Biodegradation of Polycyclic Aromatic Hydrocarbons by Associated Microbes from Abattoir Wastes in the Niger Delta, Nigeria

Abstract

The biodegradation of polycyclic aro matic hydrocarbons by associated microorganisms were studied. Soil and waste water samp les were co llected fro m four abattoirs located at Egbu and Ogbe in Imo state, Trans-Amad i and Ahoada in Rivers State. Likewise, surface water and sediment samples fro m Otamiri River and Og inigba Creek adjoined to Egbu and Trans-Amadi abattoirs, respectively were co llected using standard methods. The ability of hydrocarbon utilizing bacteria and fungi to biodegrade polycyclic aro matic hydrocarbons (PAHs) was carried out by growing isolates in a mineral salt broth amended with PAHs. Levels of polycyclic aro matic hydrocarbons (PAHs) left after incubation were determined using Gas chromatographic method. Results showed that soil samples fro m various abattoirs had high concentration of PAHs which ranged fro m 0.176 mg/kg fro m Ahoada abattoir to 2.44 mg/ kg fro m Egbu abattoir. In a 21-day biodegradation test, there was a drop in the init ial concentration of PAHs used as control fro m 0.03 mg/l to 0.024 mg/l. Test results showed decrease in the concentration of PAHs with increase in exposure time. There was observable loss of low molecular weight PAHs than the high mo lecular weight co mponents. It is evident fro m the study that both mixed cultures of bacteria and fungi can biodegrade polycyclic aro matic hydrocarbons. Results fro m this study have shown that abattoir wastes have high pollution strength and thus should be treated before being discharged into the environment. Thus bacteria and fungi isolated fro m and within the abattoirs are potential agents of remedying environ ments impacted by polycyclic aro mat ic hydrocarbons (PAHs).