Search

Coastal water pollution has a significant impact on sedimentary environments, altering the microstructure of clay-rich sediments and further destabilizing river-dominated delta strata. However, the understanding of the microstructure of clay sediment, influenced by burial depth and pore water chemistry, remains limited due to challenges in quantitatively analyzing clay texture at varying depths. The perturbable of clay microstructures, and the cost of deep sampling have hindered such efforts. To address this issue, this study aims to quantitatively analyze the clay anisotropy at different depths and pore water chemistry through laboratory-simulated sediment samples by using centrifugal modeling and 2DXRD technology. The results suggest that 1DXRD (Orientation index) is prone to generating incorrect conclusions, whereas 2DXRD (pole density) yields more precise and reliable results. Specifically, the results indicated that the introduction of salt ions promoted clay precipitation and stabilized the oriented microstructure at shallower depths. In acidic solutions, clay sediment still contained a certain proportion of edge to face (EF) microstructure at depths less than 6 m, suggesting higher soil thixotropy and lower strength than that of clay sediments in other types of solutions. Overall, our findings provide valuable insights into the relationship between water pollution, delta disappearance, and ocean acidification, highlighting the urgent need for effective environmental management strategies to prevent further damage to fragile coastal ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Natural sunlight can reduce the chemicals of emerging concern (CECs) and biological effects from the discharged domestic wastewater. But the aquatic photolysis and biotoxic variations of specific CECs detected in secondary effluent (SE) were not clear. In this study, 29 CECs were detected in the SE, and 13 medium- and high-risk CECs were identified as target chemicals based on their ecological risk assessment. To comprehensively explore the photolysis properties of the identified target chemicals, the direct and self-sensitized photodegradation of the target chemicals, even the indirect photodegradation in the mixture, were investigated and compared with these photodegradation in the SE. Of the 13 target chemicals, only five chemicals (including dichlorvos (DDVP), mefenamic acid (MEF), diphenhydramine hydrochloride (DPH), chlorpyrifos (CPF), and imidacloprid (IMI)) underwent direct and self-sensitized photodegradation processes. The removal of DDVP, MEF, and DPH was attributed to self-sensitized photodegradation, which was mainly mediated by •OH; CPF and IMI primarily relied on direct photodegradation. Synergistic and/or antagonistic actions that occurred in the mixture improved/decreased the rate constants of five photodegradable target chemicals. Meanwhile, the biotoxicities (acute toxicity and genotoxicity) of the target chemicals (including individual chemicals and the mixture) were significantly reduced, which can explain the reduction of biotoxicities from SE. For the two refractory high-risk chemicals, atrazine (ATZ) and carbendazim (MBC), algae-derived intracellular dissolved organic matter (IOM) on ATZ, and IOM and extracellular dissolved organic matter (EOM) on MBC had slightly promotion for their photodegradation; while peroxysulfate, and peroxymonosulfate served as sensitizers were activated by natural sunlight and effectively improved their photodegradation rate, and then reduced their biotoxicities. These findings will promote the development of CECs treatment technologies based on sunlight irradiation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Dimethyl arsonic acid, the most common organic arsenic pollutant, is widely present in the environment and seriously threatens the safety of drinking water. Syntheses of magnetite, magnetic bentonite, and magnetic ferrihydrite via hydrothermal methods, and the magnetic composites were examined using XRD, BET, VSM, and SEM. SEM images revealed that many monodispersible pellets were attached to the surface of magnetic bentonite. The magnetic ferrihydrite contained abundant pores and had a rich pore structure, which expanded the specific surface area of the original magnetite. The specific surface areas of the magnetic bentonite and magnetic ferrihydrite were 65.17 and 220.30 m 2 ·g -1 , respectively. The adsorption kinetics and adsorption isotherms of dimethyl arsonic acid on magnetic composites were studied. The adsorption of dimethyl arsonic acid on the magnetic composites conformed to the pseudo-second-order model and Freundlich isothermal adsorption model. By comparing the isotherms of the adsorption of dimethyl arsonic acid by the magnetic composites at pH values of 3, 7, and 11, respectively, it was found that the adsorption of dimethyl arsonic acid was the greatest at neutral pH of 7. The adsorption mechanism was analyzed via zeta potential determination, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The zeta potential results revealed that magnetic bentonite electrostatic activity occurred with dimethyl arsonic acid, and the magnetic ferrihydrite indicated a coordination complex with dimethyl arsonic acid. The XPS results revealed that the Fe-O bonds on the surfaces of the magnetic ferrihydrite had coordination complexation effects on the As-O of the dimethyl arsonic acid., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Natural sunlight irradiation is regarded as an efficient and low-carbon method for controlling the biotoxicity of effluents from domestic wastewater treatment plants (WWTPs). Dissolved organic matter in WWTPs effluent (EfOM) is responsible for the non-specific biotoxicity of effluent. In the present study, the variation in spectral characteristics, molecular composition, luminescent bacteria toxicity, and genotoxicity of EfOM of different molecular sizes (MOSs) during natural sunlight irradiation were investigated from a systematic perspective, and the standard natural organic matter from the Suwannee River (SRNOM) was synchronously assessed for comparative purposes. To further explore the cause of the biotoxicity changes, the relationships between the spectral or molecular level parameters (obtained from FT-ICR MS analysis) and biotoxicity were assessed using correlation analysis. The molecules in <1 kDa EfOM with lower molecular weight, higher unsaturation degree, and higher humification and fluorescence had higher luminescent bacteria toxicity under sunlight irradiation. However, in the <1 kDa SRNOM, the molecules which were characterized by higher humification and fluorescence had higher luminescent bacteria toxicity. The notable genotoxicity reduction of EfOM under sunlight irradiation was attributed to the photochemical degradation of components with a high unsaturation degree. Such findings could enable ecological safety improvement of aquatic environments using natural sunlight., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

