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Previous studies demonstrated long-term stimulation of some commercial personal care products (PCPs) on freshwater luminescent bacteria Vibrio qinghaiensis sp .-Q67 (Q67). However, whether a certain component can affect mixture's hormetic effect is still unknown. In this paper, two of ingredients in PCPs, 2-phenoxyethanol (PhE) and polyethylene glycol 400 (PEG400), were selected as object compounds to explore the relationship between concentration-response (CR) of mixtures and that of a single component. It was found that PEG400 has monotonic CR (MCR) on Q67 both at the short-term (0.25 h) and long-term (12 h) exposures while PhE has MCR at 0.25 h and hormetic CR (HCR) at 12 h. Here, the concentration-response curves (CRCs) of PEG400 at 0.25 and 12 h are overlapped each other and the CRCs of PEG400 are on the right of PhE. If the pEC 50 is taken as a toxic index, the toxicities of PEG400 at two times are basically the same, and those of PhE are the same, too, but PhE is twice as toxic as PEG400. For the mixtures of PEG400 and PhE, all rays except R1 have MCRs at 0.25 h while all rays have HCRs at 12 h where the higher the mixture ratio of PhE is, the more negative the maximum stimulation effect is. More importantly, the E min values of all rays are more negative (1.79–3.17-fold) than that of PhE worked alone, which implies that the introduction of PEG400 significantly enhances stimulative effect of PhE. At 0.25 h, all binary mixture rays but R1 produce a low-concentration additive action and high-concentration synergism. At 12 h, all rays display additive action, antagonism, additive action, and synergism in turn when the concentration changes from low to high. The overall findings suggested toxicological interactions should be considered in the risk assessment of PCPs and their potential impacts on ecological balances.

Although magnetic ionic liquids (MILs) are not yet industrially applied, their continued development and eventual commercial use may lead to their appearance into the aquatic ecosystem through accidental spills or effluents, consequently promoting aquatic contaminations. Furthermore, the deficient information and uncertainty surrounding the environmental impact of MILs could be a major barrier to their widespread industrial application and international registration. Thus, in the present work, a range of cholinium salt derivatives with magnetic properties was synthesized and their ecotoxicity was evaluated towards the luminescent bacteria Vibrio fischeri. The results suggest that all MILs structures tested are moderately toxic, or even toxic, to the bacteria. Furthermore, their toxicity is highly dependent on the structural modifications of the cation, namely the alkyl side chain length and the number of hydroxyethyl groups, as well as the atomic number of the metal anion. Finally, from the magnetic anions evaluated, the [MnCl4]2- is the less toxic. In order to improve the knowledge for the prospective design of environmentally safer MILs, it is important to expand this study to other aquatic organisms at different trophic levels. published

The widespread use of organic ultraviolet (UV) filters in personal care products raises concerns about their potentially hazardous effects on human and ecosystem health. In this study, the toxicities of four commonly used benzophenones (BPs) UV filters including benzophenone (BP), 2-Hydroxybenzophenone (2HB), 2-Hydroxy-4-methoxybenzophenone (BP3), and 2-Hydroxy-4-methoxybenzophenone-5-sulfonicacid (BP4) in water were assayed in vitro using Vibrio fischeri, SOS/umu assay, and yeast estrogen screen (YES) assay, as well as in vivo using zebrafish larvae. The results showed that the luminescent bacteria toxicity, expressed as logEC50, increased with the lipophilicity (logKow) of BPs UV filters. Especially, since 2HB, BP3 and BP4 had different substituent groups, namely -OH, -OCH3 and -SO3H, respectively, these substituent functional groups had a major contribution to the lipophilicity and acute toxicity of these BPs. Similar tendency was observed for the genotoxicity, expressed as the value of induction ratio=1.5. Moreover, all the target BPs UV filters showed estrogenic activity, but no significant influences of lipophilicity on the estrogenicity were observed, with BP3 having the weakest estrogenic efficiency in vitro. Although BP3 displayed no noticeable adverse effects in any in vitro assays, multiple hormonal activities were observed in zebrafish larvae including estrogenicity, anti-estrogenicity and anti-androgenicity by regulating the expression of target genes. The results indicated potential hazardous effects of BPs UV filters and the importance of the combination of toxicological evaluation methods including in vitro and in vivo assays.

