Effect of Agricultural activities on Surface water quality of Kolthur and Sampambole Lakes of Medchal Malkajgiri district, Telangana India

One essential natural resource for the existence of all ecosystems on Earth is water. Conventional irrigation techniques and the overuse of fertilizers for high product yields are the main source of contamination in a catchment’s surface water. Chemical fertilizers such as Nitrogen, Phosphorus, Potassium (NPK), urea and manure are widely applied on agricultural farm lands to improve crop yield thereby compromising the quality of the water sources. Phosphorus is an important nutrient for plant growth. In aquatic systems, a lack of phosphorus often limits aquatic plant growth. Excess phosphorus is usually considered to be a pollutant. The present study focuses on the effects of agriculture on two Lakes i.e., Kolthur Lake and Sampambole Lake of Medchal-Malkajgiri district of Telangana by assessing the NPK and physico-chemical parameters. A total of eight and six samples were collected during the pre-monsoon, monsoon and post-monsoon season from Kolthur and Sampambole Lakes respectively. The study is done to assess the nitrates, phosphates and potassium levels in these Lakes to understand the effect on surface water upon fertilizer application. The parameters, pH, TA, TH, Na+, K+, Ca2+, Mg2+, Cl– and F–, all the samples in all the three seasons were found to be in the accepted limits of the BIS standard values. The other parameters which determine the water pollution due to agricultural activities are the turbidity, total dissolved solids, potassium, nitrates, phosphates, dissolved oxygen and biological oxygen demand were found to be exceeding the BIS standards, in majority of the samples. It was clearly observed that the intense agricultural practices have increased the nitrate and phosphate concentrations as well as other dissolved ions in both the Lakes.