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Chlorination is essential to provide safe drinking water. However, this process leads to the formation of disinfection byproducts (DBPs). In this study, tryptophan (Trp) has been selected as a precursor to conduct the chlorine disinfection. Moreover, the factors that affect the formation of trihalomethanes (THMs) and iodinated trihalomethanes (I-THMs) are investigated. The formation pathway of Trp chlorination is proposed based on the intermediate products identified. According to the experimental results, the formation of THMs and I-THMs during Trp chlorination fitted a new first-order kinetic model. The dosage of chlorine, temperature, pH and the ratio of bromide and iodide had major influence on the formation of THMs and I-THMs during chlorination. In addition, the inhibition of luminescent bacteria Vibrio fischeri in the water sample increased during Trp chlorination.

Ultraviolet (UV) photodegradation is increasingly applied to control volatile organic compounds (VOCs) due to its degradation capabilities for recalcitrant compounds. However, sometimes the UV photodegradation products are also toxic and can affect human health. Here, 10 VOCs at 150~200 ppm in air were treated using a laboratory-scale UV reactor with 185/254 nm irradiation, and the biotoxicity of their off-gas was studied by investigating their off-gas absorption solutions. The CO2 increase and VOC decrease were 39~128 ppm and 0~42 ppm, respectively, indicating that the VOCs and their products were mineralized in off-gas absorption solutions. The total organic carbon (TOC) of the absorption solutions are 4~20 mg∙L&minus, 1. Luminescent bacteria and Daphnia magna were used to detect the acute toxicity, and an umu assay was used to determine the genotoxic potential. Trichloroethylene showed a highest toxicity to luminescent bacteria, while chlorobenzene had the lowest toxicity. Water-soluble UV photodegradation products for styrene are very toxic to Daphnia magna. In the umu assay, the genotoxicities of off-gas absorption solutions of trichloroethylene, methylbenzene, ethyl acetate, butyl alcohol, and styrene were 51.26, 77.80, 86.89, 97.20, and 273.62 mg (4-NQO)&middot, L&minus, 1 respectively. In addition, the analysis of the genotoxicity/TOC and intermediates products indicated that the off-gas absorption solutions of styrene, trichloroethylene, and butyl alcohol contain many highly toxic substances.

In 2013, the “Qingdao oil pipeline explosion” released an estimated 2000 tons of oil into the environment. Sediment samples were collected from ten sites in Jiaozhou Bay and Shilaoren Beach to evaluate the influence of the spilled oil on the benthic environment 3 years after the oil spill accident. The compositions of oil, bacterial diversity and biotoxicity were examined in this study. The results showed that the concentration of total petroleum hydrocarbons (TPHs) peaked near the oil leak point and gradually decreased along the coastline, ranging from 21.5 to 133.2 μg/g. The distribution of polycyclic aromatic hydrocarbons (PAHs) was correlated with TPH, and naphthalenes were dominant in the 20 detected PAHs. The bacterial diversities in seriously polluted and slightly polluted sediments were completely different. As degrading bacteria, Alcanivorax and Lutibacter were the main genera at the oil-polluted sites. The analysis of biotoxicity by the luminescent bacteria method showed great differences among the polluted sites, the control site in Jiaozhou Bay, and the non-polluted site outside of Jiaozhou Bay. The biotoxicity also peaked at the site near the oil leak point. These results indicate that the oil spill that occurred 3 years ago still affects the environment and impacts the bacterial communities in the sediments. Electronic supplementary material The online version of this article (10.1186/s13568-018-0603-6) contains supplementary material, which is available to authorized users.

In this study, peroxydisulfate (PDS) was successfully activated by nanoscale zero-valent iron (nZVI) for the degradation of sulfamethoxazole (SMX, antibiotic frequently detected in the environment) in agricultural soils. The results indicated that the degradation of SMX was affected by the nZVI dose, the ratio of SMX/PDS, the ratio of soil/water and reaction temperature, and in cinnamon soils 87.6% of SMX degradation can be achieved within 4 h at 30 °C when the initial nZVI dose was 0.03 g g−1 soil, the molar ratio of SMX/PDS = 1/75 and the soil/water = 1/1. The results of radical scavenger experiments and electron spin resonance (ESR) tests showed that hydroxyl radical ( OH) was the dominant reactive species in this system. The ecotoxicity tests of the soil by germination test, luminescent bacteria experiment and enzyme activity test indicated that the ecotoxicity of soil after treatment was obviously lower than the contaminated soil. In addition, there was almost no effect on plant growth when compared with original soil. Furthermore, this system exhibited a great degradation capacity for SMX in different types of agricultural soils, and the degradation efficiencies of SMX in other four soils were 90.6% (yellow brown earths), 80.8% (brown earths), 86.5% (black soils) and 96.1% (red earths), respectively. This work provides an optional method for agricultural soil pollution control.

Biotic ligand model (BLM) was extended to predict the toxicity of inorganic arsenate (iAs(V)) to the luminescent bacteria, Aliivibrio fischeri. As the pH increased from 5 to 9, the HAsO42- form predominated more than the H2AsO4- form did, and the EC50[As]T (50% effective iAs(V) concentration) decreased drastically from 3554 ± 393 to 39 ± 6 μM; thus, the HAsO42- form was more toxic to A. fischeri than H2AsO4-. As the HPO42- activity increased from 0 to 0.44 mM, the EC50{HAsO42-} values (50% effective HAsO42- activity) increased from 31 ± 6 to 859 ± 128 μM, indicating that the toxicity of iAs(V) decreased, owing to the competition caused by the structural similarity between iAs(V) and phosphate ions. However, activities of Ca2+, Mg2+, K+, SO42-, NO3-, and HCO3- did not significantly affect the EC50{HAsO42-} values. The BLM was reconstructed to take into account the effects of pH and phosphate, and the conditional binding constants for H2PO4-, HPO42-, H2AsO4-, and HAsO42- to the active binding sites of A. fischeri were obtained; 3.424 for logKXH2PO4, 4.588 for logKXHPO4, 3.067 for logKXH2AsO4, and 4.802 for logKXHAsO4. The fraction of active binding sites occupied by iAs(V) to induce 50% toxicity (fmix50%) was found to be 0.616.

