Plants
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In tolerant plants, atrazine is readily metabolised to hydroxyatrazine and amino acid conjugates, with further decomposition of hydroxyatrazine by degradation of the side-chains and hydrolysis of the resulting amino acids on the ring, together with evolution of CO2. In sensitive plants, unaltered atrazine accumulates, leading to chlorosis and death.
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Animals
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In mammals, following oral administration, atrazine is rapidly and completely metabolised, primarily by oxidative dealkylation of the amino groups (R. Ikonen et al., Toxicol. Lett., 1988, 44, 109; Bull. Environ. Contam. Toxicol., 1989, 43, 199; Y. Deng et al., J. Agric. Food Chem., 1990, 38, 1411), and by reaction of the chlorine atom with endogenous thiols. Diaminochlorotriazine is the main primary metabolite, which readily conjugates with glutathione. More than 50% of the dose is eliminated in the urine and around 33% in the faeces within 24 h.
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Soil/environment
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Major metabolites under all conditions are desethylatrazine and hydroxyatrazine. Field DT50 16-77 d (median 41 d), the longer values being from cold or dry conditions. In natural waters, DT50 10-105 d (mean 55 d). DT50 under groundwater conditions 105->200 d, depending on test system (M. J. Wood et al. in: A Walker (Ed.), Pesticides in soils and water: current perspectives (BCPC Monograph 1991, 47, 175-182)). Kd 0.2-18 ml/g, Koc 39-173 ml/g; desalkylated metabolites had values similar to those of atrazine, while hydroxyatrazine was much more strongly adsorbed.
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