Table 2.

Factors impacting toxicokinetics in C. elegans

Factor	Process(es) Likely Impacted	References
Worm Age	Uptake (due to cuticle thickness), Metabolism (age-related changes in gene expression), Sensitivity to toxicity	(Helmcke et al. 2009)
Worm strain	Uptake (cuticle integrity, transporter expression), Distribution (transporter expression), Metabolism (gene expression), Excretion (transporter expression), Sensitivity to toxicity	(Crone et al. 2015; Davies et al. 2003)
Delivery Method or Medium	Apparent External Dose, Uptake (pharyngeal pumping rate, cuticle diffusion, co-solvent delivery)	(Zheng et al. 2013; Alaimo et al. 2012; Burns et al. 2010)
Presence or Absence of Bacteria	Apparent External Dose, Uptake (delivery of compound by adsorption/internalization by bacteria, pharyngeal pumping rate)	(Yang et al 2017; Spann et al 2015; Höss et al 2011; Offermann et al 2009)
Bacterial Density	Apparent External Dose, Uptake (delivery of compound by adsorption/internalization by bacteria, pharyngeal pumping rate)	(Offermann et al 2009; Höss et al 2011)
Presence of Organic Matter	Apparent External Dose, Uptake (co-solvent delivery)	(Hoss et al. 2009; Haitzer et al. 1999)
Washing Worms Before Extraction	Apparent Internal Concentration	(Mitchell et al. 2007)
Co-Exposures	Uptake (competition for transport, co-solvent delivery), Metabolism (competition for metabolic enzymes), Sensitivity to toxicity	(Wyatt et al. 2016a)