Assessment of eco-toxicant using bioluminescent bacterial assay is a widely used and globally accepted method. In this work, a new luminescent bacterium was isolated from squid (Loligo duvauceli) and identified as Photobacterium leiognathi strain AK-MIE using 16S rRNA, phylogeny analysis. The predicted optimum conditions by RSM were 2.76% (w/v) NaCl, 2.28% (w/v) peptone, 0.34% (w/v) yeast extract, and pH 6.83 with 541,211.80 RLU of luminescent production whereas the predicted optimum conditions by ANN were 2.21% (w/v) NaCl, 2.27% (w/v) peptone, 0.39% (w/v) yeast extract, and pH 6.94 which produced 541,986.20 RLU. The validation analysis of both RSM and ANN show 0.60% and 0.69% deviation from the predicted results indicating that both models provided good quality predictions with ANN showing a superior data fitting capability for non-linear regression analysis. Toxicity tests show strain AK-MIE was sensitive to mercury (concentration causing 50% inhibition or IC50 of 0.00978 mg L − 1 ), followed by cadmium (IC50 of 0.5288 mg L − 1 ), copper IC50 of (0.8117 mg L − 1 ), silver (IC50 of 1.109 mg L − 1 ), and lead (IC50 of 10.71 mg L − 1 ) which are more sensitive than previously isolated luminescent bacteria, suggesting that strain AK-MIE has the potential to be used in toxicity assessment of heavy metals in the environment. Based on the field trial results, several sediment samples from industrial areas in Bangi, Selangor managed to inhibit the bioluminescence of strain AK-MIE. Validation method carried out using ICP-MS proved the presence of several toxic heavy metal elements.

A novel tool, the DAMTA analyzer (Device for Analytical Monitoring and Toxicity Assessment), designed for fully automated toxicity measurements based on luminescent bacteria as well as for concomitant determination of chemical parameters, was developed and field-tested. The instrument is a robotic water analyzer equipped with a luminometer and a spectrophotometer, integrated on a thermostated reaction plate which contains a movable carousel with 80 cuvettes. Acute toxicity is measured on-line using a wild type Photobacterium phosphoreum strain with measurable bioluminescence and unaltered sensitivity to toxicants lasting up to ten days. The EC50 values of reference compounds tested were consistent with A. fischeri and P. phosphoreum international standards and comparable to previously published data. Concurrently, a laboratory trial demonstrated the feasibility of use of the analyzer for the determination of nutrients and metals in parallel to the toxicity measurements. In a prolonged test, the system was installed only in toxicity mode at the premises of the World Fair “Expo Milano-2015″, a high security site to ensure the quality of the supplied drinking water. The monitoring program lasted for six months during which ca. 2400 toxicity tests were carried out; the results indicated a mean non-toxic outcome of −5.5 ± 6.2%. In order to warrant the system's robustness in detecting toxic substances, Zn was measured daily with highly reproducible inhibition results, 70.8 ± 13.6%. These results assure that this novel toxicity monitor can be used as an early warning system for protection of drinking water sources from emergencies involving low probability/high impact contamination events in source water or treated water.

Monitoring and assessing toxic materials which are being released into the environment along with wastewater is a growing concern in many industries. The current research describes a highly sensitive and rapid method for the detection of toxic concentrations of heavy metals in aquatic environments. Water samples were collected from southern coasts of the Caspian Sea followed by screening of luminescent bacteria. Phylogenetic analysis, including gene sequence of 16S rRNA, and biochemical tests were performed for identification of the isolate. Luminescence activity was tested and measured after treatment of the isolate with different concentrations of heavy metals and reported as EC50 value for each metal. A luminous, gram negative bacterium with the shape of a curved rod was isolated from the Caspian Sea. Biochemical tests and 16S rRNA gene sequence analysis indicated that the isolate MM1 had more than 99% similarity to Vibrio campbellii. The novel isolate is able to emit high levels of light. Bioluminescence inhibitory assay showed that the Vibrio sp. MM1 had the highest sensitivity to zinc and the lowest sensitivity to cadmium; EC50 values were 0.97mgl-1 and 14.54mgl-1, respectively. The current research shows that even low concentrations of heavy metals can cause a detectable decline in luminescence activity of the novel bacterium Vibrio sp. MM1; hence, it makes a good choice for commercial kits for the purpose of monitoring toxic materials.

