Studies on bound 14C-prometryn residues in soil and plants

A high-temperature distillation technique was developed for determining and chemically identifying the bound (nonextractable) residues of ¹⁴C-prometryn in an organic soil and plants. A considerable portion of the bound ¹⁴C residues in the incubated organic soil was identified as prometryn. These residues were absorbed by plants grown in the soil. Hono-and di-$\text{N}$-dealkylated metabolites of prometryn were present in the plant bound ¹⁴C residues and a major portion of bound residues as associated with lignin. Soil-bound ¹⁴C residues were also released from soil by microbes. The bound ¹⁴C residues in soil were associated with humin, humic acid, and fulvic acid fractions. Thermoanalytical methods were used to obtained information on the nature and location of ¹⁴C bound residues in soil and humic materials.