The quality of water supply is assessed by its physico-chemical and bacteriological properties. This study was carried-out with the aim of determining the contamination level of domestic water sources of Samaru community, Zaria, Northcentral Nigeria in order to observed the trend of change in quality of these water sources, if any. This was with a view to safeguard the public health of the riparian users against a possible outbreak of water borne diseases. Water samples were collected and analyzed for bacteriological and physicochemical quality using standard procedures. The results showed that the mean values recorded for physico-chemical parameters among the domestic water sources were within stipulated limits of WHO for safe drinking water except for chloride mean value of 314 AE 142.4 mg/L recorded in borehole water. The total heterotrophic bacterial counts recorded in tap, borehole, well, reservoir and river water samples (3.67 Â 10 6

Rivers play a vital role in rural communities, particularly for the fishing industry, for agricultural purposes and as a source of water for local people. 1,2 River contamination affects humans directly and indirectly. However, increasing anthropogenic activities and natural processes decrease the quality of water and pose a threat to all forms of life. Poultry farms provide one of the leading sources of high-grade, protein-rich foods (eggs and meat) globally, however, domestic, industrial and agricultural poultry wastes are regularly discarded into water bodies. 3 According to Okonkwo et al., about 10 percent of the Nigerian population is engaged in poultry production, mostly at subsistence levels or on small and medium-sized farms. 4 The increased use of trace elements as nutritional supplements in poultry diets to improve feed efficiency, facilitate weight increase and for disease prevention results in high levels of trace elements in poultry waste. 5,6 Many metals are added to poultry feed, including copper (Cu), manganese (Mn), iron (Fe), selenium (Se), zinc (Zn), and arsenic (As). Iron and Cu are added to prevent anemia, selenium is added to prevent oxidative damage to cells, and Zn and Mn are added to ensure proper egg shell deposition and feather development. Antioxidants are added to retard degradation of vitamins in feed. Tranquilizers maybe used to keep flocks quiet in the house and before transport. A broad spectrum of antibiotics maybe added to poultry feed, both to combat pests and to increase availability of certain nutrients. Topical pesticides are used to combat flies, lice, beetles and mice. 7 Unfortunately, contaminants from poultry farms can have adverse effects Background. Water supplies can be contaminated by anthropogenic activities. The poultry industry uses a variety of heavy metals as additives in chicken feed, but excretion, runoff and dumping of heavy metals can threaten water bodies and have adverse effects on human health. Objectives. The aim of the present study was to determine the environmental impact of heavy metals from poultry waste discharged into the Olosuru stream, located in Ikire, southwest Nigeria. Methods. In order to study changes in heavy metal loads, samples were collected six times during the wet season (September, October 2014 and April 2015) and dry season (November 2014, January and February 2015). The inhabitants of Olosuru village use water for domestic and agriculture purposes from the Olosuru stream which is located only a few meters from a poultry farm discharge point. Three stations were sampled, upstream to downstream, with 500 meter distance between each point. Results. Selected heavy metals concentrations in the Olosuru stream were all above the World Health Organization (WHO) standard for drinking water. The highest mean concentrations of heavy metals were recorded at the downstream station, while arsenic, iron and lead showed significant spatial and seasonal differences. Seasonally, the highest iron concentrations were recorded in the dry season (0.104±...

Reservoir fishes contribute significantly to freshwater fish resources in Nigeria. The composition, size variation and relative abundance of fishes in Opa reservoir, Southwest Nigeria, were investigated to establish the ecological balance of the various trophic groups of fishes in the reservoir. The study was carried out in view of recent reports on the decline in the quality and quantity of water in the aging reservoir. Fishes were collected from the reservoir monthly for twelve months using monofilament gill nets and wire cages. The fishes were identified to species level and the ecological balance of the fish community was calculated as a ratio of the forage to the carnivore groups by number and by weight. Data were subjected to statistical analysis using the Stata 13 software. 1915 fishes belonging to 17 species and 10 families were collected from the reservoir. The fish composition was dominated by the family cichlidae, with its 7 species accounting for 89.8% of the total catch. There were 2 species of clariidae, which made 6.2% of the total catch. The ecological balance of the fish community was 3.4 (by number) and 6.2 (by weight). The result obtained revealed that the fish community in the reservoir is ecologically balanced. Comparative analysis of the fish composition of the Opa reservoir with reports from other reservoirs in Southwest Nigeria showed that the reservoir has more fish species than most of the other reservoirs around. The study concludes that the reservoir still supports a rich, diverse and ecologically balanced fish community. It is recommended that the management of these fish resources should be key in the holistic management of the aging Opa reservoir.

This study investigated the impact assessment of poultry wastes discharge from a nearby poultry farm on the physico-chemical and microbiological water quality of Olosuru Stream, Ikire, Southwestern Nigeria. Five sampling stations (designated A, B, C, D and E) each located at 250 m interval along the course of the stream were selected for the study. The physico-chemical parameters in the water body vary in concentration along spatial, monthly and seasonal variation of Olosuru stream. The patterns of spatial distribution of physico-chemical parameters measured for the stream were generally similar except for calcium and hardness which showed significant difference for the five stations. The overall mean values of most of the parameters investigated; pH (7.45 ± 0.24), conductivity (628.69 ± 255.95 µs/cm), TDS (377.3 ± 153.55 mg/L), sulphate (10.89 ± 2.37 mg/L), BOD 5 (3.19 ± 2.35 mg/L), cadmium, arsenic, manganese, total heterotrophic bacteria count (15,080.67 ± 20,250.67 cfu/ml), total coliform bacteria count (3226 ± 8426.70 cfu/ml) and total heterotrophic fungi count (2567.4 ± 7652.12 cfu/ml) were negatively impacted by poultry wastes dumping into the stream. The concentrations of most parameters exceeded recommended permissible limits of the Nigerian Standard for Drinking Water and World Health Organization for freshwater quality. The water source is therefore deemed not potable and poses hazards to public health if consumed without treatment. There is urgent need for improved management strategies of this water resource for continued sustainability.