In recent years, pharmaceuticals and personal care products (PPCPs) have emerged as significant pollutants of aquatic environments and have been detected at levels in the range of ng/L to μg/L. The source of PPCPs is humans and livestock that have been administered pharmaceuticals and subsequently excreted them via urine and feces. Unlike agricultural chemicals, the environmental dynamics of PPCPs is not examined and they would undergo structural transformation by environmental factors, e.g., sunlight, microorganisms and treatments in sewage treatment plants (STPs). Processing at STPs can remove various PPCPs; however, they are not removed completely and some persist in the effluents. In this study, we examined the degradation of 9 pharmaceuticals (acetaminophen, amiodarone, dapsone, dexamethasone, indomethacin, raloxifene, phenytoin, naproxen, and sulindac) by sunlight or UV, and investigated the ecotoxicological variation of degradation products. Sunlight (UVA and UVB) degraded most pharmaceuticals, except acetaminophen and phenytoin. Similar results were obtained with UVB and UVA. All the pharmaceuticals were photodegraded by UVC, which is used for sterilization in STPs. Ecotoxicity assay using the luminescent bacteria test (ISO11348) indicated that UVC irradiation increased the toxicity of acetaminophen and phenytoin significantly. The photodegraded product of acetaminophen was identified as 1-(2-amino-5-hydroxyphenyl)ethanone and that of phenytoin as benzophenone, and the authentic compounds showed high toxicity. Photodegraded products of PPCPs are a concern in ecotoxicology.

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.

The paper examines the influence of changes in structural and physical state of water on biological activity of test organisms (luminescent bacteria of the transgenic strain Escherichia coli Z905/pPHL7). The preliminary informational effect of UHF radiation on water shifts the energy distribution in water associates, which causes a growth spurt of microorganism activity by more than a decimal exponent. The paper also shows that the energy source for ATP synthesis, produced by proton ATP synthase (F0F1-ATP synthase, where F1 and F0 are protein complexes), is connected with a nonlocal electron transfer from water to the hydrate structures of the F0-complex, which, by way of rotation, transfers protons for ATP synthesis.

In this work, PM10 samples previously subjected to thorough chemical speciation and receptor modelling, have been investigated for their bio-toxicity using an inhibition test based on bacterial luminescence modulation when in contact with airborne particulate samples. The variation of light emission intensity from a luminescent bacteria strain, the Photobacterium phosphoreum, is proposed as an efficient proxy for the quantification of bio-toxic effects induced by airborne particulate matter. PM10 samples characterized by definite levels of pollutants from the pertaining air shed were found to induce a decrease in the bacterial bioluminescence intensity, expressed as percentage of Inhibition Ratio (IR%). This behaviour suggests the decay of this energy-consuming activity because of a toxic effect. Cluster analysis on chemical composition and IR% data provides evidence of a statistically significant association between the adverse effects on living cells and the range of specific chemical species in PM10.

Acute toxicities of anaerobic ammonia oxidation (ANAMMOX) substrates and four antibiotics from pharmaceutical wastewaters on ANAMMOX process were reported. Individual and joint acute toxicity assays were performed using 50% inhibitory concentration (IC50). Results showed that IC50 values and their 95% confidence interval of ammonium chloride (A), sodium nitrite (B), penicillin G-Na (C), polymyxin B sulfate (D), chloramphenicol (E) and kanamycin sulfate (F) were 2708.9 (2247.9–3169.9), 1475.4 (1269.9–1680.9), 5114.4 (4946.4–5282.4), 10.2 (1.8–18.6), 409.9 (333.7–486.1) and 5254.1 (3934.4–6573.8) mg L−1 respectively, suggesting toxicities were in the order of D > E > B > A > C > F. Joint acute toxicities of bicomponent mixtures A and B, C and D, C and F, D and F were independent; D and E, E and F were additive while C and E were synergistic. Joint acute toxicities of multicomponent mixtures were synergistic or additive. Luminescent bacteria test is an easy and robust method for forecasting the feasibility of ANAMMOX process for pharmaceutical wastewater treatment.

Mercury and its organic compounds have been of severe concern worldwide due to their damage to the ecosystem and human health. The development of effective and affordable technology to monitor and signal the presence of bioavailable mercury is an urgent need. The Mer gene is a mercury-responsive resistant gene, and a mercury-sensing recombinant luminescent bacterium using the Mer gene was constructed in this study. The mer operon from marine Pseudomonas putida strain SP1 was amplified and fused with prompterless luxCDABE in the pUCD615 plasmid within Escherichia coli cells, resulting in pTHE30-E. coli. The recombinant strain showed high sensitivity and specificity. The detection limit of Hg(2+) was 5nmol/L, and distinct luminescence could be detected in 30min. Cd(2+), Cu(2+), Zn(2+), Ca(2+), Pb(2+), Mg(2+), Mn(2+), and Al(3+) did not interfere with the detection over a range of 10(-5)-1mM. Application of recombinant luminescent bacteria testing in environmental samples has been a controversial issue: especially for metal-sensing recombinant strains, false negatives caused by high cytotoxicity are one of the most important issues when applying recombinant luminescent bacteria in biomonitoring of heavy metals. In this study, by establishing an internal standard approach, the false negative problem was overcome; furthermore, the method can also help to estimate the suspected mercury concentration, which ensures high detection sensitivity of bioavailable Hg(2+).