Additional control indexes should be considered for the operation and design of post-treatment systems, as the wastewater treatment objectives are developing toward protecting the safety of ecological environments. In this study, two control indexes were selected and examined systematically in pilot-scale shallow open-water unit (SOWU) ponds for domestic effluent polishing: micropollutants and biotoxicities. The total risk quotient (RQ Total ≤ 1) and effect-based trigger value (EBT) were set as the thresholds for known micropollutants and biological effects, respectively. The results showed that RQ Total of micropollutants (n = 46) could be mitigated to an acceptable level and the luminescent bacteria toxicity was in compliance with the EBT after SOWU polishing in the warm season. The reduction of micropollutants and biotoxicities in the SOWUs both fit the k-C* model well (R 2 > 0.9) in the warm and cold seasons. Finally, the k-C* model integrated with the control indexes was developed to design the SOWU dimensions, and the results indicated that a pond area of 21.7-108.5 m 2 was required for every 1 m 3 /d of effluent when micropollutants were set as the control index, while a pond area of 3.6-18.2 m 2 was required when luminescent bacteria toxicity was set as the control index., (Copyright © 2021. Published by Elsevier B.V.)

Residual trace organic pollutants (TOPs) and associated biological effects from secondary effluent (SE) are attracting much attention because of their safety concerns. Granular activated carbon (GAC) adsorption, due to its low cost and high efficiency, is widely applied for further wastewater treatment, but its selective removals of TOPs and biological effects are poorly understood. In the present study, the surface physicochemical characteristics of four types of typical GACs were investigated, and their correlation with luminescent bacteria toxicity was discussed. Based on the biological effect control, shell GAC, with a great adsorption capacity and high functional group contents was selected for further study, including for the removal of fluorescent dissolved organic matter (DOM), 21 TOPs, and 3 biological effects. The shell GAC showed a promising property of removing fluorescent DOM and TOPs. The total concentration of 21 detected TOPs, including 12 pesticides and 9 pharmaceuticals, achieved 82% removal when 30 g/L shell GACs was added. Individual chemicals removal by GAC adsorption was not well described by an individual parameter (e.g., logD, molecular size, charge, functional groups), but rather by a variety of physical and chemical interactions among TOPs, DOM, and GAC. The biological effects from SE were mainly caused by TOPs and DOM. Hence, shell GACs also showed high removal efficiencies of luminescent bacteria toxicity, genotoxicity, and photosynthetic inhibition effect. The removal mechanisms of the three biological effects from SE were deeply discussed. Therefore, the GAC treatment is considered to be one of the most suitable options to ensure the ecological safety of discharged wastewater, because it can effectively control DOM, TOPs, and associated biological effects., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Currently, the wastewater treatment plants (WWTPs) attempt to achieve the shifting from general pollution parameters control to reduction of organic micropollutants discharge. However, they have not been able to satisfy the increasing ecological safety needs. In this study, the removal of micropollutants was investigated, and the ecological safety was assessed for a local WWTP. Although the total concentration of 31 micropollutants detected was reduced by 83% using the traditional biological treatment processes, the results did not reflect chemicals that had poor removal efficiencies and low concentrations. Of the five categories of micropollutants, herbicides, insecticides, and bactericides were difficult to remove, pharmaceuticals and UV filters were effectively eliminated. The specific photosynthesis inhibition effect and non-specific bioluminescence inhibition effect from wastewater were detected and evaluated using hazardous concentration where 5% of aquatic organisms are affected. The photosynthesis inhibition effect from