloticus, diesel oil also caused significant effects on oxidative stress parameters in P. anisitsi, even though this species is benthic and thus has less access to insoluble fractions of diesel oil. Therefore, both species can be used as sentinel organisms in environmental biomonitoring of diesel contamination.     

Quantitative analysis of toxic and essential elements in human hair. Clinical validity of results

Over the last three decades, there has been an increasing awareness of environmental and occupational exposures to toxic or potentially toxic trace elements. The evolution of biological monitoring includes knowledge of kinetics of toxic and/or essential elements and adverse health effects related to their exposure. The debate whether a hair is a valid sample for biomonitoring or not is still attracting the attention of analysts, health care professionals, and environmentalists. Although researchers have found many correlations of essential elements to diseases, metabolic disorders, environmental exposures, and nutritional status, opponents of the concept of hair analysis object that hair samples are unreliable due to the influence of external factors. This review discusses validity of hair as a sample for biomonitoring of essentiall and toxic elements, with emphasis on pre-analytical, analytical, and post-analytical factors influencing results.     

Biological monitoring of wood dust exposure in nasal lavage by high-performance liquid chromatography

A high-performance liquid chromatography (HPLC) method for biomonitoring of occupational wood dust exposure based on nasal lavage as a biomonitoring matrix was developed. Gallic acid (GA) was chosen as the indicator compound for oak dust exposure. From the chromatographic profile of ash dust, four peaks were chosen as indicator compounds. Phenolic indicator compounds were analysed by HPLC. Personal dust samples and corresponding nasal lavage samples were collected from 16 workers exposed to oak dust and six to ash dust. The dust concentrations in the workers' breathing zone varied between 0.7 and 13.8 mg m(-3). The indicators revealed the nature of the wood dust inhaled. For the workers who did not use respirators, the correlation between the dust and corresponding indicator compound in their nasal lavage was significant; r2 = 0.59 (n = 12) for oak dust and r2 = 0.58 (n = 6) for ash dust, respectively. Further, the correlation for oak dust workers who used respirators was r = 0.67 (n = 4). Nasal lavage sampling and HPLC analysis of polyphenol indicator compounds are promising tools for measuring wood dust exposure. Although further validation is necessary, determination of the individual dose may prove invaluable in prospective epidemiological studies.