Luminescent bacterial test is a fast and sensitive method for acute toxicity assessment of water and wastewater. In this study, an improved toxicity testing method was developed using the freshwater luminescent bacteria Vibrio qinghaiensis sp.-Q67 that involved pretreatment of water samples with reverse osmosis (RO) to eliminate the interferences caused by nutrients in concentrated samples and to improve the reliability and sensitivity of the analysis. Because water samples contain low concentrations of several target toxic substances, rapid acute toxicity testing method that is commonly employed does not achieve enough sensitivity. The proposed RO pretreatment could effectively enrich organic and inorganic substances in water samples to enable a more effective and sensitive toxicity evaluation. The kinetic characteristics of toxicity of raw sewage and secondary effluent were evaluated based on the relative luminescence unit (RLU) curves and time-concentration-effect surfaces. It was observed that when the exposure time was prolonged to 8-h or longer, the bacteria reached the logarithmic growth stage. Hence, the stimulating effects of the coexisting ions (such as Na+, K+, NO3-) in the concentrated samples could be well eliminated. A 10-h exposure time in proposed Q67 test was found to quantitatively evaluate the toxicity of the organic and inorganic pollutants in the RO-concentrated samples. © 2013 Elsevier Inc.

In Europe hazardous wastes are classified by 14 criteria including ecotoxicity (H 14). Standardized methods originally developed for chemical and soil testing were adapted for the ecotoxicological characterization of wastes including leachate and solid phase tests. A consensus on which tests should be recommended as mandatory is still missing. Up to now, only a guidance on how to proceed with the preparation of waste materials has been standardized by CEN as EN 14735. In this study, tests including higher plants, earthworms, collembolans, microorganisms, duckweed and luminescent bacteria were selected to characterize the ecotoxicological potential of a boiler slag, a dried sewage sludge, a thin sludge and a waste petrol. In general, the instructions given in EN 14735 were suitable for all wastes used. The evaluation of the different test systems by determining the LC/EC50 or NOEC-values revealed that the collembolan reproduction and the duckweed frond numbers were the most sensitive endpoints. For a final classification and ranking of wastes the Toxicity Classification System (TCS) using EC/LC50 values seems to be appropriate.

The influence of a series of quinones and phenols on bacteria bioluminescence systems was investigated. Three bioluminescence systems used in ecological monitoring were compared: (1) water-soluble; (2) immobilized in starch gel coupled enzyme systems: NADH:FMN-oxidoreductase-luciferase; (3) luminescent bacteria. Bioluminescence inhibition constants of quinones and phenols and bioluminescence induction periods were compared. These kinetic parameters are proportional to quinone concentrations and depend on the quinone redox potential. Different effects of the substances are related to structure and properties of the bioluminescence systems. The set of bioluminescence assays for quinones and phenols monitoring should include two bioluminescence systems: 1 (or 2) and 3.

Growing concern over environmental contamination has stimulated rigorous efforts to establish reliable biological monitoring assays. Methodology was developed for measuring photoinduced short- and long-term toxicity of an important group of contaminants, polycyclic aromatic hydrocarbons (PAHs), using the luminescent bacterium Vibrio fischeri. The toxicity of most PAHs can be greatly enhanced on exposure of a living organism and/or the chemicals to ultraviolet (UV) radiation. There are two major mechanisms involved in photoinduced toxicity of PAHs: photosensitization and photomodification. In the former, production of singlet oxygen leads to cellular damage. In the latter, photooxidation of PAHs results in new compounds (usually oxygenated PAHs) that are often more toxic than their parent PAHs. Microbial toxicity assays were developed to measure short- and long-term photoinduced toxicity of PAHs. The bioassays were based on inhibition of luminescence and growth of V. fischeri. The short-term assay should detect toxicity of chemicals that are taken up rapidly and/or whose photosensitization activity is immediate. The long-term assay should identify chemicals where the rate of assimilation is slow and/or time is required for photoinduced effects to be realized. The assays were tested with 12 different PAHs. The short-term assay did not reveal photoinduced toxicity for any of the test chemicals. However, photoinduced toxicity was apparent in the long-term assay, indicating that short-term assays may be opaque to this key mechanism of PAH toxicity.

The concentration addition (CA) model has been widely applied to predict mixture toxicity. However, its applicability is difficult to evaluate due to the complexity of interactions among substances. Considering that the concentration-response curve (CRC) of each component of the mixture is closely related to the prediction of mixture toxicity, mathematical treatments were used to derive a characteristic index kECx (k was the slope of the tangent line of a CRC at concentration ECx). The implication is that the CA model would be applicable for predicting the mixture toxicity only when chemical components have similar kECx in the whole or part of the concentration range. For five selected chemicals whose toxicity was detected using luminescent bacteria, sodium dodecyl benzene sulfonate (SDBS) showed much higher kECx values than the others and its existence in the binary mixtures brought about overestimation of the mixture toxicity with the CA model. The higher the mass ratio of SDBS in a multi-mixture was, the more the toxicity prediction deviated from measurements. By applying the method proposed in this study to analyze some published data, it is confirmed that some components having significantly different kECx values from the other components could explain the large deviation of the mixture toxicity predicted by the CA model.

