Microbial and Physicochemical Qualities of River Owena Sediments

Microbial quality, physicochemical parameters and heavy metals determination of sediment samples from River Owena, Oriade local government area, Owena, Nigeria. For period of dry and wet seasons. The pH of the sediment samples ranged from 6.44 to 8.00±0.01, organic matter ranged from 17.15 to 35.31%; water holding capacity ranged from 0.323 to 1.779±0.01 ml/g; composition of sand: clay: silt were 75:12:13 %, 33:17:50 %, 62:18:20 % and 50:20:30 %; 82:2:16 %, 48:22:30 %, 32:25:43 % and 43:27:30 % wet and dry seasons respectively indicated more of loamy sand, clay loam, silt clay and loam. Mean concentrations of heavy metals measured in the sediment samples included iron, zinc, manganese, lead, chromium, cadmium, nickel and copper, iron had highest values of 1.89 to 4.1±0.01 mg/kg and cadmium lowest values of 0.01 to 0.12±0.01 mg/kg. A total of fifteen bacterial species were isolated from River Owena sediments, which included Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis, Salmonella enteritidis, Bacillus subtilis, Serratia marcescens, Shigella sonnei, Bacillus cereus, Micrococcus luteus, Micrococcus varians, Pseudomonas aeruginosa, Proteus vulgaris and Erwinia amylovora. A total of ten fungal species were isolated, which included Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Penicillium chrysogenum, Cladosporium herbarum, Mucor mucedo, Mucor plumbeus, Fusarium oxysporum, Rhizopus stolonifer and Rhizopus oryzae. The total bacterial count of the sediment ranged from 4.1 x10 to 3.02 x 10 cfu/g while the total fungal count of the sediment ranged from 4 x 10 to 7.6 x 10 cfu/g. However, the pollution level due to the presence of some pathogenic microorganisms which are of public health significance, but it could be improved upon with appropriate treatment and sanitation. Keywords— Microbial, Physicochemical, Heavy metals, Sediment, Wet and Dry season, Health.

INTRODUCTION Sediment is any material that settles to the bottom of a lake, river or ocean and are composed of dead and living organisms, dust from the air, soil eroded from the continents and chemical solids as well as water and nutrients (Alexopolous, 1983, Carla,1997, Robert and Stanley, 2000. Sediments differ from soil but they both provide environments for microorganisms and play different roles in the ecosystem of a wetland. Sediments near urban areas commonly contain high levels of contaminants (Lamberson et al., 1992;Cook and Wells, 1996). This constitutes a major environmental problem faced by many human impacted aquatic environments (Magalhaes et al., 2007). The contamination of sediments with heavy metals leads to serious environmental problem (Loizidou et al., 1992). Today there is trace contamination not only of surface water but also river sediments, which are susceptible to leaching from waste dumps, mine tailings and industrial production sites (Moore et al., 1998). Organic manure, municipal waste and some fungicides often contain fairly high concentration of heavy metals. Soils receiving repeated applications of organic manures, fungicides and pesticides have exhibited high concentration of extractable heavy metals, thereby increase their concentration in runoff (Moore et al., 1998), The composition of sediments is dependent on natural factors (geological, topographical, meteorological, hydrological and biological) in the drainage basin and varies with seasonal difference in runoff volumes, weather conditions and water levels. Importantly, sediments can also be contaminated by naturally occurring sources (Muller, 2001).Heavy metals may adsorb onto sediments or be accumulated by the benthic organisms; their bioavailability and toxicity depend upon the various forms and amount bound to the sediment matrices (Chukwujindu et al., 2007). Additionally, pollutants released to surface water from industrial and municipal discharges, atmospheric deposition and run off from agricultural, urban and mining areas accumulate to harmful levels in sediments (Chukwujindu et al., 2007).
The soil pH, organic content and water are the main factors affecting the bacterial and fungal population and diversity. The organic carbon, nitrogen, phosphorus, potassium are important for fungi. In the absence of any of these the growth and sporulation of moulds as well as other microorganisms are hampered a lot. It has been reported that the density of fungal population occurred during the monsoon (rainy) season when the soil moisture was significantly high. Also environmental factors such as pH, moisture, temperature, organic carbon, organic nitrogen play an important role in the distribution of mycoflora (Muller, 2001). Soil texture can have a profound effect on many other properties and is considered among the most important physical properties. Texture is the proportion of three mineral particles, sand, silt and clay, in a soil. These particles are distinguished by size, and make up the fine mineral fraction. Particles over-2 mm in diameter (Olaitan and Lombin 1984). River Owena is a good source of domestic water to Owena people, during collection of water from this river, sediments sometimes get into the water. Therefore there is need to study the level of pollution by determining the microbial and physicochemical qualities of sediments because of its potential health hazard.

II. MATERIALS AND METHODS The study area
River Owena is located about four kilometers from Joseph Ayobabalola University Ikeji Arakeji along Ilesha-Akure express way in Oriade local government area of Osun State, Nigeria on latitude N 7.403135 and longitude E 5.014589. It is a fresh water and free-flowing during raining season but slow-moving at the onset of dry season.

