Use of polyethylene membrane devices for monitoring diesel oil contamination on and within beaches

In the spring of 2002, routine monitoring in Port Chalmers in Prince William Sound Alaska, detected a small unreported diesel fuel spill that resulted from commercial fishing activity. A series of 12 polyethylene membrane devices (PEMDs) had been initially placed on the beach to assess any remaining hydrocarbons from the 1989 Exxon Valdez oil spill. During the course of the routine monitoring study, these PEMDs detected an increase in polycyclic aromatic hydrocarbons (PAH) several thousand-fold from a few hundred ng per device in the winter deployment. The beaches of the affected area have semi-diurnal tides with a maximum vertical range of 6 metres. The beach at one monitoring station is exposed to high-energy waves and the other is more sheltered. This study compared and reported the results of the surface and subsurface impacts of this small diesel spill. PAH in sediments and in interstitial water in the beach were measured after the diesel spill. A comparative evaluation revealed that PEMDs can be a low cost and and effective method for monitoring interstitial water flow within porous beaches because they accumulate organic pollutants from intermittent exposures. Results for the PEMDs, sediments and interstitial water samples from the mid-tide elevations at the sheltered station demonstrate the high sensitivity of PEMDs as environmental hydrocarbon monitors. 8 refs., 4 figs