New concepts for dynamic plant uptake models

Abstract

Models for the prediction of chemical uptake into plants are widely applied tools for human and wildlife exposure assessment, pesticide design and for environmental biotechnology such as phytoremediation. Steady-state considerations are often applied, because they are simple and have a small data need. However, often the emission pattern is non-steady. Examples are pesticide spraying, or the application of manure and sewage sludge on agricultural fields. In these scenarios, steady-state solutions are not valid, and dynamic simulation is required.We compared different approaches for dynamic modelling of plant uptake in order to identify relevant processes and time-scales of processes in the soil-plant-air system. Based on the outcome, a new model concept for plant uptake models was developed, approximating logistic growth and coupling transpiration to growing plant mass. The underlying system of differential equations was solved analytically for the inhomogenous case, i.e., for constant input. By superposition of the results of n periods, changes in emission and input data between periods are considered. This combination allows to mimick most input functions that are relevant in practice.The model was set up, parameterised and tested for uptake into growing crops. The outcome was compared to a numerical solution, to verify the mathematical structure.

Estimation of herbicide bioconcentration in sugarcane (Saccharum officinarum L.)

“…These assumptions reflect the results of several studies (TRAPP, 2007;REIN et al, 2011;TRAPP & LEGIND, 2011;TRAPP & EGGEN, 2013).…”

The Glasgow consensus on the delineation between pesticide emission inventory and impact assessment for LCA

“…Care should be taken to avoid double counting between the multimedia transfers of these emission fractions and the impact assessment fate model, thus the decision to only have the emission to environmental media via initial distribution in the inventory and subsequent transfers considered in the impact assessment. This is supported by furthermore distinguishing between initial distribution processes in LCI, where steady-state conditions are typically not (yet) reached and a dynamic assessment is required (Rein et al 2011;, and fate processes in LCIA, for which steady state is typically assumed based on continuous diffusive, advective, and degradation processes.…”

A review of measured bioaccumulation data on terrestrial plants for organic chemicals: Metrics, variability, and the need for standardized measurement protocols

“…Plant biotransformation rates are available for a few pesticides [17,22,23], pharmaceutical chemicals [24], and plasticizers [25,26]. Furthermore, plant dissipation rates (degradation and transport loss mechanisms) can vary considerably between different plant compartments and environmental conditions [27,28]. For chemicals with a high Henry's law constant (K H , Pa.m 3 /mol or K AW , dimensionless) that have been translocated to shoots, volatilization from leaves and stems, often referred to as "phytovolatilization," can be a measurable loss mechanism [29,30].…”

“…When plant biomass increases faster than contaminant uptake, growth dilution can influence BCF values. The importance of growth dilution in predicting foliar and root uptake of organic contaminants has been well documented [28,[39][40][41].…”