The applicability of direct bioautography, the combination of planar chromatography with antimicrobial assay, is demonstrated with special emphasis on its recent developments such as BioArena and the use of genetically modified luminescent bacteria. Its methodological advancement is put into a historical perspective. In comparison with other commonly used antimicrobial susceptibility tests, the main advantage of direct bioautography resides in its simplicity, rapidity, and ability to detect separated individual matrix components exhibiting antimicrobial activity in situ. It is confirmed with examples that high-throughput direct bioautography is suitable as a biomonitoring-screening system for bioassay-guided isolation.

One of the major problems of airport operation is the impact of pollution caused by runoff waters. Runoff waters at an airport may contain high concentrations of different contaminants resulting from various activities of its operation. High quantities of aircraft de-icing/anti-icing fluids are used annually at airports worldwide. Aircraft de-icers and anti-icers may have negative environmental impacts, but their effects on aquatic organisms are virtually unknown. In order to address this issue, aircraft de-icers, pavement de-icers and wastewater samples were obtained from a regional airport. To evaluate the toxicity of wastewater samples and aircraft de-icing/anti-icing fluids (ADAFs), two bio-tests were performed: the Lemna growth inhibition test according to OECD guideline 221 and the luminescent bacteria test according to ISO guideline 11348-2. In the Lemna growth inhibition test, phytotoxicity was assessed using the endpoints frond number and frond area. The luminescent bacteria test involved the marine bacterium Vibrio fischeri. The estimates of effective concentrations (EC50) values were determined using the free software R and the "drc" library. Aquatic plants and marine bacteria showed a higher sensitivity towards ADAFs than to wastewater samples. Experiments showed that aircraft de-icing/anti-icing fluids and wastewater samples were relatively more toxic towards Lemna gibba L. in comparison to V. fischeri.

Crassostrea virginica (the Eastern or American oyster) bioaccumulates pollutants from the water column, and therefore, its tissues can be used as bioindicators of past and present estuarine health. In this pilot project, we decided to investigate whether its tissues would be a suitable medium for toxicity testing using tissues from a variety of southern Texas locations of known and suspected anthropogenically impacted and unimpacted areas. We also conducted toxicity tests on sediments adjacent to oyster reefs using standard protocols for sediment toxicity. We tested the toxicity of tissues and sediments on the luminescent bacteria Vibrio fischeri, whose bioassays are commonly referred to by the trade name Microtox®. Microtox tests are quick, relatively inexpensive and sensitive to a range of contaminants. Evidence from this preliminary study suggests that conducting toxicity tests on oyster tissues may predict localized contamination better than when conducting toxicity tests on subtidal sediment. The refinement of these methods to use oyster tissues to detect contamination may be especially useful for environmental impact studies and/or studies where rapid and inexpensive information is needed.

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.

Surface water used for drinking water production is frequently monitored in The Netherlands using whole organism biomonitors, with for example Daphnia magna or Dreissena mussels, which respond to changes in the water quality. However, not all human-relevant toxic compounds can be detected by these biomonitors. Therefore, a new on-line biosensor has been developed, containing immobilized genetically modified bacteria, which respond to genotoxicity in the water by emitting luminescence. The performance of this sensor was tested under laboratory conditions, as well as under field conditions at a monitoring station along the river Meuse in The Netherlands. The sensor was robust and easy to clean, with inert materials, temperature control and nutrient feed for the reporter organisms. The bacteria were immobilized in sol-gel on either an optical fiber or a glass slide and then continuously exposed to water. Since the glass slide was more sensitive and robust, only this setup was used in the field. The sensor responded to spikes of genotoxic compounds in the water with a minimal detectable concentration of 0.01 mg/L mitomycin C in the laboratory and 0.1 mg/L mitomycin C in the field. With further optimization, which should include a reduction in daily maintenance, the sensor has the potential to become a useful addition to the currently available biomonitors.

The increasing application of nanoparticles (NPs) to a variety of new technologies has become a matter ofconcern due to the potential toxicity of these materials. Many questions about the fate of NPs in the environmentand the subsequent impact on ecosystems need to be answered. The aim of this work was to evaluate theecotoxicity of two alumina-based nanoceramics, γ-Al2O3 (NC) and Ni/ γ-Al2O3 (NiNC) by means of three differentstandardized tests: Biochemical Oxygen Demand (BOD5), bioassay with luminescent bacteria (Vibrio fischeri;Microtox), and bioassay on amphibian larvae (Rhinella arenarum) (AMPHITOX). BOD5 values of a verybiodegradable mixture (glucose/glutamic acid) decreased with the addition of NiNC(43.8%) and NC (31.6%)with respect to control samples (52.9%). Microtox test results indicated that NiNC presents higher toxicity thanNC, with EC50s values of 16.1% and 29.9% respectively; a reduced toxicity was observed, however, in presenceof organic matter, thus obtaining EC50s of 37.8% and 19.4%. The results of AMPHITOX test showed a significantincrease in the toxicity of both substances over time, the NiNC toxicity being greater than that of NC. The valuesof 96 h-LC50 and 504 h-LC50 determined for NiNC were 1.58 and 0.83 mg/L, respectively, and 14.5 and10.5 mg/L for NC samples. Amphibian larvae exhibited collapsed cavities, edema, axial flexures, and behavioralalterations as hyperkinesia and reduced movements. These results evidence the vulnerability of wildlife to xenobioticsand the need to develop specific standardized ecotoxicity tests in order to help environmental sustainabilityand natural species conservation. Fil: Svartz, Gabriela Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina Fil: Papa, Mariana Inés. Instituto Nacional de Tecnología Industrial; Argentina Fil: Gosatti, Marina. Comisión Nacional de Energía Atómica. Gerencia Complejo Tecnológico Pilcaniyeu; Argentina Fil: Jordán, Marianela Paula. Instituto Nacional de Tecnología Industrial; Argentina Fil: Soldati, Analía Leticia. Comisión Nacional de Energía Atómica. Gerencia Complejo Tecnológico Pilcaniyeu; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Samter, Paula. Instituto Nacional de Tecnología Industrial; Argentina Fil: Guraya, María M.. Comisión Nacional de Energía Atómica. Gerencia Complejo Tecnológico Pilcaniyeu; Argentina. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires; Argentina Fil: Perez Coll, Cristina Silvia. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Perez Catán, Soledad. Comisión Nacional de Energía Atómica. Gerencia Complejo Tecnológico Pilcaniyeu; Argentina

