Types and abundance of arthropod fauna in relation to physico-chemical properties of the bottom sediment of Warri river, Nigeria

The occurrence of arthropods associated with the bottom sediment of Warri River was investigated, and samples were collected from January 2002 to May 2003. The values of pH, alkalinity, magnesium and total hardness were significantly different (P < 0.01) between the study stations, while organic matter recorded for the bottom sediment shows no significant difference (P>0.05). The dominant fauna were Dipteran larvae, which constitute90.47%. Two rare groups of fauna (Arachnida and Ephemeropterans) were restricted to the upstream (Agbarho) station. Megapus sp. had a single record and is being recorded for the first time in Nigerian water bodies. All theorganisms did not show any correlation with pH, conductivity and percentage (%) organic matter. Fauna densities were maxima only in the dry season period

Physicochemical Profiles and Water Quality Indices of Surface Waters Collected from Falcorp Mangrove Swamp, Delta State, Nigeria

Surface water samples were collected at a frequency of once monthly for a period of 18 months; February 2013- July 2014, from several points on the Falcorp mangrove swamp, Ijala, Warri, Delta State. The abstracted samples were subjected to several physical and chemical analyses which were conducted in accordance with referenced procedures. The recorded data were subjected to statistical analysis and multivariate analysis using Microsoft excel, SPSS version 16.0 and PAST respectively. There was no significant difference (P>0.05) across the stations; Stations 1, 2, 3, 4 and 5 respectively for pH, Temperature, Electrical conductivity, DO, BOD5, TSS, Turbidity, Chloride, Salinity, Sulphate, Nitrate, Hardness, Ca, Ma, Zn, Cd and Pb. There were significant difference (P<0.05) across the 5 stations for the following parameters; TDS, Bi-carbonate, Phosphate, Fe and Cu. The mean concentrations of most of the physical and chemical parameters in the surface water with the exception of pH were below acceptableWHO limits for portable water. The water quality index (WQI) at stations 1, 2, 3, 4 and 5 ranged from 8.45-24.9, 8.31-23.95, 8.36-16.26, 8.24-10.11 and 8.43-23.58 respectively. The Principal component analysis (PCA) of the data sets yielded 35 variables under 22 components with Eigenvalues < 1 (PC1-PC6) and >1 (PC7-PC22). There was a positive correlation between pH, water temperature, TDS, EC, TSS, turbidity, Cl, HCO3, salinity, SO4, hardness, Ca, Mg, and Cd whilst a negative relationship existed between DO, BOD5, PO4, NO3, Fe, Zn, Cu and Pb respectively. Keywords: Physicochemical, surface water, Falcorp, Mangrove swam

Toxicity Evaluation and Cytogenetic Screening of Process Water Using a Plant Bioassay

The effect of toxic substances on aquatic lives from a wastewater indiscriminately discharged into the environment during oil and gas exploration activities in Nigeria is the focus of this study. A plant bioassay, the Allium cepa test, was used for the cytogenotoxicity screening of process water on root growth inhibition and chromosome abnormalities in the meristematic roots of the plant. Results of the physicochemical analysis of the wastewater collected from Nigerian Agip Oil Company (NAOC) facility at Ogboinbiri in Bayelsa State at the point of discharge into the environment showed that it had an unpleasant odour, was slightly alkaline (pH 7.72) and had high electrical conductivity (2793.33 μS/cm). Lead, manganese, iron, chromium and nickel were present at amounts (0.13, 0.33, 4.47, 0.17 and 0.10 mg/l respectively) above national (NESREA) and international (USEPA) limits for effluent discharge. Macroscopic evaluation of A. cepa cultivated in the wastewater resulted in significant (p<0.05) concentration-dependent root growth inhibition with an EC50 value of 14.8 % at 96 h. Root tip cells of the onion bulbs processed for cytological studies by the aceto-orcein squash technique after exposure to the wastewater for 48 h at concentrations of 0.5, 1.0, 2.5, 5.0, and 10% (v/v; wastewater/tap water) showed chromosomal aberrations at all concentrations. Statistical analysis of microscopic results show significant (p<0.05) concentration-dependent frequency of aberrant chromosomes and reduction of mitotic index. The findings in this study calls for proper treatment of process water before its discharge into water bodies to avoid cyto-genetic damages to aquatic lives.Keywords: Toxicity, chromosome aberration, Allium cepa, process wate

Diversity and Distribution of Benthic Macroinvertebrate Fauna of Obazuwa Lake in Benin City, Nigeria

