Principal Investigator
Dr. Karsten Schlich
Fraunhofer Institute for Molecular Biology and Applied Ecology (IME)
Auf dem Aberg 1
DE-57392 Schmallenberg
Germany
Email: karsten.schlich@ime.fraunhofer.de
Phone no: +49 297 2302495
Collaborators
Chris Hughes, Associate Director, Ricardo Energy & Environment, chris.hughes@ricardo.com
Description
Recently a number of publications have drawn attention to various concerns related to the reliability and relevance of data published in the peer-reviewed literature with respect to the quality of ecotoxicological effects data for microplastic particles (MPs) (de Ruitjer et al., 2020 and Mehinto et al., 2022). An important observation from these studies regards the poor reporting of particle properties, with most studies limited to the testing of polystyrene (PS) spheres, which are not representative of an environmentally relevant type of particle and which are typically tested at concentrations well above those reported in the environment. Currently there is no mechanism available that can enable the extrapolation of effects data reported for PS to other types of particles of varying shape, size and polymeric composition. Given that the observation of MPs in the environment is characterized by a complex heterogeneous mixture of particles, data that report adverse effects for a homogenous group of particles are insufficient to enable an assessment of risk, although they may be useful towards developing an improved mechanistic understanding between a specific suite of particle properties and a toxicological mode of action. Consequently, there is a need for future research to evaluate the adverse effects of environmentally relevant MPs.
It is also notable that the majority of ecotoxicological data available in the peer-reviewed literature relates to various aquatic test species, which have been recently summarized and critically reviewed by de Ruitjer et al. (2020), with only a limited number of studies publishing original data on effects for terrestrial species. The paucity of effects data for terrestrial species represents an important limitation towards enabling the development and application of risk assessment for the terrestrial environment (Du et al., 2021; Wang et al, 2019; Hurley and Nizetto, 2018; Horton et al., 2017). Nevertheless, based on recent advances aimed at identifying the importance of considering various quality assurance and quality control (QA/QC) criteria in the context of aquatic toxicity testing of MPs (de Ruitjer et al., 2020), as well as the potential to leverage learnings obtained through the terrestrial toxicity testing of engineered nanomaterials (ENMs), there exists an opportunity to develop an intelligent testing strategy specific to testing MPs where emissions to the terrestrial environment represent a potential cause for concern. Of particular interest is a need to better understand the potential risks associated with the use of plastic in agricultural practices, where it is known that a substantive number of plastic products are used, such as in the form of plastic films used in a number of applications (Bläsing and Amelung, 2018). Other sources of MPs into agricultural soils include the release of polymeric materials used as encapsulates coating seeds as well as inputs associated with the application of biosolids, where the efficient removal of MPs from waste water treatment practices due to sorption by biosolids can potentially represent an important source of MPs to the terrestrial environment (Schlich et al., in preparation; Nizetto et al, 2016).
