EVALUATION OF BACTERIAL AND HEAVY METAL STATUS OF WATER, SEDIMENT AND FISH SAMPLES FROM KAINJI AND JEBBA LAKES, NIGERIA

ABSTRACT

Information on limnology and status of heavy metals of Kainji and Jebba Lakes are key in the development and management of the Lakes. These Lakes receive organic and inorganic wastes through animal husbandry operations, illegal mining activities, direct waste disposal and other human activities. Quantitative and qualitative analyses of bacterial isolates in water, sediment and fish samples (Clarias gariepinus and Oreochromis niloticus) from Kainji and Jebba Lakes were carried out using primary isolation media, microbact identification  kits  (12A  and  12B  MB1132A/Ausralia) and  molecular  analysis  of some species. Concentrations of heavy metals: lead (Pb), copper (Cu), cadmium (Cd), chromium (Cr) and arsenic (As) in water, sediment and fish samples were determined using atomic absorption spectrophotometer (AA500).   Physico-chemical parameters of the Lake water samples were determined. Biosorption potentials of bacterial isolates were also evaluated. Faecal  coliform  counts  of  water  samples  from  Kainji  Lake  were  below  maximum permissible limit of 5.0 x 102 MPN/100 mL while sampling station 1 (580.83 MPN/100 ml) and 2 (700.83 MPN/100 ml) of Jebba Lake were above maximum permissible limit of 5.0 x 102  MPN/100 mL according to Federal Environmental Protection Agency (FEPA). Faecal coliform counts during wet season were higher than those obtained during the dry season in both Lakes. Bacterial species such as Aeromonas aquatilis strain AE 207, Burkholderia pseudomallei, Bacillus lacus AK 74, Pseudomonas donghuensis HYS, Escherichia coli, Herbaspirillum aquaticum strain  IEH 4430,   Alcaligenes faecalis  strain  Sihong 663-1, Alcaligenes faecalis strain HPRTAK198, Oceanobacillus oncorhynchi subsp. incaldanensis strain AM-75 were isolated from the water samples in both Lakes. Vibrio alginolyticus, Moraxella   species,   Escherichia   hermannii,   Vibrio   parahaemolyticus,   Aeromonas hydrophila were isolated from fish intestines and gills. Concentrations of Cu, Cr and As in water  samples  were  below  maximum  permissible  limit  (2.0,  0.05  and  0.1  mg/L respectively). However, the concentrations of Cd were higher (0.09 and 0.17 mg/L for Kainji and Jebba Lakes respectively) than the maximum permissible limit of 0.01 mg/L according to Federal Environmental Protection Agency (FEPA). Concentrations of Pb in sample stations; Kl.2 (0.082 mg/L), Kl.3 (0.078 mg/L), Kl.4 (0.057 mg/L), Jl.1 (0.066 mg/L), Jl.2 (0.380 mg/L), Jl.3 (0.141 mg/L) and Jl.5 (0.064 mg/L) were above maximum permissible limit of 0.05 mg/ L. The concentrations of heavy metals in the water samples were  higher  during  the  wet  season  compared  to  the  dry season.  In  fish  samples,  the concentrations  of  Pb  in  Oreochromis  niloticus  fish  intestines  (ONFI)  and  Clarias gariepinus fish intestines (CGFI) were above maximum permissible limit. Fish muscles of Oreochromis niloticus and Clarias gariepinus in both Lakes had low heavy metal concentrations. Heavy metal concentrations in sediment from the Lakes were found to be below threshold effect concentration (TEC). Physicochemical qualities of all the parameters examined in both Lakes were found to be within acceptable limit that is favourable for aquatic lives. Biosorption potentials of bacterial isolates revealed that Bacillus lacus strain AK 74 had high potential to biosorp Pb (99.0 %), Cu (98.0 %) and Cr (96.5 %) within 28 days  at  initial  concentration  of  1.0  parts  per  million.  Kainji  and  Jebba  Lakes  are experiencing pollution due to increasing human activities. The results of this study showed high heavy metal concentrations in some of the sample stations; hence human activities such as mining in these stations should follow best practices.

CHAPTER ONE

1.0       INTRODUCTION

1.1       Background to the Study

Microorganisms and heavy metals are common pollutants that originate from agricultural livestock areas, residential wastes, industries, mining zones, exhaust from automobiles and also natural factors such as weathering of soil and rocks. Aquatic pathogenic microorganisms constitute health-hazard to other aquatic lives and man. Most common pathogens include: Salmonella, Shigella, Aeromonas, Leptospira species, enteropathogenic E.coli, Pasteurella, Vibrio and Mycobacterium species. These organisms can be acquired by man and other animals through consumption of contaminated food and water sources. Fish exposed to certain contaminated food or water sources harbors different human pathogens and may carry these pathogens to clean streams and recreational areas. Direct faecal contamination by humans and other animals, wildlife, farm animals and farm runoffs are the major sources of microbial water pollution (Payment and Riley, 2002; Okafo et al., 2003).