Since aminophosphonate-based herbicides like glyphosate are currently one of the most popular and widely applied active agent in agrochemistry, there is an urgent need for searching new compounds among this family with potential herbicidal activity, but exhibiting low toxicity against surrounding environment. Six new (5-nitrofurfuryl)-derived aminophosphonates were synthesized for the first time and apart from the only one example of N-benzylamino(5-nitrofuryl)-methylphosphonic acid, it was the first time in the history, when this class of compounds was prepared. Their prospective and real biological properties have been followed up by evaluation of their preliminary ecotoxicology. They have been then investigated in aspect of their phytotoxicity against oat (A. sativa) and common radish (R. sativus) exhibiting moderate-to-severe toxicity for these plants. The significant selectivity towards radish (up to 3 times greater toxicity against radish) was observed in some cases. Title compounds were also tested in terms of their toxicity for freshwater crustaceans H. incongruens (ostracods) and marine luminescent bacteria A. fischeri. Although their harmful action on ostracods was not too much elevated, they were found to be highly toxic for bacteria. Various aspects of their ecotoxicity are discussed in this paper.

A wide range of biological activities of aminophosphonates predisposes them to find applications as anticancer, antiviral, antimicrobial, antifungal, or herbicidal agents. Despite a number of positive aspects of the use of aminophosphonates, their applications may cause a risk to the environment, which is well exemplified by the case of glyphosate. Therefore, scientists see a pressing need to rate ecotoxicity of aminophosphonates. Nowadays, it is recommended to use comprehensive tools to carry out appropriate and effective risk assessments of toxic substances. For these purposes, tests based on the acute toxicity of the luminescent bacteria Aliivibrio fischeri, as well as the measurement of sub-chronic toxicity of the crustacean Heterocypris incongruens seem to be the most convenient. A series of five diphenyl N-arylamino(pyrrole-2-yl)methylphosphonates was synthesized and preliminary evaluation of their ecotoxicological properties was performed. In order to carry out such investigations, we applied the two biotests mentioned above. Results showed that the N-(4-nitrophenyl) derivative was the most toxic for bacteria in comparison to other tested compounds. As for crustaceans, N-phenyl and N-naphthyl derivatives were found to be the most harmful, simultaneously being relatively harmless for bacteria. Such a phenomenon are discussed in correlation with the literature, while its reason is discussed with respect to the aspect of structure of the tested compounds.

Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-E) are becoming increasingly widespread in Vietnam. Antibiotics are detected in many Vietnamese foods; however, the effect of ESBL-E and antibiotic consumption on intestinal bacteria has not been studied sufficiently. Here, we investigated the effect of oral administration of ESBL-E (TB19) and cefotaxime on luminescence-emitting cefotaxime-sensitive E. coli (X14). Mice were given water containing TB19 and then received three injections of 1.0 × 108 CFU of X14 harboring a luciferase gene. The mice were administered 100 μg of cefotaxime and luminescent bacteria were monitored over 24 h, following which luminescent bacteria were isolated from mouse feces. Luminescence continued to be detected in mice administered TB19 24 h after cefotaxime ingestion. Fecal analysis revealed two types of luminescent colonies: cefoxitin-resistant E. coli (X14-R) and Pseudomonas aeruginosa. Pulse-field gel electrophoresis confirmed that X14-R was a clonal strain of X14, suggesting that X14 survived using ESBLs originating from TB19 and acquired cefoxitin resistance due to cefotaxime consumption. Moreover, in vitro analysis of X14 indicated that expression of the ampC gene was upregulated by cefotaxime. Overall, ESBL-E and cefotaxime promoted the expansion of cefoxitin-resistant E. coli in the absence of plasmid-mediated gene transfer.

Although the production of compost from sewage sludge is well established in developed countries, the use of sludge-based compost may represent a source of pollutants. The present study assessed the levels of potentially harmful compounds in compost as well as their rates of decrease during composting. The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), three fragrance compounds (OTNE, HHCB and AHTN) and triclosan were determined in the initial sewage sludge and in compost over the span of 1 year. Simultaneously, the toxicity to luminescent bacteria (Aliivibrio fischeri) and aryl hydrocarbon receptor reactivity of organic solvent extracts of sludge and compost samples were assessed. Higher PAH, fragrance compounds, and triclosan concentrations were found in sewage sludge from urban areas compared with rural regions, and the urban sludge was also more toxic than the rural sludge. The high pollutant concentrations in urban sludge raised the concentrations of these compounds in the raw materials for composting and in the resulting composts. The organic matter was decomposed by 65% during the composting process, and the measured toxic substances were decreased by a similar amount, with the exception of triclosan, which decreased by only 35%. The toxicity to A. fischeri decreased to a greater extent (90%) than did the organic matter, while the aryl hydrocarbon receptor reactivity decreased by only 35%. This lower decrease coincided with that of the aryl hydrocarbon receptor-reactive PAHs (37%).

