Dissipation of pencycuron in greenhouse soil and its bioconcentration factor for estimation of the residue in spinach

The soil-applied pesticide can transfer to cultivated crops, and the residue concentration in the crops is decreased time-dependently by biological decomposition and crop growth. Pencycuron was most popularly used as a fungicide in field soil; however, the residue dissipation in greenhouse soil and its bioconcentration factor (BCF) for spinach, one of the most popular leafy vegetables, were not investigated. To estimate the residue dissipation of the soil-applied pencycuron, the residue dissipation was monitored in the recommended dose and the double dose treatments, and the 50% dissipation times ranged from 50 to 54 days; these times were met by the spinach cultivation time from seedling to harvest. The pencycuron residues in the spinach at the recommended dose and the double dose treatments were 0.006 mg kg⁻¹ and 0.025 mg kg⁻¹ at 48 days after the treatment (DAT), and 0.003 mg kg⁻¹ and 0.008 mg kg⁻¹ at 55 DAT, respectively. From the experimental data, the estimated BCFs of pencycuron were 0.003–0.008 for the spinach at 48 DAT and 0.001–0.002 at 55 DAT. During the seven-day additional cultivation, the fresh weights of the spinach were increased 1.5–1.8 times; thus, the crop growth would be considered as a main factor for the estimation of the crop residue.