Metallic elements that have relatively high density of 5 g/cm3  and above and are toxic or poisonous even at low concentration are referred to as heavy metals (Alloway and Ayres, 1993; Lenntech, 2004). Heavy metals such as cadmiun, aluminiun, arsenic, antimony, lead and mercury are classed as potentially toxic heavy metals. Nickel, vanadium and cobalt are classified as semi essential heavy metals while copper, zinc and selenium as essential heavy metals (Szentmihalyi and Then,   2007). The essential heavy metals are taken up from water, food or sediment for normal metabolism of fish (Canli and Atli, 2003). Excessive intake of essential heavy metals results in toxic effect (Tuzen, 2003). Aquatic ecosystem is at the receiving end of these pollutants either through natural course (run off) or direct dumping of the waste into aquatic system by man.

Kainji Lake is the first man-made Lake in Nigeria with the main objective of providing hydro-power electricity generation for the country (Raji et al., 2011). However, it was realized that the Lake formation will have other impacts on the lives of the communities around it, particularly in the areas of agriculture – fisheries, wildlife and range; public health, human and infrastructural development of the fishing communities (with the experience from other parts of the world where similar man-made Lake have been established). Kainji Lake is a lentic water body on the Niger River, and it is located on the Niger and Kebbi State boarder in Northern Nigeria. The history of Kainji Lake dates back to the dam construction, which commenced in March 1964 and completed in December 1968 (Raji et al., 2011). The dam was built across the Niger River in Nigeria and is called Kainji Dam. Huge amount of electricity is generated in the dam and supplied to all the large cities in Nigeria and also sold to neighboring country, Niger. The formation of Kainji Lake is an epitome of history and also an important fish resources reservoir, contributing to the fish consumption and supplying important markets in Abuja, Lagos, Ibadan, Onitsha and Kano among others (Raji et al., 2011).

Niger River, which formed Kainji Lake, takes its source from the highlands of central Guinea located near the border between Guinea and Sierra Leone. The river flows Eastward between Timbuktu and Bourem and then takes a course in the Southeast direction through Gao in Mali and Niamey in Niger Republic, and finally to Kainji Lake in Nigeria.

The river forms part of the Niger-Benin border at the South of Niamey prior to entering Nigeria. Two distinct floods occur annually in the Lake. The first is the “black flood,” which originates from Niger River (with its headwater from Guinea). The Niger River rise from the Fouta Djallon highlands in Central Guinea (an altitude of 1000 meter above sea level) and flows into Kainji Lake, a distance of 2737 km (Raji et al., 2011). As the water flows downstream, it drains the swamp of Timbuktu where it loses 65 percent of its water to evaporation and infiltration. Having deposited its silt in this swampy area, the water becomes relatively clean and appears black at a distant on its arrival at the Lake, hence, it is called ’black flood’. This flood occurs between December and March anually. The second flood is called “white flood” which originates from local runoffs around the catchments of Kainji Lake and this appears around August to November annually (with lot of silt and mud), thus, giving it the milky or whitish look from which it gets its name ’white flood’. The flood reaches its peak by September with higher volume than that of the black flood (Raji et al., 2011).

The construction of Kainji Lake led to the establishment of “Kainji Lake Research Project,” which today is called “National Institute for Freshwater Fisheries Research, New-Bussa”. The main function of Kainji Lake Research Project was to develop the natural resources of the Lake area in terms of fisheries, agriculture and socio-economic development. It also studied public health and vector of human diseases (Abiodun, 2002).

Jebba Lake is a watershed of Kainji Lake and is about 100 km from Kainji Dam to Jebba Dam. It is rich in fish biodiversity (Adelakun et al., 2017). Jebba Lake is located in North- Central Nigeria and is characterized mainly by two seasons- dry and rainy (Adelakun et al., 2017). Oreochromis niloticus and Clarias gariepinus constitute some of the commercially important fish species in Jebba Lake (Oladipo et al., 2018) and Kainji Lake. Abiodun and Odunze (2011) observed  51  species  of fish  under 12  families  from  Jebba  Lake.  It  is expected that Jebba Lake will habour many fish species but because only few research have been conducted on the Lake, about half the number of fish species in Kainji Lake have been reported for Jebba Lake (Abiodun and Odunze, 2011).

