| Summary: | Aims and Objectives ? The aim of this study was the following: (1) to assess the dermal exposure of workers to PAH‘s during an entire eight hour work shift; (2) to assess the short term dermal exposure of workers to PAH‘s while performing certain identified tasks; (3) to identify the areas and occupations that poses the highest risk to the health of the workers; (4) to assess the skin barrier function of workers that may be exposed to PAH‘s by measuring TEWL, skin hydration and skin surface pH.
Methods ? Workers from three different plants in a South African petrochemical factory participated in the study. Their dermal exposure was assessed during a single 8–hour shift by using dermal adhesive patches and during specific 30 minute tasks by means of dermal wipes. Their baseline skin barrier function was also determined at the beginning of the eight hour shift by measuring skin surface hydration, skin surface pH and the Transepidermal water loss (TEWL). Surface PAH–samples were also collected from various surfaces in two of the plants.
Results: Eight hour study– Cleaner 3 from the Solids Filtration Plant (SFP) experienced the highest average dermal exposure to total PAHs (759.6 ng/cm2) as well as the highest total PAH–concentration on the outside of his clothing (28596.3 ng/cm2). At the Tar Separation Plant (TSP) Cleaner 2 experienced the highest average dermal exposure (274.4 ng/cm2). Cleaner 3 and Process controller at SFP as well as Truck loader 2 at TSP were all exposed to benzo[a]pyrene on the surface of their skin (37.20 ng/cm2; 57.66 ng/cm2 and 9.30 ng/cm2 respectively). Statistical significant differences were seen between the skin surface hydration values (p=0.013) as well as the TEWL values (p = 0.033) of TSP and SFP workers.
Short term study– Slop pit cleaner 3 from TSP experienced the highest dermal exposure to total PAHs (1659.04 ng/cm2). A splash of tar landed on Slop pit cleaner 3‘s cheek which contained 14871.45 ng/cm2 total PAHs. The following workers were exposed to benzo[a]pyrene on various anatomical areas during their tasks: Truck loader 3 at TSP (2.7 ng/cm2); Cleaner 6 at SFP (6.2 ng/cm2 and 3.5 ng/cm2); Slop pit cleaner 2 at TSP (20.8 ng/cm2 and 12.8 ng/cm2) and Slop pit cleaner 3 at TSP (72.8 ng/cm2 and 108 ng/cm2). Slop pit cleaner 3 at TSP was exposed to dibenz[a,h]anthracene (9.6 ng/cm2 and 15.2 ng/cm2)
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The surface with the highest contamination is on top of the dirty lockers in the SFP (519.0 ng/cm2).
Conclusions: In both studies, Cleaners were identified as the greatest exposed occupation. Cleaning the slop pit at TSP and cleaning the plant at SFP were identified as tasks with the highest potential exposure. Cleaners are probably the highest exposed workers because they come in direct contact with the tar more often. Workers exposed to benzo[a]pyrene or dibenz[a,h]anthracene face the greatest health risk as these substances are highly carcinogenic. SFP workers are in general exposed to higher concentrations of PAHs than workers in other areas. Workers at both SFP and TSP had high baseline TEWL and low baseline skin surface hydration values which indicated disrupted skin barrier function and may lead to an increase in their susceptibility to skin disorders. Dirty surfaces can also contain PAHs including benzo[a]pyrene and dibenz[a,h]anthracene. === Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2012.
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