Evaluations of the Levels of Heavy Metals in River Water and Selected Species of Fish from Ogba River in Benin City, Nigeria

Ogba River provides source of drinking water in Benin City metropolis and also serves as repository for urban drainage and agrochemical wastes which could potentially impact the water and biota such as fish. This study was therefore aimed at assessing the concentrations of copper, cadmium, chromium and lead in water and fish from Ogba River (Nigeria). The dominant fish species encountered in the study are Clarias gariepinus, Hemichromis fasciatus and Tilapia mariae with mean weight of 127.86g, 116.60 and 74.46g respectively. Water and whole fish tissues were acid digested and analyzed for metal concentrations using the atomic absorption spectrophotometer. The results showed that in water and fish species, copper concentrations of 0.211 mg/l and 0.760 mg/kg were highest in station one, while chromium concentrations of 0.002 mg/l and 0.040 mg/kg were lowest in station two. There was significant difference in the mean concentration of the heavy metals in the selected fish species (P<0.05). The need for enforcement of regulations inhibiting unwise use of aquatic resources and regular monitoring of environmental matrices (water, sediment, and fauna) is advocated given that fish from Ogba River is unfit for human consumption. Key words: Heavy metals, Ogba River, fish

Water Quality of Perturbed Egbokodo River, Delta State, Nigeria.

Purpose: An aquatic ecological survey was carried out across the stretch of Egbokodo River; located in Warri South Local Government Area of Delta State, Nigeria. Biomonitoring survey of the river was carried out around important sections along the river. Methodology: 10 samples of surface water were collected at 10 sub-stations; marked using the Global Positioning System device (GPS); randomly around each station (1, 2, 3, 4, and 5) from November, 2014 to February, 2016 (16 months). The pH of water was taken and recorded in-situ using a WTW water sampler probe. All samples were transported immediately to the laboratory for analysis of the physico-chemical variables. The mean and standard error values of 10 samples collected from each station were subjected to a two-way analysis of variance (ANOVA) to analyse the differences across the stations and the months; using SPSS version 19.2 at probability level of 0.05. Duncan Multiple Range test (DMR) to ascertain the actual locations of the significant differences across the stations and among the months. Results: Results show that anthropogenic activities around the river are of higher impacts on the ecological equilibrium than most neighbouring rivers. Data assures the suitability of the river for aquatic life, agriculture and domestic use. However, need for amelioration of the anthropogenic perturbations cannot be overemphasised. High conductivity in the dry season was coeval with high salinity; indicating a substantial contribution of the dissolved salts to the conductivity of the river. The high values of BOD observed at Station 2 was accompanied by low dissolved oxygen (DO). This can be attributed to disposal of organic wastes at this section of the river. The DO at Station 3 was significantly higher than other stations throughout the study period (P < 0.05). This can be attributed to the surface turbulence by dredging agitation and high standing aquatic macrophytes. The levels of the essential primary productivity nutrients such as nitrate, phosphate and sulphate in the river indicate that the river is oligotrophic. Conclusion and Recommendations: The study has provided a proof of trophic stratification by anthropogenic perturbations. The study has also provided a general picture of the aquatic environment over an extended period of time; a database useful for reference in subsequent studies aimed at protecting the ecological integrity Egbokodo River

Water Quality of a Perturbed Tropical Forest Aquatic Environment in Nigeria

Purpose: Egbokodo River was surveyed from November, 2014 to February, 2016 (covering wet and dry seasons); on monthly basis. 10 samples of surface water were collected at 10 sub-stations randomly around each station; labelled Stations 1, 2, 3, 4, and 5 using 250 litres sampling bottles. Methodology: Two-way ANOVA was used to test for significant differences across the months and across the stations. High conductivity in the dry season was coeval with high salinity; indicating a substantial contribution of the dissolved salts to the conductivity of the river. The outstandingly high levels of total dissolved solids and turbidity at Station 3 can be attributed to the intense dredging activities carried out at this location. The high values of BOD observed at Station 2 was accompanied by low dissolved oxygen (DO). This can be attributed to disposal of organic wastes at this section of the river. The DO at Station 3 was significantly higher than other stations throughout the study period (P < 0.05). This can be attributed to the surface turbulence by dredging agitation and high standing aquatic macrophytes. The levels of the essential primary productivity nutrients such as nitrate, phosphate and sulphate in the river indicate that the river is oligotrophic. Results show that anthropogenic activities around the river are of higher impacts on the ecological equilibrium than neighbouring rivers. The river is supports aquatic life, it is also suitable for agriculture and domestic use; though not without proper water treatment before drinking

