ABSTRACT:In this study, the lower and upper lethal limits, LC 50 and respiration of the freshwater cichlid fishes, Tilapia zillii, Sarotherodon galilaeus, S. melanotheron and Oreochromis niloticus exposed to effluents from Chemistry Department Laboratories were investigated. The mixing of the effluents produced a reduction in pH and dissolved oxygen and a fairly constant temperature and salinity of the media, while the toxicity of the effluents increased. The LC 50 values after 24 and 48-h exposure in the effluent media were 0.24% and 0.21% for T. zillii; 0.26% and 0.24% for O. niloticus; 0.25% and 0.23% for S. galilaeus; 0.27% and 0.26% for S. melanotheron, respectively. The effect of chemical effluent on the rate of respiration of the treated cichlids produced lower rates of oxygen consumption in the order of S. galilaeus>O. niloticus>S. melanotheron>T. zilili in the highest concentration of the effluent. The results obtained from this study have shown that the effluents from Chemistry Department Laboratories are not treated as they produced respiratory impairment and physiological dysfunction in the exposed fish. It is suggested that proper treatment of these effluents be carried out before being discharged into the surrounding stream. @ JASEM Investigations were made on the impact of chemical effluent from laboratories of the Chemistry Department, University of Ibadan, Nigeria on the lethal limits and respiration of the freshwater cichlids, Tilapia zillii, Sarotherodon galilaeus, S. melanotheron and Oreochromis niloticus. These species are delicacies in Nigeria and are cultured in large numbers in Awba Lake located near to the effluent discharge site of the Department of Chemistry laboratories, University of Ibadan and Eleyele reservoir, Ibadan. It had been observed that chemical effluents such as mercury, sulphuric acid ) ,

The aim of the study is to evaluate the cytotoxic effect of effluents at inducing chromosomal aberrations, using this as a biomarker tool in wild Clarias pachynema for assessing and monitoring pollution of the aquatic environment. A total of 60 live fish (30 each downstream and upstream) were obtained and subjected to chromosomal analysis. Chromosomal aberration in the fish samples from the downstream sector was recorded at a rate of 30%, while there were no aberrations in the samples collected upstream the effluent discharge point. Water sample analysis revealed a high concentration of Ammonia and Nitrates above permissible standards of Federal Environmental Protection Agency (FEPA) guidelines. Heavy metal analysis also revealed the presence of Cr (0.05), Cu (0.01), Pb (0.05), Zn (5.0) and Fe (0.3) above permissible standards from the downstream section of the river. This study shows clearly that the ever increasing discharge of effluents from the industry could increase chromosomal damage in the aquatic components.

The outbreak of yellow fever transmitted by Aedes aegypti has been of major concern in Nigeria, this mosquito also transmits several other arboviruses globally. The control of many of the Aedes aegypti borne diseases relies heavily on the use of insecticides. Therefore, constant monitoring of insecticide resistance status and associated mechanisms in crucial within the local population. Here, we determined the resistance profile of adult Aedes aegypti from Ikorodu Local Government Area of Lagos State, Nigeria to different classes of insecticides using WHO procedures. The presence of kdr mutations F1534C, S989P and V1016G were also determined among resistant populations using molecular methods. High level of resistance to DDT and pyrethroid was rec-orded in Aedes aegypti in this study, though possible resistance to deltamethrin was reported in one of the locations. Resistance to bendiocarb was recorded in Majidun community while Aedes aegypti in both locations were susceptible to malathion. The presence of F1534C mutation associated with resistance in Aedes aegypti was detected for the first time in Nigeria, and the presence of S989P mutation was detected singly and in co-occurrence with F1534C for the first time in Africa. The role of these mutations in resistance phenotype expressed in Aedes aegypti in this study area need to established.