Slaughterhouse industry produces large volumes of polluted wastewater, which cause negative impacts on the environment. The objective of this study was to assess the effect of electron-beam irradiation on the ecotoxicity of slaughterhouse effluents with absorbed doses up to 35 kGy. Two acute toxicity assays were applied to evaluate the efficiency of irradiation onto toxicity of wastewater. The exposed living-organisms were a luminescent bacteria Vibrio fischeri, and a freshwater microcrustacean Daphnia similis. Also, the total organic carbon was analysed in order to determine any possible organic carbon removal after irradiation. The ecotoxicological results evidenced that both living-organisms were suitable for the measurements. Therefore, the results demonstrated the toxicity of the effluent and its similarity for both organisms as well as the potential of radiation to reduce these effects. The 35 kGy dose was very effective for reducing toxic effects of slaughterhouse wastewater for daphnids suggesting that ionizing radiation could be used as a tool for removing toxic charge of such effluents. The type of contamination presented by the effluent justify the needs for alternatives of treatment.

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.

A European round robin test according to ISO 5725-2 was conceptually prepared, realised, and evaluated. The aim was to determine the inter-laboratory variability of the overall process for the ecotoxicological characterization of construction products in eluates and bioassays. To this end, two construction products BAM-G1 (granulate) and HSR-2 (roof sealing sheet), both made of EPDM polymers (rubber), were selected. The granular construction product was eluted in a one stage batch test, the planar product in the Dynamic Surface Leaching test (DSLT). A total of 17 laboratories from 5 countries participated in the round robin test: Germany (12), Austria (2), Belgium (1), Czech Republic (1) and France (1). A test battery of four standardised ecotoxicity tests with algae, daphnia, luminescent bacteria and zebrafish eggs was used. As toxicity measures, EC50 and LID values were calculated. All tests, except the fish egg test, were basically able to demonstrate toxic effects and the level of toxicity. The reproducibility of test results depended on the test specimens and the test organisms. Generally, the variability of the EC50 or LID values increased with the overall level of toxicity. For the very toxic BAM-G1 eluate a relative high variability of CV = 73%-110% was observed for EC50 in all biotests, while for the less toxic HSR-2 eluate the reproducibility of EC50 varied with sensitivity: it was very good (CV = 9.3%) for the daphnia test with the lowest sensitivity, followed by the algae test (CV = 36.4%). The luminescent bacteria test, being the most sensitive bioassay for HSR-2 Eluate, showed the highest variability (CV = 74.8%). When considering the complex overall process the reproducibility of bioassays with eluates from construction products was acceptable.

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 350 km 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 >C 10 –C 21 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.

In this research, the effect of modified bentonite on removing harmful organisms in ballast water was discussed using HDTMA+ modified bentonite as flocculating material, and Alexandrium tamarense, Nitzchia closterium, and Photobacterium phosphoreum as the objects of harmful organisms, and also through an observation of the reaction mechanism between HDTMA+ and bentonite with Fourier transform infrared spectroscopy (FTIR). The result showed that there was an effective combination of HDTMA+ with bentonite, and the modified organic bentonite possessed a powerful ability to remove harmful organisms. The removal rate against Alexandrium tamarense within 24h was greater than 85% if the dosage of the organic bentonite was 0.03 g/L; the removal rate against Nitzchia closterium was approximate to 80% if the dosage was 0.06 g/L; the luminous intensity could not be displayed by luminescent bacteria under the condition of concentration 0.30 g/L, and also the original soil with modification did not shown a significant removal effect under the same dosage. Therefore, it was concluded that the conditions such as aging time, organic bentonite’s particle size, and HDTMA+ dosage were the important factors affecting the harmful biological removal efficiency.

The effect of different genetically engineered bacteria, Pseudomonas syringae, Pseudomonas savastanoi, and Ralostonia solanacerum and also a natural marine bacterial species, Vibrio fischeri NRRL B-11177, is studied in producing gold nanoparticles. This is the first report about the biosynthesis of gold nanoparticles by natural and genetically engineered luminescent bacteria. These microorganisms reduced gold ions and produced fairly monodisperse nanoparticles. TEM analysis indicated that spherical nano gold particles in the different diameters and shapes were obtained at pH values of 6.64. In this biosynthesis protocol, the gold nanoparticles with desired shape and size can be prepared.

The purpose of this study was to discuss the effect of the chemical structure of anionic and non-ionic surfactants and surface activity on toxicity. Single and binary mixtures of three ether carboxylic derivative sur- factants and three amine-oxide-based non-ionic surfactants were used. Toxicity was determined using three test organisms: freshwater crustaceans (Daphnia magna), luminescent bacteria (Vibrio fischeri), and microalgae (Selenastrum capricornutum). The toxicity of surfactants is related to the hydrophobic alkyl chain, the degree of eth- oxylation, and the critical micelle concentration of sur- factants. Relationships found agreed with the fact that the lower toxicity is shown by the shorter alkyl chain. There is a strong relation between surface activity and toxicity: the toxicity increased as the CMC of the surfactant or mixtures of surfactants decreased. Commercial products are formu- lated using surfactants mixtures, so it is important to know their behavior using an easily measured property: the least toxic mixtures were formed by the surfactants having lower individual toxicity. Around the CMC, our data show a synergism for the binary mixtures. The results have given rise to a classification of the different surfactants and their mixtures according to the organism test, as safe, harmful or toxic. V. fischeri was in general the most sensitive micro- organism to the toxic effect of the surfactants, followed by Daphnia magna, while Selenastrum capricornutum was more tolerant. These results can be useful for selecting technically efficient surfactants and their mixtures with a lower ecotoxicity on the aquatic environment.

In this study, chemical analysis and ecotoxicity tests of leachate from disposal site for foot-and-mouth disease carcasses (FMD leachate) were conducted to collect fundamental data that will be used to develop environmental risk assessment tools for FMD leachate. For chemical analysis, concentration of , , Korea standard method indicators for detection of leachate released from animal carcasses burial site into groundwater and NRN (Ninhydrin-Reactive Nitrogens), a newly suggested screening test indicator to detect groundwater contamination by FMD leachate, were assessed. For ecotoxicity tests, luminescent bacteria (V. fischeri), micro-algae (P. subcapitata) and water flea (D. magna) were selected as test species. Correlation analysis between the concentration of , , NRN and the toxicity to V. fischeri was performed to identify the better indicators to monitor FMD leachate contamination. From regression analysis, the concentration of the indicators in FMD leachate contaminated sample that induced halfmaximal toxic effect to V. fischeri was evaluated. Results obtained from this study can be applied to assess the risk by FMD leachate and to establish the guideline to manage risk in relation to FMD leachate.

