| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1996: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
Estuarine sediments in urban rivers contain petroleum hydrocarbons which are derived from numerous deverse sources such as motor vehicle exhaust, fuel combustion products, airborne particulate matter, and high-boiling temperature petroleum distilllates. We determine the aerobic and anaerobic biodegradation rates of the substrates of petroleum hydrocarbons using estuarine sediment from the Tama River in urban Tokyo.
Known amounts of the selected petroleum hydrocarbons were added to a sediment sulurry which was prepared by mixing the sediment with river bottom water (sediment : water, 1 : 1. v/v). We added petroleum hydrocarbons to a test tube (100ml volume), and then added 10ml of sediment slurry. We periodically extracted petroleum hydrocarbons from the sediment slurry using ethyl acetate, and then determined their concentration by FID gas chromatography or spectrophotometer.
When the maximum microbial purification potentials of petroleum hydrocarbons are estimated under anaerobic conditions, the degradation ratio by the stationary culture is better than by the shaking culture. For example, the degradation ratio of hexadecane for 30 days is 45% by shaking and 89% by stationary. In hexadecanol, it is 31% by shaking and 97% by stationary for 15 days. In p-chlorphenol, it is 6% by shakin and 94% by stationary for 25 days. In m-aminobenzoic acid, it is trace by shaking and 96% by stationary for 19 days. It is obvious that the reason is not the cell damage by shaking or short contact time between substrate and degrading cell, but adaptaion of cultivation condition. The[ sediment core experiments suggested that aerobic microorganisms in oxidized surficail sediment were more capable of degrading petroleum hydrocarbon than microorganisms in anaerobic sediment. The bio-purification potential of hexadecane, phenanthrene and anthracene in Tama River were evalutated in anaerobic core sediment.
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