Research Product

Weathered Alaska North Slope crude oil (ANS 521) was stirred for 2 and 14 days in 20o/oo salinity sterile seawater or for 14 days in seawater with nutrients and a group of three (GO3) microorganisms from Prince William Sound, Alaska, (PWS) that were capable of biodegrading hydrocarbons. A total of 0.65 and 0.69 mg/L water soluble fraction (WSF) of neutral fraction hydrocarbons were recovered from the 2 and 14 day stirred sterile systems, respectively. In contrast, a total of 7.5 mg/L WSF neutral fraction hydrocarbons was recovered from systems containing ANS 521 that was stirred and biodegraded by the GO3 microbes for 14 days. Toxicity/teratogenicity tests were conducted with neutral fraction hydrocarbons recovered from the sterile and biodegraded systems using embryonic inland silversides, Menidia beryllina. Hydrocarbons from the sterile systems did not cause statistically significant teratogenic responses at concentrations of 1%, 10% and 100% of recovered fractions (redissolved in 20o/oo sterile seawater). Counts of heart contraction rate were significantly lower (a< or = to 0.05) at the 100% WSF concentration of hydrocarbons on day 5 and 6 of embryogenesis. Recovered and redissolved neutral fraction hydrocarbons from ANS 521 that were biodegraded for 14 days caused statistically significant (a< or = to 0.05) teratogenic responses at the 10% and 100% WSF concentrations. Measurement of heart contraction rates showed statistically significant (a< or = to 0.05) reductions at the 100% WSF concentration on days 2 through 6 of embryogenesis, compared with controls.