Estrogenic compounds are widely released to surface waters and may cause adverse effects to sensitive aquatic species. Three hormones, estrone, 17β-estradiol and 17α-ethinylestradiol, are of particular concern as they are bioactive at very low concentrations. Current analytical methods are not all sensitive enough for monitoring these substances in water and do not cover mixture effects. Bioassays could complement chemical analysis since they detect the overall effect of complex mixtures. Here, four chemical mixtures and two hormone mixtures were prepared and tested as reference materials together with two environmental water samples by eight laboratories employing nine in vitro and in vivo bioassays covering different steps involved in the estrogenic response. The reference materials included priority substances under the European Water Framework Directive, hormones and other emerging pollutants. Each substance in the mixture was present at its proposed safety limit concentration (EQS) in the European legislation. The in vitro bioassays detected the estrogenic effect of chemical mixtures even when 17β-estradiol was not present but differences in responsiveness were observed. LiBERA was the most responsive, followed by LYES. The additive effect of the hormones was captured by ERα-CALUX, MELN, LYES and LiBERA. Particularly, all in vitro bioassays detected the estrogenic effects in environmental water samples (EEQ values in the range of 0.75-304 × EQS), although the concentrations of hormones were below the limit of quantification in analytical measurements. The present study confirms the applicability of reference materials for estrogenic effects' detection through bioassays and indicates possible methodological drawbacks of some of them that may lead to false negative/positive outcomes. The observed difference in responsiveness among bioassays - based on mixture composition - is probably due to biological differences between them, suggesting that panels of bioassays with different characteristics should be applied according to specific environmental pollution conditions.

• Klíčová slova
• Bioassay, Chemical mixture, Endocrine disrupting compound (EDC), Environmental quality standard (EQS), Estrogenicity, Hormone mixture,
• MeSH
• biotest MeSH
• chemické látky znečišťující vodu * analýza   toxicita   MeSH
• endokrinní disruptory * analýza   MeSH
• estrogeny analýza   toxicita   MeSH
• estron MeSH
• monitorování životního prostředí MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chemické látky znečišťující vodu * MeSH
• endokrinní disruptory * MeSH
• estrogeny MeSH
• estron MeSH

The present study demonstrates development of a rapid testing protocol based on a small portable luminometer using flash kinetic assessment of bacterial bioluminescence. The laboratory comparisons based on six model organic toxicants and two metals showed significant correlations between responses of freshwater bacteria Photorhabdus luminescens and standard marine bacterial species Vibrio fisheri. While P. luminescens was less sensitive in standard arrangements, the responses of both organisms were comparable in the newly introduced portable luminometer setup. The applicability and reproducibility of the portable luminometer protocol was further demonstrated in the assessment of 43 European wastewater effluents that were simultaneously tested for toxicity and analysed for 150 organic and 20 inorganic contaminants grouped into 13 major chemical classes. Clear association between the toxic responses in both compared bacterial species and the elevated levels of inorganic compounds (toxic metals), chlorophenols and benzotriazole anticorrosives was observed. The new protocol with a portable luminometer provides a fast (30 s) response and may be used as a tool for rapid in situ toxicity evaluation of freshwater environmental samples such as effluents.

• Klíčová slova
• In situ testing, Photorhabdus luminescens, Portable biotest, Vibrio fisheri, Whole effluent testing (WET),
• MeSH
• Aliivibrio fischeri růst a vývoj   MeSH
• časové faktory MeSH
• luminiscence MeSH
• luminiscenční měření metody   MeSH
• Photorhabdus růst a vývoj   MeSH
• reprodukovatelnost výsledků MeSH
• sladká voda MeSH
• testy toxicity metody   MeSH
• Publikační typ
• časopisecké články MeSH