Luminescent Bacteria Assay Research Articles

Chlorination of Biopterin in Water: Deciphering the Kinetics, Disinfection Byproducts, and Toxicity.

Pterins, including biopterin prevalent during cyanobacterial blooms, are nitrogen-containing heterocyclic compounds ubiquitous in both natural and engineered environments. However, their roles and associated human risks in water treatment remain poorly understood. This study systematically investigated the kinetics, disinfection byproducts (DBPs), and toxicity of biopterin in chlorination. For deciphering the reaction kinetics, 1,3,5-trimethoxybenzene proved to be a more effective chlorine quencher than the commonly used reducing agents, as it preserved N-chlorinated intermediates without reversing them back to biopterin. The pH-dependent kinetics demonstrated that both chlorine and biopterin species had a significant influence on the reaction rates, with deprotonated biopterin exhibiting a markedly higher reactivity toward HClO/ClO-. Based on time-of-flight mass spectrometry, ten transformation products (TPs) including seven halogenated N-Cl ones, have been identified for the first time. These cyclic TPs were transformed into various aliphatic carbonaceous and nitrogenous DBPs during the subsequent chlorination process. Notably, theoretical predictions and the luminescent bacteria assay confirmed potential higher toxicities of these products than biopterin. These findings highlight the potential risks of pterins during water disinfection and provide a reference framework for accurately revealing the chlorination behavior of emerging nitrogenous chemicals.

Toxicity changes of wastewater during various advanced oxidation processes treatment: An overview

Advanced oxidation processes (AOPs) have been widely applied for the advanced treatment of recalcitrant wastewater. However, the toxicity changes during AOPs are still unclear because in some cases the intermediate products could exhibit equivalent or even higher toxicity compared with the original pollutants. Therefore it is necessary to evaluate the toxicity evolution during AOPs. This review mainly focused on the toxicity changes of wastewater during various AOPs treatment, including Fenton/Fenton-like oxidation, ozonation/catalytic ozonation, persulfate radical-based oxidation, photocatalytic oxidation, ionizing radiation, electro-catalytic oxidation, ultrasound oxidation and wet oxidation. Firstly, the toxicity assessment methods were summarized, including acute toxicity (such as luminescent bacteria assay, fish assay, water flea assay and algae assay), genetic toxicity (Ames assay, SOS/umu assay, comet assay and micronucleus assay), estrogenic activity, immunity toxicity, and endocrine disrupting effect (such as yeast two-hybrid assay and fish endocrine disrupting assay), the applications of these methods in determining the toxicity changes of wastewater during AOPs treatment were summarized and analyzed in detail. Secondly, the toxicity prediction by computational simulation was introduced, mainly focusing on two common software, including TEST and ECOSAR. Thirdly, the strategies for eliminating the toxicity of wastewater after AOPs treatment were proposed. Finally, the concluding remarks and perspectives were presented for further study. This review will deepen to understand the toxicity evolution of wastewater during AOPs.

Acute toxicity assessment of indoor dust extracts by luminescent bacteria assays with Photobacterium Phosphoreum T3

In the last decades, there has been an increasing concern about the human exposure to indoor dust. Therefore, it is imperative to assess the toxicity of indoor dust and associated dust extracts. In this study, the acute toxicity assessment of indoor dust was performed using a bioluminescence test, with Photobacterium phosphoreum T3 (PPT3) chosen as the test bacterium. The different indoor dust samples were collected from residences, offices, dormitories and laboratories in Shanghai, China. Our data reveal that PPT3 is more active to water-soluble ions and organic contaminants at low concentrations, while extract solutions elicit increased bacterial toxicity at high concentrations. The results of a bioluminescence assay by PPT3 indicated that the dust organic extracts exhibited increased toxicity compared with the water exacts. Dust extracts from the laboratory exhibited the greatest bacterial toxicity when compared with office, dormitory and residence samples. Moreover, office dust exhibited higher bacterial toxicity than residence dust. Furthermore, the comprehensive toxicity of dust on PPT3 was assessed by extracts toxicity -addition (i.e. IRaddition). The calculated values were close to the corresponding experimental data. The bioluminescence test showed the indoor dust samples are weakly toxic to PPT3, which are equivalent to 0.046–0.123 mg Hg•L−1. Different dust extracts among the different sampling sites showed varying toxicity to PPT3. This study provides some important information to understand the potential health risk from different indoor environment using a rapid bioluminescence assay.