1.2       Statement of the Research Problem

According to World Health Organization (WHO), about 80% of ill-health in developing countries like Nigeria is water related (Cheesbrough, 2000). Cattle and other livestock are reared in the surroundings of Kainji and Jebba Lakes. These livestock drink and defecate into the Lake. Other anthropogenic factors like washing, bathing and electricity generation are regularly done in the Lakes. Illegal mining activities are also carried out around the Lakes. Undoubtedly, these activities may constitute the major sources of pollution to the Lakes (such as microbial pathogens and heavy metals). The direct or indirect consumption of these microbial pathogens and heavy metals by man through water intake and consumption  of  contaminated  fish  bring  about  varying  diseases  in  man  and  animals. Various  cases  of  water-borne  diseases,  involving  the  coliform  organisms  such  as Escherichia coli, Vibrio cholerae, Salmonella species and Shigella, have been widely reported (Gugnani, 1999; Licence et al., 2001). Pollution due to heavy metals in aquatic environments is a global concern because they are not utilizable by the organisms and most of them are toxic to organisms (ÖztÜrk et al., 2009). Heavy metals amongst other environmental pollutants, are of serious public and other animal health concern. This is due to their potential toxicity and ability to bioaccumulate in aquatic ecosystems (Censi et al.,2006).

Heavy metals have great affinity for sulphur, and within enzymes, immobilize them. Heavy metals could also bind to cell membranes, thereby interfering with transportation processes in the body. Other vulnerable sites of attack include the protein, carboxylic acid (- COOH) and amino (- NH3) groups (Adekola et al., 2010).

Severe health hazards are linked to the consumption of fish scarcely or greatly polluted by lead (Pb). Lead poisoning causes dagames to the central nervous system especially among children causing mental impairment. This condition affects oxygen transport in the body and leads to other digestive problems. Exposure of humans to lead for a long term can cause coma or death (Etim et al., 2013).

Cadmium (Cd), known to be a heavy metal, can cause cancer by interfering with the body metabolic processes. Cadmium being one of most harmful heavy metals is capable of causing renal, hepatic and testicular injury. Some adverse effects of acute cadmium toxicity include kidney damage, testicular tissue damage, high blood pressure and red blood cells destruction (Etim et al., 2013).

Weak immune system, likely disease of lung cancer, ulcer and liver damages may result from exposure and consumption of chromium (Cd)- containing substances. Long – term exposure to chromium can cause kidney, liver and nerve tissue damage. Many chromium compounds are also known to cause cancer, thus, making them carcinogenic (Etim et al., 2013).

1.3       Justification for the Study

Baseline data on the microbiological and heavy metal content of Jebba and Kainji Lakes are scanty. This information is essential for management of these inland water fisheries and utilization of the inland water bodies. Water quality in many Lakes and rivers are being impaired by high levels of pollutants. These constitutes health hazard to aquatic lives and also to humans that use the raw water for drinking, bathing, irrigation purposes and also consumption of fish from such polluted water bodies. About sixty seven million (6.7 x 107) Nigerians still rely exclusively on surface water source to meet their domestic needs, yet pollutant discharge into surface water by individuals and industries go on unmitigated, unregulated and unpunished  (Longe et al., 2010). Large populations of human beings in the world today use fish as staple source of proteins and also as source of income. In recent time, fish is preferred more by people as a healthy alternative to red meat (Adebayo-Tayo et al., 2012). Fish is easily digestible. It contains less fats and high proportion of poly or mono unsaturated fatty acids (Omega – 3 fatty acid) and is thought to be associated with reducing the risk of human cardiovascular disease. Omega 3 fatty acids have been found to have cholesterol  lowering  properties  as  well  as  decreasing  blood  clotting  activity (Browne, 1990).

Fish performs all their body functions in an aquatic environment; hence the quality of water is  very important  for  their  survival,  productivity and  quality.  Fishes  are  major  faunal components of aquatic environments and are usually used as excellent environmental bio- indicator of the health of aquatic system (Widianarko et al., 2000). These highlight the need to determine the bacteriological and heavy metal status of the water, sediment and fishes from Kainji and Jebba Lakes, which are surrounded by various anthropogenic activities (including illegal mining around the Lakes), yet serving as sources of drinking water and fish supply for many communities around the Lakes. The quality of groundwater has been greatly affected by the rapid growth of urban areas due to overexploitation of resources and improper waste disposal practices (Ojutiku et al., 2013). Hence, the need for concern over the protection and management of surface water and groundwater quality is highly significant (Ojutiku et al., 2013). The results of this study would help to create public health awareness on the hazards associated with the use of polluted water bodies and also in the effective monitoring and management of the Lake water quality and health status of the aquatic organisms particularly the fish, through evidence based policy decisions.

1.4    Aim and Objectives of the Study

This study was aimed at evaluating the bacteriological and heavy metal status of water, sediments and fish samples from Kainji and Jebba Lakes, Niger State, Nigeria.

The objectives were to determine:

i. Bacteriological quality of water, sediments and fishes from Kainji and Jebba Lakes.

ii. Heavy metals (Pb, Cu, Cd, Cr, As) status of water, sediments and fishes from Kainji and Jebba Lakes.

iii. Physico-chemical qualities of water from Kainji and Jebba Lakes.

iv. Heavy metal biosorption potential of the bacterial isolates from the Lakes.

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