The composition and distribution of fish in the Ikpoba reservoir were investigated. A total of fifty-seven species of fish belonging to thirty-nine genera and twenty-three families were recorded. Of these, 46 species were recorded at the upstream station, 35 at the reservoir, 24 at the slope and 32 at the downstream station. The percentage compositions were 81%, 61%, 42% and 56% respectively. There were 21 ubiquitous species while the distribution of the other species showed variability indicating effects of habitat condition. Species diversity indices showed that the upstream section was richer, more diverse with species more evenly distributed than the other stations. Heavy metal analysis of the dominant fish species showed higher mean levels than the background levels. Metal contamination factor and bioaccumulation quotient were variable in the fishes and in the stations but followed a ranked order of 3 > 2 > 4 > 1 by station. Comparison of stations using ANOVA revealed a significant difference (P < 0.05) between the upstream and the slope stations.

ABSTRACT:One hundred and twenty normal post juvenile catfish (Clarias gariepinus) of both sexes with a mean weight of 135.44±1.99 g and mean length of 28.32±0.844 cm were purchased from Osayi farm. They were kept in 60 l aquaria at 27.5±0.4 •C, pH 7.3, with 12:12 h photoperiod, well aerated, provided with external filtration and a layer of gravel on the bottom. Histopathological alteration in the brain tissues when the fish were exposed to various concentrations (18 mg/L, 32mg/L and 75 mg/L) of glyphosate for a period of 7 -28 days revealed that glyphosate hervicide may be neurotozic to post juvenile African catfish C. gariepinus as characterized by severe degeneration of dark-stained purkinje neurons, oedema, vacuolar changes with empty spaces which appeared as moth eaten area and showed proliferation of glial cells. There is need for more research work on the histopathology of brain tissue of fish exposed to pesticide. © JASEM http://dx.doi.org/10.4314/jasem.v18 i2.19Introduction:Nervous and sensory systems are an integral part of these adaptations and the relative contributions of phylogeny and ecology in determining brain and sense organ morphology have been a longstanding question in ecomorphology. Although the relationships between brain morphology and ecology are well established for some teleost fishes (Evans, 1931;Evans, 1952;Schnitzlein, 1964;Davis and Miller, 1967;Ito et al., 2007), the strength of this relationship has subsequently been found to vary in different taxa. For example within North American catostomids (Miller and Evans, 1965), African Great Lakes cichlids (Huber et al., 1997), and deep-sea eels and grenadiers (Wagner, 2002), the interspecific variation in sensory and association areas of brains is tightly correlated with ecology, especially habitat and feeding. However in some European cyprinids (Kotrschal and Palzenberger, 1992) and coral reef dwelling perciform angelfish and butterflyfishes (Bauchot et al., 1989), interspecific variation is not as pronounced and the link between brain morphology and ecology is less robust. In a comprehensive review of this field, Kotrschal et al., (1998) noted that primary sensory areas of the brain relate more closely to feeding whereas integration centers reflect differences in microhabitat, and in phyletically advanced teleosts like perciforms there is a relative shift of brain mass from sensory areas to integration centers. As a means of apportioning the influence of phylogenetic and ecological factors shaping brain morphology, Kotrschal et al., (1998) called for investigations of closely related perciform species that differ in body size, habitat utilization and behaviour.

Recent empirical evidence suggests that herbicides have damaging effects on non-target organisms in both natural and semi-natural ecosystems. The African mound building termite, Macrotermes bellicosus, is an important beneficial insect that functions as an ecosystem engineer due to its role in the breakdown of dead and decaying materials. Here, we examined the effects of 2,4-D amine salt (2,4-D) and atrazine based herbicides viz. Vestamine ® and Ultrazine ® on the survival and locomotion response of M. bellicosus. Worker termites were treated with a range of concentrations of Vestamine ® (the recommended concentration: 6.25 ml per 500 ml of water, 0.25-and 0.5-fold below the recommended concentration and distilled water as control) and Ultrazine ® (the recommended concentration: 3.75 ml per 500 ml of water, 0.25-, 0.5-, 2.0-and 4-fold of the recommended concentration and distilled water as control) for 24 hours for the mortality test, and allowed to run for 15 seconds for the locomotion trial. All concentrations of both Vestamine ® and Ultrazine ® were highly toxic to worker termites and mortality increased as the concentration and time after treatment increased. For both herbicides, concentrations far less than the recommended rates caused 100% mortality. The speed of termites was significantly influenced by both Vestamine ® and Ultrazine ® as termites exposed to all tested concentrations of the herbicides exhibited reduced running speed than the control. These findings suggest that beneficial insects, especially M. bellicosus may experience high mortality (up to 100%) and reduced mobility if they are sprayed upon or come in contact with plant materials that have been freshly sprayed with (less or more than) the recommended concentrations of Vestamine ® and Ultrazine ®. The findings of our study calls for the reassessment of the usage of 2,4-D and atrazine based herbicides in weed control in termite and other beneficial insect populated habitats.

