Predicting the accumulation of organic contaminants from soil by plants

Analytic expressions for maximum chemical concentration attained in plants, and time this takes for uptake from surrounding soil were derived from a simple two-compartment soil/water-plant model. To illustrate, for the antibiotic norflxacin undergoing first order loss in the soil/water phase with a rate constant of 0.544 days⁻¹, maximum concentration in soybean P(MAX) is predicted to occur after 2.79 days exposure and be independent of initial soil/water concentration SW₀ of 52.5 mg kg⁻¹ dry weight. For soybean, the relationship between P(MAX) and SW₀ is P(MAX) = 0.047SW₀, resulting in predicted maximum levels of 2.20 mg kg⁻¹ dry weight. Modelled plant concentrations agreed well with experimental data (R² = 0.91).