Determination of Acute Toxicity of NPK  Fertilizers to Eisenia Foetida Using a  Simple Paper Contact Method

K. S. Abbiramy; P. Ronald Ross

Volume : II, Issue : II, February - 2013

Determination of Acute Toxicity of NPK Fertilizers to Eisenia Foetida Using a Simple Paper Contact Method

K. S. Abbiramy, P. Ronald Ross

Abstract :

NPK fertilizers were the most widely used growth promoters in agricultural fields. They were applied to the soil to increase and to maintain soil nutrient levels. The ultimate goal was of maximizing productivity and economic returns, while side effects on soil organisms were often neglected. Another important indirect effect especially of NPK fertilization was soil acidification, with considerable negative effects on earthworms. Earthworms are typically inferred as soil indicators without which soil fertility cannot be measured directly. An acute toxicity test of NPK fertilizers to earthworms (Eisenia foetida) was performed using a simple paper contact method proposed by OECD (Organization for Economical and Cooperative Development) testing guideline no. 207. The worm was exposed to the deposit of NPK fertilizers (4:2:1 ratio) kept uniform on filter paper for 48 h and the mortality was recorded. The concentrations were expressed in μg/cm2. Based on the resulting LC50 value, the NPK fertilizers combined were classified as �very toxic� to earthworm. The result of this study further demonstrates that the inorganic chemical fertilizers can also be toxic to earthworms when contacted directly. Thus there arises an unavoidable need of monitoring the usage of fertilizer dosages on agricultural lands, particularly the NPK.