Degradation of water quality is an emerging problem in many developing countries. Bioassay is an effective approach to monitor quality of water in aquatic environments. Studies have used luminescent bacteria and zebrafish embryos as bioassay tools in monitoring river water quality. In this study, luminous bacteria (Vibrio qinghaiensis sp. Q67) assay and zebrafish (Danio rerio) embryo toxicity test were performed to assess the ecotoxicity of surface water from the Huangpu River, China, collected during 2012–2013. River water samples inhibited the luminescence [inhibition rates 0–34.6% (±4.82%)] of Q67 and increased the lethal rates and induced morphological abnormalities in zebrafish embryos. The toxicity to luminous bacteria and zebrafish embryos were higher in winter than in summer months. In addition, samples collected in industrial area, urban sampling sites near drainage outlets, and at the intersection of the tributary that flows into the Huangpu River showed higher toxicity.

Cholinium-based ionic liquids are receiving crescent interest in diverse areas of application given their biological compatibility and potential for industrial application. In this work, mono and dicationic cholinium ionic liquids as well as cholinium derivatives were synthesized and their toxicity assessed using the luminescent bacteria Vibrio fischeri. A range of cholinium derivatives was synthesized, using different amines and the correspondent brominated derivatives, through the alkylation of the amine with the halide in MeCN. The results indicate that their toxicity is highly dependent on the structural modifications of the cholinium cation, mainly related to the alkyl side or linkage chain length, number of hydroxyethyl groups and insertion of carbon-carbon multiple bonds. The data indicated that it is possible to perform environmentally advantageous structural alterations, namely the addition of double bonds, which would not negatively affect V. fischeri. Moreover, the dicationic compounds revealed a significantly lower toxicity than the monocationic counterparts. The picture emerging from the results supports the idea that cholinium derivatives are promising ionic liquids with a low environmental impact, emphasizing the importance of a careful and directed design of ionic liquid structures. (C) 2014 Elsevier Inc. All rights reserved.

This study explored the use of luminescent bacteria ( Vibrio fischeri ) for chronic aquatic toxicity tests. The evaluated inhibition of growth to Cu 2+ , Cr 6+ , Zn 2+ , Hg 2+ , Cd 2+ , Pb 2+ , cetyltrimethylammonium bromide, 3,4-dichloroaniline, acetone, dimethylsulfoxide, ethanol, nitrobenzene, methanol, and 3,5-dichlorophenol was compared with results from another investigation, where the inhibition was determined by bioluminescence. Growth inhibition was found to indicate more reliably the presence of substances with chronic toxic properties than the loss of bioluminescence. But growth responded weaker to the majority of the analyzed toxicants than bioluminescence. This must be connected with the test parameters and the experimental conditions. But among growth experiments with freshwater bacteria species the sensitivity of the growth inhibition assay with V. fischeri is competitive when a poor medium is employed.

Luminescence bioassay using Vibrio fischeri and in vitro ethoxyresorufin-O-deethylase (EROD) induction bioassay using H4-IIE rat hepatoma cell were employed to test toxicity changes during the photoelectrocatalysis process for the degradation of pentachlorophenol (PCP) on TiO2 nanotubes electrode. Acute toxicity of the reaction solution reduced by 83% after 120min of irradiation. Bioassay-derived 2,3,7,8-TCDD equivalents (TEQ(bio)) increased from 0.72 to 6.72 ng 1(-1) during the former reaction stage, decreasing rapidly to 1.25 ng 1(-1) during the latter reaction stage. HRGC/HRMS analysis detected polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) congeners in the reaction mixtures. TEQ(bio) and chemical-derived 2,3,7,8-TCDD equivalents (TEQ(cal)) were about of the same order of magnitude. Both results illustrated the formation of dioxins and their removal by photoelectrocatalysis. Moreover, photoelectrocatalysis showed a significant priority over direct photolysis and photocatalysis depending on the reaction conditions, not only for PCP removal but also for reduction in toxicity. (C) 2007 Elsevier Inc. All rights reserved.

Leaching tests, CEN prEN 12457-2, CEN PrEN 12457-3, and NEN 7349, were conducted for varnish residue and urea resin waste, two industrial wastes containing organic chemicals. The leaching test eluates were analyzed for solvent concentrations and total organic carbon. Aqueous leaching tests were found to be suitable for both chemical and biological testing. Ecotoxicity was assessed by luminescent bacteria, plant root growth, reverse electron transport, and ToxiChromopad. The eluates were highly toxic but the toxicity decreased in later stages of the multistep leaching test (NEN 7349). Urea resin eluates were significantly less toxic than varnish residue eluates. The solid wastes markedly inhibited plant seed germination before and after the leaching test (CEN prEN 12457-3). The solid wastes were not biologically degradable in the standard test (ISO 14593), whereas the eluates from the CEN prEN 12457-3 test degraded slowly.