The dietary exposure of Polycyclic Aromatic Hydrocarbon (PAHs) and potential risk to human health was instigated in two different traditionally smoked species of fish (Parachanna obscura and Ethmalosa frimbriata) purchased from three markets in Benin City. Identification and quantitative analysis of PAHs components were achieved by Gas Chromatography/High Performance Liquid Chromatography. The result obtained showed that, Benzo(a)pyrene had an occurrence of 83.33% in all samples analysed. Risk assessment conducted using benzo(a)pyrene carcinogenic and mutagenic toxicity equivalent factor (TEQ & MEQ) showed slight to high risk (7.44 x10 -5 -1.95 x10 -3 ) and exceeded the USEPA guideline (1.0 x 10 -5 ) for potential Cancer. Levels of PAHs present in smoked fish prepared using traditional method may pose elevated cancer risks if consumed at high rates over many years.

This study evaluates ameliorative effect of different concentrations of mushroom (Pleurotus tuberregium) on the effects of lead (Pb). Ninety albino rats were divided into six groups with three replicates (5 rats per group) for 21 days pre-experimental stage for acclimatization. The experimental groups were exposed to 0.1 g/l of lead daily for 21 days. At the end of exposure period, lead salt was discontinued for 21 and 42days to verify possible ameliorative effect of mushroom in the post-experimental stage. Samples of liver and kidney tissues were then collected and subsequently analyzed for structural changes every 21 days. The tissues of the pre-experimental stages showed normal tissues as those of the control except in the liver which showed mild periportal chronic inflammatory cell. However, the experimental groups, showed liver with focal periportal vascular congestion and hypertrophy, moderate chronic inflammatory cell infiltration and interstitial oedema. The kidney showed focal proximal tubular necrosis, transmural oedema, interstitial haemorrhage, and chronic inflammatory cell infiltration. The tissues of liver and kidney in the post experimental stages were improved with increased mushroom content in the feed. Results of this study demonstrated that P. tuberregium may ameliorate lead toxicity in liver and kidney tissues.

The study was conducted to determine the possible ameliorative activity of coconut oil on the toxic effects of untreated refinery effluents on the ovaries of Norwegian rats. Three experimental groups of 10 rats each were used for the study; all animals had feed and water ad libitum. Group 1 was untreated and served as the control group, Group 2 was treated with 2 ml of untreated refinery effluent daily PO and group 3 was treated with 2 ml of untreated refinery effluent and 2 ml of coconut oil daily PO for 9 weeks. Every 3 weeks 2 rats in each group were euthanized with chloroform and ovarian tissues were surgically harvested; tissue concentration of heavy metals was assayed and histology was carried out. Treatment was discontinued at nine weeks and rats in group 2 and 3 were designated groups 4 and 5; allowed a 21 days resting period after which they were euthanized, ovaries surgically harvested and assayed as well. Results indicate that changes in ovarian tissue concentration of Chromium and Lead in the treated groups were of statistical significance (P ≤ 0.05) compared to control. Results also showed that rats treated with coconut oil as abatement had normal histological architecture. Coconut oil had ameliorative effects on the ovary of rats intoxicated with refinery effluent and the ovaries returned to normal activities within 21 days post exposure.

The study was aimed at determining the effects of untreated refinery effluent on the spermatogenic status of the testes in Norwegian rats and possible ameliorative effects of coconut oil. Thirty Norwegian rats were used for the study, divided into 3 groups of 10 animals each. Group 1 were given feed and drinking water, group 2 were given feed, drinking water and 2 mL of 100% of the untreated refinery effluent while group 3 were given feed, drinking water, 2 mL of 100% of refinery effluent and 2 mL of Coconut oil continuously for 9 weeks. At 3 weeks intervals, two rats were sacrificed from each group. Testicular tissues were harvested and analyzed. Treatment was discontinued after nine weeks. Groups 2 and 3 were re-designated groups 5 and 6, left for a period of 21 days without treatment. At the 21 st day, testicular tissues were collected and analyzed. There was a significant increase (P > 0.05) in body and organ weight of treated rats compared to control. Organ morphology varied from control but was not statistically defined. Lead and chromium concentrations in testes were significantly different (P > 0.001) in effluent treated rats. Histopathology of the gonads showed evidence of pathologies in rats treated with effluent only compared to control and ameliorated groups. Testes of rats treated with coconut oil revealed normal spermatogenic architecture during and after exposure to refinery effluent. Coconut oil was effective in ameliorating the deleterious effects of untreated refinery effluent on the testicles of intoxicated Norwegian rats.

Aims: To investigate the chemo-therapeutic potential of Dailum guineense leaf extract on dumpsite leachate induced hepatoxicity of Wistar rats.