Yves Morele

Behavior of the GABIE, 3M 3500, PerkinElmer tenax TA, and RADIELLO 145 diffusive samplers exposed over a long time to a low concentration of VOCs

Diffusive sampling is particularly suited to determine time-weighted average volatile organic compound (VOC) concentration in occupational hygiene and environmental air monitoring. The purpose of this study was to measure the sampling rate variation of four different samplers in a special use—the exposure to a low concentration of volatile organic compound (10 to 200 ppb) for a long period (1 to 14 days). PerkinElmer tube-type adsorbent was packed with Tenax TA and RADIELLO cartridge packed with Carbograph 4. Badge-type activated carbon diffusive samplers 3M 3500 and GABIE were exposed to the same controlled atmospheres of benzene as meta-xylene (BTX) during the same exposure times. Performance samplers were observed for variability of uptake rates according to concentration levels, exposure duration, back diffusion, and competition phenomena at the adsorption sites. Particular benzene behavior has been noted for the thermally desorbable tube-type diffusive sampler: the measured sampling rates decrease with time following an exponential profile. With badge-type active charcoal diffusive samplers, the uptake rates were found to be highly stable and unaffected by time exposure. Overall, in the region of a few tens of ppb, for long-time exposure and for the lightest compounds, 3M 3500 and GABIE diffusive samplers seem the most appropriate diffusive sampling technique in terms of performance and facility in use.

Inhalation study on exposure to bitumen fumes. Part 2: Analytical results at two exposure levels

During the hot application of bitumen-containing materials, e.g. in road paving or roofing, fumes are emitted that contain traces of polycyclic aromatic compounds (PACs). Although workers exposure to these fumes is low, it might lead to health problems. For studying DNA adduct formation as a consequence of inhalation of bitumen fumes we developed and validated an inhalation system (a dynamic fume generator plus a nose only inhalation chamber). This paper presents and discusses the analytical results from the different laboratories involved in this study on the fumes sampled in the inhalation chamber during three series of experiments where the animals were exposed to fumes at the 5 mg/m3 and 50 mg/m3 level, coming from bitumen heated at 200 degrees C and, as a positive control, fumes from coal tar, heated to 110 degrees C at the 5 mg/m3 level. The following parameters were controlled: temperatures at different key places in the generator; humidity of the chamber; the bitumen or coal tar flow rate; and Total Particulate Matter (TPM). Analyses were performed for Benzene Soluble Matter (BSM), the EPA polycyclic aromatic hydrocarbon (PAH) mixture and for a number of heteroatom-containing PACs. The data show that the coal tar fumes produced at 110 degrees C were very volatile and that most of the differences in particulate matter found between the laboratories can be attributed to evaporative losses. The bitumen fumes boil 25-50 degrees C higher and contain higher boiling compounds. A comparison is made between the PAC exposure profiles for bitumen experiments aimed at 5 and 50 mg/m3. Although the same molecules are found in both fumes their proportion is dramatically different. This effect is largest with the 2- and 3-ring PACs, the ratio of the concentrations found in the 50 mg/m3 TPM concentration to that in the 5 mg/m3 experiment gradually declines from 5500 for acenaphthene to 500 for pyrene, for the 5-ring PACs this ratio is 20-30. As function of their vapour pressure, the ratios of the concentrations of the hetero PACs follow the same trend as that of the 16 EPA PAHs and are of the same order of magnitude. In conclusion, for the compounds investigated, the equipment delivers a fume atmosphere in a reproducible manner. The 50 mg/m3 bitumen fumes are not representatives of field fumes. The reason for these quantitative differences is unclear and further work would be needed to clarify this. Nevertheless it was felt that these fumes at 50 mg/m3 might be a useful tool for qualitative detection of DNA adducts in an animal exposure study.

