Assessing The Microbiological and Heavy Metal Burden in Some Fresh Water and Marine Fishes in a Segment of the Bight of Bonny, Niger Delta Area of Nigeria. Favour A. Eyo and Alfred Y. Itah* Department of Microbiology University of Uyo, Uyo, Akwa Ibom State, Nigeria 1

Fig. 1: Map of Nigeria showing study area (Bight of Bonny) 2 BACKGROUND OF THE STUDY The Bight of Bonny, on the Southern Atlantic coast of Nigeria (4°15’- 4° 35’ N; 7°30’- 8°25’ E) (Fig. 1). This coastal aquatic system is about 100 km long and more than 30 km wide. Its constitutes the eastern flank of the Niger Delta (Ntekim et al., 1992 and Benson et al; 2007 ), spanning the shorelines of Akwa Ibom, Cross River and Rivers States of Nigeria. The entire ecosystem is made up of extensive network of rivers, estuaries, creeks and tributaries which together form a significant commercial hydrographic feature within the region. The estuaries with the major creeks constitute a rich assemblage of fluvial ecohydrological biotopes, dominated predominantly by intertidal mangrove and Nipa forested wetlands. The study area is exposed to significant anthropogenic inputs such as oil spills, untreated sewage and industrial waste waters. Several other smaller fluvial and domestic effluents are also disposed in the shallow marginal estuarine beaches and creeks.

Background of the Study Area Cont’d Callinectes pallidus Fin fishes  The contamination of aquatic ecosytems with a wide range of pollutants has become a matter of concern in the Niger Delta Area of Nigeria over the last few decades, as a result of rapid human population growth and industrial output.  Petrogenic and anthropogenic activities, urbanization, industrialization and agricultural practices have increased the amount of heavy metals in the environment especially in aquatic ecosystem.  Fishes are conditioned by their environment and hence it is obvious that if the growing and harvesting environment of fish is polluted chemically or microbiologically, the fishes are also polluted. Hence the use of fish to evaluate the health of aquatic ecosystems because pollutants build up in the food chain and are responsible for adverse effects and death in the aquatic systems.  It has been established that the microbiological and heavy metal load of fish is a reflection of the contamination level of their habitat and thus a potential indicator of pollution  This work will therefore establish the contamination level of the aquatic ecosystems in question by determining the contamination levels of fishes inhabiting them. 3

Background of the Study Area Cont’d Gas flaring Mangrove oyster (Crassostrea tulipa) Callinectes pallidus Fin fishes Artisanal fishing  Ecosystem pollution  Aquatic resources harvested for human consumption 4 Figure 2: Evidence of Pollution

Objectives  Quantitative and qualitative microbiological assessment of sediment, water and fish samples from marine and freshwater ecosystems  Assess the heavy metal concentration and total petroleum hydrocarbon degrading microorganisms in the different samples  Determine the physicochemical characteristics of sediment and water samples 5

Materials and Methods Sample (water, sediment and fish) collection and processing Physicochemical analysis Culture-dependent microbiological analysis Total heterotrophic micro- organisms Total coliform bacteria Heavy metal content Total hydrocarbon content Petroleum hydrocarbon degrading microorganisms Temperature, pH, total alkalinity, total hardness, turbidity, electrical conductivity, Total and suspended solids, Dissolved O ₂, COD, BOD ₅, TOC, NH ₄, NO ₂, NO, N ₂, PO ₄, SO ₄, Sodium, Potassium, Statistical analysis performed using Statistica® software with levels of significance maintained at 95% for each test 6

Fish Samples and their Local Names Fresh water fin fishesCommon nameTotal weight Parachanna africanaSnake head105.21g Malapterus electricusElectric fish32.78g Heterobranchus bidorsalisFresh water cat fish38.00g Tilapia zilliTilapia35.21g Oreochromis niloticusTilapia34.01g Fresh water shell fish Callinectes pallidusBlue crab14.4g Macrobrachium vollenhoeveniiBrackish water prawn5.68g Macrobrachium macrobractiionShrimp5.01g Penaeus notialisShrimp4.68g Callinectes amnicotaCrab4.68g 7

