Model parameters used for predicting root uptake of CP by lettuce.

<p>Model parameters used for predicting root uptake of CP by lettuce.</p

Residual patterns of isomers and sulfate-metabolite of ED in soils in (a) 20 mg kg^-1 and (b) 40 mg kg^-1-treated plots as observed in an outdoor greenhouse experiment.

<p>Residual patterns of isomers and sulfate-metabolite of ED in soils in (a) 20 mg kg^-1 and (b) 40 mg kg^-1-treated plots as observed in an outdoor greenhouse experiment.</p

Uptake amount of chlorpyrifos (CP) from the contaminated soil by lettuce.

<p>Uptake amount of chlorpyrifos (CP) from the contaminated soil by lettuce.</p

Physicochemical properties of the tested soils.

<p>^aOM, organic matter;</p><p>^bEC, electrical conductivity;</p><p>^cGW, soil sampled in the Gunwi region</p><p>^dWG, soil sampled in the Waegwan region</p><p>Physicochemical properties of the tested soils.</p

Residue amounts of the isomers and sulfate-metabolite of ED in various compartments of cucumber plants grown for 120 d under greenhouse conditions.

<p>^aMean of triplication ± SD</p><p>^bLess than the limit of quantification (LOQ), 0.02 mg kg^-1</p><p>Residue amounts of the isomers and sulfate-metabolite of ED in various compartments of cucumber plants grown for 120 d under greenhouse conditions.</p

Distribution patterns of isomers and sulfate-metabolite of ED absorbed from the soil into cucumbers grown for 120 d under greenhouse conditions.

<p>Distribution patterns of isomers and sulfate-metabolite of ED absorbed from the soil into cucumbers grown for 120 d under greenhouse conditions.</p

Comparison between modeled and measured uptake amounts of CP from soil by lettuce (<i>dotted line</i> is the ideal relation between both values).

<p>Comparison between modeled and measured uptake amounts of CP from soil by lettuce (<i>dotted line</i> is the ideal relation between both values).</p

Comparison of theoretical and experimental values for plant uptake of pesticide from soil

<div><p>Pesticides that persist in soils may be taken up by the roots of plants. One way to assess plant uptake is to theoretically predict the extent of plant uptake using a mathematical model. In this study, a model was developed to predict plant uptake of pesticide residues in soils using various parameters, such as pesticide mobility within soil, plant transpiration stream, root–soil transfer rate, plant growth, and pesticide dissipation in either soils or plants. The accuracy of the model was evaluated by comparing the modeled concentrations with measured uptake concentrations of chlorpyrifos (CP) in lettuce, grown on treated soils with concentrations of approximately 10 and 20 mg kg^-1 CP. Measured concentrations of CP in lettuce at 21, 30, and 40 d after planting were between the 5^th and 95^th percentiles of model variation. A high correlation coefficient of > 0.97 between modeled and measured concentrations was found. Coefficients of variation of mean factors to residual errors were between 25.3 and 48.2%. Overall, modeling results matched the experimental results well. Therefore, this plant uptake model could be used as an assessment tool to predict the extent of plant uptake of pesticide residues in soils.</p></div

Time-dependent distribution of α- (a, b) and β-isomers of ED (c, d), as well as its sulfate-metabolite (e, f), in each cucumber compartment under treatment concentrations of 20 mg kg^-1 (a, c, e) and 40 mg kg^-1 (b, d, f) as observed in the indoor test.

<p>Time-dependent distribution of α- (a, b) and β-isomers of ED (c, d), as well as its sulfate-metabolite (e, f), in each cucumber compartment under treatment concentrations of 20 mg kg^-1 (a, c, e) and 40 mg kg^-1 (b, d, f) as observed in the indoor test.</p

Correlation between modeled and measured concentrations of CP in leaves of lettuce (<i>dotted line</i> is the ideal relation between both values).

<p>Correlation between modeled and measured concentrations of CP in leaves of lettuce (<i>dotted line</i> is the ideal relation between both values).</p