Toxicokinetics of Chromium in Enchytraeus crypticus (Oligochaeta)

Abstract

Chromium is naturally occurring, but emission from anthropogenic sources can lead to increased soil concentrations. Information on its toxicokinetics is essential in order to understand the time needed to reach toxicity and the mechanisms of uptake/elimination. In this study the toxicokinetics of Cr(III) was evaluated using the soil standard species Enchytraeus crypticus. The animals were exposed to 180 mg Cr/kg dry soil, a sublethal concentration, in LUFA 2.2 natural soil. OECD guideline 317 was followed, with a 14-day uptake phase in spiked soil followed by a 14-day elimination in clean soil. Exposure to Cr led to fast uptake and elimination, with Ku = 0.012 kgsoil/kgorganism/day and Ke = 0.57 day−1. The bioaccumulation factor was 0.022, and DT50 for elimination was 1.2 days. The concentration of Cr reached an internal equilibrium in the animals after 10 days. Transfer to clean soil allowed body Cr concentrations to return to background levels after approximately 7 days. E. crypticus seemed able to efficiently regulate internal Cr concentrations by actively eliminating Cr (an essential element). Although Ku and Ke deviated from the values reported in other studies for other soil invertebrates, the bioaccumulation factors were similar. These findings show the importance of toxicokinetic studies in evaluating toxicity based on internal metal concentrations that can more accurately represent the bioavailable concentration.

Physical, chemical and biological characteristics of clays from Durban (South Africa) for applications in cosmetics

“…Cr in the +III and +VI oxidation states is a potential hapten in the development of contact allergy 62,63 . Prolonged exposure to Cr can cause skin ulcers, and severe redness and swelling of the skin 64 …”

“…62,63 Prolonged exposure to Cr can cause skin ulcers, and severe redness and swelling of the skin. 64 The detection of Fe, Zn, and Ti showed that our clay samples can be used as a suitable ingredient in the world of cosmetics. Moreover, red clay had a higher content of Fe than any other metal and consequently, higher potential for UVB protection as higher Fe content has been shown to significantly enhance the UV protection value of clays by reducing UVB-transmission levels.…”

The effect of polystyrene microplastic and biosolid application on the toxicity and bioaccumulation of cadmium for Enchytraeus crypticus

“…Further studies using more advanced bioaccumulation methodologies, such as the one used by Santos et al (2022), are suggested to clarify the bioaccumulation potential. Also, the results in this paper, which are generated for Cd sourced from cadmium nitrate, might be interpreted for the other Cd sources such as cadmium chloride by referring to toxicokinetic and toxicodynamic of Cd (Santos et al, 2022).…”

“…The main aim of this study was to fill the gap in the literature by generating data for toxic concentrations and observing the accumulation of Cd as internal body concentrations in the presence of PS-MPs and biosolids. Further studies using more advanced bioaccumulation methodologies, such as the one used by Santos et al (2022), are suggested to clarify the bioaccumulation potential. Also, the FIGURE 4 Reproductive dose-response curve for Enchytraeus crypticus exposed to Lufa 2.2 soil mixed with cadmium, 0.5% polystyrene microplastics (PS-MPs), and 0.6 g biosolids results in this paper, which are generated for Cd sourced from cadmium nitrate, might be interpreted for the other Cd sources such as cadmium chloride by referring to toxicokinetic and toxicodynamic of Cd (Santos et al, 2022).…”

“…In addition, E. crypticus are small organisms that live in the upper layer of the soil, and so they can be used to conduct experiments in small jars or vessels (Castro‐Ferreira et al, 2012). For these reasons, they are regarded as a species for ecotoxicology studies and are used widely in soil toxicity experiments for many pollutants including metals such as Cr, Pb, Zn, Cu, Ni, and Co (Renaud et al, 2020; Santos et al, 2022; Zhang et al, 2019), silver nanoparticles (Padilha Mendonca, 2020), and microplastic (Lahive et al, 2019b). The studied endpoints of these toxic chemicals were morphology change, survival, reproduction, lethality, and cell biochemistry analyses (S. Li, Jia, et al, 2021).…”