wastewater in the WWTP was negligible, even the untreated raw wastewater. However, the bioluminescence inhibition effect from wastewater which was defined as the priority biological effect, posed potential ecological risk. To decrease non-specific biological effects, especially of macromolecular dissolved organic matter, overall pollutant reduction strategy is necessary. Meanwhile, the ozonation process was used to further decrease the bioluminescence inhibition effects from the secondary effluent; ≥ 0.34 g O 3 /g DOC of ozone dose was recommended for micropollutants elimination control and ecological safety., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

It has been proven that the raw wastewater, secondary effluent and even reclaimed water may have toxic effects on aquatic organisms. In the present study, fractionation procedures combined with bioassays using luminescent bacteria were conducted to identify the fractions that contributed to the acute and long-term toxicity of municipal wastewater. Solid phase extraction was used to divide dissolved organic matter from the wastewater into three fractions, including non-polar, medium-polar and polar fraction. Among these fractions, although the acute toxicity of municipal wastewater was mainly caused by polar and medium-polar chemicals, the acute toxicity induced by the unit mass of the medium-polar fraction was the greatest. Using three kinds of resins, the organic substances in municipal wastewater were classified into six fractions, and the long-term toxicity of these fractions was further identified. The long-term toxicity of the hydrophobic neutrals, which were the primary toxic substances in raw wastewater, decreased after the conventional secondary biological treatment. Hydrophilic neutrals, which accounted for the majority of organic substances in the secondary effluent, were the main substances with long-term toxicity in the secondary effluent. The identification of fractions with acute and long-term toxicity in municipal wastewater is beneficial for further treatment to attenuate the ecotoxicity of wastewater before discharge into the aquatic environment.

The occurrence of 18 types of disinfection by-products (DBPs) in two waterworks and the corresponding water supply networks of H City in Zhejiang Province was determined by gas chromatography coupled with electron capture detector (GC-ECD). The correlation between DBPs and organic precursors, and health risks caused by DBPs, were discussed. Results showed that the disinfection by-products detected in drinking water in H City mainly include trihalomethanes (THMs), haloacetic acid (HAAs), haloacetonitrile (HANs) and trichloronitromethane (HNMs), with highest concentrations of THMs followed by HAAs. In the finish water of CX Waterworks and tap water supplied by CX Water works, concentrations of THMs ranged from 7.70 to 32.73μg·L -1 and 9.00 to 51.42μg·L -1 , respectively, and those of HAAs 3.05 to 21.30μg·L -1 and 6.00 to 26.79μg·L -1 , respectively. The THMs in finished water and tap water of TH Waterworks were in the range 8.65-38.76μg·L -1 and 12.09-42.04μg·L -1 , respectively, and those of HAAs were 2.42-14.79μg·L -1 and 2.80-33.40μg·L -1 , respectively. The DBPs in the finished and tap water of the two waterworks were at lower levels than the limitations regulated by the Sanitary Standard for Drinking Water (GB 5749-2006). The index of dissolved organic carbon (DOC) and UV 254 were adopted to describe the organic compounds, and it was found that trichloromethane (TCM) was significantly negatively correlated with DOC and UV 254 in tap water. Based on the EPA recommended health risk assessment model, the carcinogenic and non-carcinogenic risks of chlorine disinfection by-products in the oral intake route were calculated. It was found that the carcinogenic risks caused by the disinfection by-products in the finished water and tap water of H City were 5.94×10 -6 -4.76×10 -5 and 5.94×10 -6 -5.56×10 -5 , respectively, while the non-carcinogenic risks were 0.91×10 -2 -4.20×10 -2 and 1.26×10 -2 -4.72×10 -2 , respectively. The carcinogenic risk is mainly from THMs:bromodichloromethane (BDCM) contributes the highest cancer risk, and the non-carcinogenic risk is mainly from TCM.

