OBJECTIVEIn this study, a pilot-scale investigation was conducted to examine and compare the biotoxicity of the organic compounds in effluents from five treatment processes (P1-P5) where each process was combination of preoxidation (O3), coagulation, sedimentation, sand filtration, ozonation, granular activated carbon, biological activated carbon and chlorination (NaClO).

METHODSOrganic compounds were extracted by XAD-2 resins and eluted with acetone and dichlormethane (DCM). The eluents were evaporated and redissolved with DMSO or DCM. The mutagenicity and estrogenicity of the extracts were assayed with the Ames test and yeast estrogen screen (YES assay), respectively. The organic compounds were detected by GC-MS.

RESULTSThe results indicated that the mutation ratio (MR) of organic compounds in source water was higher than that for treated water. GC-MS showed that more than 48 organic compounds were identified in all samples and that treated water had significantly fewer types and concentrations of organic compounds than source water.

CONCLUSIONTo different extents, all water treatment processes could reduce both the mutagenicity and estrogenicity, relative to source water. P2, P3, and P5 reduced mutagenicity more effectively, while P1 reduced estrogenicity, most effectively. Water treatment processes in this pilot plant had weak abilities to remove Di-n-butyl phthalate or 1, 2-Benzene dicarboxylic acid.

Estrogens ; toxicity ; Gas Chromatography-Mass Spectrometry ; Mutagens ; toxicity ; Organic Chemicals ; toxicity ; Pilot Projects ; Water Pollutants, Chemical ; toxicity ; Water Purification ; methods

Well water could be a stable source of drinking water. Recently, the use of well water as drinking water has been encouraged in developing countries. However, many kinds of disorders caused by toxic elements in well drinking water have been reported. It is our urgent task to resolve the global issue of element-originating diseases. In this review article, our multidisciplinary approaches focusing on oncogenic toxicities and disturbances of sensory organs (skin and ear) induced by arsenic and barium are introduced. First, our environmental monitoring in developing countries in Asia showed elevated concentrations of arsenic and barium in well drinking water. Then our experimental studies in mice and our epidemiological studies in humans showed arsenic-mediated increased risks of hyperpigmented skin and hearing loss with partial elucidation of their mechanisms. Our experimental studies using cultured cells with focus on the expression and activity levels of intracellular signal transduction molecules such as c-SRC, c-RET, and oncogenic RET showed risks for malignant transformation and/or progression arose from arsenic and barium. Finally, our original hydrotalcite-like compound was proposed as a novel remediation system to effectively remove arsenic and barium from well drinking water. Hopefully, comprehensive studies consisting of (1) environmental monitoring, (2) health risk assessments, and (3) remediation will be expanded in the field of environmental health to prevent various disorders caused by environmental factors including toxic elements in drinking water.
Animals ; Arsenic ; toxicity ; Barium ; toxicity ; Drinking Water ; analysis ; Environmental Exposure ; Environmental Health ; Environmental Monitoring ; Humans ; Mice ; Water Pollutants, Chemical ; toxicity ; Water Wells

The research on endocrine disrupters has become one of the key directions in the field of environmental medical science. Nonylphenol ethoxylates (NPEs) are widely used in industry and family washing as one of the non-ionic surfactants. NPEs can be degraded biologically to nonylphenol (NP), whose estrogenic effects or toxicity may do harm to the reproductive systems of male fish, amphibians and mammals. Thus it is an urgent affair to develop perfect assays, evaluate the harm of these chemicals to human beings, find the exact mechanism of action and restrict the use of NPEs.
Animals ; Dose-Response Relationship, Drug ; Fishes ; Genitalia, Male ; drug effects ; Male ; Phenols ; toxicity ; Rats ; Water Pollutants, Chemical ; toxicity ; Xenopus

OBJECTIVETo study the correlation of toxicity with biodegradability (BODT) in order to promote QSBR development and understand the degradation mechanism.

METHODSToxicity of substituted phenols to river bacteria was determined by the turbidities that were measured using a spectrophotometer (UV-190) at 530 nm against a blank control. The biodegradability of substituted phenols was expressed as BODT and the DO concentrations were determined by the iodometric titration method.

RESULTSThe BODT and toxicity(log 1/IC50) of 12 substituted phenols to bacteria from the Songhua River were determined respectively. The correlation of biodegradability with toxicity was developed: BODT=8.21 (+/-2.22) pKa -32.44 (+/-8.28) log 1/IC50 +89.04 (+/-38.20), n=12, R2=0.791, R2(adj)=0.745, SE=9.134, F=17.066, P=0.001.

CONCLUSIONThe BODT of substituted phenols was influenced by their toxicity and the ionization constant pKa. The stronger the toxicity, the less readily the compound was degraded by river bacteria.

