A root bioassay procedure for the determination of chlorsulfuron, diclofop acid and sethoxydim residues in soils

Measurement of the root lengths of pre-ger-minated oat seedlings (Avena sativa L. var. Sioux) grown in the dark in treated soils was used to assay residues of diclofop acid (2-4-(2,4-dichloro-phenoxy)phenoxy]propionate) and sethoxydim (2-1-(ethoxyimino)-butyl]-5-2-(ethylthio)-propy]-3-hydroxy-2-cyclohexene-1-one). Similar measurements involving maize seedlings (Zea Mays L. var. Sunny Vee) were also used to determine residues of the herbicide chlorsulfuron (2-chloro-N-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbony]benzenesulfonamide) in soils. The procedure appeared to be reproducible with residues of chlorsulfuron, diclofop acid and sethoxydim being detectable at amounts of 0.001, 0.2 and 0.05 μg g^?1 respectively.