“…3,4 Considered to be relatively benign to the ecosystem, CLZ has been widely used in Europe in recent decades, particularly in maize and sugar beet. 2,5 However, it penetrates into the soil and is converted into two metabolites, desphenyl-chloridazon and methyl-desphenylchloridazon, [6][7][8][9] which may migrate through the soil due to their solubility and polarity, resulting in surface water and groundwater contamination. [10][11][12] In groundwater, CLZ concentrations have reached 3.5 μg L −1 in some parts of Europe, while desphenyl-chloridazon and methyl-desphenyl-chloridazon have been reported to be present at 24.0 μg L −1 and 6.1 μg L −1 , respectively, which greatly exceed the limit set by the European Union (0.1 μg L −1 ).…”