Fraunhofer Institute for Molecular Biology and Applied Ecology IME“A risk assessment based on ecotoxicological data from both terrestrial and aquatic systems should also be carried out for natural polymers.”
Polymers can be found in various agrotechnical products. While synthetic polymers and modified natural polymers are subject to EC 2023/2055 regulation, natural polymers, also referred to as biopolymers, can be regarded as unregulated substituents. However, there is no comprehensive data-based evidence which proves environmental safety of (modified) natural polymer exposure to terrestrial and aquatic ecosystems. In order to assess the ecotoxicity potential, we conducted a systematic study with six economically relevant bio- and modified natural polymers.
As an evaluation strategy for the ecotoxicity of polymers, which is missing in the European regulation, we considered different relevant organism groups within the agricultural landscape for testing. For the aquatic environment, tests with algae, water fleas and fish embryos were carried out and transcriptome analysis was performed. Unlike in REACH-related hazard assessment, physical effects of the substances were considered in this hazard assessment next to chemical intrinsic effects, as most of the substances tested had very low solubility. Tests with filtrates and suspensions of the substances led to the conclusion that the physical effects of the substances predominate and tests with suspensions represent an environmental relevant exposure scenario. In the terrestrial ecosystem, ecotoxicological responses to soil microbial functions were increasingly observed, while the exposed substances had mostly no effect on springtails and earthworms. These results support the idea of an application rate-based risk assessment using aquatic and terrestrial tests equally to close data gaps.
