Remarkable hormesis induced by 1-ethyl-3-methyl imidazolium tetrafluoroborate on Vibrio qinghaiensis sp.-Q67.

Room-temperature ionic liquids (ILs) are a class of the salts in the liquid state. ILs typically consist of a bulky organic cation in combination with various anions and are designed to replace traditional volatile organic solvents in industry. However, it is not neglected that the possible release of ionic liquids into aquatic environments may lead to water pollution. We systematically investigated the effect of ILs on the luminescence of Vibrio qinghaiensis sp.-Q67 (Q67). When the ionic liquid, 1-ethyl-3-methyl imidazolium tetrafluoroborate ([emim]BF(4)), was exposed on Q67, the luminescence of Q67 was stimulated after 12 h and the maximal stimulatory amplitude (Emin) was surprisingly about 1000%. In comparison with the generally reported stimulating amplitude of about 30-60% such great stimulating effect induced by [emim]BF(4) was indeed unexpected. The main aim of this study was to systematically investigate the remarkable hormesis induced by [emim]BF(4). Results showed that there was good reproducibility on the observation of hormesis induced by [emim]BF(4) and such obvious hormesis had a close relation to the test organisms and exposure time. In addition, we confirmed that this surprising phenomenon did not only depend on range and spacing of exposure concentration of ILs but also on their structure components. Only joint influence of both anion, BF(4)(-) and ethyl side chain of cation made [emim]BF(4) induce such remarkable hormesis on Q67. The experimental findings of hormesis induced by [emim]BF(4) provided a good case for the hormesis database.