Charcoal Cloth Pad as a Qualitative Dermal Sampler for Toluene while Spray Painting in an Auto Body Repair Shop

Abstract

Small auto body repair (ABR) shops in Thailand mostly do not have spray painting booths, so workers are likely to have inhalation and dermal exposure to paint mist, but only inhalation exposure has been of concern. Objective: The objectives of this study were to explore the possibility of using a charcoal cloth pad (CCP) as a simple tool to assess dermal exposure qualitatively, and investigate the body site where the CCP should be placed. Material and Method: A Small ABR was selected as a case study. Four painters in a small ABR were recruited in to the study. The CCPs were made of 100% activated charcoal pad and attached on the potential exposed areas of the participants’ bodies. Thirty-one CCP sample sets
were collected in 13 days (1 set/day/participant). Respirators were provided to wear while working. Pre- and post-shift urine samples were collected and analyzed for hippuric acid (HA) using GC. Linear regression was used to analyzed for the relationship of net HA and toluene on the CCP (TolCCP). Result: The net urinary hippuric acid  (HA) correlated well with TolCCP attached at painters’ chests of net HA (mg/g creatinine)
= 227.5 + 0.162 TolCCP (mg), r2 = 0.258, p-value = 0.003. The suitable dermal sampling site on spray painter was the chest, where the average
quantity of toluene on the CCPs was the highest. Conclusion and recommendation: The CCP could be used as a tool for qualitative dermal exposure assessment by attached the pad at the painter’s chest. Substitute 50% BEI of toluene (1.25 g HA/g creatinine) for net HA in the above equation and round up the number to obtain a recommended limit of toluene on CCP of 8,800 mg. The quantity indicates that the worker have high dermal exposure and may permeate through the workers’ skin at signifcant amount to harm their health. Therefore, it was suggested that protective cloth should be provided to the spray painting workers from 8,800 mg or more toluene was found on CCP.