As increasing attention is paid to surface water protection, there has been demand for improvements of domestic wastewater treatment plant (WWTP) effluent. This has led to the application of many different advanced treatment processes (ATPs). In this study, the treatability of trace organic pollutants in secondary effluent (SE) and associated biotoxicity reduction by four types of ATPs, including coagulation, granular activated carbon (GAC) adsorption, ultraviolet (UV) photolysis and photocatalysis, and ozonation, were investigated at the bench-scale. The ATPs showed different removal capacity for the 48 chemicals, which were classified into seven categories. EDCs, herbicides, bactericides and pharmaceuticals were readily degraded, and insecticides, flame retardants, and UV filters were relatively resistant to removal. During these processes, the efficiency of the ATPs in reducing four biological effects were investigated. Of the four biological effects, the estrogenic activity from SE was not detected using the yeast estrogen screen. In contrast with genotoxicity and photosynthesis inhibition, bacterial cytotoxicity posed by SE was the most difficult biological effect to reduce with these ATPs. GAC adsorption and ozonation were the most robust treatment processes for reducing the three detected biotoxicities. UV photolysis and photocatalysis showed comparable efficiencies for the reduction of genotoxicity and photosynthesis inhibition. However, coagulation only performed well in genotoxicity reduction. The effect-based trigger values for the four bioassays, that were derived from the existing environmental quality standards and from HC5 (hazardous concentration for 5% of aquatic organisms), were all used to select and optimize these ATPs for ecological safety. Conducting ATPs in more appropriate ways could eliminate the negative effects of WWTP effluent on receiving water bodies., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Systematically studied the oxidation of enrofloxacin (ENR) in a nanoscale zero-valent copper (nZVC)-activated molecular oxygen system. The results show that nanoscale copper powder has a higher surface area than microscale copper powder, non-porous structure, and rough surface and exists in form of agglomerates. Nanoscale ZVC shows a superior activated performance toward molecular oxygen compared with microscale ZVC, which is due to its larger specific area and the fact that it corrodes easier. The H 2 O 2 generated from the activation of molecular oxygen and the Cu + released from surface corrosion form a novel Fenton-like system in which hydroxyl radicals are continuously produced, resulting in high-efficiency removal of ENR from water. The superoxide radicals produced during the reaction promote the reduction of Cu 2+ to Cu + , thus speeding up the removal of ENR. The reaction conditions have a certain effect on the ENR degradation in nZVC-activated molecular oxygen systems. A higher nZVC dosage, lower ENR concentration, higher reaction temperature, and strong acidic conditions are favorable for the ENR removal.

CoFe 2 O 4 /ordered mesoporous carbon (OMC) nanocomposites were synthesized and tested as heterogeneous peroxymonosulfate (PMS) activator for the removal of rhodamine B. Characterization confirmed that CoFe 2 O 4 nanoparticles were tightly bonded to OMC, and the hybrid catalyst possessed high surface area, pore volume, and superparamagnetism. Oxidation experiments demonstrated that CoFe 2 O 4 /OMC nanocomposites displayed favorable catalytic activity in PMS solution and rhodamine B degradation could be well described by pseudo-first-order kinetic model. Sulfate radicals (SO 4 - ·) were verified as the primary reactive species which was responsible for the decomposition of rhodamine B. The optimum loading ratio of CoFe 2 O 4 and OMC was determined to be 5:1. Under optimum operational condition (catalyst dosage 0.05 g/L, PMS concentration 1.5 mM, pH 7.0, and 25 °C), CoFe 2 O 4 /OMC-activated peroxymonosulfate system could achieve almost complete decolorization of 100 mg/L rhodamine B within 60 min. The enhanced catalytic activity of CoFe 2 O 4 /OMC nanocomposites compared to that of CoFe 2 O 4 nanoparticles could be attributable to the increased adsorption capacity and accelerated redox cycles between Co(III)/Co(II) and Fe(III)/Fe(II).

