Seasonal effect on the bacterial and fungal population of an oilfield waste water-polluted soil in Nigeria

Abstract

Seasonal effect on the bacterial and fungal populations of an oilfield wastewater – polluted soil was investigated for a period of 12 months. Many bacterial and fungal species were present in the soil and the wastewater of the area investigated. Some of the organisms occurred in both the soil and oilfield wastewater while others occurred only in the soil. Eighteen (18) organisms were isolated; 4 species (2 bacteria and 2 fungi) occurred in all the seasons whereas the other organisms occurred in at least one season. This showed that different seasons selectively favour the growth of certain microbial types. The chemical analysis of the oilfield wastewater revealed the presence of inorganic components and oil residues in the wastewater. The microbial counts of the polluted soil when compared to the control samples in all the locations did not reveal a clear seasonal-pollutant effect on the microbial densities. However, fungal counts showed somewhat seasonal-pollutant effect in two locations. The chemical constituents of the wastewater are relatively of low toxicity and hence had no toxic effects on the soil microbial population. Seasonal variations show that the drier seasons supported large active population and wetter season had smaller population of microbial densities. However, seasonal influence was more pronounced on the fungi than on the bacteria.


(Journal of Applied Sciences & Environmental Management: 2002 6(2): 17-22)