Assessment of some heavy metals and total hydrocarbons in Clarias gariepinus fish of Osse River, Edo State, Nigeria

The sequence of the heavy metals (Fe, Mn, Zn, Cu, Pb, Cd and Cr) and total hydrocarbons (THC) in the water and tissues (gills, intestine and muscle) of an abundant and economically significant fish (Clarias gariepinus) harvested from Osse River were investigated from April, 2014 to September, 2015. Water and fish samples were collected from 4(four) chosen stations and were analysed for the levels of heavy metals and total hydrocarbons. The ecological risk of the study area and health risk indices of the fishes were assessed. Generally, accumulation of heavy metals and total hydrocarbons in the fish was gills > intestine > muscles (anomalous sequence). The sequence may pose some threats to the health of the consumers. Iron, zinc, copper, cadmium and THC showed significant health risk indices in the fish despite their insignificant ecological risk indices. Further in-depth study on the actual levels of risks to consumers is recommended

Comparative Studies of the Impacts of Freshwater, Cultivated and Preserved Tiger Shrimps on Consumers’ Health

Aim: The study was aimed at comparing the levels of heavy metals in Tiger shrimps- Penaeus monodon from different source categories, to ascertain the impacts of the selected heavy metals on the consumers’ health. Hypothesis: Heavy metals in blood serum of shrimp consumers were accumulated solely from the shrimps

Evaluations of the Levels of Heavy Metals in River Water and Selected Species of Fish from Ogba River in Benin City, Nigeria

Ogba River provides source of drinking water in Benin City metropolis and also serves as repository for urban drainage and agrochemical wastes which could potentially impact the water and biota such as fish. This study was therefore aimed at assessing the concentrations of copper, cadmium, chromium and lead in water and fish from Ogba River (Nigeria). The dominant fish species encountered in the study are Clarias gariepinus, Hemichromis fasciatus and Tilapia mariae with mean weight of 127.86g, 116.60 and 74.46g respectively. Water and whole fish tissues were acid digested and analyzed for metal concentrations using the atomic absorption spectrophotometer. The results showed that in water and fish species, copper concentrations of 0.211 mg/l and 0.760 mg/kg were highest in station one, while chromium concentrations of 0.002 mg/l and 0.040 mg/kg were lowest in station two. There was significant difference in the mean concentration of the heavy metals in the selected fish species (P&lt;0.05). The need for enforcement of regulations inhibiting unwise use of aquatic resources and regular monitoring of environmental matrices (water, sediment, and fauna) is advocated given that fish from Ogba River is unfit for human consumption. Key words: Heavy metals, Ogba River, fish

Ecological survey of freshwater ecosystems of Ovia, Edo state Nigeria for gastropod molluscs

The survey for freshwater snails in streams, rivers and a lake in Ovia Southwest LGA of Edo State, Nigeria was carried out from June to November, 2013. Samples were collected by using sweep-net and by hand picking of snails within the open water habitat, at marginal areas and on submerged vegetation at edges of the habitats. A total number of 579 individual snails belonging to 6 families, Ampullariidae (Lanistes varicus), Mutelidae (Aspatharia subreniformis), Thiaridae (Melanoides tuberculata), Bulimlidae (Bulimulus teniussimus, Drymaeus multilineatus), Bithyniidae (Gabbiella humerosa), Hygrniidae (Monacha catiana) were collected. In terms of number and distribution, the Lanistes varicus was the most dominant species consisting of 258(44.6%) of the total number of snails collected. 330(56.9%) number of snails were collected from the open water, 209(36.1%) in the marginal areas and 40(6.9%) on submerged vegetation.Keywords: Freshwater snails, Ampullariidae, Mutelidae, Thiaridae, Bulimlidae, Bithyniidae,Hygrniidae, Submerged vegetation, Ovia, Edo State, Nigeri