Targeting at the characteristics of low concentration but high risk of endocrine disrupting compounds in the aquatic environment, the current study investigated the distribution of estrogenicity and E2 level using recombinant yeast estrogen screen (YES) and enzyme linked immunosorbent assay (ELSIA) during domestic wastewater treatment processes. The results showed that the levels of estrogenicity and E2 in influents of wastewater treatment plants were 4.35-7.58 ng·L -1 and 36.95-83.43 ng·L -1 , respectively. It was found that biological treatment processes played a crucial role in the removal of estrogenicity and E2, such as oxidation ditch, A 2 /O and A 2 /O followed by MBR, where the removal of estrogenicity and E2 was 71.10%-75.54% and 75.88%-80.72%, respectively. The activated sludge, with an estrogencity level of 1.84-2.43 ng·g -1 and an E2 level of 8.45-12.84 ng·g -1 , had the function of eliminating estrogenic effect to a certain extent by adsorption. The estrogenic activity in the effluent of domestic wastewater was 1.06-2.19 ng·L -1 , which will pose potential risk to the aquatic life in the environment. Last but not least, ELISA had a good correlation with YES assay, which provides a new method for rapid screening and assessment of water environmental estrogen.

In order to accurately evaluate the comprehensive ecotoxicity of domestic wastewater and the toxicity reduction efficiency of different treatment processes, standardized assays focusing on Vibrio fischeri , SOS/umu test and yeast estrogen screen were applied. Simultaneously, male zebrafish was used to address the mode of action of endocrine disrupting effects of wastewater and reclaim water on aquatic life. Results of this study indicated that the influent was severely polluted:highly acute toxicity, genotoxicity and estrogenicity were observed. After the secondary biological treatment, the above toxicities were significantly reduced, making the water quality improved. However, the estrogencity of secondary effluent was detected at 1.89 ng·L -1 , which still posed potential risk on the aquatic life in receiving water. In addition, the up-regulation of estrogen receptor ( esr 1 ) and vitellogenin ( vtg 1 ) in the livers of zebrafish was observed after exposure to 2.5 times concentrated wastewaters, which demonstrated that wastewater modulates hormonal activities of aquatic life by disturbing target genes expression. Moreover, the slight down-regulation of esr 1 was observed in the gonads. These observations reflect that the evaluation of biological toxic effect should be analyzed in different tissues or organs, so that more comprehensive information about the adverse effects of wastewaters on aquatic life can be obtained.

The storage of water in a landscape lake can act as a buffer zone between reclaimed water production and reuse, but there is still uncertainty about the variation of water quality and toxic effects during the open-storage process. In this study, long-term sample collection, chemical analyses and biotoxicity assessments were conducted on reclaimed water before and after open storage in a landscape lake. The organic contents, in terms of chemical oxygen demand and total organic carbon, were found to be slightly higher in the lake water than that in the reclaimed water, but substantial reduction of the total concentration of 52 trace organic chemicals was obtained and microorganism toxicity, phytotoxicity, aquatic vertebrate toxicity and genotoxicity, were significantly weakened after open storage. Furthermore, the total risk quotient (RQTotal) decreased from 5.12 (potential ecological risk level) in the reclaimed water to 0.18 (negligible ecological risk level) in the lake water. The removal of chlorpyrifos, dichlorphos and tetracycline was identified as the main reason for biotoxicity reduction after open storage. The seminatural environment of the landscape lake would have provided a favorable condition for the decay of toxic trace organic chemicals so that the stored water turned to be safer for further reuse., (Copyright © 2016. Published by Elsevier B.V.)

