A STUDY OF THE MICROBIOLOGY AND POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) COMPOSITIONAL PROFILE AND SOURCES IN DRILL CUTTINGS FROM OLOGBO OILFIELD WELLS AT EDO STATE, NIGERIA

摘要

A? study? was? carried? out? on? the? drill cuttings? from? three different oil and gas wells located at Ologbo Community at? Edo? State? with? respect? to? their? microbiology? and polycyclic? aromatic? hydrocarbons? (PAHs)? compositional profile? and? sources.? Isolation? and? enumeration? of heterotrophic? bacteria? and? fungi? was? carried? out? using pour plate techniques. pH and electrical conductivity were monitored? using? single? electrode? meters.? Polycyclic Aromatic? Hydrocarbon? was? determined? using? gas chromatography,? oil? and? grease? concentration? was analyzed? using? spectrophotometric? method.? Results? of total heterotrophic bacterial counts ranged between 5.4 x 105? cfu/g? at? well? 2? to? 7.23? x? 105? cfu/g? while? the heterotrophic fungal counts ranged from 3.7 x 104 cfu/g to 3.0? x? 105? cfu/g.? Total? heterotrophic? anaerobic? bacterial counts? also? ranged? from? 0.8? x? 102? cfu/g? to? 1.7? x? 102 cfu/g.? The? most? predominant? bacterial? isolates? were Clostridium? spp.? (16.6%)? and? Mycobacterium? spp. (14.5%).? Species? of? Aspergillus? (16.6)? and? Penicillium (14.2)? also? had? the? highest? frequency? of? occurrence among? the? fungi? isolates.? The? pH? ranged? from? 5.42? to 5.78.? The? highest? electrical? conductivity? value? was? 383 μS/cm.? The? range for? oil? and? grease? was? from? 8352? to 9654.61 mg/kg. Of the heavy metals iron had the highest concentration? (126? ppm)? while? least? concentration? was observed? in? zinc? (61? ppm).? The? 3-ring? PAHs? had? the highest? percentage? composition? for? samples? from? the three (3) different wells (53, 73 and 89 for well 1, 2 and 3 respectively). The source identification by isomer ratios of PAHs revealed that drill cuttings from Wells 1 -? 2 were of pyrogenic? origins,? while? cuttings? from? well? 3? indicated both? petrogenic? and? pyrogenic? origin.? It? was? quite? clear that? drill? cuttings? emanating? from? Ologbo? oilfield? wellswere unsafe for disposal and therefore will require a strict adherence? of? the? procedures? and? instructions? described for oil drilling exploration and procedure (E and P) waste management in Nigeria.