Heavy Metal and Microbiological Characteristics of Wastewater Impacted by Anthropogenic Activities around Ntanwogba Creek in Port Harcourt City

Abstract

Ntanwogba creek is associated with beehive of anthropogenic activities such as mechanics and workshops, welders, sale of various household materials/accessories, motor parts, washing of cars and so many other sources of income for families living around the area in Port Harcourt. This study also investigates the impact of these human activities and its negative impact on the open drainage system along the Ntanwogba creek and the environment. Wastewater and sediment samples were collected at five different sampling points designated along the Ntanwogba creek with sterile containers using standard microbiological methods. Sampling was done by plunging about 30 cm below the water surface with the mouth of the sample container positioned in an opposite direction to water flow. The sediment samples were collected with plastic scooper to scoop the samples. The samples were labelled and transported in a cooler packed with ice blocks to the laboratory for analysis. This exercise was repeated at all the sampling stations starting from the upstream by Afam /Kaduna Street behind the Winners Chapel in D-Line to the downstream at Abacha Road off the Agip roundabout. Standard analytical protocols were employed to determine the heavy metal and  microbiological characteristics of the wastewaters and sediments for a period of one year.Results obtained from the study showed that the bacterial isolates were identified as Vibrio cholerae, Shigella sp, E.coli, Vibrio parahaemoliticus, Salmonella sp, Bacillus sp, Klebsiella sp, Actinomycetes, Serratia sp, Listeria sp, Acinetobacter and Pseudomonas sp while the fungal isolates were Aspergillus niger, Penicillium sp, Aspergillus flavus, Rhizopus, Mucor sp and Candida sp. The cumulative percentage distribution of bacterial isolates across the sampling stations revealed that E. coli had the highest with 15.22%, Vibrio cholerae 13.69%, Pseudomonas 12.43%, Klebsiella 11.31% and Shigella 10.61%. Total heterotrophic count showed that bacteria was more than the fungi in both sediment and wastewater samples. Results of heavy metal analyses revealed that the mean values for all the metals determined were significantly higher (P<0.05) in the sediments than in the wastewater samples. Metals like Cadmium (Cd), Vanadium (V), Iron (Fe), Zinc (Zn), Nickel (Ni) and Copper (Cu) concentrations were significantly higher (P<0.05) in the sediments than in the wastewater samples across sampling stations. Cd had 1.25 ppm, Cu 18.30 ppm, Ni 5.26 ppm, Pb 58.12 ppm, and Zn 57.28 ppm thus suggesting impairment of the water quality in the Ntanwogba creek and the alteration of the ecological dynamics of the receiving water bodies. Pollution of water resources by human activities might lead to destruction of primary producers and this in turn leads to diminishing consumer populations in water resources. The consequences of such anthropogenic pollution can also lead to the transmission of diseases by water borne pathogens. Consequently this may cause changes in environmental conditions in such ecosystems due to their toxicity and biomagnification attributes of metals.