Obazuwa Lake is located in Ovia North East Local government area of Edo state. This study was conducted for a period of six (6) months from January to June, to evaluate the benthic macroinvertebrate structure, abundance, distribution and diversity. The Fauna were collected seasonally and three (3) sites were sampled fortnightly. A total of 748 benthic macroinvertebrates composing of 46 taxa, 13 groups and 25 families were recorded. Dominant taxonomic taxa varied considerably; Diptera (64.77%), Hemiptera (64.56%), Coleoptera (48.43%), Mollusca (29.06%), Oligocheata (19.28%), Nematoda (16.03%) and Odonata (15.83%). The variations in taxa and number of individuals between stations were not significantly different (P>0.05). Sorenson’s quotient (Q/S) indicates similarities in the species composition between the sites. Keywords: Benthic fauna, lake, water quality, Benin City, tax

Physico-Chemical Characteristics and Bacteriological Studies in Hand Dug Wells in Udu Community of Delta State, Nigeria

Sixty (60) water samples of hand-dug wells were collected from Udu community (delta state) and analysed physico-chemically and microbiologically using standard methods. The results of the physico-chemical analysis were obtained in the following range; pH (7.12 - 7.45), conductivity (78.38-397.55µScm-1), turbidity (3.58-8.17NTU), DO(3.77-4.76mg/l), BOD5 (1.49-1.75mg/l), bi-carbonate (2.77-27.97mg/l), chloride (16.37-58.27mg/l), nitrogen (0.002-0.01mg/l), calcium (1.79-7.22mg/l), magnesium (0.41-2.18mg/l), sulphate (0.13-1.78mg/l), nitrate (0.001-0.72mg/l) and phosphate (0.12-0.38mg/l). All the water samples were found to harbor coliform organisms in numbers greater than the required WHO/SON standards for drinking water; Presumptive coliform count ranged from 1.69×102 to 1.66×103cfu/ml; aerobic mesophillic count 2.82×102 to 1.50×103cfu/ml and Escherichia Coli; 1.35×101 to 2.19×102cfu/ml. High coliform count was recorded during the rainy season as compared to dry season of this research. However, regular monitoring as well as purification measures such as boiling and filtration is recommended before use to ensure a healthy living. Keywords: hand-dug wells, water quality, physico-chemical parameter, bacterial analysis, WHO/SON

Water quality assessment of Osse River, Gele-gele: a tributary of Benin River, southern Nigeria

The physical/chemical characteristics and some heavy metals of Osse River, Gele-gele, Southern Nigeria was assessed during the dry and wet seasons. Four stations were studied from upstream to downstream with an average distance of 500meters between each station. A total of twenty-one (21) physical/chemical parameters were studied. pH ranged from 6.2-7.5, Suspended Solid 4-48mg/l, Turbidity 0-39NTU, Electrical Conductivity 20-110μS/cm, Alkalinity 8-48mg/l, Chloride 7.1-17.7mg/l, Hardness 8-56mg/l, Phosphate 0.01-0.53mg/l, Sulphate 5-33mg/l, Nitrate 1.2-9.3mg/l, Dissolved Oxygen 2.0-8.4mg/l, Biochemical Oxygen Demand 0.6-5.8mg/l. Heavy metals level generally ranged from 0.1 to 1.8mg/l for Iron, Zinc 0.0 to 0.93mg/l, Chromium 0.0 to 0.65mg/l, Cadmium 0.0 to 0.041mg/l, Lead 0.0 to 0.26mg/l, Manganese 0.0 to 0.082mg/l, Copper 0.0 to 0.059mg/l, Nickel 0.0 to 0.49mg/l. The mean concentration of metallic ions in Station 3 was significantly higher across the four sampled, with manganese, iron, cadmium, and copper responsible for this difference. Water Quality Index showed that all four stations had a range of 8.03-9.07. The concentration of the metals in the Osse river are within background concentration level, the mean Dissolved Oxygen and Biological Oxygen Demand obtained indicate the water is rated between fairly clean and clean, and the Water Quality Index indicates excellent water quality. Thus, the water is presently suitable for domestic use, but its quality may deteriorate with time if the current rate of anthropogenic activities around the water body is not curtailed.Keywords: Water Quality, Osse River, Gele-gel

Assessment of Metal Accumulation and Bioaccumulation Factor of Some Trace and Heavy Metals in Freshwater Prawn and Crab

