Laboratory fate monitoring on the model substance imazalil in biochar amended soil; Laboratory fate monitoring senyawa model imazalil pada biochar yang ditambahkan ke tanah

Miranda Adihimawati, Eko Sugiharto

2013 | Disertasi | PROGRAM STUDI S2 KIMIA

The laboratory tests on sorption and biotransformation in accordance with OECD guidelines had been done to study the effects of biochar amended soil on the soil properties as well as on the sorption capacity and on the degradation of pesticides. For this purpose, soils, i.e., German arable and Jordanian soils, together with biochars, i.e., pyrolysis and hydrothermal carbonization (HTC) were used, while, imazalil was chosen as a model substance. Prior to the tests, all of the samples were analyzed for their characteristic such as pH value, redox potential (Eh), total organic carbon (TOC), water holding capacity (WHC) and substrate-induced respiration (SIR) as well as for polycyclic aromatic hydrocarbons (PAHs) and multielement screening. The fate of imazalil in biochar amended silty sand soil (from German arable field) was investigated using 14C-labeled radiotracer by determining the mineralization (MIN), extractable residues (ER) and non-extractable residues (NER) to set up mass balances under laboratory condition. In addition, the sorption capacity of imazalil in the silty sand soil was investigated in comparison with a Jordanian sand soil. The results of matrix characterization show that the amendment of biochars could influence the soil properties, i.e., the pH values of sand soil and the total organic carbon as well as the substrate-induced respiration of both soils under study. Furthermore, in comparison with the conventional standard application on the sorption tests of imazalil, Kd and Koc values of imazalil in both soils under study increased by the amendment of 1% both biochars as well as by the increasing of shaking time, 6, 12 and 24 h. For this case, the sorption capacity of imazalil in silty sand soil with 1% HTC biochar was higher in comparison with sand soil with 1% HTC biochar and contradictive results were found in sand soil. The degradation tests of 14C-imazalil in silty sand soil showed considerably different results, similar tendencies were found in silty sand soil without and with 1% pyrolysis or HTC biochars amendment. Within 103 d incubation period, imazalil was slowly degraded in silty sand soil without and with 1% biochars amendment. This was confirmed with the result of the extractable residues, which amounted to 41, 43 and 44% in silty sand soil, with 1% pyrolysis and with 1% HTC biochar, respectively.

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