Validation and comparison of two sampling methods to assess dermal exposure to drilling fluids and crude oil.

Dermal exposure to drilling fluids and crude oil is an exposure route of concern. However, there have been no published studies describing sampling methods or reporting dermal exposure measurements. We describe a study that aimed to evaluate a wipe sampling method to assess dermal exposure to an oil-based drilling fluid and crude oil, as well as to investigate the feasibility of using an interception cotton glove sampler for exposure on the hands/wrists. A direct comparison of the wipe and interception methods was also completed using pigs' trotters as a surrogate for human skin and a direct surface contact exposure scenario. Overall, acceptable recovery and sampling efficiencies were reported for both methods, and both methods had satisfactory storage stability at 1 and 7 days, although there appeared to be some loss over 14 days. The methods' comparison study revealed significantly higher removal of both fluids from the metal surface with the glove samples compared with the wipe samples (on average 2.5 times higher). Both evaluated sampling methods were found to be suitable for assessing dermal exposure to oil-based drilling fluids and crude oil; however, the comparison study clearly illustrates that glove samplers may overestimate the amount of fluid transferred to the skin. Further comparison of the two dermal sampling methods using additional exposure situations such as immersion or deposition, as well as a field evaluation, is warranted to confirm their appropriateness and suitability in the working environment.

Laboratory Validation and Field Assessment of Petroleum Laboratory Technicians' Dermal Exposure to Crude Oil Using a Wipe Sampling Method.

Crude oil may cause adverse dermal effects therefore dermal exposure is an exposure route of concern. Galea et al. (2014b) reported on a study comparing recovery (wipe) and interception (cotton glove) dermal sampling methods. The authors concluded that both methods were suitable for assessing dermal exposure to oil-based drilling fluids and crude oil but that glove samplers may overestimate the amount of fluid transferred to the skin. We describe a study which aimed to further evaluate the wipe sampling method to assess dermal exposure to crude oil, with this assessment including extended sample storage periods and sampling efficiency tests being undertaken at environmental conditions to mimic those typical of outdoor conditions in Saudi Arabia. The wipe sampling method was then used to assess the laboratory technicians' actual exposure to crude oil during typical petroleum laboratory tasks. Overall, acceptable storage efficiencies up to 54 days were reported with results suggesting storage stability over time. Sampling efficiencies were also reported to be satisfactory at both ambient and elevated temperature and relative humidity environmental conditions for surrogate skin spiked with known masses of crude oil and left up to 4 h prior to wiping, though there was an indication of reduced sampling efficiency over time. Nineteen petroleum laboratory technicians provided a total of 35 pre- and 35 post-activity paired hand wipe samples. Ninety-three percent of the pre-exposure paired hand wipes were less than the analytical limit of detection (LOD), whereas 46% of the post-activity paired hand wipes were less than the LOD. The geometric mean paired post-activity wipe sample measurement was 3.09 µg cm-2 (range 1.76-35.4 µg cm-2). It was considered that dermal exposure most frequently occurred through direct contact with the crude oil (emission) or via deposition. The findings of this study suggest that the wipe sampling method is satisfactory in quantifying laboratory technicians' dermal exposure to crude oil. It is therefore considered that this wipe sampling method may be suitable to quantify dermal exposure to crude oil for other petroleum workers.

Dermal exposure from transfer of lubricants and fuels by consumers.

Consumer uses of fuels and lubricants in Europe are subject to the Registration, Evaluation, Authorization and restriction of CHemicals (REACH) legislation. Ten volunteers completed a series of exposure situations to simulate filling a vehicle fuel tank with diesel (ES1 Diesel), adding lubricant to a car engine (two situations, one filling point easier to reach (ES2 Easy) than the other (ES3 Hard)) and lubricating a bicycle chain (ES4 Bike). Dermal exposure to the hands and forearms was assessed using a wipe sampling method. A high proportion of samples was less than the limit of detection (ES1=38%, ES3=60%, ES2 and 4, both 78%). In ES1 Diesel, dermal exposure to the hands and forearms ranged from <0.25 µg/cm(2) to 96.21 µg/cm(2). Significantly higher dermal exposure was observed when a lower level of care was taken to complete the task. In ES2 Easy and ES3 Hard, the hand and forearm results ranged from <0.1 µg/cm(2) to 3.33 µg/cm(2) and from <0.1 µg/cm(2) to 3.54 µg/cm(2), respectively. In ES4 Bike, the hand and forearm exposures ranged from <0.35 µg/cm(2) to 5.25 µg/cm(2). Not all volunteers fully complied with the ES4 instructions, thus highlighting that this situation may have more variability in consumer behaviour. The ratio of the amount measured on the hands and forearms to the amount of product handled for ES1 Diesel, ES2 Easy and ES3 Hard was less than 0.0001%, for ES4 Bike it was 0.04%. Mixed effect models showed that the between and within volunteer variations are small for all except ES1 Diesel, where the within volunteer variation was relatively large (likely due to the few high measurements). This study reports dermal exposure measurement data, which will be of value when updating REACH and other exposure assessments for these, and similar, petroleum products.