Twelve kinds of lignite from different areas of China were used for the study of solid-phase biodenitrification. The amount of released carbon, rate of nitrate removal and acute toxicity were examined for all the lignite samples. The results showed that the averaged nitrate removal rates of lignite from Wangniutan and Zhangjiakou were higher than the others, which can reach above 30%. The averaged removal rates of lignite from Zhaotong, Aksu and Faku were more than 20%, and others were less than 10%. Lignite from Wangniutan, Zhangjiakou, Aksu and Faku were more suitable fillers as biodenitrification carbon for its less luminescent bacteria acute toxicity.

Following urbanization, a large number of urban rivers were contaminated and turned to black-odor rivers. The traditional approach for detecting water quality is based on chemical or physical analysis. However, biological toxicity of black-odor water has been less addressed. As two typical black-odor rivers, Jiushanwai River (JS) and Shanxia River (SX) are tributaries of Wen-Rui Tang River in Wenzhou (south of China). The eco-safety of the urban rivers was evaluated by bioassay for water toxicity in this study. Ten and 5 sampling sites were respectively set along JS and SX. Water samples were collected monthly from October 2010 to October 2011. The general physical and chemical parameters of river water were monitored. In order to investigate the ecotoxicological effects of black-odor water, the following bioassays were used: (1) Fish acute toxicity test (Danio rerio, comprehensive toxicity), (2) luminescent bacteria bioassay (Qinghaiensis vibrio, toxicity to bacteria), and (3) tropical claw embryo assay (Xenopus tropicalis, embryo toxicity). Biotoxicity of black-odor rivers water was demonstrated by D. rerio, Q. vibrio, and X. tropicalis embryos. Toxicological effects of black-odor water were respectively shown by mortality of zebrafish, and by the relative inhibitory light rate of luminescent bacteria. However, luminescent bacteria were more sensitive to inspect biotoxicity than zebrafish. In X. tropicalis embryos test, toxicological effects of black-odor water were mostly shown by embryos’ survival rate and teratogenic rate. Bioassay results showed that toxicity of SX water was higher than that of JS water, especially in summer. Statistical analysis of luminescent bacteria toxicity test showed that biotoxicity of SX and JS was high in summer, but low in winter and spring. The seasonal changes of water toxicity of the black-odor river were positively correlative with changes of water temperature (p

Bioassay based on the luminescent bacteria was used as a new method for the determination of the kinetic constants of ligand binding to the complexion agent. Miramistin as the cationic surface-active antiseptic and serum blood albumin was taken as a model of interacting agent’s. It was concluded that this approach might have a wide range for applications, namely, in all cases where the ligand is an inhibitor of bacterial luminescence and its complex dose not effect the intensity of this process.

A photodegradation technology based on the combination of ultraviolet radiation with H2O2 (UV/H2O2) for degrading tri(chloroisopropyl) phosphate (TCPP) was developed. In ultrapure water, a pseudo-first order reaction was observed, and the degradation rate constant reached 0.0035 min−1 (R2 = 0.9871) for 5 mg L−1 TCPP using 250 W UV light irradiation with 50 mg L−1 H2O2. In detail, the yield rates of Cl− and PO43− reached 0.19 mg L−1 and 0.58 mg L−1, respectively. The total organic carbon (TOC) removal rate was 43.02%. The pH value of the TCPP solution after the reaction was 3.46. The mass spectrometric detection data showed a partial transformation of TCPP into a series of hydroxylated and dechlorinated products. Based on the luminescent bacteria experimental data, the toxicity of TCPP products increased obviously as the reaction proceeded. In conclusion, degradation of high concentration TCPP in UV/H2O2 systems may result in more toxic substances, but its potential application for real wastewater is promising in the future after appropriate optimization, domestication and evaluation.

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.

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.

Triclosan, one of the most widely used disinfectants, has been found to be toxic to animals and human beings. In this paper, triclosan was degraded on TiO 2 nanotube arrays, using a photoelectrocatalytic (PEC) process under UV illumination, with Na 2 SO 4 as the supporting electrolyte. The effect of bias potential was investigated and the results showed that 0 V was the most appropriate potential for the degradation of triclosan. In 30 min, 78.7% of triclosan had degraded during the PEC process. Intermediate analysis showed that 2,7-dichlorodibenzodioxin (DCDD) had formed during the degradation. The toxicity change during the PEC process was investigated using a luminescent bacteria test, with the results demonstrating that the toxicity of the reaction liquid decreased at the beginning and subsequently increased to a stable level. The indications were that some intermediates such as 2,7-dichlorodibenzodioxin was more toxic and stable than triclosan in the solution.

