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Acetaminophen is widely used to treat mild to moderate pain and to reduce fever. Under the worldwide COVID-19 pandemic, this over-the-counter pain reliever and fever reducer has been drastically consumed, which makes it even more abundant than ever in municipal wastewater and drinking water sources. Chlorine is the most widely used oxidant in drinking water disinfection, and chlorination generally causes the degradation of organic compounds, including acetaminophen. In this study, a new reaction pathway in the chlorination of acetaminophen, i.e., oxidative coupling reactions via acetaminophen radicals, was investigated both experimentally and computationally. Using an ultraperformance liquid chromatograph coupled to an electrospray ionization-triple quadrupole mass spectrometer, we detected over 20 polymeric products in chlorinated acetaminophen samples, some of which have structures similar to the legacy pollutants "polychlorinated biphenyls". Both C-C and C-O bonding products were found, and the corresponding bonding processes and kinetics were revealed by quantum chemical calculations. Based on the product confirmation and intrinsic reaction coordinate computations, a pathway for the formation of the polymeric products in the chlorination of acetaminophen was proposed. This study suggests that chlorination may cause not only degradation but also upgradation of a phenolic compound or contaminant.

Chlorine disinfection of saline wastewater effluents rich in bromide and iodide forms relatively toxic brominated and iodinated disinfection byproducts (DBPs). Ultrasonication is a relatively new water treatment technology, and it is less sensitive to suspended solids in wastewaters. In this study, we examined the effects of ultrasonication (in terms of reactor type and combination mode with chlorination) on the DBP formation and toxicity in chlorinated primary and secondary saline wastewater effluents. Compared with the chlorinated wastewater effluent samples without ultrasonication, ultrasonic horn pretreatment of the wastewater effluent samples reduced the total organic halogen (TOX) levels in chlorination by ∼30%, but ultrasonic bath pretreatment of the wastewater samples did not significantly change the TOX levels in chlorination, which might be attributed to the higher energy utilization and decomposition extent of organic DBP precursors in the ultrasonic horn reactor. Moreover, the TOX levels in the chlorinated samples with ultrasonic horn pretreatment (USH-chlorination), simultaneous treatment (chlorination+USH) and subsequent treatment (chlorination-USH) were also significantly reduced, with the maximum TOX reductions occurring in the samples with ultrasonic horn pretreatment. A toxicity index was calculated by weighting and summing the levels of total organic chlorine, total organic bromine and total organic iodine in each treated sample. The calculated toxicity index values of the chlorinated wastewater effluent samples followed a descending rank order of "chlorination""chlorination+USH""chlorination-USH""USH-chlorination", with the lowest toxicity occurring in the samples with ultrasonic horn pretreatment. Then, a developmental toxicity bioassay was conducted for each treated sample. The measured toxicity index values of the chlorinated wastewater samples followed the same descending rank order.

In recent decades, there has been a growing interest in the recycling of organic materials such as paper mill biosolids (PB) and biochar for use as soil amendments. However, the benefits of co-application of PB and biochar and its effects on soil phosphorus (P) availability remain unknown. An incubation study was conducted on two acidic soils to assess the effect of two PB types (2.5% w/w) co-applied with three rates (0%, 2.5%, and 5% w/w) of pine (Pinus strobus L.) biochar on soil P fractions. An unfertilized control and a mineral NP fertilizer were used as a reference. Soil P fractions were determined by Hedley procedure after 2 and 16 wk of incubation. Material fractionation indicated that the PB containing the highest total P and the lowest Al content had the highest proportion of labile P, whereas most P in the biochar was in a stable form. The incubation study revealed that the P-rich PB increased P availability in both soils to a level comparable to mineral fertilizer at the end of the incubation. The addition of biochar to PB, however, did not affect soil P availability, but the highest rate induced a conversion of P fixed to Al and Fe oxides towards recalcitrant forms, particularly in the sandy loam soil. We conclude that co-applying biochar and PB could be more beneficial than application biochar alone and soils amended with such a mixture would be expected to release part of their P slowly over a longer period of time.