Optimization of electrochemical sequential reduction-oxidation of chlorophene with CoNi alloy anchored ionic liquid-graphene cathode: Comparison, mechanism and toxicity study

Electrochemical sequential reduction-oxidation is process shows great promise for decomposition of organic compounds in aqueous solution. We performed comparative experiments to investigate the effects of ionic liquid on catalytic cathode for chlorophene removal. Electrochemical sequential reduction-oxidation processes with CoNi nanoparticles anchored on the ionic liquid functionalized graphene (CoNi/IL-rGO) cathode showed better performance in terms of removal efficiency, mineralization, and dechlorination rate of chlorophene compared with the performance of a similar cathode without the ionic liquid (CoNi/rGO). The results suggest that the combination of graphene and ionic liquid promoted dispersion of CoNi nanoparticles and formation of small particle sizes, contributed to higher electrocatalytic activity. We investigated the factors affecting chlorophene degradation in the CoNi/IL-rGO cathode system in detail. Under the optimal conditions the removal rates of chlorophene reached 99.6%, 99.7%, and 95.1% in cathodic compartment 1, cathodic compartment 2, and the anodic compartment, respectively, at pH 5.3 after 120 min with 0.05 mol L−1 at a current of 68 mA cm−2. The intrinsic reaction kinetics showed that removal of chlorophene followed pseudo first-order reaction kinetics and kinetic constants were calculated. Several reaction products were identified by liquid chromatography/mass spectrometry (LC-MS/MS) and ion chromatography (IC) and detailed a reaction pathway is proposed. In the cathodic compartment, reductive dechlorination occurred during bubbling of hydrogen to form dechlorination products. These intermediates were prone to further oxidization by OH generated from H2O2 on the CoNi/IL-rGO electrode under air. We also evaluated the toxicity of products by a luminescent bacteria assay, which confirmed that the toxicity of chlorophene was effectively eliminated during the electrochemical sequential reduction-oxidation process.

Rapid detection and toxicity assessment of citreoviridin using luminescent Vibrio qinghaiensis sp.‐Q67 in drinking water

SummaryCitreoviridin (CIT), one of the mycotoxins produced by Penicillium citreoviridin (PCV), is a common contaminant in a wide range of agricultural products and is detrimental to human and animal health. There is potential threat that terrorists can extract CIT from mouldy cereals, such as rice which forms the major source of starch intake in Asia–Pacific diets and corns which are readily available. The objective of this study was to develop a rapid method for detection of citreoviridin and evaluate its performance on luminescent bacterium Vibrio qinghaiensis sp.‐Q67 (Q67). A good correlation (R2 > 0.98) between concentrations of CIT and the relative luminosity unit of Q67 was obtained with a linear range from 0.0005 to 0.01 mg L−1. The precision expressed as relative standard deviation (RSD) was 3.2% for eleven replicate determinations of 0.005 mg L−1 CIT, and the recoveries of spiked samples were 88%–93%. The luminescence inhibition ratio of CIT increased from 0.0005 to 0.5 mg L−1, and the luminescence inhibition ratio remained stable at approximately 85% in the range of 0.5–10 mg L−1. The system detected low traces (≤0.0005 mg L−1) of CIT, and it has potential to be used as rapid detection method for mycotoxins. The effect of pure CIT on Q67 was time dependent and, it was the strongest (EC50 = 0.0066) at 20 min which indicated the high effect of CIT on Q67. Results obtained in this study suggest that Q67 is a promising method for rapid evaluation of the toxicity of CIT. Therefore, the luminescent bacteria assay can potentially be used as a system in monitoring sudden pollution in drinking water.

Upgrading the Chinese biggest petrochemical wastewater treatment plant: Technologies research and full scale application

The components of petrochemical wastewater (PCWW) are very complex and it is one of the most important sources of organic micropollutants (OMPs) in water bodies. To improve the effluent qualities of PCWW, the Chinese government has promulgated a new Emission Standard of Pollutants for Petroleum Chemistry Industry. More than 60 types of OMPs, most of which are toxic organics, are added and strictly limited in the standard. Based on the bench- and pilot-scale experiments, a pretreatment (microaerobic hydrolysis and acidification, MOHA), biological (anoxic/oxic process, A/O) and advanced treatment (micro-flocculation dynasand filtration and catalytic ozonation, MFDF-CO) integrated process is proposed. The full-scale application in the Chinese biggest petrochemical wastewater treatment plant has demonstrated that the performance of the integrated process is stable and it can significantly improve the effluent qualities. The effluent COD decreased from 84.7 to 47.0mg/L and most of the OMPs were removed. The EC50 of the effluent for luminescent bacteria assay, algal growth inhibition, Daphnia magna inhibition test and zebrafish eggs test are all higher than 100% and the induction rate (IR) for genotoxicity is only 0.76. The energy demand, however, with the electricity consumption increase by 44.1%, is very high for OMPs removal, leading to high indirect carbon emission.