Fish Samples and their Local Names Cont’d. Marine water fin fishCommon nameTotal weight Ethmalosa fimbriataBonga fish128.34g Pseudotolithus senegalensisCroacker128.54g Pseudotolithus elongatusCroaker143.80g Chrysichthys nigrodigitusCatfish101.18g Pseudotolithus typusCroacker32.54g Marine water shellfish Parapenaeopsis altanticaGuinea shrimp5.70g Geryon maritaeWest African geryon4.02g Parapenaens congirostrisDeep water rose7.05g Anadara senegalensisSenegal ark6.70g Cardium costatumCostate cockle8.9g 8

Physicochemical Characteristics of fresh and marine water samples Physicochemical parametersSampleWHO Standard Fresh waterMarine water AppearanceSlightly cloudySlightly cloudy with suspended particles Clear Colour (H.U) OdourInoffensiveMarshyInoffensive Temperature ( o c) Turbidity (NTU) Total suspended solids (mg/l) <10.0 Electrical conductivity ( µ S/cm) Dissolved oxygen (mg/l) Total dissolved solids (mg/l) pH Biochemical oxygen demand (mg/l) Sodium (mg/l) Potassium (mg/l) Sulphate (mg/l) Nitrate (mg/l) Phosphate (mg/l) Nitrite (mg/l) Salinity as Cl - (mg/l)

Physicochemical Characteristics of Marine and Fresh Water Fish Physicochemical parametersSample WHO Standard Fresh waterMarine water AppearanceSlightly cloudy Slightly cloudy with suspended particles Clear Alkalinity (mg/l) Total hardness (mg/l) Calcium hardness (mg/l) Magnesium hardness (mg/l) Aluminium (mg/l) Lead (mg/l)< Cadmium (mg/l)< Nickel (mg/l)< Zinc (mg/l) Copper (mg/l) Iron (mg/l) HU=Hazen unit NTU=Nephelometric Turbidity Unit µS/cm=Microsiemen per centimetre 10

Figure 3: Comparative evaluation and distribution of different physiological groups of microorganisms from marine and freshwater 11

Figure 4: Comparative evaluation and distribution of different physiological groups of microorganisms from marine and freshwater sediment 12

Figure 5: Comparative evaluation and distribution of different physiological groups of microorganisms in finfishes from freshwater 13

Figure 6: Comparative evaluation and distribution of different physiological groups of microorganisms in shell fishes from freshwater 14

Figure 7: Comparative evaluation and distribution of different physiological groups of microorganisms in finfishes from marine water 15

16 Figure 8: Comparative evaluation and distribution of different physiological groups of microorganisms in shell fishes from marine water

Heavy metal concentration in fresh water and marine sediment SampleAluminiumLeadCadmiumNickelZincCopperIron Fresh Water Marine Water

Figure 9: Level of heavy metals concentration in finfish parts from marine water 18

Figure 10: Level of Heavy metal concentration in finfish parts from freshwater 19

Figure 11: Level of heavy metal concentration in shell fish parts from freshwater 20

Figure 12: Level of heavy metals concentration in shell fish parts from marine water 21

Summary and Conclusion  The study on the whole evidenced the microbial and heavy metal status of shell and fin-fishes found in freshwater and marine ecosystems.  The heavy metal concentration in the fish organs vary directly with the concentration values in the water and sediment samples analyzed in this study, pointing to the fact that the heavy metals have their way into the fish organs from the environment through respiratory and feeding activities.  Some microbiological analysis, such as, Total heterotrophic counts; Total coliforms; Petroleum hydrocarbon degraders and Total fungal counts, were performed on different fish organs, water and sediment samples.  The presence of Petroleum hydrocarbon degraders e.g. Chromobacterium violaceum, B. subtilis, Penicillium italicum, C. albicans and Micrococcus varians in the fishes present some ecological advantages in the event of oil spill as the degraders in fish could multiply and biodegrade the pollutant for their survival.  It also confirms the fact that both shell and fin fishes remain a promising option in bio-monitoring and pollution assessment in lenthic aquatic systems. 22

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