Bacteria ; metabolism ; Biodegradation, Environmental ; Data Interpretation, Statistical ; Models, Biological ; Phenols ; chemistry ; metabolism ; toxicity ; Rivers ; microbiology ; Water Pollutants, Chemical ; metabolism ; toxicity

OBJECTIVE1-Bromo-3-chloro-5,5-dimethylhydantoin (BCDMH) is a solid oxidizing biocide for water disinfection. The objective of this study was to investigate the toxic effect of BCDMH on zebrafish.

METHODSThe developmental toxicity of BCDMH on zebrafish embryos and the dose-effect relationship was determined. The effect of BCDMH exposure on histopathology and tissue antioxidant activity of adult zebrafish were observed over time.

RESULTSExposure to 4 mg/L BCDMH post-fertilization was sufficient to induce a number of developmental malformations, such as edema, axial malformations, and reductions in heart rate and hatching rate. The no observable effects concentration of BCDMH on zebrafish embryo was 0.5 mg/L. After 96 h exposure, the 50% lethal concentration (95% confidence interval (CI)) of BCDMH on zebrafish embryo was 8.10 mg/L (6.15-11.16 mg/L). The 50% inhibitory concentration (95% CI) of BCDMH on hatching rate was 7.37 mg/L (6.33-8.35 mg/L). Histopathology showed two types of responses induced by BCDMH, defensive and compensatory. The extreme responses were marked hyperplasia of the gill epithelium with lamellar fusion and epidermal peeling. The histopathologic changes in the gills after 10 days exposure were accompanied by significantly higher catalase activity and lipid peroxidation.

CONCLUSIONThese results have important implications for studies on the toxicity and use of BCDMH and its analogs.

Animals ; Antioxidants ; metabolism ; Disinfectants ; toxicity ; Dose-Response Relationship, Drug ; Embryo, Nonmammalian ; drug effects ; Hydantoins ; toxicity ; Time Factors ; Water ; chemistry ; Water Pollutants, Chemical ; toxicity ; Zebrafish

An accidental spill of phenol (100%) into the Nakdong river with subsequent contamination of the tap water for about two million consumers in Teagu city of Korea occurred in March 1991. A historical cohort study of 6,913 individuals was undertaken to determine association with illness. Population subjects were divided into two groups of exposed and unexposed. Exposed subjects were reported to have significantly more phenol associated symptoms than those in a nearby unexposed area (39.6% vs. 9.4%, p < 0.01). Especially, in the related symptoms, highly significant differences were noted in the number of subjects reporting gastrointestinal illness such as nausea, vomiting, diarrhea, or abdominal pain. During the accident, study subjects who experienced peculiar taste or odor in the tap water were significantly more in the exposed areas (92% vs. 34.3%).
*Accidents ; Adolescent ; Adult ; Aged ; Child ; Child, Preschool ; Cohort Studies ; Female ; Human ; Infant ; Infant, Newborn ; Male ; Middle Age ; Phenol ; Phenols/*toxicity ; Water Pollutants, Chemical/analysis/*toxicity ; Water Supply/*analysis

OBJECTIVETo measure the 96h-LC50 values of 32 substituted benzenes to the carp and to study the relationship between quantitative structure-activity and structural parameters of chemicals.

METHODSThe acute toxicity values of 32 substituted benzenes to the carp were determined in a semistatic test. The energy of the lowest unoccupied molecular orbital, and the highest occupied molecular orbital, the dipole moment and the molecular weight of substituted benzenes were calculated by the quantum chemical method MOPAC6.0.

RESULTSThe range of the toxicity of studied compounds was broad, and the most toxic compound was pentachlorophenol, while the least toxic compound was 4-methylaniline. By the stepwise regression analyses, a series of Quantitative structure-activity relationships (QSAR) equations were derived from all compounds and subclasses. The equation log1/LC5o=0.759logP + 2.222 (R2 (adj)=0.818) was found to fit well and the average predicted percentage error was 6.16%.

CONCLUSIONThe toxicity of anilines and phenols to the carp could be modeled well by logP alone, whereas the toxicity of the halogenated benzenes and nitrobenznes not containing hydroxyl or amino group can be controlled by hydrophobic and electronic factors.

1-Octanol ; chemistry ; Aniline Compounds ; toxicity ; Animals ; Benzene Derivatives ; toxicity ; Carps ; Hydrophobic and Hydrophilic Interactions ; Lethal Dose 50 ; Models, Chemical ; Molecular Weight ; Phenols ; toxicity ; Quantitative Structure-Activity Relationship ; Water ; chemistry ; Water Pollutants, Chemical ; toxicity

OBJECTIVETo find a sensitive cytotoxic response to reflect the bio-toxicity of trace organic pollutants, the sensitivity and reliability of morphological change and proliferation inhibition of Vero cells exposed to 2, 4, 6-trichlorophenol (TCP) and the leachate from products related to drinking water (PRDW) were compared, and the mechanism of the morphological change in Vero cells exposed to chemical pollutants was studied.