The standard Microtox test involving the bioluminescent bacterium Vibrio fischeri is a frequently used ecotoxicological bioassay whose EC50, values have been correlated to acute toxicity parameters of vertebrates, to irritancy measures, and to cytotoxicity indices. The aims were to explore the dependence of light output on viable cell number, with the latter estimated with the naked eye using a colorimetric tetrazolium salt method, the effects of dust on the bioluminescence and cell viability, how the viability of the cells is affected after spills, and how spills can be sampled. The lower limit of the linear dynamic range of the light-emitting bacterium was first defined to be 3.7 x 10(7) cells/ mL, compared with 37 x 10(7) cells/mL in the Microtox assay. The effects of dust were then explored in the working range by the method of standard additions by adding 5-, 10-, and 20-mg amounts of Standard Reference Material Urban Dust 1649a. This simulated dust samples collected by a cordless vacuum technique involving a filter cassette. A mass of 20 mg dust totally inhibited the Microtox test at all times (5, 15, and 30 min). Masses of 5 and 10 mg dust lowered the luminescence significantly by 20 and 64%, respectively, after 30 min. However, the viability test was totally inhibited by 5 mg of dust. A spectrophotometric modification of the viability test using a wavelength of 508 nm was developed that was twice as sensitive as the naked eye test, and was as sensitive as the Microtox test. Mechanical shock involved with spilling and sampling bacterial reagent on hard surfaces killed the luminescent bacteria as shown by inhibition of luminescence. The optimum filter cassette for Microtox reagent collection was a 25-mm 1.00-microm PTFE filter in a 25-mm Delrin holder operated at 4.0 L/min, with a Tygon sampling probe.

The presented study explored the suitability of aquatic bioassays based on the marine luminescent bacterium Vibrio fischeri as screening indicators for soil toxicity and mutagenicity. The study consists of two parts: (i) determination of the bacterial toxicity and mutagenicity of the single substance 2,4,6-trinitrotoluene (TNT) and its primary reduced metabolites using three different luminescent bacteria assays and (ii) determination of the water-extractable toxicity and mutagenicity of soil samples taken at a former production plant for TNT showing complex contamination (TNT, metabolites of TNT, PAHs, and heavy metals). Resulting data indicate TNT to be predominantly responsible for the observed biological effects of soil leachates. A strategy for soil toxicity screening based on luminescent bacteria is proposed which may especially be applicable for the case of bioremediation of TNT-contaminated soils. Potentials and restrictions of this approach to soil toxicity assessment are discussed.

The Mutatox test has been developed by Microbics Corp., U.S.A., in addition to the widely used acute toxicity test Microtox. The Mutatox test indicates the presence of any material in a test sample that causes genetic damage to dark variants of the luminescent bacteria Vibrio fischeri. As the Microtox test is less time-consuming and more cost-effective than the Mutatox test, the possibility of using the EC 50 measured by Microtox for range-finding of genotoxic concentrations for the Mutatox test was examined. Both tests were applied on single compounds and several waste elutriates. The genotoxic potential of two PAH metabolites—1-hydroxypyrene and 9-fluorenone-1-carboxylic acid—was detected. According to the present results the highest concentration of a sample in the Mutatox test should in general exceed the EC 50 by about 5–10 times. Elutriates were submitted to analyses of TOC, heavy metals, phenols, and PAH; additionally GC/MS screening analyses were carried out. In most cases correlations of ecotoxicological effects with single contaminants were not possible, but it can be assumed that these effects were produced by the interaction of inorganic and organic compounds present in the elutriates.

The nitrification inhibition test and the luminescent bacteria test were used to determine the inhibiting effect of different phenolic compounds. The chlorinated phenols demonstrated an increased toxicity in the nitrification inhibition test, which was much more sensitive to these compounds than other bacterial toxicity tests. In practice, the nitrification inhibition test was very useful for estimating the toxicity of chemical compounds to nitrifying bacteria, but the test is not recommended for the assessment of general bacterial toxicity. In comparison to other bacterial toxicity tests, the luminescent bacteria test also proved to be very sensitive. Due to its character, which measures a certain physiological parameter, this test system could be used as a screening tool for possible inhibitory effects to bacteria, although positive results should be confirmed by other bacterial toxicity tests.