Mercury is a ubiquitous environmental pollutant of dominantly anthropogenic origin. A critical concern for human health is the introduction of mercury to the food chain; therefore, monitoring of mercury levels in agricultural soil is essential. Unfortunately, the total mercury content is not sufficiently informative as mercury can be present in different forms with variable bioavailability. Since 1990, the use of bioreporters has been investigated for assessment of the bioavailability of pollutants; however, real contaminated soils have rarely been used in these studies. In this work, a bioassay with whole-cell bacterial bioreporter Escherichia coli ARL1 was used for estimation of bioavailable concentration of mercury in 11 soil samples. The bioreporter emits bioluminescence in the presence of Hg(II). Four different pretreatments of soil samples prior to the bioassay were tested. Among them, laccase mediated extraction was found to be the most suitable over water extraction, alkaline extraction, and direct use of water-soil suspensions. Nevertheless, effect of the matrix on bioreporter signal was found to be severe and not possible to be completely eliminated by the method of standard addition. In order to elucidate the matrix role, influences of humic acid and selected metal ions present in soil on the bioreporter signal were tested separately in laboratory solutions. Humic acids were found to have a positive effect on the bioreporter growth, but a negative effect on the measured bioluminescence, likely due to shading and Hg binding resulting in decreased bioavailability. Each of the tested metal ions solutions affected the bioluminescence signal differently; cobalt (II) positively, iron (III) negatively, and the effects of iron (II) and nickel (II) were dependent on their concentrations. In conclusion, the information on bioavailable mercury estimated by bioreporter E. coli ARL1 is valuable, but the results must be interpreted with caution. The route to functional bioavailability bioassay remains long.

• Klíčová slova
• Escherichia coli ARL1, bioluminescent bioreporter, mercury detection, pollution bioavailability, whole-cell biosensor,
• MeSH
• biosenzitivní techniky * MeSH
• Escherichia coli MeSH
• huminové látky * MeSH
• látky znečišťující půdu * analýza   MeSH
• monitorování životního prostředí MeSH
• půda MeSH
• rtuť * analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• huminové látky * MeSH
• látky znečišťující půdu * MeSH
• půda MeSH
• rtuť * MeSH

Cell wall envelopes treated with sodium hydroxide and spray-dried were used as mercury sorbents. The sorbent having sorption capacity 17.7 ± 0.1 μmol/g determined was employed for preconcentration of mercury containing 1-10 ng/L. After preconcentration, bioavailable mercury was detected in samples of soil, stream, and tap water via induction of bioluminescence of E. coli ARL1. Iron and manganese at concentrations of tenth microgram per liter interfered bioluminescence detection of mercury. In tap water was detected semiquantitatively 0.127 ± 0.1 nmol/L by the induction of bioluminescence of E. coli ARL1 in medium with tryptone after preconcentration using a method of standard addition.

• Klíčová slova
• Bioreporters, Biosorbents, Mercury detection, Mercury sorption,
• MeSH
• biosenzitivní techniky metody   MeSH
• Escherichia coli genetika   metabolismus   MeSH
• luminiscenční měření MeSH
• půda chemie   MeSH
• rtuť analýza   MeSH
• voda chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• půda MeSH
• rtuť MeSH
• voda MeSH