METHODSVero cells were treated by different concentration of TCP and the leachate from PRDW. Methylthiazol-2-yl-2, 5-diphenyl tetrazolium bromide (MTT) assay was carried out for proliferation inhibition. Bioluminescence method was carried out as another method to test the toxicity of TCP. Flow Cytometry assay was used to test cell Apoptosis and damage of cell-membrane.

RESULTS0.25 mg/L TCP had an effect on cell morphology, and the proportion of morphologically changed cells increased with increasing TCP concentration. At low TCP concentrations, inhibition of cell proliferation did not seem to correlate to TCP concentration, and was negative when TCP concentration was <1.0 mg/L. After exposure to leachate from PRDW extracted at different temperatures, the percentage of morphologically changed cells increased with extracting temperature, but the inhibition of cell proliferation failed to reflect the correlation between extracting temperature and proliferation inhibition of Vero cells. Although the Sensitivity of bioluminescence method seems to be similar to morphological change in Vero cells, the bacterial in this method is not homologous enough with human body cells to reflect the toxicity to human body. These imply cell morphological change is a more sensitive and reliable method to reflect bio-toxicity of organic pollutants than proliferation inhibition. Flow cytometry analysis and cell rejuvenation experiments indicated cell membrane damage, which results in cell morphological change, was an early and sensitive cytotoxic response comparing with necrosis.

CONCLUSIONThese results indicated that the cell membrane toxicity represented by morphological changes is a more sensitive and reliable method to indicate the composite bio-toxicity of trace chemicals than proliferation inhibition, inhibition on bioluminescence and necrosis. Nevertheless, the quantification of morphological change should be studied further.

Animals ; Cell Division ; drug effects ; Cell Survival ; drug effects ; Cercopithecus aethiops ; Vero Cells ; Water Pollutants, Chemical ; toxicity

OBJECTIVETo measure the acute toxicity of halogenated benzenes to bacteria in natural waters and to study quantitative relationships between the structure and activity of chemicals.

METHODSThe concentration values causing 50% inhibition of bacteria growth (24h-IC50) were determined according to the bacterial growth inhibition test method. The energy of the lowest unoccupied molecular orbital and the net charge of carbon atom of 20 halogenated benzenes were calculated by the quantum chemical MOPAC program.

RESULTSThe log1/IC50 values ranged from 4.79 for 2,4-dinitrochlorobenzene to 3.65 for chlorobenzene. A quantitative structure-activity relationship model was derived from the toxicity and structural parameters: log1/IC50 = -0.531(E(LUMO)) + 1.693(Qc) + 0.163(logP) + 3.375. This equation was found to fit well (r2 = 0.860, s = 0.106), and the average percentage error was only 1.98%.

CONCLUSIONHalogenated benzenes and alkyl halogenated benzenes are non-polar narcotics, and have hydrophobicity-dependent toxicity. The halogenated phenols and anilines exhibit a higher toxic potency than their hydrophobicity, whereas 2,4-dinitrochlorobenzene is electrophile with the halogen acting as the leaving group.

Aliivibrio fischeri ; drug effects ; Benzene ; chemistry ; toxicity ; Halogens ; chemistry ; Quantitative Structure-Activity Relationship ; Rivers ; chemistry ; microbiology ; Toxicity Tests, Acute ; Water Pollutants, Chemical ; chemistry ; toxicity

OBJECTIVETo measure the toxicity of phenol, aniline, and their derivatives to algae and to assess, model, and predict the toxicity using quantitative structure-activity relationship (QSAR) method.

METHODSOxygen production was used as the response endpoint for assessing the toxic effects of chemicals on algal photosynthesis. The energy of the lowest unoccupied molecular orbital (E(LUMO)) and the energy of the highest occupied molecular orbital (E(HOMO)) were obtained from the ChemOffice 2004 program using the quantum chemical method MOPAC, and the frontier orbital energy gap (deltaE) was obtained.

RESULTSThe compounds exhibited a reasonably wide range of algal toxicity. The most toxic compound was alpha-naphthol, whereas the least toxic one was aniline. A two-descriptor model was derived from the algal toxicity and structural parameters: log1/EC50 = 0.268,logKow - 1.006deltaE + 11.769 (n = 20, r2 = 0.946). This model was stable and satisfactory for predicting toxicity. CONCLUSION Phenol, aniline, and their derivatives are polar narcotics. Their toxicity is greater than estimated by hydrophobicity only, and addition of the frontier orbital energy gap deltaE can significantly improve the prediction of logKow-dependent models.

Aniline Compounds ; toxicity ; Oxygen ; metabolism ; Phenols ; toxicity ; Photosynthesis ; drug effects ; Quantitative Structure-Activity Relationship ; Scenedesmus ; drug effects ; metabolism ; Water Pollutants, Chemical ; toxicity