Study design
The analysis cover a period of six months, from July 2015 to January 2016 covering wet and dry season, sediment samples were collected at four sampling points (two each at both side of the bridge). The human activities around the river and the sampling points were evaluated and noted on monthly basis.

Sampling points
The four sampling points along the longitudinal course of River Owena (Figure 2), were river water flowing across the right-side of the bridge along Akure-Ilesha express-way at N 7 o 24′ 11′′ E 5 o 0′ 52′′, this point was about 64 cm deep (point One); Two-This point was across the river about one hundred metres away from sampling point One, It is about one hundred and thirty metres from the palm plantation at N 7 o 24′ 1′′ E 5 o 0′ 49′′, this point was about 80 cm deep; Three-This point was one hundred and fifty metres away from sampling point two. It was close to the farmland along the bank of the river at N 7 24′ 12′′ E 5 o 0′ 48′′, this point was about 50 cm deep; and four-This point was one hundred metres away from sampling point three at N 7 o 24′ 12′′ E 5 o 0′ 46′′, this point which was about 90 cm deep used to be the site where domestic water was collected. Water from this river is still collected for domestic purposes at the peak of dry season especially by the people living near and close to the river. Prior to this study, water from sampling point four was used for domestic purposes. Human activities on the river recently before the conclusion of this research included use of the water for cement blockmoulding, car wash, commercial water supply to people, along the bank of the river are farms with crops such as maize, sugar cane and vegetables such as spinach and pepper plantation. The river also serves as recreational swimming pool for small children from nearby primary and secondary schools. Various types of birds and egrets were seen on the river. Sample collection Sediment samples were collected during wet and dry season from the four points. Sterile bottles of 500 ml were used for sample collection. Samples for microbial analysis were collected aseptically, labeled and stored in ice packed plastic coolers and transported to the laboratory where analysis within 24 hours of collection was carried out (Dubey and Maheshwari, 2004).

Trace and heavy metals
Trace and heavy metals determination was carried out using standard of Ravera et al. (2003) and Aiyesanmi (2006). This technique permits the measurement of a series of elements at the same time, the sediments were analyzed for zinc, manganese, cadmium, lead and iron, chromium, copper, nickel and their concentrations.

Determination of physicochemical characteristics of River Owena sediments
The pH, organic matter content and water holding capacity were determined using the method of Pramer and Schmidt (1984). Determination of sediments texture was done using the method of Awolumate, (1977); Olaitan and Lombin, (1984). Appropriate textural classification was then referred to get the soil texture.

Statistical analysis
All the data obtained in this study were subjected to analysis of variance (ANOVA) Followed by Duncans New multiple range test was used to separate means using SPSS 11.09 for windows and significance level was set at p<0.05 (Norusis, 2006).

III.
RESULTS AND DISCUSSION The pH, total alkalinity, organic matter content, nitrate and phosphate of the sediment samples ranged from 6.44 to 7.00 ±0.01, 19.40 to 138.16±0.01 mg/l CaCo3, (% dry wt) 17.16 to 20.04%, 0.42 to 1.03±0.01mg/kg, and 28.87 to 30.00±0.01mg/kg respectively during wet season (Table 1). While pH, total alkalinity, organic matter content, nitrate and phosphate ranged from 6.98 to 8.00±0.01, 119.40 to 138.16±0.01 mg/l CaCo3, (% dry wt) 27.26 to 35.32%, 1.55 to 2.30±0.01 mg/kg, 0.40 to 1.30±0.01 mg/kg respectively during dry season ( Table 2).The pH of the sediments was slightly acidic during wet season and slightly alkaline during dry season which could be as a result of seasonal variation. This is similar to the results obtained by Tamaki Figure 3). This was similar to the findings of Morgan (2010), which stated that the texture of a soil is not readily subject to change, so it is considered a basic property of a soil. The water holding capacity (ml/g) of sediment from River Owena from July 2015 to Jan. 2016 is shown in (Table 3)

Heavy metals of River Owena sediments (dry and wet season)
The    Values represents means ± Standard error of means.

Total fungal counts (sfu/g) of River Owena sediments
Total fungal counts for the four samples points of sediments determined from July 2015 to Jan. 2016 covering (wet and dry seasons) ranged from 4 x 10 3 to 7.6 x 10 3 ±0.01 sfu/g ( Table 6). The lowest count occurred in sample point four in Dec., 2015.While, the highest count occurred in sample point one in Aug., 2015.Wet season had a range of 2.3 x 10 3 ±0.01 sfu/g in Sept., 2015 to 7.6 x 10 3 ±0.01sfu/g in Aug., 2015. Dry season had a range of 4 x 10 3 ±0.01 sfu/g in Dec., 2015 to 4.9 x10 3 ±0.01sfu/g in Nov. This result is similar to the result obtained by Alabi, (1994).  Values represents means ± Standard error of means Fungi and bacteria are part of the group of living organisms found in sediments, they may be found in the surface of decaying plant or animals materials in river. Human activities such as farming, swimming, grazing of animals and car wash park in and around the river bank which will increase the contamination level along-side run-offs should be reduced or totally discouraged.