Ecology, Environment and Conservation Paper

EXPERIMENTAL INVESTIGATION AND MODELING ON IMPACTS OF LEACHATE FROM BIO-MANURES AND FERTILIZERS USED IN THE AGRICULTURAL FIELDS ALONG NOYYAL RIVER

E. Sarojini, Varatharajaperumal Thangavel, S. Kanchana, S.D. Anitha Selvasofia and S.T. Sudharsan

Abstract

Agriculture is the back bone of India and it is the source of life for all the people who thrive to live. But in the recent years, the biological hazards like bio- accumulation and environmental ill-effects like Eutrophication due to the impacts of improper fertilization and leaching of bio-manures and fertilizers into the ground water aquifers from the agricultural fields. Thus this project shows a clear view on the impacts of leached bio-manures and fertilizers/pesticides over the ground water aquifers along Noyyal River, Coimbatore-South (10.9899° N, 76.8409° E), Tamil Nadu. The modelling of the sampling stations from 5 km buffer region along the river which predicts the impacts in the form of map using the GIS software. Ten samples per season are collected from 10 different sampling stations and the seasons are namely the winter and the monsoon seasons. The physical, chemical, mineral and biological tests are carried out and it is inferred with the allowable limits (WHO) for both the seasons and the tests are namely pH, Hardness, Alkalinity, Phosphate, Potassium and Conductivity. The pH values varying from 6.5 to 8.1, the hardness values varying from 37.6 ppm to 567.4 ppm, Alkalinity values varying from 35 ppm to 155 ppm, Phosphate values varying from 1.87 ppm to 4.89 ppm, Potassium values varying from 3 ppm to 27 ppm and Electrical conductivity values varying from 120 m/cm to 930 m/cm are identified. For the turbidity test, the test results from all the sampling stations are exceeding the allowable limits in both the seasons with the values ranging from 16.4 NTU to 20.8 NTU. The Plate count test values ranging from 120 Cfu/ml to 610 Cfu/ml where the field 6 exceeds the allowable limit and for the Nitrate test values ranging from 0 ppm to 70 ppm where the field 8 exceeds the allowable limit. From the GIS map obtained it is inferred that the pH, alkalinity, plate count values of fields using bio-manure are less and the fields using fertilizers are high during the winter season; whereas the values of fields using bio-manure are high and the fields using fertilizers are less during the monsoon season. From the nitrate, phosphate, potassium and conductivity tests it is inferred that in winter season all the fields are having less values and in monsoon season all the fields are having high values. To overcome the water supply demand, water treatment for the high water toxic areas are necessity. The sampling points having high turbidity (all Fields) can employ coagulation and sedimentation using alum stones, for the high Nitrates (Field: 8) Reverse osmosis can be carried out and for high total solids (Field: 2, 4, 5, 7) activated carbon filters can be implemented. The safest sampling stations were identified.