Globally, freshwater decapods have been one of the major food delicacies because of their rich deposits of minerals. High metals are usually accumulated in the body tissues of these organisms because of their lifestyle. Metal accumulation in freshwater decapods has been acclaimed and perceived to cause serious health concerns when transferred to humans along the food chain. A recent study has shown that freshwater biota, prawn (Macrobrachium rosenbergii), showed significant differences (p  0.05) in Fe, Zn and Cd. In contrast, the freshwater biota, crab (Sudanonautes africanus), showed significant differences (p  0.05) in Pb, Cr and Cd. A high accumulation of Fe in the whole tissues of Macrobrachium rosenbergii and Sudanonautes africanus was also established. This is because Fe in the Nigerian soil and sediment is naturally very high beyond slated thresholds and tend to accumulate and transcend or magnify in benthic. It was noticed that Zn (2.68) and Cr (4.52) had the highest bioaccumulation factors in prawn and crab, respectively. Chromium has been observed to be carcinogenic. The consumption of Cr in the muscles of crab might constitute probable serious health risk

Status and the Diversity of Macrobenthos of Udu - Ghievwen Wetlands in the Niger Delta, Nigeria

A survey on the status and diversity of benthic fauna community of Udu – Ughievwen wetlands was carried out for a period of six months. Benthic samples were collected using the Ekman Grab made by Hydrobios. Water Hyancinth (Eichornia crassipes) was also sampled for benthic organisms. A total of twelve taxonomic groups were recorded in this study and they include; Ephemeroptera (37.63%), Diptera (20.45%), Decapoda (14.39%), Odonata (6.48%), Annelida (5.97%), Coleopterans (4.21%) and Trichoptera (3.87%). Others were; Mollusca (3.45%), Amphibian (2.85%), Hemiptera (2.27%) and Arachnida (0.42%). The highest number of individuals was collected from Ohwawha (171) and least at Ofri (60). Shannon – Weiner diversity (H) was highest at Ujevwu and least at Ofri sampling stations respectively. The suitability and diversity of the macrohabitats in the various study sites have favoured the abundance of benthic macroinvertebrates particularly the Decapoda, Ephemeroptera, and Diptera in these water bodies. The dominance of Ephemeroptera in most of the sites indicates a healthy nature or sound environmental quality of the entire Udu – Ughievwen wetlands. The study revealed that wetlands are populated by a rather different assortment of macroinvertebrates. Keywords: Dominant, Wetlands, Macrobenthos, Niger Delta, Biodiversity

Assessment of Anthropogenic Influences on the Benthic Invertebrate Community of Oghan River in Edo State, Nigeria

The influence of anthropogenic activities on a freshwater ecosystem was investigated by sampling for physicochemical parameters, heavy metals and benthic invertebrates of Oghan River in Ora Community, Ovia South-West Local Government Area of Edo State, Nigeria. Samples were collected monthly for a ten months period across three stations between 09:00 and 12:00 hrs on each sampling day for laboratory analysis following standard procedure. No significant variation (P > 0.05) was observed between the parameters, although heavy metals in sediments were above the WHO recommended limit for freshwater ecosystems. For benthic organisms, about 386 individuals belonging to 23 taxa, 11 families and 6 orders were recorded. Among the orders, the most dominant were Diptera (44.94%), Odonata (28.31%), Ephemeroptera (13.77%) while the least was Diplogasterida (0.26%). The families were dominated by Chironomidae (32.47%), Baetidae (13.77%) and Libellulidae (12.73%). Species diversity (2.677) and richness (4.002) were highest in station 1 and lowest in stations 2  (2.357) and 3 (2.745) while species evenness was highest in station 3 (0.791) and lowest in station 1 (0.6924). The elevated levels of heavy metals and the decrease in sensitive benthic taxa observed in the river is an indication that anthropogenic activities could be impacting the water quality and benthic invertebrate community of the river

Ecological Survey of Macrobenthic Invertebrates of Selected Ponds in Agbede Flood Plain, Southern Nigeria

Ecological study on three selected ponds of Agbede flood plain was fortnightly carried out between January and June, 2007 to assess and document the macrobenthic fauna composition, abundance and distribution, as well as the physicochemical status of some parameters in water which were collected and analyzed monthly.  Benthos was sampled for using the Ekman Grab operated by hand in shallow waters together with the Kick sampling method. Among the eight physicochemical characteristics investigated, pH fluctuated from slightly acidic to slightly alkaline with range of values (5.90 – 7.35) at the studied stations. Significant difference (P<0.05) was observed for biological oxygen demand (BOD5) and dissolved oxygen (DO). A total of ten (10) groups comprising macroinvertebrates taxa with one thousand and thirty one (1,031) individuals were recorded in this study. Most dominant groups were represented by Coleopterans (35.79% and 374 individuals), Hemiptera (20.19% and 211 individuals) and Dipterans (18.47% and 193 individuals).  Evenness was highest in pond 1 (0.4973). The highest number of macroinvertebrates were collected from pond 2 (416) where no human activities occurred and however implied that human activities can rapidly alter any previously stable communities of aquatic environments. Keywords: Ecology, Flood plain, Macrobenthos, Ponds, Fadama, Nigeri