Biological activity of aryl hydrocarbon receptor ligands in sediments from remote European lakes

Abstract

1. Sediment extracts from 63 European remote lakes were tested for the presence of ligands of the aryl hydrocarbon receptor (AhR), using a yeast-based bioassay. The lakes belong to different European mountain regions in Central Norway, Scotland, Piedmont (Italy), Tyrol (Austria and Italy) and the Julian Alps (Slovenia). 2. AhR ligand activity varied about 40-fold among the examined lakes, with Scotland having the highest proportion of lakes with high AhR ligand activity, whereas samples with low AhR ligand activity predominate in the Julian Alps. 3. AhR ligand activity in sediment samples correlated with the concentration of several environmentally relevant compounds, including polycyclic aromatic hydrocarbons, hexachlorobenzene and several polychlorobiphenyl ether congeners. These correlations suggest an anthropogenic origin for the detected AhR ligands, rather than being generated from natural processes. 4. We conclude that pollutants deposited in remote lakes by atmospheric processes are active AhR ligands at the concentrations found in these lakes. Given the high toxicity associated with ectopic activation of AhR in different animal systems, this activity may represent a significant risk for the exposed fauna.

Remote European mountain lake ecosystems: regionalisation and ecological status

“…, 2009), an assessment of pan‐European heavy metal pollution (Camarero et al. , 2009b), an examination of the regional variability of organochlorine compounds in snow (Grimalt, Fernández & Quiroz, 2009), a study of sediment hydrocarbon toxicity (Boronat et al. , 2009), and a regional assessment of acid deposition and climate change effects based on diatom records (Curtis et al.…”

“…However, the evaluation of toxic effects at individual, population and ecosystem levels still provides significant challenges. Boronat et al. (2009) used a yeast‐based bioassay to test the presence of ligands of the aryl hydrocarbon receptor (AhR) in sediment extracts of European mountain lakes from Central Norway to the Julian Alps.…”

“…However, the evaluation of toxic effects at individual, population and ecosystem levels still provides significant challenges. Boronat et al (2009) used a yeast-based bioassay to test the presence of ligands of the aryl hydrocarbon receptor (AhR) in sediment extracts of European mountain lakes from Central Norway to the Julian Alps. Activation of AhR constitutes the initial step of the metabolic chain leading to toxic effects of a variety of very harmful pollutants, such as 2,3,7,8-tetrachlorodibenzo-(p)-dioxin and benzo[a]pyrene.…”

Origin and distribution of polycyclic aromatic hydrocarbon pollution in sediment and fish from the biosphere reserve of Urdaibai (Bay of Biscay, Basque country, Spain)

“…The capacity of substances or environmental samples to activate the AhR system (the so-called dioxin-like activity, as dioxins are known to bind to AhR with extremely high affinity) can be quantified by a variety of aryl hydrocarbon-responsive reporter assays based on either in vivo animal tests (Willey et al, 1998) or different vertebrate cell lines (Villeneuve et al, 2002). Yeast-based bioassays represent a fast and cheaper alternative, although reports of their use for detection of AhR ligands in environmental samples are still scarce (Boronat et al, 2009;Lee et al, 2005;Murahashi et al, 2007). Yeasts lack AhR or any equivalent receptor, but their genetic make-up can be easily modified to reconstruct at least partially the mammalian pathway (Miller, 1999;Miller, 1997).…”

Application of bioassay panel for assessing the impact of advanced oxidation processes on the treatment of reverse osmosis brine

“…While these values are clearly higher than the maximum observed concentration of pharmaceuticals in the samples, they are not uncommon in environmental samples. AhR ligands have been detected in both wastewaters and superficial waters . Therefore, their removal from brines and wastewaters in general by the oxidation procedure is an interesting result, as they are not eliminated (at least, not completely) by standard secondary treatment procedures.…”