Invertebrate Species for the Bioavailability and Accumulation Assessment of Manufactured Polymer-Based Nano- and Microplastics.

Bioaccumulation tests with invertebrates have recently been discussed as a suitable alternative to bioaccumulation tests with metal- or metal oxide-based nanoparticles in fish for regulatory assessment. In the present study, as a first step, we investigated the suitability of three invertebrate species for bioaccumulation tests with nano- and microplastics. In a laboratory approach the freshwater bivalve Corbicula fluminea, the freshwater amphipod Hyalella azteca, and the terrestrial isopod Porcellio scaber were exposed to fluorescently labeled nano- and microplastics to evaluate their suitability to estimate the bioavailability and bioaccumulation of these test items. No bioaccumulation was observed in H. azteca or P. scaber. In contrast, the measurement of the relative fluorescence of the test items in the soft tissue and the feces of the filter-feeding bivalve allowed us to derive data that may be useful for the regulatory bioaccumulation assessment of manufactured nano- and microplastics. The developed measurement method using fluorescence represents a time-efficient and cost-effective analytical method for manufactured nano- and microplastics in laboratory studies for regulatory assessment. Environ Toxicol Chem 2022;41:961-974. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Comparison of Alternative Methods for Bioaccumulation Assessment: Scope and Limitations of In Vitro Depletion Assays with Rainbow Trout and Bioconcentration Tests in the Freshwater Amphipod Hyalella azteca.

Bioaccumulation assessment predominantly relies on the bioconcentration factor (BCF) as the sole decisive metric. The test guideline 305 by the Organisation for Economic Co-operation and Development (OECD) provides the standard procedure for deriving this in vivo fish BCF, which is not only expensive and labor-intensive, but also requires many animals. Accordingly, there is a great need for and interest in alternative methods that can help to reduce, replace, and refine vertebrate tests, as described in the 3R principles. Two alternative approaches have been developed: the bioconcentration test with the freshwater amphipod Hyalella azteca and the OECD test guideline 319 which provides a method to determine experimentally derived in vitro metabolism rates that can then be incorporated into in silico prediction models for rainbow trout BCF calculation. In the present study both alternative methods were applied to 5 substances of different physicochemical characteristics. The results were compared with literature values of fish in vivo BCFs and additional BCFs obtained with the alternative methods, if available. Potential differences between the results of the test methods are discussed utilizing information such as in vivo metabolism rates. The currently available data set suggests that these 2 alternative methods pose promising alternatives to predict bioaccumulation in fish, although defined applicability domains have yet to be determined. Environ Toxicol Chem 2020;39:1813-1825. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Fish bioconcentration studies with column-generated analyte concentrations of highly hydrophobic organic chemicals.

The performance of aqueous exposure bioconcentration fish tests according to Organisation for Economic Co-operation and Development (OECD) guideline 305 requires the possibility of preparing stable aqueous concentrations of the test substances. For highly hydrophobic organic chemicals (HOCs; octanol-water partition coefficient [log KOW ] > 5), testing via aqueous exposure may become increasingly difficult. A solid-phase desorption dosing system was developed to generate stable concentrations of HOCs without using solubilizing agents. The system was tested with hexachlorobenzene (HCB), o-terphenyl (oTP), polychlorinated biphenyl (PCB) 153, and dibenz[a,h]anthracene (DBA) (log KOW 5.5-7.8) in 2 flow-through fish tests with rainbow trout (Oncorhynchus mykiss). The analysis of the test media applied during the bioconcentration factor (BCF) studies showed that stable analyte concentrations of the 4 HOCs were maintained in the test system over an uptake period of 8 wk. Bioconcentration factors (L kg-1 wet wt) were estimated for HCB (BCF 35 589), oTP (BCF 12 040), and PCB 153 (BCF 18 539) based on total water concentrations. No bioconcentration could be determined for DBA, probably because of the rapid metabolism of the test item. The solid-phase desorption dosing system is suitable to provide stable aqueous concentrations of HOCs required to determine the bioconcentration in fish and represents a viable alternative to the use of solubilizing agents for the preparation of test solutions. Environ Toxicol Chem 2017;36:906-916. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC.

Bioaccumulation in aquatic systems: methodological approaches, monitoring and assessment.

Bioaccumulation, the accumulation of a chemical in an organism relative to its level in the ambient medium, is of major environmental concern. Thus, monitoring chemical concentrations in biota are widely and increasingly used for assessing the chemical status of aquatic ecosystems. In this paper, various scientific and regulatory aspects of bioaccumulation in aquatic systems and the relevant critical issues are discussed. Monitoring chemical concentrations in biota can be used for compliance checking with regulatory directives, for identification of chemical sources or event-related environmental risk assessment. Assessing bioaccumulation in the field is challenging since many factors have to be considered that can affect the accumulation of a chemical in an organism. Passive sampling can complement biota monitoring since samplers with standardised partition properties can be used over a wide temporal and geographical range. Bioaccumulation is also assessed for regulation of chemicals of environmental concern whereby mainly data from laboratory studies on fish bioaccumulation are used. Field data can, however, provide additional important information for regulators. Strategies for bioaccumulation assessment still need to be harmonised for different regulations and groups of chemicals. To create awareness for critical issues and to mutually benefit from technical expertise and scientific findings, communication between risk assessment and monitoring communities needs to be improved. Scientists can support the establishment of new monitoring programs for bioaccumulation, e.g. in the frame of the amended European Environmental Quality Standard Directive.