It is widely accepted that hydrogeochemistry of saline springs is extremely important to understand the water circulation and evolution of saline basins and to evaluate the potential of potassiumrich evaporites. The Kuqa Basin, located in the northern part of the Tarim Basin in Northwest China, is a saline basin regarded as the most potential potash-seeking area. However, the origin and water circulation processes of saline springs have yet to be fully characterized in this saline basin. In this study, a total of 30 saline spring samples and 11 river water samples were collected from the Qiulitage Structural Belt (QSB) of the Kuqa Basin. They were analyzed for major (K+, Ca2+, Na+, Mg2+, SO42−, Cl− and HCO3−) and trace (Sr2+ and Br−) ion concentrations, stable H-O-Sr isotopes and tritium concentrations in combination with previously published hydrogeochemical and isotopic (H-O) data in the same area. It is found that the water chemical type of saline springs in the study area belonged to the Na-Cl type, and that of river water belonged to the Ca-Mg-HCO3-SO4 type. The total dissolved solid (TDS) of saline springs in the QSB ranged from 117.77 to 314.92 g/L, reaching the brine level. On the basis of the general chemical compositions and the characteristics of the stable H-O-Sr isotopes of saline springs, we infer that those saline springs mainly originated from precipitation following river water recharging. In addition, we found that saline springs were not formed by evapo-concentration because it is unlikely that the high chloride concentration of saline springs resulted in evapo-concentration and high salinity. Therefore, we conclude that saline spring water may have experienced intense evapo-concentration before dissolving the salty minerals or after returning to the surface. The results show that the origin of salinity was mainly dominated by dissolving salty minerals due to the river water and/or precipitation that passed through the halite-rich stratum. Moreover, there are two possible origins of saline springs in the QSB: one is the infiltration of the meteoric water (river water), which then circulates deep into the earth, wherein it dissolves salty minerals, travels along the fault and returns to the surface; another is the mixture of formation water, or the mixture of seawater or marine evaporate sources and its subsequent discharge to the surface under fault conditions. Our findings provide new insight into the possible saltwater circulation and evolution of saline basins in the Tarim Basin.

The L1 cell adhesion molecule (L1CAM) plays important roles in the development and plasticity of the nervous system as well as in tumor formation, progression, and metastasis. New ligands are necessary tools for biomedical research and the detection of L1CAM. Here, DNA aptamer yly12 against L1CAM was optimized to have much stronger binding affinity (10–24 fold) at room temperature and 37 °C via sequence mutation and extension. This interaction study revealed that the optimized aptamers (yly20 and yly21) adopted a hairpin structure containing two loops and two stems. The key nucleotides for aptamer binding mainly located in loop I and its adjacent area. Stem I mainly played the role of stabilizing the binding structure. The yly-series aptamers were demonstrated to bind the Ig6 domain of L1CAM. This study reveals a detailed molecular mechanism for the interaction between yly-series aptamers and L1CAM and provides guidance for drug development and detection probe design against L1CAM.

Chlorine is extensively used in disinfection processes in water and wastewater treatment processes. The chlorine is typically dosed by jet mixing, and yet no systematic study of chlorine jets has been conducted. In the Stonecutters Island Sewage Treatment Works (SCISTW) of the Hong Kong Harbour Area Treatment Scheme (HATS), concentrated chlorine solution (in sodium hypochlorite form) is injected into primary treated effluent in the form of turbulent dense jets. In view of the importance of sewage disinfection to the environmental impact, it is essential to understand the mixing and reaction of chlorine with ammonia nitrogen for disinfection dosage optimization. In this study, an integral buoyant jet model is developed for a chlorine jet reacting with ammonia nitrogen in CEPT sewage. The jet mixing and chlorine demand is studied by accounting for the stoichiometric reaction of chlorine and ammonia including breakpoint chlorination. Based on experiments of chlorine jet in ammonia solution, the stoichiometric mass ratio of chlorine to ammonia under dynamic mixing process is found to be 7.48. The chlorination kinetics model is then incorporated in a general model of a chlorine jet discharging into a coflowing primary treated sewage effluent, with the reaction ratio calibrated based on experimental measurements for the stagnant case. Significant chlorine demand can occur within a short distance (in the order of 0.1 m, or 1 s or less of travel time) from the dosing point due to the turbulent mixing and reaction with ammonia nitrogen and organic impurities. The chlorine demand of CEPT effluent increases with jet dosing total residual chlorine (TRC) concentration. At TRC 60%), while for TRC ≫ 2000 mg/L, up to two thirds of chlorine demand can be induced by the oxidation of organic debris. Model predictions of chlorine demand and concentration agree well with laboratory experiments and field data.

