EVALUATION OF WORK-RELATED VOLATILE ORGANIC COMPOUNDS (VOCs) EXPOSITION IN AUTOMOTIVE PAINTING CABINS INDUSTRIAL CLEANING

M.G. Rosell1 , A. Carrasco2 , E. Gallego3

1Centro Nacional de Condiciones de Trabajo. INSHT. C/Dulcet, 2-10. E 08034 Barcelona. e-mail: cnctinsht@mtin.es

2ACCIONA Facility Services. Departamento de Seguridad y Salud, Pº Zona Franca, 69-63. E 08038. Barcelona e-mail: antonio.carrasco@accionafs.com

3Laboratori del Centre de Medi Ambient. Universitat Politècnica de Catalunya (LCMA-UPC). Avda. Diagonal, 647. E 08028 Barcelona. e-mail: lcma.info@upc.edu

INTRODUCTION AND OBJECTIVEAutomotive painting cabins are cleaned with several solvents, being great part of them mixtures of volatile organic compounds (VOCs), where the three xylene isomers are the most important constituents. To evaluate the work-related exposition of the cleaners that use these mixtures of solvents, xylenes have been determined in the working ambient air as well as its metabolite, o-m-p-methyl hippuric acid, has been analysed in urine to establish the dermal and respiratory exposition. This evaluation has been done in order to assess the occupational exposure to VOCs and to know the working conditions of the cleaners, but also to evaluate the effectiveness of personal protective equipment (PPE), the engineering control and the work practices.The xylenes have been chosen as indicators of exposition because they are the main components in the cleaning solvents used, with a level of concentration between 50% and 85%.The Xylenes have an occupational exposure limit (8 h TWA) of 50 ppm (221 mg/m3) and a short-term exposure limit (STEL) of 100 ppm (442 mg/m3). On the other hand, the biological exposure index (BEI) for xylenes is the sum of the total methyl hippuric acids in urine at the end of the work-shift, being the value 1500 mg/g creatinine.

SAMPLING AND ANALYSIS •Gas phase VOCs were dynamically sampled connecting a solid sorbent tube (coconut shell charcoal, 100 mg / 50 mg) to an air collector pump sampler SKC whit a flow rate of 0.2 L/min. The diffusive sampling was carried out with an ORSA 5 ® (Dräger). Both sampling tubes were extracted with CS2 (1 ml for Charcoal tubes and 2 ml for diffusive samplers) during 30 min.•The urine samples were taken at the end of the work-shift.

LABORATORI DEL CENTRE DE MEDI AMBIENT

D.E.Q. (E.T.S. D’ENGINYERIA INDUSTRIAL BARCELONA)

CONCLUSIONS

Even though the three xylene isomers are the main constituents of the solvents used in the cleaning process, other hazardous VOCs (e.g. sensory irritants, hazardous for masculine reproduction) have been found in ambient air samples, such as limonene and 1-metoxy-2-propanol. The presence of these compounds has to be taken into account when taking protective measures for the workers.

-Significant differences have been observed in metil hipuric acid concentration in urine between exposed and non exposed workers.

-Among exposed workers, significant differences have not been observed between smokers and non smokers. This data indicates that smoking habits do not interfere in the metil hipuric burden in urine of the workers, as their exposition to xylenes through the solvent is higher than the one that comes from smoking.

-The working conditions in B Company are not adequate. They have to improve environmental air quality increasing the ventilation rates.

-A Company can be considered safe.

REFERENCES

Henry J. McDermott,Shirley A. Ness Air monitoring for toxic exposures Wiley Publishiers Science. 2007 2ond Ed.

