Sediment Toxicity Tests: A Critical Review of Their use in Environmental Regulations

Abstract

Sediments are an integral component of aquatic systems, linking multiple water uses, functions, and services. Contamination of sediments by chemicals is a worldwide problem, with many jurisdictions trying to prevent future pollution (prospective) and manage existing contamination (retrospective). The present review assesses the implementation of sediment toxicity testing in environmental regulations globally. Currently, the incorporation of sediment toxicity testing in regulations is most common in the European Union (EU), North America, and Australasian regions, with some expansion in Asia and non‐EU Europe. Employing sediment toxicity testing in prospective assessments (i.e., before chemicals are allowed on the market) is most advanced and harmonized with pesticides. In the retrospective assessment of environmental risks (i.e., chemicals already contaminating sediments), regulatory sediment toxicity testing practices are applied inconsistently on the global scale. International harmonization of sediment toxicity tests is considered an asset and has been successful through the widespread adoption and deployment of Organisation for Economic Co‐operation and Development guidelines. On the other hand, retrospective sediment assessments benefit from incorporating regional species and protocols. Currently used toxicity testing species are diverse, with temperate species being applied most often, whereas test protocols are insufficiently flexible to appropriately address the range of environmental contaminants, including nanomaterials, highly hydrophobic contaminants, and ionized chemicals. The ever‐increasing and ‐changing pressures placed on aquatic resources are a challenge for protection and management efforts, calling for continuous sediment toxicity test method improvement to insure effective use in regulatory frameworks. Future developments should focus on including more subtle and specific toxicity endpoints (e.g., incorporating bioavailability‐based in vitro tests) and genomic techniques, extending sediment toxicity testing from single to multispecies approaches, and providing a better link with ecological protection goals. Environ Toxicol Chem 2024;00:1–20. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Recent Developments in Sediment Toxicity Testing

“…An important choice to make when one is designing a sediment toxicity test is whether to use artificial or natural sediment. As also mentioned by Leppanen et al (2024), the use of natural sediment could make a test more ecologically relevant. This consideration prompted Grønlund et al (2023) to critically evaluate the pros and cons of applying natural fieldcollected sediments and to formulate a list of criteria to fulfill when using such sediments in actual toxicity testing.…”

“…Subsequently, used actual field-collected sediments to perform sediment toxicity tests with the aim of answering the (mechanistic) questions of whether mixture toxicity occurs when multiple contaminants are tested simultaneously and whether any observed toxicity can be described and predicted with models. The last question seamlessly links to one of the recommendations by Leppanen et al (2024), that is, to explore the potential use of models in sediment toxicity testing in more detail. For this reason and because models are not being used to their fullest potential, Burgess et al (2023) finally provide a critical review of the different types of models that can be used for this purpose.…”

“…In the first paper, Leppanen et al (2024) provide an overview of where (in which countries), why (with what purpose), and how sediment toxicity tests should be performed. Moreover, in their critical review, they list several current needs and challenges and identify possible improvements in terms of regulations and actual testing.…”