Automated column-switching high-performance liquid chromatography method for the determination of 1-hydroxypyrene in human urine

An on-line sample treatment method to determine 1-hydroxypyrene (1-OHP), a metabolite of polycyclic aromatic hydrocarbons (PAHs), in human urine has been developed. The hydrolysed biological fluid was directly injected into the chromatographic system after only centrifugation. A miniature precolumn loop packed with a preparative phase and coupled on-line to a liquid chromatographic (LC) system was used for analyte enrichment. The analytes were non-selectively desorbed with the LC eluent and cleaned by means of a column-switching procedure comprising two purification columns and an analytical column. Pre-treatment and analysis were performed within 2 and 20 min, respectively. Average 1-OHP recovery reached 99% in the 1-25 microg/l range of urine, and the quantitation limit was 20 ng/l for 100 microl of injected sample. A comparison with a more time-consuming off-line method was performed by analysing 120 urine samples of PAH-exposed and expected unexposed workers; the statistical treatment indicated that both methods are in agreement.

Excretion of Urinary 1-Hydroxypyrene in Relation to the Penetration Routes of Polycyclic Aromatic Hydrocarbons

In order to determine the respective contribution of cutaneous and respiratory exposure to urinary PyOH excretion, some experimental follow-ups were carried out during cathode relining in the aluminum industry, leading to qualitative (excretion profiles) and quantitative assessments (excreted PyOH/inhaled pyrene). The procedure was as follows: no exposure on Monday, Wednesday, and Friday; polluting operations on Tuesday and Thursday without or with different protections. For workers with cutaneous protection only, a significant peak of PyOH concentration is observed at the postshift, which is followed by a fast decrease to the background level. For workers with respiratory protection, the maximum is in the shape of a plateau which extends for several hours after the postshift and then decreases slowly. For people with contaminated working clothes, a significant amount of PyOH is excreted on the days with no exposition. The mean ratio of urinary excreted PyOH to inhaled pyrene dose is 15.3% for workers with cutaneous protection and 24.5% for workers with no protection.

Automated column-switching high-performance liquid chromatography for the determination of aflatoxin M1

An extractionless method for determining aflatoxin M1 (AFM1), a major metabolite of aflatoxin B1 (AFB1), in human urine was developed. The biological fluid is injected directly into the chromatographic system after simple dilution and centrifugation. A pre-column, packed with a cation-exchange phase and coupled on-line to a column-switching liquid chromatography (LC) system, is used for sample pre-treatment and concentration. The analytes are non-selectively desorbed with the LC eluent and cleaned by means of a column-switching procedure. Pre-treatment and analysis were performed within 40 min. Average AFMI recovery reached 97% in the 10-100 ng/l range of urine. The detection limit of AFM1 in urine and milk was 2.5 ng/l for 1 ml of injected sample. A comparison with an immunoaffinity column clean-up and LC method was performed. The method was applied to determine AFM1 in the urine of AFB1 gavaged rats, and in the urine of both potentially exposed and supposedly unexposed workers. The method was also extended to milk.

Relationship Between Urinary Levels of 1-Hydroxypyrene and 3-Hydroxybenzo[ a ]pyrene for Workers Exposed to Polycyclic Aromatic Hydrocarbons

Biomonitoring of workers was carried out in three working areas--an artificial target factory, an aluminum plant, and an electrometallurgy plant--to assess exposure to PAHs. All the 48 hr-voided urine samples of the exposed workers were collected and the 3-hydroxybenzo[ a ]pyrene (3-OHB a P) and 1-hydroxypyrene (1-OHPy) analyzed according to procedures using automated column-switching high-performance liquid chromatography. The exposure profiles indicate an important lag between the excretion of the two metabolites: the maximum of 3-OHB a P urinary excretion is observed 10 to 17 hr after the 1-OHPy maximum, with a much closer correlation ( r = 0.81) than that obtained with both metabolites in real time ( r = 0.21). This delayed excretion agrees with data from animal intoxication studies (intravenous administration or inhalation). Mean ratios of 1-OHPy to 3-OHB a P were studied without lag (varying from 2,230 to 15,330) and with a lag of 16 hr (varying from 940 to 8,390).

