Sorption of imidacloprid and its metabolites on tropical soils

• Published in: Journal of environmental science and health. Part B, Pesticides, food contaminants, and agricultural wastes Vol. 35; no. 1; pp. 39 - 49
• Main Authors: Oliveira, R.S. Jr, Koskinen, W.C, Werdin, N.R, Yen, P.Y
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA Taylor & Francis Group 2000; Taylor & Francis
• Subjects: Absorption; Agronomy. Soil science and plant productions; Applied sciences; Biological and medical sciences; Biological and physicochemical properties of pollutants. Interaction in the soil; Brazil; cation exchange capacity; Environmental Monitoring - methods; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Humans; imidacloprid; Imidazoles - chemistry; Insecticides - chemistry; metabolites; Neonicotinoids; Nitro Compounds; Pollution; Soil - analysis; Soil and sediments pollution; Soil and water pollution; soil organic matter; Soil science; Sorption; Tropical Climate; tropical soils; Brazil; South America; America; Organic carbon; Insecticide; Nitroguanidine derivatives; Pollutant behavior; Metabolite; Treatment efficiency; Pesticides; Guanidines; Soil pollution; Entisols; Tropical soil; Sorption; Cation exchange capacity; Sandy clay loam soil; Ultisols; Comparative study; Environmental protection
• ISSN: 0360-1234; 1532-4109
• DOI: 10.1080/03601230009373252

The sorption of imidacloprid (l-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolid-inimine) (IMI) and its metabolites imidacloprid-urea (l-[(6-chloro-3-pyridinyl)-methyl]-2-imidazol-idinone) (IU), imidacloprid-guanidine (l-[(6-chloro-3-pyridinyl)-methyl]-4,5-dihydro-lH-imidazol-2-amine) (IG), and imida-cloprid-guanidine-olefin ( 1 -[(6-chloro-3-pyridinyl)methyl]-lH-imidazol-2-amine) (IGO) was determined on six typical Brazilian soils. Sorption of the chemicals on the soil was characterized using the batch equilibration method. The range and order of sorption (Kd) on the six soils was IG (4.75-134) > IGO (2.87-72.3) > IMI (0.55 -16.9) > IU (0.31-9.50). For IMI and IU, Kd was correlated with soil organic carbon (OC) content and CEC, the latter due to the high correlation between OC and cation exchange capacity (CEC) (R 2 =0.98). For IG and IGO, there was no correlation of sorption to clay, pH, OC or CEC due to the high sorption on all soils. Average Koc values were IU = 170, IMI = 362, IGO = 2433, and IG = 3500. Although Kd and Koc values found were consistently lower than those found in soils developed in non-tropical climates, imidacloprid and its metabolites were still considered to be slightly mobile to immobile in Brazilian soils.