Purpose During the late 1950s and early 1960s, industrial waste material highly enriched with various contaminants (e.g., heavy metals, polycyclic aromatic hydrocarbons (PAHs)) was dumped in the inner Bay of Mecklenburg, western Baltic Sea. Between 2002 and 2004, a research program was initiated using chemical analysis in combination with bioanalytical techniques to assess the extent and variability in contamination at this dump site (DS). The data were compared to a reference area (RS) with similar environmental conditions, which is representative of the western Baltic Sea. Materials and methods Twelve PAHs were investigated to assess their ecological hazard, as theywere identifiedas major pollutants in the dumped material. In addition to analyzing the actual PAH contamination status in the sediments, PAHs measured in the soft tissue of Arctica islandica were also used as an indicator of contaminant bioaccumulation. A biotest battery was applied to determine the toxic effects of contaminants in the sediment. Results and discussion Significantly elevated PAH concentrations (sum of 12 PAHs) of ∼3,000 ng g −1 dw and higher bioaccumulation factors (BAFs) were determined in the soft body tissue of A. islandica collected at DS (t test, p=0.025). The results also showed that the sediment PAH contamination was significantly higher at DS (1,952–5,466 ng g −1 dw) than at RS (1,384– 2,315 ng g −1 dw). The results revealed a major heterogeneity in the PAH concentration at DS due to an attempt to cover the toxic material with clean clay. This resulted in a more heterogeneous distribution of the dump material rather than covering it up completely. However, not all relevant contaminants were included in this study, not only because it is too costly to determine them all but also because unidentified contaminants present at concentrations below the limit of detection cannot be measured. Bioassays were used to fill this gap in the hazard assessment in a cost-effective way by investigating the possible effects of sediment contamination on benthic organisms. The results showed a high variability and magnitude of growth and luminescence inhibition. Bacterialcontact tests withmarineorganisms showeda high toxicity response (>80 % inhibition) from DS sediments. In contrast, the luminescent bacteria test (Vibrio fischeri) showed equivalent effects of sediments from both DS and RS. Conclusions The spatial distribution of toxicity in DS, the bioaccumulation in mussels and the analytical evidence of

Aim To carry out the isolation and characterization of novel marine luminescent bacteria from Diu beach, India. Materials & methods In the present study attempt has been made to isolate luminescent bacterial species from marine water sampled from Diu beach, India, using standard plating method on nutrient medium. Obtained isolate was analyzed susceptibility against antibiotics and heavy metals in order to use them in bio-sensing system. Isolated bacterium was amplified for 16S rRNA gene by PCR and further identified by aligning through BLAST and MEGA software. Result The Vibrio rotiferianus when growing prominently at 22 °C shown tolerance to low concentration of heavy metals & resistance to few antibiotics which makes isolate, a potential bio-sensing agent. Further, molecular characterization including 16S rRNA gene and its phylogenetic analysis confirmed that the isolated strain as V. rotiferianus. Conclusion The use of pharmaceuticals products is on the rise and in turn its pollution is rising in an ecosystem. The isolated strain may act as a potential biosensing agent as it responded to change in luminescence for even nanomolar quantities of several heavy metals/antibiotics. In conclusion, study highlighted V. rotiferianus isolated from Diu beach could be utilized in detection and quantitative estimation of pollutant by change in luminescence level of V. rotiferianus.

The aim of the present study was the chemical characterization of some medically relevant essential oils (tea tree, clove, cinnamon bark, thyme, and eucalyptus) and the investigation of antibacterial effect of the components of these oils by use of a direct bioautographic method. Thin-layer chromatography (TLC) was combined with biological detection in this process. The chemical composition of the oils was determined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Eucalyptol (84.2%) was the main component of the essential oil of eucalyptus, eugenol (83.7%) of clove oil, and trans-cinnamic aldehyde (73.2%), thymol (49.9%), and terpinen-4-ol (45.8%) of cinnamon bark, thyme and tea tree oils, respectively. Antibacterial activity of the separated components of these oils as well as of their pure main components (eucalyptol, eugenol, trans-cinnamic aldehyde and thymol) was observed against the Gram-negative luminescence gene-tagged plant pathogenic bacterium Pseudomonas syringae pv...

Crude oil is a complex mixture of petroleum hydrocarbons (PHC) with distinct chemical, physical and toxicological properties relevant for contaminated site risk assessment. Ecotoxicological effects of crude oil distillation fractions on luminescent bacteria (Vibrio fischeri), earthworms (Dendrobaena hortensis) and invertebrates (Heterocypris incongruens) were tested using two spiked soils and their elutriates. Fraction 2 (F2) had an equivalent carbon number (ECN) range of >10 to 16, and F3 from >16 to 39. F2 showed a substantially higher ecotoxicological effect than F3 for Vibrio and Dendrobaena. In contrast, severe inhibition of Heterocypris by the poorly soluble F3 is attributed to mechanical organ blockage. Immediate sequestration of PHC to the organic matter-rich soil effected reduced toxicity for all organisms. This study indicates that a more differentiated consideration (i) of PHC mixtures based on ECN range and (ii) of model soil properties employed for ecotoxicity testing should be included into PHC-contaminated site risk assessment.

A lot of various applications of the Electronic Tongue (ET) related to the detection and quantification of taste and flavour of different products were reported so far. For obvious reasons, one relies upon human perception and taste panel marks working with ET in this domain. However, there is an unusual, albeit wide, realm of perception-related analysis based on the “marks” produced by other biological species, besides human beings, from different mammals to microorganisms. Thus, a series of methodologies, which are based on an ample variety of species (e.g. Daphnia, algae, unicellular organisms, luminescent bacteria and many others) were applied for the evaluation and monitoring of water quality and detection of acute water toxicity. The present paper deals with the application of the potentiometric multisensor system for water toxicity estimation in terms of the bioassay with three living test organisms: Daphnia magna , Chlorella vulgaris and Paramecium caudatum. The prediction of water toxicity with relative errors 15–26% (depending on the test object) is possible using PLS (projection on latent structures) regression from the data obtained by potentiometric multisensor system.

