A simple pre-factor for contaminant biodegradation potential and its application to pesticides risk assessment

Abstract

<p>In this study, we extend our earlier work presented in the 22nd International Congress on Modelling and Simulation (MODSIM 2017) and propose a simple parametric pre-factor (the biodegradation potential <i>ψ_B</i>), which can be used to estimate the biodegraded fraction of a contaminant in soil. <i>ψ_B</i> can be determined based on either first-order or Michaelis-Menten-Monod (MMM) kinetics. We show the application in the environmental risk assessments of the herbicides atrazine (ATZ) and glyphosate (GLP). We compare the ATZ and GLP biodegraded fractions estimated with <i>ψ_B</i> against those predicted with bioreactive models accounting for more comprehensive ATZ and GLP biodegradation reaction networks. Our analyses show that <i>ψ_B</i> matched relativity well the biodegraded fraction predicted by the mechanistic model, with <i>ψ_B</i> calculated using the MMM framework providing a more accurate result. We conclude that <i>ψ_B</i> can be used to scale the predicted environmental concentration of a contaminant to account for its biodegradation potential in simplistic transport models.</p>