Measurement of the Nanoparticles Distribution in Flat and Pleated Filters During Clogging

It is currently admitted that for each filtration process using pleated filters, at least three steps can be distinguished: depth and surface filtration, which are common to flat filters, and surface reduction. This step is caused by inefficient filling of the pleat due to the filter geometry. For combustion aerosol, it has been proved that this third step strongly depends on the filtration velocity resulting in an increase of the resistance when air flow decreases. This observation leads one to think that Brownian diffusion, higher for low velocities, could influence the clogging dynamic of a pleated filter. In this article, a protocol derived from the dust cake preparation method published by Schmidt is developed. The aim of this study is to measure the aerosol penetration inside a filter media as well as in a pleat using a scanning electronic microscope and energy dispersive X-ray spectroscopy elementary detection. This method has also been extended to the study of pleated filters to measure the particle distribution inside the pleat. Filters were loaded with nanoparticles in order to evaluate the specificity of the diffusional regime on the clogging of pleated HEPA filters. For pleated filters, two filtration velocities were investigated: 2.5 and 0.2 cm/s. Copyright 2014 American Association for Aerosol Research

Inhalation Study on Exposure to Bitumen Fumes: Formation of DNA Adducts in Various Rat Tissues Following Nose-only Inhalation

Abstract During the hot application of bitumen containing materials, e.g., in hot paving or roofing, fumes are emitted that contain traces of polycyclic aromatic compounds (PACs) including heterocyclic and/or substituted PACs. Previous studies of DNA adduct formation by bitumen and coal-tar fume condensates (BFCs and CTFCs, respectively) indicated that the genotoxic compounds responsible for DNA adduct formation in BFCs and CTFCs were of different nature. Moreover, it was suggested that the major adduct found in the lungs and also in skin and lymphocytes of BFC-treated rats might be usable as a marker of exposure to bitumen fumes.

Aerosols Deposits on the Inner Cassette Walls During Pah Sampling : Underestimation of the Inhaled Fraction and of the Occupational Risk

Abstract The inhalable fraction of PAHs is generally collected using a 37 mm glass-fiber filter for particulate matter, followed by a XAD-2 adsorbent tube for gas phase and semi-volatiles. The glass-fiber filter is placed in a closed polystyrene cassette. Under these conditions, a significant part of the sampled fraction is not collected on the filter, but is retained on the inner walls. In order to determine the amount of PAH deposits, 158 samplings were performed in various situations (especially workplaces). For BaP, the deposits represent on average 29% of the whole sampled fraction (44% during cathode relining in an aluminium plant). For pyrene, they represent on average 33% of the sampled fraction (41% at the restoration of soils contaminated by creosote). As deposits on the inner cassette walls are rarely taken into consideration by the occupational hygienists, this may result in a significant risk underestimation when using atmospheric values. Accordingly, percutaneous penetration may be overestim...

Improving the work environment in the fluorescent lamp recycling sector by optimizing mercury elimination

One of the main issues in the fluorescent lamp recycling sector is the mercury contamination of output fractions and occupational exposure associated with recycling operations. The aim of this study is to carry out effective mercury mass balance determinations and improve mercury recovery by finding the optimal levels for the recycling process parameters. These optimizations will allow upstream mercury emissions to be reduced, which will help to avoid mercury exposure among WEEE recycling workers. Firstly, the distribution of mercury was assessed in new and spent lamps. For new fluorescent tubes, the mean percentage of mercury in the solid phase is lower in new fluorescent tubes (19.5% with 5.5% in glass, 9.7% in end caps and 4.3% in luminescent powder) than in spent tubes (33.3% with 8.3% in glass, 12.9% in end caps and 12.1% in luminescent powder). The parametric study also shows that the finer the grains of glass, the higher the concentration of mercury (1.2 µg Hg/g for glass size particle >1000 µm and 152.0 µg Hg/g for glass size particle <100 µm); the crushing time required for the optimal removal of mercury from spent tubes is 24 h; on average 71% of the mercury is desorbed at a temperature of 400 °C. The effects of air flow rate, rotation speed and number of balls could not be determined due to wide variations in the results. It is recommended that recycling companies employ processes combining as heating and mixing techniques for the recovery of mercury from lamps in order to both (i) remove as much of the mercury as possible in vapor form and (ii) avoid adsorption of the mercury at new sites created during the crushing process.