ABSTRACT
Approximately 5,500 barrels of unleaded gasoline escaped from a ruptured pipeline in Bellingham, Washington on June 10, 1999. The majority of the product entered Whatcom Creek, with a flow of approximately 0.3 m3/s (10 cfs). The gasoline affected approximately 4.8 km (3 miles) of the creek. After a period of approximately 4 hours, the product contacted an ignition source.
Twenty hours following the incident, a water-sampling program at 8 stations in Whatcom Creek and 12 stations in Bellingham Bay was implemented. Ultimately, nearly 400 water-column samples were analyzed for gasoline range hydrocarbons (GRHs), including BTEX compounds and MTBE. Samples were collected every 4 hours for the first 5 days, daily for the next 17 days, and 16 of the following 32 days. Initial maximum concentrations found in water samples were 20,800 ug/L GRH, 2,600 ug/L total xylenes, 1,300 ug/l toluene, 340 ug/L ethylbenzene, 110 ug/L benzene, and 6.9 ug/L MTBE. Product concentrations in the stream declined rapidly.
Within 140 hours of the incident, GRHs subsided two orders of magnitude. Instream waters met State of Washington Groundwater Cleanup Standards (Washington Administrative Code, Chapter 173–340.) in an average of 131 hours from the time of the release for benzene, 127 hours for ethylbenzene, 66 hours for toluene, and 207 hours for xylene. Volatilization of BTEX during transport downstream was evidenced by a consistent gradient of reduced concentrations with distance from the source. Sediment pore water and bulk sediments were also sampled. Initial pore-water GRH ranged widely from nondetect to 110,000 ug/L. GRH in bulk sediment samples ranged from nondetect to 447,000 ug/L. A remediation program was conducted to release product trapped in the streambed that reduced contaminants to levels deemed acceptable by a risk-based approach for survival of salmonid fry populations. This approach and resultant guidelines are described.
Phosphorous Supply to a Eutrophic Artificial Lake: Sedimentary versus Groundwater Sources