The Khorat Plateau is one of the largest potash deposits in the world. In recent years, exploitation of potash resources accompanied by leakage of underground brines (UB) in potassium-bearing strata has threatened mining safety. However, there is little research on origin of UB in Laos. In this study, twelve samples of UB, salt springs (SS) and river waters were collected in Khammouane mining area, central Laos and analyzed for ionic and boron isotopic compositions. The results show that both of UB, dominated by K+, Mg2+, Na+ and Cl– ions, and SS, enriched in Na+ and Cl–, are chloride-type brines, while river waters abundant in Ca2+ and HC$${\text{O}}_{3}^{ - }$$ ions are carbonate-type waters. K+ (35.1–53.7 g/L) and Rb+ (12.9–16.6 mg/L) concentrations of UB are higher than the peak (25.9 g/L, 9.4 mg/L) of seawater evaporation trajectories (SET). UB is also characterized by high Mg2+ (32.7–68.0 g/L) and Br– (1795.2–2801.3 mg/L) concentrations and its lg(Cl/Br) ratios (1.9–2.1) deviate from the halite dissolution line. These comparisons indicate that the water chemistries of UB are mainly influenced by dissolution of carnallite and sylvite. High Sr2+ concentrations (31.8–58.6 mg/L) in UB might be simultaneously associated with dissolution of potash salt and Ca-bearing minerals (carbonate and anhydrite). The negative saturation indices (SI) of different salt minerals in UB suggest that salt minerals are unsaturated in UB. Meanwhile, boron (B) concentrations (396.0–426.0 mg/L) and δ11B values (+19.8–+21.0‰) of UB fall in between low B–δ11B end member (0.02 mg/L, +2.31‰) of river water and high B-δ11B end member (126.7–890.8 μg/g, +25.94–+32.94‰) of evaporitic minerals. The comparison implies that UB was influenced and mixed by two end members. Therefore, combining with major and trace ionic concentrations, isotopic compositions and lithologies of salt-bearing strata revealed by drillings in mining area, we conclude that the major solute source in UB is derived from dissolution of carnallite and sylvite. These geochemical evidences provide insights into dealing with leakage of underground brines occurred in the underground mining of potash deposits in Laos.

Chlorine-disinfected sewage effluents are typically dechlorinated by using NaHSO3, Na2SO3, or Na2S2O3, as chlorine residual could be harmful to aquatic organisms upon discharge of sewage effluents into receiving marine water. In this study, we systematically investigated the effects of dechlorination-related factors on the developmental toxicity of a chlorinated saline primary sewage effluent, via direct exposure of the embryos of a marine polychaete to the effluent. The results showed that dechlorination ratio (i.e., the ratio of the dosed amount to the requisite stoichiometric amount of a dechlorination agent) and mixing condition were critical factors affecting the toxicity of the effluent. The toxicity of the effluent under insufficient dechlorination conditions was mainly caused by residual chlorine, especially monochloramine. Although the three dechlorination agents generally performed similarly, dechlorination with Na2S2O3 required a more vigorous mixing condition than that with NaHSO3 or Na2SO3, as the relatively high density of Na2S2O3 might affect the mixing efficiency. Under insufficient mixing conditions, a prolonged dechlorination time was beneficial to achieving complete dechlorination and thus lowered the toxicity of the effluent. Moreover, because disinfection byproducts (DBPs) may have chronic effects on aquatic organisms, the developmental toxicity of the DBP mixtures in the chlorinated effluent in different dechlorination scenarios was also evaluated. The results indicated that increasing the dechlorination ratio reduced the developmental toxicity of the DBP mixture in the chlorinated saline sewage effluent, which might be ascribed to the decrease of the levels of overall brominated and iodinated DBPs; the dechlorination agent (NaHSO3 or Na2S2O3) might act as a nucleophile in the nucleophilic substitution and cause the substitution of bromine or iodine atoms in brominated and iodinated DBPs. The results from this study might aid in the design and operation of dechlorination facilities in sewage treatment plants.