Over the years, there is a direct linkage of township drains and streams to the Opa reservoir, Obafemi Awolowo University, Nigeria. Hence the spatial and temporal variations of the reservoir's water quality were studied between November 2012 and October 2013 to investigate the effect of these discharges on these. Physical, chemical as well as the oxygen parameters of the water were investigated using standard techniques. The parameters determined revealed considerable temporal variations with the rainy season averaged concentration of COD, TOC, OM, TSS, TS, turbidity, apparent colour, true colour, sodium, and phosphate significantly higher (p<0.05) than those of the dry season. Spatially, DO, TSS, TS, organic matter and TOC decreased significantly (p<0.05) from riverine to the lacustrine (dam site). However, calcium, sulphate, and electrical conductivity showed significant increases (p<0.05) from the riverine zone section towards the dam site. Vertically, sulphate, bicarbonate, COD, TOC, chloride, TSS, TS, turbidity, apparent colour, true colour and sodium ion values increased significantly (p<0.05) from the surface down to the bottom. Conversely, magnesium, total hardness, nitrate, BOD, DO, electrical conductivity, acidity, carbonate, alkalinity, TDS and pH values decreased (p<0.05) from water surface to the bottom of the reservoir. Therefore, the discharges from the catchment area of Opa reservoir could pose a level of risk to the aquatic ecosystem as well as the community if not well treated before being supplied.

No abstract

The aim of this study was to investigate the impact of anthropogenic stressors on environmental variables, sediment properties and benthic macroinvertebrate assemblages of Lagos Lagoon. Four sampling stations were established with respect to their importance/ anthropogenic activities within Lagos Lagoon. Surface water, bottom substrates and benthic macroinvertebrate fauna samples were collected at all sampling stations for a year while samples were analyzed using appropriate standard methods and procedures. The highest pH ranged of 7.96–8.01 (7.98 ± 2.35) was recorded at Site IV while the lowest pH mean value of 6.15 ± 1.14 was observed at Site II. Seasonally, the highest values of temperature, electrical conductivity, nitrate and THB (38.10 ± 3.66°C, 61842.83 ± 11777.45 µs/cm, 6.09 ± 3.70 mg/L and 38174.83 ± 79509.21 cfu/ml) were observed at Site I during dry season. The highest sediment pH ranged of 6.18–9.18 (7.58 ± 0.27 mV/pH) for sediment was recorded at Site I while the lowest mean pH was observed at Site II (6.87 ± 0.19 mV). The mean of sulphate, lead, chromium, cadmium and total coliform counts were higher at Site II during the dry season while nickel was higher in the rainy season. A total number of 26 species of benthic macroinvertebrates were observed during the period of study belonging to 8 classes namely: grastropoda (11), polychaeta (7), malacostraca (3), bivalvia (2), clitellata (1), thecostraca (1) and insecta (1). Gastropoda recorded highest percentage contribution of 39.12% followed by Polychaeta accounting for 30.34%, while Malacostraca contribution was 2.63%. High abundance of macroinvertebrates was recorded at Site I (256 Indiv/m2) followed by Site IV (252 Indiv/m2) and least abundance was observed at Site II (195 Indiv/m2). Low macrobenthos recorded in this study could be due to high tolerate of physico-chemical changes. The encroaching into aquatic environment around the globe often introduce toxic chemicals into waterbodies which has led to loss of certain organisms, destabilization of sediments, and thriving of tolerant benthic macroinvertebrates. Concerned authority should pass a law to stop encroaching into aquatic environment for land reclamation as a result of high urbanization around the world.

Study to determine the ecological status of Opa reservoir, Ile Ife Nigeria was conducted based on the plankton's diversity and physicochemical characteristics of the reservoir. Water samples for the analyses were collected from three established investigated stations on the reservoir for a period of one year between November 2012 and October 2013. Most of the physicochemical parameters' result were within recommended limits of the NESREA for aquatic life, but some heavy metals (Ni and Cr) were above permissible limits. One hundred and thirty-six (136) plankton species belonging to thirteen taxa were encountered whose total abundance and distribution were influenced greatly by dissolved oxygen, salinity and light obstruction parameters. Notable, recorded species at the riverine (Cryptomonas ovata, Branchionus angularis and Cyclops) revealed the unacceptable quality of the reservoir's influx. Besides, the observed low species diversity index, at all zones of the reservoir investigated, revealed dominance by few species that characterized eutrophicated waters. Furthermore, the presence of plankton pollution tolerant species (Anabaena sp., Navicula sp. and Peridinium sp.) also suggested a minimal level of organic pollution in the reservoir. The water qualities of Opa reservoir at the Lacustrine zone (76.14) and Transition zone (67.89) were of occasional threatened while Riverine zone (63.57) was frequently impaired according to the CCME Water Quality Index.