Appling hydrolysis acidification-anoxic–oxic process in the treatment of petrochemical wastewater: From bench scale reactor to full scale wastewater treatment plant

A hydrolysis acidification (HA)-anoxic–oxic (A/O) process was adopted to treat a petrochemical wastewater. The operation optimization was carried out firstly by a bench scale experimental reactor. Then a full scale petrochemical wastewater treatment plant (PCWWTP, 6500m3h−1) was operated with the same parameters. The results showed that the BOD5/COD of the wastewater increased from 0.30 to 0.43 by HA. The effluent COD was 54.4mgL−1 for bench scale reactor and 60.9mgL−1 for PCWWTP when the influent COD was about 480mgL−1 on optimized conditions. The organics measured by gas chromatography-mass spectrometry (GC–MS) reduced obviously and the total concentration of the 5 organics (1,3-dioxolane, 2-pentanone, ethylbenzene, 2-chloromethyl-1,3-dioxolane and indene) detected in the effluent was only 0.24mgL−1. There was no obvious toxicity of the effluent. However, low acute toxicity of the effluent could be detected by the luminescent bacteria assay, indicating the advanced treatment is needed. The clone library profiling analysis showed that the dominant bacteria in the system were Acidobacteria, Proteobacteria and Bacteriodetes. HA-A/O process is suitable for the petrochemical wastewater treatment.

Potential contribution of inorganic ions to whole effluent acute toxicity and genotoxicity during sewage tertiary treatment

Two acute toxicity tests (luminescent bacteria assay and cladoceran assay) and one genotoxicity test (broad bean assay) were used to evaluate whole effluent toxicity during the standard anion exchange resin-based pilot-scale sewage tertiary treatment that stably achieved significant dissolved organic carbon and inorganic ions reduction. The effect of six representative inorganic ions (i.e., Cl−, SO42−, NO3−-N, NO2−-N, NH4+-N and PO43−-P) on the acute toxicity and genotoxicity was further investigated. Significant whole effluent genotoxicity reduction was observed as an ∼57% micronucleated cell frequency reduction and ∼46% mitotic index increment during the pilot-scale periods, which should be attributed to significant organic removal since no significant (p≥0.116) increase in genotoxicity was observed with the increase in these ionic concentrations. However, no significant (p≥0.14) reductions were observed for whole effluent acute toxicity using two acute toxicity assays during the pilot-scale periods, and these inorganic ions, especially NH4+-N, contributed considerably to the acute toxicity. Based on Pearson correlation coefficients, whole effluent acute toxicity showed significant positive (p<0.001, r≥0.758) correlations with the NH4+-N concentration. Two optimal models were finally developed using step-wise multiple linear regression to predict the whole effluent acute toxicity via NH4+-N concentrations.

Toxicity assessment in marine sediment for the Terra Nova environmental effects monitoring program (1997–2010)