Ozonation is widely used in wastewater treatment but the associated byproduct formation is a concern. When ozonation is used in the presence of bromide, bromate is generally considered as a major byproduct, and few studies have examined the toxicity of organic byproducts. This study was designed to investigate the cytotoxicity, genotoxicity and DNA/RNA oxidative damage to Chinese hamster ovary (CHO) cells of organic extracts from ozonated wastewater in the absence or presence of bromide. Ozonation effectively detoxified secondary effluents containing no bromide. However, ozonation significantly increased the cytotoxicity and genotoxicity of the effluents spiked with a bromide concentration as low as 100 μg/L, compared with the bromide-free effluent. When the bromide concentration in the effluent was increased to 2000 μg/L, ozonation resulted in 1.4–1.5 times the cytotoxicity and 1.5–5.0 times the genotoxicity of the non-ozonated secondary effluent. Besides, the oxidative stress (including reactive oxygen species and reactive nitrogen species) and DNA/RNA oxidative damage also became more severe and a high level of 8-hydroxy-(deoxy)guanosine was detected in the CHO cell nucleus in the presence of bromide. Cytotoxicity and genotoxicity were found to increase with the formation of total organic bromine (TOBr). When the CHO cells were exposed to both the organic byproducts and bromate formed from wastewater containing 500 and 2000 μg/L bromide, bromate significantly increased oxidative stress and DNA/RNA oxidative damage at relatively high concentration factors, suggesting both organic byproduct and bromate can contribute to toxicity increase. During ozonation of the effluent containing bromide, particular attention should be paid to the organic byproducts such as TOBr.

Phosphorus (P) in calcareous soil often needs to be replenished repeatedly. P-enriched biochar is expected to improve soil available P. However, the effect of acid biochar incorporated with other P activators on the P availability in calcareous soil is rarely reported. One soil incubation for 56 days was conducted to investigate the influence of individual application of acid biochar (B), phosphatase (E), Bacillus megaterium (M), and their combined application (BE, BM, EM, BEM) on soil P availability, based on analysis of Olsen-P, water-soluble P, P forms, acid phosphomonoesterase (AcP), alkaline phosphomonoesterase (AlP) activity, and pH after 7, 14, 28, and 56 days of incubation. Results indicated that individual application of B significantly increased soil Olsen-P and AcP compared with CK in the whole incubation period. Individual application of M significantly increased soil AcP and AlP on the 14th and 56th day of incubation, but decreased soil Olsen-P significantly in the whole incubation. Individual application of B was the best measure for improving P availability in calcareous soil, followed by application of BM. But individual application of E or M was not recommended. Further investigations are required to investigate the influence of acid biochar on P availability in calcareous soil at the field scale.

The boron (B) isotope-pH proxy for marine carbonates has been widely used to reconstruct past ocean pH values. Unlike seawater, the apparent dissociation constant of boric acid (KB) and the δ11B values of brines from the terrestrial salt lakes in western China vary. However, relevant studies concerning the B isotope geochemistry of brine-carbonate systems in terrestrial salt lakes are limited. In this study, thirty-nine clastic samples from a sediment core (ISL1A) from the Qarhan Salt Lake in the Qaidam Basin were collected. These carbonates were analyzed for δ11B, B, Mg, Sr and Ca. Using our new data as well as published pH values, total dissolved solids (TDS), element concentrations, and δ11B values of brines in western China, we reached the following conclusions. (1) During evaporation process, salinity increases, the δ11B values of brines in salt lakes increase, and the pKB (−logKB) and pH values simultaneously decrease. (2) The large heterogeneity in the δ11B values of the carbonates (−2.74‰ to +7.64‰) from core ISL1A is mainly due to the δ11B values of the brines, rather than pKB and pH. (3) B isotopic fractionation with a small αcarbonate-brine of 0.997 in a brine-carbonate system conforms to the Rayleigh fractionation model. (4) Our comparison of the δ11B values of these carbonates with other records from core ISL1A suggests that the δ11B values of the carbonates in the arid Qaidam Basin can be used as a new proxy for the salinity of paleo-lake water.