The quality of sewage sludge-based products, such as composts and growth media, is affected by the contamination of sewage sludge with, potentially, hundreds of different substances. Therefore, it is difficult to achieve the reliable environmental quality assessment of sewage sludge-based products solely based on chemical analysis. In the present work, we demonstrate the use of the kinetic luminescent bacteria test (ISO 21338) to evaluate acute toxicity and the Vitotox™ test to monitor genotoxicity of sewage sludge and composted sewages sludge. In addition, endocrine-disrupting and dioxin-like activity was studied using yeast-cell-based assays. The relative contribution of industrial waste water treated at the Waste Water Treatment Plants led to elevated concentrations of polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) in sewage sludge. The effect of elevated amounts of organic contaminants could also be identified with biotests able to demonstrate higher acute toxicity, genotoxicity, and potential for endocrine-disruptive properties. Additional extraction steps in kinetic luminescent bacteria test with DMSO and hexane increased the level of toxicity detected. Composting in a pilot-scale efficiently reduced the amounts of linear alkylbenzensulphonates (LASs), nonylphenols and nonylphenolethoxylates (NPE/NPs) and PAH with relative removal efficiencies of 84%, 61% and 56%. In addition, decrease in acute toxicity, genotoxicity and endocrorine-disrupting and dioxin-like activity during composting could be detected. However, the biotests did have limitations in accessing the ecotoxicity of test media rich with organic matter, such as sewage sludge and compost, and effects of sample characteristics on biotest organisms must be acknowledged. The compost matrix itself, however, which contained a high amount of nutrients, bark, and peat, reduced the sensitivity of the genotoxicity tests and yeast bioreporter assays.

The isolation of actinomycetes was performed from soil samples influenced by car-traffic. The acute toxicity of soil leaches was tested by the help of Microtox® bioassay testing system which uses freeze dried luminescent bacteria Photobacterium phosphoreum as the test organisms. The content of heavy metals in biomass of soil microorganisms and in whole soil samples was determinate. 115 strains of actinomycetes were isolated and their total numbers in soil samples were estimated. The acute toxicity of soil influenced the total numbers of actinomycetes. By the help of DNA-DNA reassociation procedure the generic diversity of bacteria was estimated. The identification and differentiation of streptomycetes from the total isolated actinomycetes was made using specific morphological criteria and the gas chromatography-fatty acid methyl ester (GC-FAME) analysis. FAME method is adequate only for differentiation of members of genus Streptomyces from other actinomycetes because of their characteristical profile of fatty acids.

Ethyl-4-aminobenzoate (Et-PABA) is currently used as a substitute for 4-aminobenzoate (PABA) in sunscreens and anesthetic ointments. Despite its widespread use and hydrophilicity, Et-PABA has never been found in environmental waters. This study, probed the occurrence of Et-PABA in both seawater and drinking water sources in Hong Kong, and evaluated its transformation products (TPs) and environmental fate via cumulative potency and photocatalytic profile analyses. Another 11 UV filters used in skin-care products were also studied. Et-PABA was not detected in any water sample. Four other UV filters were dominant at ng/L level in both seawater and drinking water sources. UHPLC-QTOF-MS was used to elucidate the structure of TPs. With high resolution accurate mass data and fragment rationalization, 11 Et-PABA TPs were characterized, including seven intermediates firstly proposed as TPs; two compounds were reported for the first time. It is proposed that photocatalysis induces transformation pathways of (de)hydroxylation, demethylation and molecular rearrangement. Luminescent bacteria tests showed decreasing toxicity with increasing irradiation of Et-PABA, suggesting that irradiation TPs are less toxic than the parent compound. Transformation of Et-PABA appears to explain why Et-PABA has not been detected in the natural environment.

Fenamic acids, one important type of non-steroidal anti-inflammatory drugs, are ubiquitous in environmental matrices. Thus it is of high significance to know the fate of them during chlorination disinfection considering their potential toxicity to the environment and humans. In the present study, the chlorination kinetics of three fenamic acids, i.e. mefenamic acid (MEF), tolfenamic acid (TOL) and clofenamic acid (CLO), were examined at different pHs, which followed second-order reaction under studied conditions. The studied fenamic acids degraded fast, with the largest apparent second-order rate coefficient ( k app ) values of 446.7 M −1 s −1 (pH 7), 393.3 M −1 s −1 (pH 8) and 360.0 M −1 s −1 (pH 6) for MEF, TOL and CLO, respectively. The transformation products (TPs) were identified by solid-phase extraction-liquid chromatography-mass spectrometer and ion-pair liquid-liquid extraction and injection port derivatization-gas chromatography-mass spectrometer. Despite different numbers of TPs were detected for each studied fenamic acid through these two analytical methods, the types of TPs were almost the same; chlorine substitution, oxidation and the joint oxidation with chlorine substitution are transformation reactions involved in chlorination. Moreover, the total toxicity of the TPs was assayed based on luminescent bacteria. Under different pHs, the different types of TPs might form, resulting in the varied total toxicity. The toxicity of all three fenamic acids chlorinated at pH of 8 was greater than those at pHs of 6 and 7. This study provided the information about the kinetics, transformation and toxicity of three fenamic acids during water chlorination, which is important to the drinking water safety.

A bioluminescent enzyme inhibition-based assay was applied to predict the potential toxicity of carbon nanomaterials (CNM) presented by single- and multi-walled nanotubes (SWCNT and MWCNT) and aqueous solutions of hydrated fullerene С60 (C60HyFn). This assay specifically detects the influence of substances on parameters of the soluble or immobilised coupled enzyme system of luminescent bacteria: NAD(P)Н:FMN-oxidoreductase+luciferase (Red+Luc). A protocol based on the optical properties of CNM for correcting the results of the bioluminescent assay was also developed. It was shown that the inhibitory activity of CNM on Red+Luc decreased in the following order: MWCNT>SWCNT>C60HyFn. The soluble enzyme system Red+Luc had high sensitivity to MWCNT and SWCNT, with values of the inhibition parameter IC50 equal to 0.012 and 0.16mg/L, respectively. The immobilised enzyme system was more vulnerable to C60HyFn than its soluble form, with an IC50 equal to 1.4mg/L. Due to its technical simplicity, rapid response time and high sensitivity, this bioluminescent method has the potential to be developed as a general enzyme inhibition-based assay for a wide variety of nanomaterials.