This paper discusses toxicity test results on sediments from the Terra Nova offshore oil development. The Terra Nova Field is located on the Grand Banks approximately 350km southeast of Newfoundland (Canada). The amphipod (Rhepoxynius abronius) survival and solid phase luminescent bacteria (Vibrio fischeri, or Microtox) assays were conducted on sediment samples collected from approximately 50 stations per program year around Terra Nova during baseline (1997), prior to drilling, and in 2000, 2001, 2002, 2004, 2006, 2008 and 2010 after drilling began. The frequency of toxic responses in the amphipod toxicity test was low. Of the ten stations that were toxic in environmental effects monitoring (EEM) years, only one (station 30(FE)) was toxic in more than one year and could be directly attributed to Terra Nova project activities. In contrast, 65 (18%) of 364 EEM samples were toxic to Microtox. Microtox toxicity in EEM years was not related to distance from Terra Nova drill centres or concentrations of >C10–C21 hydrocarbons or barium, the primary constituents of the synthetic-based drill muds used at Terra Nova. Of the variables tested, fines and strontium levels showed the strongest (positive) correlations with toxicity. Neither fines nor strontium levels were affected by drill cuttings discharge at Terra Nova, except at station 30(FE) (and that station was not toxic to Microtox). Benthic macro-invertebrate abundance, richness and diversity were greater in toxic than in non-toxic sediments. Therefore, Microtox responses indicating toxicity were associated with positive biological responses in the field. This result may have been an indirect function of the increased abundance of most invertebrate taxa in less sandy sediments with higher gravel content, where fines and strontium levels and, consequently, toxicity to Microtox were high; or chemical substances released by biodegradation of organic matter, where invertebrates are abundant, may be toxic to Microtox. Given the lack of association between Microtox results and discharge from Terra Nova, coupled with the confounding effects of other variables, the usefulness of Microtox toxicity tests within the context of environmental monitoring for the Terra Nova and, potentially, other offshore oil operations needs to be questioned. The amphipod toxicity tests showed that sediments in the vicinity of discharges of synthetic-based drilling mud cuttings are rarely toxic.

Tetracycline degradation by ozonation, and evaluation of biodegradability and toxicity of ozonation byproducts

Tetracycline was exposed to ozone by bubbling at different pH levels, and the acute toxicity of ozonation byproducts was tested by luminescent bacteria (Vibrio qinghaiensis sp.-Q67). Residual tetracycline in the solutions was detected by high performance liquid chromatography (HPLC). The results indicated that tetracycline was immediately degraded by ozonation and the degradation was favored at higher pH. Tetracycline (20 mg L−1) was completely degraded after 5 min of ozonation. However, total organic carbon (TOC) hardly decreased even though the ozonation time was extended to 40 min, suggesting that the ozonation process could not mineralize tetracycline. The luminescent bacteria assay indicated that the toxicity of the tetracycline solution was changed after ozonation. Chemical oxygen demand (COD) dropped by 15%, and the BOD5/COD ratio increased from 0·09 to 0·26, suggesting that the biodegradability of tetracycline was enhanced after 20 min of ozonation treatment.

Tetracycline degradation by ozonation, and evaluation of biodegradability and toxicity of ozonation byproductsPaper submitted to the Journal of Environmental Engineering and Science.

Tetracycline was exposed to ozone by bubbling at different pH levels, and the acute toxicity of ozonation byproducts was tested by luminescent bacteria (Vibrio qinghaiensis sp.-Q67). Residual tetracycline in the solutions was detected by high performance liquid chromatography (HPLC). The results indicated that tetracycline was immediately degraded by ozonation and the degradation was favored at higher pH. Tetracycline (20 mg L–1) was completely degraded after 5 min of ozonation. However, total organic carbon (TOC) hardly decreased even though the ozonation time was extended to 40 min, suggesting that the ozonation process could not mineralize tetracycline. The luminescent bacteria assay indicated that the toxicity of the tetracycline solution was changed after ozonation. Chemical oxygen demand (COD) dropped by 15%, and the BOD5/COD ratio increased from 0.09 to 0.26, suggesting that the biodegradability of tetracycline was enhanced after 20 min of ozonation treatment.

Photo-induced transformation of hexaconazole and dimethomorph over TiO 2 suspension

The photo-induced transformation in aqueous solution of hexaconazole and dimethomorph over irradiated titanium dioxide was studied. The investigation involved monitoring pesticides decomposition, identifying intermediate compounds, assessing mineralization, and evaluating toxicity of pesticides derivatives. HPLC/UV and HPLC/MS were used to follow the disappearance of the initial pesticides and the formation of intermediate products, while the acute toxicity was evaluated by using the Vibrio fischeri luminescent bacteria assay. Hexaconazole photocatalytic transformation proceeds through the formation of highly persistent compounds. The formation of cyanuric acid, a non-toxic compound refractory to photocatalytic treatment, was recognized. Conversely, the toxicity assays prove that neither hexaconazole nor its intermediates exhibit acute toxicity. Dimethomorph under photocatalytic treatment is completely mineralized within 14 h of irradiation. However, its transformation proceeds through the formation of toxic intermediates. A correlation exists between the evolution of the intermediate compounds and the toxicity profile, as the highest toxicity is measured when the intermediates with lower EC50 (hydroquinone and 4-chlorophenol) are formed.

