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Bioconcentration factors (BCF) for regulatory purposes are usually determined by fish flow-through tests according to technical guidance document OECD 305. Fish bioconcentration studies are time consuming, expensive, and use many laboratory animals. The aim of this study was to investigate whether the freshwater amphipod Hyalella azteca can be used as an alternative test organism for bioconcentration studies. Fourteen substances of different hydrophobicity (log Kow 2.4–7.6) were tested under flow-through conditions to determine steady state and kinetic bioconcentration factors (BCFss and BCFk). The results were compared with fish BCF estimates for the same substances described in the literature to show the relationship between both values. Bioconcentration studies with the freshwater amphipod H. azteca resulted in BCF estimates which show a strong correlation with fish BCF values (r2 = 0.69). Hyalella BCF values can be assessed in accordance with the regulatory B criterion (BCF > 2000, i.e., REACH) and thereby enable the prediction of B or non-B classification in the standard fish test. Therefore, H. azteca has a high potential to be used as alternative test organism to fish for bioconcentration studies.Electronic supplementary materialThe online version of this article (10.1007/s11356-018-3677-4) contains supplementary material, which is available to authorized users.

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

The outstanding selectivity and sensitivity of the atmospheric pressure laser ionization (APLI), which is a two-photon ionization process, in combination with a mass spectrometric detection, is demonstrated for the analysis of DNA adducts. Preparative HPLC with a HILIC-phase and a fraction sampler was used to separate the polar 4-hydroxy-1-(3-pyridyl)-butanone (HPB) and 4-hydroxy-1-(3-pyridyl)-butanol (Diol), which will be formed after acid hydrolysis of the POB- and PHB-DNA adducts. The adducts eluted in the fractions to be analyzed were collected, concentrated to dryness and dissolved in dichloromethane. Then 4-(dimethylamino)pyridine as a base, N,N′-dicyclohexylcarbodiimide as an activator and anthracene-9-yl-methoxyacetic acid as an ionization marker, in analogy to a fluorescence marker, were added, and after several hours at 35 °C the sample was injected into an HPLC-APLI-TOF(MS). With this novel method, only aromatic compounds are ionizable; because the ionization marker of the DNA adducts carries an aromatic group, this allows ionization by the two-photon process. For the first time we have used a new strategy to analyse DNA adducts by HPLC-APLI-TOF(MS) after derivatization with an ionization marker. To demonstrate the utilizability of this method, we analyzed POB and PHB adducts, which are formed by metabolic activation pathways from 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N′-nitrosonornicotine (NNN). In summary, we have demonstrated that the derivatization strategy significantly increases the analytical applicability of APLI-MS and shows new methods for the important DNA adduct analysis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4661. doi:10.1158/1538-7445.AM2011-4661