2种原油中烃类生物标志物生物降解性评价

通过室内微生物降解模拟实验,考察了海上中质原油BZ34-1和重质原油SZ36-1中类异戊二烯类、萜烷类和甾烷类生物标志物组分的生物降解性.结果表明,在60 d的实验周期内,尽管2种原油中类异戊二烯类生物标志物包括姥鲛烷和植烷都发生明显降解,其中,中质原油BZ34-1中姥鲛烷和植烷的降解率分别为20.2%和15.0%,重质原油SZ36-1中姥鲛烷和植烷的降解率分别达到95.6%和75.4%;但2种原油中类异戊二烯类生物标志物发生降解的阶段不同,重质原油SZ36-1中类异戊二烯类生物标志物在实验初期(20 d)就开始发生降解,中质原油BZ34-1中类异戊二烯型生物标志物的降解主要发生在中后期(20～60 d).而2种原油中萜烷和甾烷类生物标志物在整个实验周期内都未发生明显降解.这表明在设定的实验周期内,植烷或姥鲛烷适用于评价降解初期的中质原油生物修复效果;而萜烷和甾烷类则适用于2种原油不同阶段生物修复效果评价.

Evaluation on Biodegradability of Hydrocarbon Biomarkers in Two Crude Oils Under Laboratory Conditions

Biodegradabilities of several hydrocarbon biomarker groups, including isoprene, hopanes and steranes in a medium-crude oil BZ34-1 and a heavy-crude oil SZ36-1 from offshore, were determined under laboratory conditions. The results of GC-MS analysis showed that isoprene biomarkers such as pristane and phytane in both crude oils degraded obviously in 60-day experiment period. The degradation ratios of pristane and phytane in the medium-crude oil BZ34-1 reached 20.2% and 15.0%, respectively; while those in the heavy-crude oil SZ36-1 reached 95.6% and 75.4%, respectively. Pristane and phytane in the heavy-crude oil SZ36-1 were degraded in the early period of biodegradation, but these two biomarkers in the medium-crude oil BZ34-1 were degraded in middle and late biodegradation phases. However, hopanes and steranes in the both oils were not biodegraded obviously during the whole period. These results indicated that pristane and phytane could be used to evaluate bioremediation efficiency in the early biodegradation phase for light or medium oils, while hopanes and steranes could be used to evaluate bioremediation efficiency within the whole given experiment process.