Solar driven production of toxic halogenated and nitroaromatic compounds in natural seawater

Natural seawater (NSW) sampled in March and June 2007 in the Gulf of Trieste, Italy, has been spiked with phenol and irradiated in a device simulating solar light spectrum and intensity. Opposite to the case of artificial seawater, for which phenol is slightly degraded by direct photolysis, in NSW the phenol degradation mediated by natural photosensitizers occurs, forming several secondary pollutants, including hydroxyderivatives (1,4-benzoquinone, resorcinol), three chlorophenol isomers, 2,3-dichlorophenol, 2- and 4-bromophenol, 2- and 4-nitrophenol, and several condensed products (2 and 4-phenoxyphenol, 2,2′-, 4,4′- and 2,4-bisphenol). These compounds are toxic to bacteria and other living organisms. Ecotoxicologic effect has been evaluated by using the Vibrio Fischeri luminescent bacteria assay. This technique uses marine organisms, and it is therefore well suited for the study on marine samples. A correlation exists between the intermediates evolution and the toxicity profile, as the largest toxicity is observed when compounds with the lower EC50 (halophenols, phenoxyphenols) are formed at higher concentration.

Toxicity of leachate from bottom ash in a road construction

A test road constructed with municipal solid waste incineration (MSWI) bottom ash was monitored over a period of 36 months. Using chemical and toxicological characterisation, the environmental impact of leachates from bottom ash was evaluated and compared with leachates from gravel used as reference. Initial leaching of Cl, Cu, K, Na, NH 4–N and TOC from bottom ash was of major concern. However, the quality of the bottom ash leachate approached that of the gravel leachate with time. Leachates from the two materials were compared regarding the concentration of pollutants using multivariate data analyses (MVDA). A standardized luminescent bacteria assay using Vibrio fischeri did not show any toxicity, most likely because saline contamination can mask the toxic response and stimulate luminescence in these marine bacteria. A mung bean assay using Phaseolus aureus revealed that the toxicity of bottom ash leachate collected at the very beginning of the experimental period (October 2001 and May 2002) might be attributed to the following components and their respective concentrations in mg l −1: Al (34.2–39.2), Cl (2914–16,446), Cu (0.48–1.92), K (197–847), Na (766–4180), NH 4–N (1.80–8.47), total-N (12.0–18.5), and TOC (34.0–99.0). The P. aureus assay was judged as a promising environmental tool in assessing the toxicity of bottom ash leachate.

Brominated Indoles and Phenols in Marine Sediment and Water Extracts from the North and Baltic Seas–Concentrations and Effects

This work presents results from analytical as well as ecotoxicologic investigations of sediment and water samples from the North and Baltic Seas. A bioassay-directed procedure was used to investigate cause-effect relationships between observed effects in acute laboratory bioassays (luminescent bacteria assay with Vibrio fischeri and embryo test with Danio rerio) and analyte concentrations in extracted samples. Brominated phenols and indoles-including 4-bromophenol; 2,4-dibromophenol; 4- and 6-bromoindole; 3,4-, 4,6-, and 3,6-dibromoindole; and tribrominated compounds-were identified in partly remarkable concentrations (up to 40,000 ng g(-1) total organic carbon TOC for 4-bromophenol) in North Sea sediment samples and water samples (913 ng L(-1) 3,6-dibromoindole) from the German Bight. The toxicity of some of the identified brominated substances was low, with median effect concentration levels (EC(50)) ranging from 0.08 to 21.7 mg/L for V. fischeri and 4.3 to 46.3 mg/L for D. rerio. Comparison of the concentrations of analytes with ECs showed a toxicity contribution of brominated phenols and indoles to overall toxicity of the fraction. In the case of one water sample from the German Bight, brominated phenols and indoles accounted for the observed toxicity. Brominated phenols and indoles, which are assumed to be of biogenic origin, have rarely been discussed so far in the context of ecotoxicologic effects in marine ecosystems.

Soil microbial parameters and luminescent bacteria assays as indicators for in situ bioremediation of TNT-contaminated soils.

