Abstract

• The main aim of this research is to examine the optimization of the organic amendments for remediation of insecticide contaminated soil. The waste materials for crude protein contents, fish scale (Cirrhinus cirrhosus), chickpea shell (Cicer arietinum L.) and peanut shell (Arachis hypogaeal L.) were collected from Pyay Township, Bago Region. The crude proteins were extracted from the selected sources by trichloroacetic acid (TCA) method, and evaluated the yield % of nitrogen. The nitrogen contents of fish scale, chick pea shell and peanut shell were found to be 1.527 %, 0.901%, and 0.990%, respectively. Furthermore, the protein extract from selected sources were confirmed by chemical tests. According to the result, the fish scale waste was found to possess the highest content of protein. The fish scale could be potentially applied as a nitrogen source in the determination of soil enzyme activity and degradation of insecticide in soil. Before treatment, two types of amendments were prepared by fermentation for 10 days on mixing the samples viz., FSJ (fish scale-FS: Jaggery-J - 10:10 w/v) and FST (FS: Treacle-T - 10:10 w/v). A laboratory bench study was conducted to assess the removal efficiency of FSJ and FST on 1 ppm insecticide contaminated soil. Three different nitrogen additives from two natural sources; FSJ, FST and one chemical, NH4-N source with a concentration 4%each treatment were applied on insecticide contaminated soil along with control (no treatment). The residual insecticide (as its metabolite 3-phenoxybenzoic acid 3-PBA) in soil samples extracted from the experimental plot was examined using UV-vis spectrophotometer. After five weeks treatment, the removal efficiency of FSJ and FST treatments was found significantly increased. The profile of soil urease activity in the treated and contaminated soil was also determined by Phenol-Hypochlorite method. The overall results indicated that appropriate waste- amendment application can promote the removal of PBA as well as maintain the activity of urease enzyme in soil.