Estimation of Dermal Exposure to Oil Spill Response and Clean-up Workers after the Deepwater Horizon Disaster

Abstract

The GuLF STUDY is investigating health outcomes associated with oil spill-related chemical exposures among workers involved in the spill response and clean-up following the Deepwater Horizon disaster. Due to the lack of dermal exposure measurements, we estimated dermal exposures using a deterministic model, which we customized from a previously published model. Workers provided information on the frequency of contact with oil, tar, chemical dispersants applied to the oil spill and sea water, as well as the use of protective equipment, by job/activity/task. Professional judgment by industrial hygienists served as a source of information for other model variables. The model estimated dermal exposures to total hydrocarbons (THC), benzene, ethylbenzene, toluene, xylene, n-hexane (BTEX-H), polycyclic aromatic hydrocarbons (PAHs), and dispersants in GuLF DREAM units (GDUs). Arithmetic means (AMs) of THC exposure estimates across study participants ranged from <0.02 to 5.50 GDUs for oil and <0.02 to 142.14 GDUs for tar. Statistical differences in the estimates were observed among the AMs of the estimates for some broad groups of worker activities over time and for some time periods across the broad groups of activities. N-Hexane had ranges similar to THC for oil exposures (e.g. AMs up to 2.22 GDUs) but not for tar (up to 5.56 GDUs). Benzene, ethylbenzene, toluene, and xylene, in contrast, were characterized by higher exposure levels than THC for oil (AMs up to 12.77, 12.17, 17.45, and 36.77 GDUs, respectively) but lower levels than THC to tar (AMs up to 3.69, 11.65, 42.37, and 88.18 GDUs, respectively). For PAHs, the AMs were as high as 219.31 and 587.98 for oil and tar, respectively. Correlations of these seven substances to each other were high (>0.9) for most of the substances in oil but were lower for some of the substances in tar. These data were linked to the study participants to allow investigation of adverse health effects that may be related to dermal exposures.

Keywords: Deepwater Horizon; dermal exposure; exposure assessment; oil spill; total hydrocarbons.

Figure 1.

Modeled dermal exposure estimates of oil components (total hydrocarbons, benzene, ethylbenzene, toluene, xylene, n-hexane, and polycyclic aromatic hydrocarbons by broad activity groups by time period). Note that the scales (in GDUs) vary among the substances. ROVs = vessels piloting remotely operated vehicles. GDU = GuLF DREAM unit.

Figure 2.

Modeled dermal exposure estimates of tar components (total hydrocarbons, benzene, ethylbenzene, toluene, xylene, n-hexane, and polycyclic aromatic hydrocarbons by broad activity groups by time period). Note that the scales (in GDUs) vary among the substances. ROVs = vessels piloting remotely operated vehicles. GDU = GuLF DREAM unit.