In situ bioremediation is increasingly being discussed as a useful strategy for cleaning up contaminated soils. Compared to established ex situ procedures, meaningful and reliable approaches for monitoring the remediation processes and their efficiency are of special importance. The subject of this study was the significance of two bioassays for monitoring purposes. The work was performed within the scope of a research project on the in situ bioremediation of topsoil contaminated with 2,4,6-trinitrotoluene (TNT). To evaluate changes within different experimental fields during a 17-month remediation period, the results of soil microbial assays and luminescent bacteria assays were compared with chemical monitoring data. The luminescent bacteria assays showed a significant reduction of the water-soluble soil toxicants in the treated fields. This bioassay proved to be a sensitive screening indicator of toxicity and may effectively aid the ecotoxicological interpretation of chemical monitoring data. Microbial biomass (C(mic)), the metabolic quotient (qCO2), and the ratio of microbial to organic carbon (C(mic)/C(org)) showed a highly significant correlation with total concentrations of TNT in the soil. But, in contrast to luminescent bacteria assays, this approach did not reveal any recovery of the soil at the end of the remediation period. There is clear evidence for persistent adverse effects of chronic TNT contamination on the site-specific microbial community and the local carbon cycle in the soil. The study clearly exhibits the differences between, as well as the complementary value of both bioassay approaches for monitoring short-term and long-term effects of soil contamination and the efficiency of remediation.

Ecotoxicological evaluation of in situ bioremediation of soils contaminated by the explosive 2,4,6-trinitrotoluene (TNT)

To evaluate the environmental relevance of in situ bioremediation of contaminated soils, effective and reliable monitoring approaches are of special importance. The presented study was conducted as part of a research project investigating in situ bioremediation of topsoils contaminated by the explosive 2,4,6-trinitrotoluene (TNT). Changes in soil toxicity within different experimental fields at a former ordnance factory were evaluated using a battery of five bioassays (plant growth, Collembola reproduction, soil respiration, luminescent bacteria acute toxicity and mutagenicity test) in combination to chemical contaminant analysis. Resulting data reveal clear differences in sensitivities between methods with the luminescent bacteria assay performed with soil leachates as most sensitive toxicity indicator. Complete test battery results are presented in so-called soil toxicity profiles to visualise and facilitate the interpretation of data. Both biological and chemical monitoring results indicate a reduction of soil toxicity within 17 months of remediation.

Screening for Soil Toxicity and Mutagenicity Using Luminescent Bacteria—A Case Study of the Explosive 2,4,6-Trinitrotoluene (TNT)

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.

Bioassay-directed chemical analysis of River Elbe surface water including large volume extractions and high performance fractionation

A bioassay-directed fractionation and identification (toxicity identification evaluation procedure) was performed on extracts of 10 l River Elbe water samples. The experimental method included a SDB-1 solid phase extraction followed by RP-HPLC fractionation and subfractionation. Chemical analysis by GC–MS as well as acute toxicity testing using a luminescent bacteria assay were conducted in the respective fractions. Many substances were identified, among which were pesticides and pharmaceuticals, but many compounds remained unknown.

Sediment quality assessment of flowing waters in South-West Germany using acute and chronic bioassays

Four bioassays were selected to examine sediment-elutriates of three flowing waters in the Saarland (South-West Germany). The aims of this study were the determination of the most sensitive bioassay for a sediment assessment within routine screening procedures and the comparison of a recently developed long-term bacterial assay with other commonly used and standardized bioassays. Sediment samples were elutriated with water and also with dimethyl sulphoxide in order to extract organic compounds. An expected accumulation of toxicants in the sediments was checked by additional examination of surface water at respective sampling sites, applying bioassays as well as chemical analysis methods. Whereas the sensitivity of the Daphnia magna assay was relatively low, the Scenedesmus subspicatus chlorophyll fluorescence test denoted the presence of high loads of nutrients at all sites. The results obtained using the Vibrio fischeri short-term bioassay suggested that an ecotoxicological risk can be excluded. The long-term luminescent bacteria assay is a further development of the short-term V. fischeri-assay. Prolonging the test duration from 30 min to 24 h should track down subacute toxicities, thus leading to a greater degree of sensitivity. However, the prolongation caused severe problems in respect of an accurate interpretation of the results. The long-term assay is not suited for routine deployment without major improvements. The extractable content of metals, pesticides, polychlorinated biphenyls and chlorinated hydrocarbons remained below their threshold values by several orders of magnitude. The use of dimethyl sulphoxide as solvent caused a decrease of bioluminescence in both bacterial assays. The inhibition was caused by toxic metabolic products of dimethyl sulphoxide formed by autochthonous bacteria from the sediment samples during the elutriation procedure. Thus, the use of dimethyl sulphoxide is not recommended for examinations of environmental samples when applying a luminescent bacteria assay.