W J Hunter, G Aresini, R Haigh, P Papadopoulos, W Von der Hude Occupational exposure limits for chemicals in the European UnionOccup. And Environ. Medecine, 1997; 54; 217-222

INSHT. Límites de Exposición Profesional para Agentes Químicos en España, 2010

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GC conditions:

Column: DBWax (60 m x 0.53 mm x 1 µm)Oven: 40 ºC during 6 min, then at 2 ºC/min until 100 ºC Injector: 200 ºC FID Detector: 250 ºCInjection volume: 1 µl

HPLC Analytical conditions Mobil phase: 9:1 Buffer solution: ACN:acetic acid (pH 2.8) Flow 1 m/minColumn: Sinergy 4 µ Hydro (150 mm x 4.6 mm) Detector: PHD, at 254 nmInjection volume:10 µL

Methyl hippuric acid Minimum Maximum Mean ± SD Median

Non exposed

All workersmg/l 1.5 70.3 21.6 ± 23.1 11.3mg/g creatinine 2.7 67.3 18.7 ± 20.4 10.6

No smokersmg/l 1.5 70.3 18.6 ± 22.5 9.9mg/g creatinine 2.7 67.3 17.2 ± 19.2 10.3

Exposed

All workersmg/l 32.8 357.2 134.5 ± 93.9 88.9mg/g creatinine 14 142.3 57.8 ± 35.9 54.3

No smokersmg/l 53.8 286.4 131.6 ± 80.7 91.7mg/g creatinine 14 133.2 56.1 ± 32.3 54.8

The BEI is 1500 mg/g creatinine of methyl hipuric acids in urine at the end of working day.

Diffusive samplingORSA (7 h)

ΣXylene isomers

mg/m3 ppm

P - 1 24.0 5.4P - 2 29.4 6.6P - 3 2.6 0.6P - 4 8.5 1.9P - 5 3.1 0.7P - 6 12.1 2.7P - 7 11.4 2.6Environmental 15.9 3.6TWA for long term exposure

221 50

Active samplingCharcoal tube (15 min)

ΣXylene isomers

mg/m3 ppm

P - 1 4.6 1.0

P - 2 8.2 1.8

STEL for short term exposure

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Active samplingCharcoal tube (15 min)

ΣXylene isomers

mg/m3 ppm

P - 1 105.4 23.8

P - 5 157.4 35.6

P - 8 249.7 56.5

P - 9 516.0 116.8

STEL for short term exposure

442 100

MATERIALS AND METHODSThe study was carried on in two different automotive companies, Company A and Company B. A total of 12 personal air samples and 32 urine samples (both from exposed and non exposed workers) were taken. In addition to that, a query form was filled by each employee to determine personal aspects that could interfere in the study (e.g. smoking habits). The air samples were analyzed by gas chromatography (NIOSH Analytical Method 1501) and the urine samples by HPLC (Method MTA/MB-022/A95 INSHT).

Methyl hippuric acid Minimum Maximum Mean ± SD Median

Non exposed

All workersmg/l 4.8 47.6 15.7 ± 11.4 13.1mg/g creatinine 4.4 40.4 12.4 ± 9.1 9.9

No smokersmg/l 7.3 28.7 14.3 ± 6.7 13.1mg/g creatinine 5.2 19.8 11.4 ± 4.5 9.9

Exposed

All workersmg/l 181.2 10412 2306.1 ± 3247.8 886.3mg/g creatinine 229.3 2042.5 938.9 ± 664.3 646.9

No smokersmg/l 181.2 3717.4 1463.7 ± 1392.3 864.7mg/g creatinine 229.3 2042.5 890.9 ± 667.8 612.2

A Company B Company

DETERMINATION OF XYLENES IN AMBIENT AIR SAMPLES BY GAS CHROMATHOGRAPHY

URINE SAMPLES

A Company B Company

Diffusive sampling

ORSA 5 CHARCOAL TUBE

Active sampling

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B Company

Diffusive samplingORSA (7.5 h)

ΣXylene isomers

mg/m3 ppm

P - 1 304.0 68.9P - 2 427.2 96.7P - 3 551.9 125.0P - 4 73.0 16.5P - 5 368.7 83.4P - 6 20.8 4.7P - 7 66.6 15.1P - 8 350.4 80.5P - 9 550.5 124.6TWA for long term exposure

221 50

Significant correlation observed between the metil hipuric concentration in urine (mg/g creatinine) and the concentration of the xylenes in ambient air (µg/m3) (F-Snedecor, p <0.05).

Urine/creatinine/environment R2 = 0,874

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