Highlights: • Overview on oxidative treatment processes for different industrial applications • Compilation of disinfection by-product types/concentrations in marine water uses • Estimation of global DBP inputs into marine water from different industries • Comparison of anthropogenic bromoform production to emissions from natural sources Abstract: Oxidative treatment of seawater in coastal and shipboard installations is applied to control biofouling and/or minimize the input of noxious or invasive species into the marine environment. This treatment allows a safe and efficient operation of industrial installations and helps to protect human health from infectious diseases and to maintain the biodiversity in the marine environment. On the downside, the application of chemical oxidants generates undesired organic compounds, so-called disinfection by-products (DBPs), which are discharged into the marine environment. This article provides an overview on sources and quantities of DBP inputs, which could serve as basis for hazard analysis for the marine environment, human health and the atmosphere. During oxidation of marine water, mainly brominated DBPs are generated with bromoform (CHBr3) being the major DBP. CHBr3 has been used as an indicator to compare inputs from different sources. Total global annual volumes of treated seawater inputs resulting from cooling processes of coastal power stations, from desalination plants and from ballast water treatment in ships are estimated to be 470 – 800 × 109 m3, 46 × 109 m3 and 3.5 × 109 m3, respectively. Overall, the total estimated anthropogenic bromoform production and discharge adds up to 13.5 – 21.8 × 106 kg/a (kg per year) with contributions of 11.8 – 20.1 × 106 kg/a from cooling water treatment, 0.89 × 106 kg/a from desalination and 0.86 × 106 kg/a from ballast water treatment. This equals approximately 2 – 6 % of the natural bromoform emissions from marine water, which is estimated to be 385 – 870 × 106 kg/a.

In this study, nineteen brine samples from the Qarhan Salt Lake (QSL) in western China were collected and analyzed for boron (B) and chlorine (Cl) concentrations, total dissolved solids (TDS), pH values and stable B isotopic compositions. The B concentrations and δ11B values of brines in the QSL range from 51.6 mg/L to 138.4 mg/L, and from +9.32‰ to +13.08‰, respectively. By comparison of B concentrations and TDS of brines in QSL with evaporation paths of brackish water, we found that B enrichment of brines primarily results from strong evaporation and concentration of Qarhan lake water. Combining with comparisons of B concentrations, TDS, pH values and δ11B values of brines, previously elemental ratios (K/Cl, Mg/Cl, Ca/Cl, B/Cl) and δ11B values of halite from a sediment core (ISL1A), we observe good correlations between B concentrations and TDS, TDS and pH values, pH and δ11B values of brines, which demonstrate that higher B concentrations and more positive δ11B values of halite indicate higher salinity of the Qarhan paleolake water as well as drier paleoclimatic conditions. Based on this interpretation of the δ11B values of halite in core ISL1A, higher salinity of the Qarhan paleolake occurred during two intervals, around 46–34 ka and 26–9 ka, which are almost coincident with the upper and lower halite-dominated salt layers in core ISL1A, drier climate phases documented from the δ18O record of carbonate in core ISL1A and the paleomoisture record in monsoonal central Asia, and a higher solar insolation at 30°N. These results demonstrate that the δ11B values of halite in the arid Qaidam Basin could be regarded as a new proxy for reconstructing the salinity record of paleolake water as well as paleoclimate conditions. Keywords: B isotope compositions, Brine, Chemical concentrations, Qarhan salt lake, Western China, Salinity of paleolake water

