Toxicity and neurotoxicity profiling of contaminated sediments from Gulf of Bothnia (Sweden): a multi-endpoint assay with Zebrafish embryos

Riccardo Massei,Peter Haglund,Martin Krauss,Henner Hollert,Werner Brack,Mats Tysklind,Christine Gallampois,Eberhard Küster,Wolf Von Tümpling,Cindy Weidauer

doi:10.1186/s12302-019-0188-y

Abstract

BackgroundThe toxicological characterization of sediments is an essential task to monitor the quality of aquatic environments. Many hazardous pollutants may accumulate in sediments and pose a risk to the aquatic community. The present study provides an attempt to integrate a diagnostic whole mixture assessment workflow based on a slightly modified Danio rerio embryo acute toxicity test with chemical characterization. Danio rerio embryos were directly exposed to sieved sediment (≤ 63 μm) for 96 h. Sediment samples were collected from three polluted sites (Kramfors, Sundsvall and Örnsköldsvik) in the Gulf of Bothnia (Sweden) which are characterized by a long history of pulp and paper industry impact. Effect data were supported by chemical analyses of 237 organic pollutants and 30 trace elements.ResultsThe results show that malformations and neurotoxic compounds are the main drivers of differentiation in chemical and effects analyses, respectively. Specific spinal cord malformations and delayed hatching were observed only in sediments from Kramfors while light hyperactivity was seen only after exposure to sediments from Sundsvall.ConclusionsOur experiments demonstrate that specific chemical profiles lead to specific effect patterns in Danio rerio embryos. In fact, behavioral endpoints could help detect the exposure to neurotoxins, and the observation of body malformations seems to be a potential tool for the identification of site-specific pollutants as polychlorinated biphenyl (PCBs), brominated flame retardants (BFRs) and several pesticides. Overall, results show the suitability of Danio rerio embryos for the fast screening of sediment samples.

Highlights

The toxicological characterization of sediments is an essential task to monitor the quality of aquatic environments
The three sites have a long history of pulp and paper industry, saw mills, as well as other industrial activities with possibly elevated levels of a series of legacy contaminants in the sediments, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyl (PCBs), organochlorine insecticides (OCPs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and metals
The area of Kramfors showed the highest loads of chemicals with 53 identified compounds and a cumulative concentration of 3.6 μg/mg total organic carbon (TOC)

Summary

Introduction

The toxicological characterization of sediments is an essential task to monitor the quality of aquatic environments. The present study provides an attempt to integrate a diagnostic whole mixture assessment workflow based on a slightly modified Danio rerio embryo acute toxicity test with chemical characterization. Risk assessment of complex mixtures may involve component-based approaches by applying chemical analysis together with measured or predicted toxicity data. Massei et al Environ Sci Eur (2019) 31:8 of environmental samples and were successfully applied for the characterization of aquatic sediments [11–17]. Despite the undoubted advantages of cell-based assays for the analysis of toxicological patterns in sediments, in vitro results cannot directly predict the biological responses in more complex organisms and aquatic communities [18]. Accepted and validated workflows for the in vivo toxicological profiling of complex mixtures including sediment contamination are still lacking

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