In this study, zebrafish (Danio rerio) were exposed to a UV-filter-octocrylene (OCT) with elevated concentrations for 28 d. The total body accumulation of OCT in zebrafish was found to reach 2321.01 ("L" level), 31,234.80 ("M" level), and 70,593.38 ng g(-1) ("H" level) when the average OCT exposure concentration was controlled at 28.61, 505.62, and 1248.70 μg L(-1), respectively. Gross and histological observations as well as RT-qPCR analysis were conducted to determine the effects of OCT accumulation on zebrafish. After exposure, the gonad-somatic index and percentage of vitellogenic oocytes were found to increase significantly in the ovaries of female zebrafish at the H accumulation level. Significant up-regulation of esr1 and cyp19b were observed in the gonads, as well as vtg1 in the livers for both female and male zebrafish. At M and H accumulation levels, apparent down-regulation of ar was observed in the ovaries and testis of the female and male zebrafish, respectively. Although the extent of the effects on zebrafish differed at different accumulation levels, the induction of vtg1 and histological changes in the ovaries are indications of estrogenic activity and the inhibition of esr1 and ar showed antiestrogenic and antiandrogenic activity, respectively. Thus, as OCT could easily accumulate in aquatic life such as zebrafish, one of its most of concern hazards would be the disturbance of the histological development and its multiple hormonal activities., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Chinese Loess Plateau is considered as one of the most serious soil loss regions in the world, its annual sediment output accounts for 90 % of the total sediment loads of the Yellow River, and most of the Loess Plateau has a very typical characteristic of "soil and water flow together", and water flow in this area performs with a high sand content. Serious soil loss results in nitrogen and phosphorus loss of soil. Special processes of water and soil in the Loess Plateau lead to the loss mechanisms of water, sediment, nitrogen, and phosphorus are different from each other, which are greatly different from other areas of China. In this study, the modified export coefficient method considering the rainfall erosivity factor was proposed to simulate and evaluate non-point source (NPS) nitrogen and phosphorus loss load caused by soil and water loss in the Yanhe River basin of the hilly and gully area, Loess Plateau. The results indicate that (1) compared with the traditional export coefficient method, annual differences of NPS total nitrogen (TN) and total phosphorus (TP) load after considering the rainfall erosivity factor are obvious; it is more in line with the general law of NPS pollution formation in a watershed, and it can reflect the annual variability of NPS pollution more accurately. (2) Under the traditional and modified conditions, annual changes of NPS TN and TP load in four counties (districts) took on the similar trends from 1999 to 2008; the load emission intensity not only is closely related to rainfall intensity but also to the regional distribution of land use and other pollution sources. (3) The output structure, source composition, and contribution rate of NPS pollution load under the modified method are basically the same with the traditional method. The average output structure of TN from land use and rural life is about 66.5 and 17.1 %, the TP is about 53.8 and 32.7 %; the maximum source composition of TN (59 %) is farmland; the maximum source composition of TP (38.1 %) is rural life; the maximum contribution rates of TN and TP in Baota district are 36.26 and 39.26 %, respectively. Results may provide data support for NPS pollution prevention and control in the loess hilly and gully region and also provide scientific reference for the protection of ecological environment of the Loess Plateau in northern Shaanxi.

Chlorination of the secondary effluent from domestic wastewater treatment plants (WWTP) is suspicious of toxic effects due to the formation of trihalomethanes (THMs). In order to clarify this mechanism, samples were collected from the inlet and outlet of a WWTP, and a series of analyses were conducted on the relationship between THMs formation and the toxicity of the secondary effluent after chlorination. By three-dimensional fluorescence spectrometry it was clarified that the biological wastewater treatment process was accompanied with the formation of humic- and fulvic-like substances which were typical THMs precursors as shown by their high thihalomethane formation potential (THMFP) as well as high specific ultraviolet absorbance (SUVA). As a result of bioassay using a freshwater luminescent bacterium Vibrio-qinghaiensis sp.-Q67, a linear relationship was obtained between the concentration of THMs after chlorinating the effluent and its toxicity expressed as the inhibition of the luminescent light. The effective THMs concentration corresponding to a 50% inhibition was 318 μg/L at a chlorine dose of 19.6 mg/L as Cl2. THMs formation may be the direct reason for the increase of toxicity in the secondary effluent when chlorine was used as disinfectant., (Copyright © 2013 Elsevier B.V. All rights reserved.)

