~ 84 ~ International Journal of Fisheries and Aquatic Studies 2014; 1(5): 84-92 ISSN: 2347-5129 IJFAS 2014; 1(5): 84-92 © 2013 IJFAS www.fisheriesjournal.com Received: 14-04-2014 Accepted: 05-05-2014 Ajibare Adefemi Olatayo Contact Address: Christ’ School P.O. Box 50, Ado-Ekiti, Ekiti State Nigeria. Email: mrajifem@yahoo.com. Correspondence: Ajibare Adefemi Olatayo Contact Address: Christ’ School P.O. Box 50, Ado-Ekiti, Ekiti State Nigeria. Email- mrajifem@yahoo.com. Assessment of Physico-Chemical Parameters of Waters in Ilaje Local Government Area of Ondo State, Nigeria Ajibare Adefemi Olatayo ABSTRACT The quality of water from four coastal towns (Ayetoro, Idiogba, Bijimi and Asumogha) in Ilaje local government area of Ondo State was assessed using standard methods with the view of determining the level of pollution through anthropogenic activities and state of the aquatic ecosystem. The results of the analyses of the water samples showed that Dissolved Oxygen (DO) had the highest mean of 7.66 mg/l in Ayetoro while the lowest mean (7.53 mg/l) was recorded in Bijimi; Temperature had minimum mean value of 29.42 o C in both Bijimi and Idiogba and maximum mean of 29.75 o C recorded in Asumogha. The minimum mean of pH across the four locations was recorded in Asumogha (6.63) and the maximum mean was recorded in Idiogba (6.71). The conductivity of Idiogba had the least mean value of 41.00 μS/cm and Ayetoro had the highest mean value of 41.83 μS/cm. Salinity ranged from 16.35 o /oo in Asumogha to 16.65 o /oo in Idiogba and the minimum mean of hardness (84.57 mg/l) was recorded in Asumogha while the maximum mean of 87.16 mg/l was recorded in Ayetoro. Also, turbidity ranged between 41.95 NTU in Bijimi and 45.36 NTU in Asumogha. The result revealed that all the physico-chemical parameters of water determined (except turbidity and hardness) showed no significant difference across the four sampling stations at P<0.05. The result obtained is within the permissible level of aquatic biodiversity, set by United State Environmental Protection Agency and World Health Organization thus, the water can be classified as brackish and a good, stable and healthy aquatic ecosystem. Keywords: Physico-chemical, Coastal water, Salinity, Conductivity, Dissolved Oxygen. 1. Introduction Curing In recent years, a number of events affecting water quality have resulted in increased public concern about surface water quality [1] . Macer [2] postulated that the presence of impurities, reduces the quality and uses to which water may be deployed as well as well serve as a major factor controlling the state of health in both cultured and wild fishes. Water must be analysed to determine its acceptability for the intended purpose. Non availability of portable water to settlements necessitates heavy reliance on coastal waters for domestic, agricultural or recreational purposes. The possibility of trans-boundary transportation of coastal pollutants [3] makes determination of coastal water quality and monitoring essential. The ever-increasing pollution of the environment has been one of the greatest concerns of science and the general public in the last fifty years [4, 5] . Idowu et al. [6] positioned that the pollution of the aquatic environment by inorganic and organic chemicals is a major factor posing serious threat to the survival of aquatic organisms. Man-made toxic compounds are also resistant to physical, chemical, or biological degradation and thus represent an environmental burden of considerable magnitude [4] . Opukri and Ibaba [7] opined that the effect of anthropogenic activities on the quantity and quality of water resources are felt over a wide range of space and time scales. In advanced countries, environmental monitoring agencies are more effective and environmental laws are strictly followed. General environmental quality monitoring is compulsory and the monitoring of the quality of water resources is done on a regular basis [8, 9, 10, 11] . Water pollution in Nigeria occurs in both rural and urban areas. In rural areas, water from natural sources such as rivers and streams is usually polluted by organic substances from upstream users who use water for agricultural activities [12] . As a result, any abnormal changes in the environment or water quality can easily be detected and appropriate action taken before the outbreak of epidemics. The case is quite opposite in many developing countries.