Evaluation of models to estimate the bioaccumulation of organic chemicals in earthworms

A User-Friendly Kinetic Model Incorporating Regression Models for Estimating Pesticide Accumulation in Diverse Earthworm Species Across Varied Soils

“…Kinetic Model of Jager et al 14 We previously found that of the three existing kinetic models, that of Jager et al 14 performed best. 12 Our current study confirms that this model works fairly well when applied to independent data for PCB 153. When the model was implemented using the parametrized values for all input parameters provided in Jager et al, 14 only 56.8% of predicted internal concentrations of PCB 153 in E. fetida and E. andrei fell within a factor of 3 of measured values (Figure S5C).…”

“…Existing EP models, such as those developed by Jager 44 and Connell and Markwell, 45 which are recommended by the Technical Guidance Document 9,10 for risk assessment of secondary poisoning via earthworms perform less well than those developed by Belfroid et al 12,22 In this study we show that relative to our new models, the model of Belfroid et al 22 performs less well when different earthworm species are considered, and provides less accurate predictions for hydrophilic compounds. Additionally, the kinetic model of Jager et al 14 has limited applicability and accessibility for assessing the risks of pesticides to earthworms associated with time-varying exposures due to its complexity.…”

“…We compared the performance of our newly developed model to that of an existing EP model 22 and a kinetic model, 14 which we had previously found to be the best performing of existing models for estimating bioconcentration of organic compounds in earthworms. 12 The EP model of Belfroid et al 22 calculates steady-state internal concentration of earthworms as the sum of chemical uptake from interstitial water, via passive diffusion as determined by a bioconcentration factor, and soil ingestion as determined by soil uptake rate (estimated by feeding rate multiplied by uptake efficiency) and the total elimination rate. Its performance was evaluated using a subset of our independent data taken from the literature (Table S3) comprising 217 data points representing steady-state or maximum internal concentrations in earthworms.…”

“…The developed models are as simple as possible while showing great potential for generalization to predict bioconcentration across earthworm species, addressing a significant limitation of existing EP and kinetic models. 12,13 However, the data available in the literature to test our models for L. terrestris and A. caliginosa are relatively few and show limited variation. A large and high-quality data set on uptake kinetic data for earthworm species other than E. fetida and E. andrei is required for further evaluation of our models.…”

“…We identified three previously developed kinetic bioconcentration models that simulate chemical uptake and elimination over time by earthworms in soil. , Jager et al and Jager reported similar closed mass balance models incorporating dermal and intestinal uptake routes to estimate the total body residues of the earthworm Eisenia andrei resulting from chemical exposure via contaminated soils and/or food. The Armitage and Gobas model quantifies kinetic uptake of contaminants from air, porewater, soil, and food by earthworms, and their elimination through respiratory exchange, fecal and urinary pathways, reproduction, and metabolic transformation.…”