This study focused on acclimating a microbial enrichment to biodegrade benzene, toluene, ethylbenzene and xylenes (BTEX) in a wide range of salinity. The enrichment degraded 120 mg/L toluene within 5d in the presence of 2M NaCl or 150 mg/L toluene within 7d in the presence of 1-1.5M NaCl. PCR-DGGE (polymerase chain reaction-denatured gradient gel electrophoresis) profiles demonstrated the dominant species in the enrichments distributed between five main phyla: Gammaproteobacteria, Sphingobacteriia, Prolixibacter, Flavobacteriia and Firmicutes. The Marinobacter, Prolixibacter, Balneola, Zunongwangia, Halobacillus were the dominant genus. PCR detection of genotypes involved in bacterial BETX degradation revealed that the degradation pathways contained all the known initial oxidative attack of BTEX by monooxygenase and dioxygenase. And the subsequent ring fission was catalysed by catechol 1,2-dioxygenase and catechol 2,3-dioxygenase. Nuclear magnetic resonance (NMR) spectroscopy profiles showed that the bacterial consortium adjusted the osmotic pressure by ectoine and hydroxyectoine as compatible solutes to acclimate the different salinity conditions., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

A bioassay using the luminescent bacterium Vibrio-qinghaiensis sp.-Q67 associated with solid-phase extraction (SPE) was developed for evaluating the variation of ecotoxicity along with the reduction of organic substances in a domestic wastewater treatment plant employing an oxidation ditch process. With effective elimination of the interference from all inorganic substances by the SPE operation, the ecotoxicity of the water, as expressed by the toxicity impact index, TII(50) (%) after a model-based regression and parameter transformation, was found to decrease from 50.51% in the influent to 25.84% after the grid chamber and then to 1.38% for the secondary effluent, but the final chlorination stage resulted in a slight TII(50) increase. Of the two typical tertiary treatment processes, coagulation could not assist further reduction of the ecotoxicity while carbon adsorption could reduce the TII(50) to as low as 0.96%. When enhanced primary treatment was conducted, the influent TII(50) could be directly reduced to 7.36%. A good correlative relationship was found between the total COD concentration and the TII(50) value at different stages of the wastewater treatment process., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Liquid-liquid microextraction/GC/MS analysis method was employed in detecting trace odorants in drinking water. A-year-long investigation on odor chemicals was carried out in source water and drinking water in a certain waterworks of Shanghai. The results showed that 2-MIB was the main contaminant which induce disgusting odor to drinking water of Shanghai in July, August, September and October in a year with the peak concentration of 2-MIB 152.82 ng/L in raw water and 97.94 ng/L in finished water from waterworks. Oscillatoria was suspected as the resource of 2-MIB.

Background & Objective: The pollution of drinking water, for example river and pool, has long been recognized to be associated with an increased risk of colorectal cancer (CRC) in previous epidemiological studies. There is little prospect cohort study with person-years directly on the relative risks of different sources of drinking water for CRC., Methods: From May 1989 to April 1990, a screening for CRC was carried out among residents aged 30 and over 30 years in 10 villages and towns of Jiashan in China. A total of 64115 residents who participated the screening were classified into 5 cohorts by the source of drinking water and were followed-up for CRC incidence through a tumor reporting system including a rapid reporting system of CRC Registry and for death instance through Death Registration of Jiashan. After 11 years of follow-up, person-years calculated with every cohort member, the incidence densities of CRC with different sources of drinking water were analyzed respectively. Poisson regression was used to control potential confounding variables including demography variables and smoke history and to attain crude and adjusted relative risks based on person-years., Results: A trend was seen toward increasing incidence rates of colorectal cancer from municipal, river, channel, mixed water to well source in turn as shown as 29.61, 32.67, 33.45, 40.87, 58.67 per 100,000 inhabitants, and only the role in risk of well water was marked different from municipal water (P< 0.05). After adjusted the confounding variables by multi-Poisson regression, we found the significant risk of drinking well water for colon cancer, rectal cancer, and colorectal cancer. The relative risks were 1.741 (95%CI 1.001-3.029), 2.228 (95%CI 1.432-3.466), and 2.022 (95%CI 1.432-2.854), respectively., Conclusion: Drinking well water long is a risk factor for colorectal cancer in Jiashan, especially for rectal cancer.