Research Student Davangere University, Davangere, Karnataka India, India
This is the first report from Yadgir district in Karnataka state of India. The district has highest number of lakes (380) in the state and the ground water reveals highest amount of fluoride content. However, there is not a single report on the quality of lake waters, where there is good amount of ichthyofaunal diversity. Hence the current study was carried out. For the foresaid purpose the surface water sample was collected for a period 7 months including pre-monsoons and post-monsoons from two taluka i.e., Shahapur (Spot -1 from 37 lakes) and Gurmitkal (Spot -2 from 60 lakes). Post collection the samples were analyzed for parameters such water temperature (on spot), pH, Turbidity, TDS, total alkalinity, Dissolved oxygen (DO), BOD, total hardness, Calcium (Ca2+), Magnesium (Mg2+), Chloride (Cl−) and Fluoride (F −) in the lab. According to classification of lake on the basis of total alkalinity and total hardness lake falls in the category of normal during rainy and winter season and mildly hard in summer season respectively. The overall water quality index (WQI) shows that lake water belongs to little bit fluoride water class. The results from spot -1 revealed that 9 lakes had normal pH value (7-8.5), while 5 lakes pH ranged from 8.6 -9 and 7 lakes were with highest pH i.e., 9.1-9.5, whereas from spot -2 not a single lake had pH above the permissible level. The altered pH in the first study area may be due to human activities such as runoff from paddy fields and washing of clothes, bathing of cattle and human in the lakes. Fluoride content was highest in spot -1 with 3.1-4.0mg/l of water in 4 lakes, 27 lakes had fluoride content of 2.1-3.0mg/l of water and 5 lakes had fluoride ranging1.6-2.0mg/l. The study revealed that in spot -2, 30 lakes water had 1.6-2.0mg/l fluoride content and 29 lakes had 2.1-3.0mg/l fluoride content. This study clearly reveals that fluoride content is beyond permissible limits for fish sustainability. Therefore it becomes inevitable to evaluate water quality of the lakes from the study area which depicts good diversity of fishes. Further actions have to be initiated to minimize/stop human interference for improvement of Lake Ecosystem.