Adsorbable organic halogen (AOX) is a parameter conventionally used to indicate the sum of organic halogenated disinfection byproducts (DBPs), which are formed from the reactions of disinfectants with dissolved organic matter, bromide and iodide in water. To overcome the issues of the AOX analytical method, we proposed a new facile and green pretreatment method to enable the analysis of nonionic total organic halogen (NTOX) via the following three steps: 1) separation of NTOX and halides with electrodialysis, 2) conversion of NTOX with ultraviolet (UV) photolysis, and 3) analysis of halides with ion chromatography. To verify this proposal, we mainly evaluated the efficiency of vacuum ultraviolet (VUV) coupled with UV photolysis (VUV−UV) in converting NTOX into halides. Results showed that by applying VUV irradiation for 60 min and UV irradiation at pH 10–11 for another 30 min, over 85.5% of each halide from 20 representative small molecular weight DBPs (each at 100 μg-X/L level) was recovered. The purpose of UV photolysis under alkaline conditions was to reduce oxyhalides (such as bromate and iodate) formed in the VUV process back to halides. With the aid of electrospray ionization-triple quadrupole mass spectrometry, we captured the whole pictures of high molecular weight polar DBPs in a chlorinated drinking water before and after VUV−UV, through which averagely 96.4% of dehalogenation with the VUV−UV treatment was observed. An illustrative comparison of the conventional AOX method and the proposed NTOX method indicates that although the detected NTOX was lower (by 2.3–30.6%) than AOX, the results of the two methods were highly correlated (R2 > 0.97). All these hence verified the photolysis as a mature yet novel tool for sample pretreatment in environmental analytical chemistry.

Granular activated carbon (GAC) adsorption has been traditionally used to remove natural organic matter (NOM), the major precursor of halogenated disinfection byproducts (DBPs), in drinking water treatment plants. Recently, a new approach has been developed to effectively control the formation of trihalomethanes, haloacetic acids, and total organic halogen (TOX) in chlorinated drinking water by targeting intermediate aromatic halogenated DBPs instead of NOM using GAC adsorption. However, the applicability of this new approach to different source water matrices and disinfection conditions remained unclear. In this study, the effects of bromide and contact time on the performance of the new approach for DBP control were investigated. Same source waters were also treated with the traditional approach (i.e., using GAC to remove NOM prior to chlorination) and with chlorination only for comparison. With increasing the initial bromide level from 0 to 2 mg/L, the TOX removal with the new approach increased from 52% to 74%, while the removal with the traditional approach increased from 18% to 37%. Besides, as the chlorine contact time increased from 0.5 to 3.0 h, the TOX removal with the new approach increased from 61% to 75%, while the removal with the traditional approach increased from 21% to 36%. Increasing the bromide level and chlorine contact time enhanced the halogenated DBP removal with both new and traditional approaches, but the removal with the new approach was always two times higher or more than that with the traditional approach, which justified the superiority of the new approach. Moreover, various intermediate aromatic halogenated DBPs were detected in the chlorinated water samples and their levels were significantly decreased after the GAC adsorption, which further corroborated the effectiveness of the new approach for DBP control.

This study characterized the dissolved organic matter (DOM) and byproducts generated after the exposure of activated sludge to ozone and NaClO in ceramic MBR. It was found that NaClO triggered more significant release of DOM than ozone. Proteins with the molecular weight greater than 20 kDa and humic acid like-substances were the principal components of DOM generated by NaClO, while ozone was found to effectively degrade larger biopolymers to low molecular weight substances. The results showed that more than 80% of DOM generated by NaClO and ozone could pass through the 0.2-μm ceramic membrane. Furthermore, total organic chlorine (TOCl) was determined to be the principal species of halogenated byproducts in both cases, while the generation of TOCl by NaClO was much more significant than that by ozone. Only a small fraction of TOCl was removed by the 0.2-μm ceramic membrane. More importantly, the toxic bioassays further revealed that the supernatant of sludge suspension and permeate in the MBR with NaClO cleaning exhibited higher developmental toxicity to the polychaete embryos than those by ozone. The results clearly showed that on-line chemical cleaning with ozone should be a more eco-friendly and safer approach for sustaining long-term membrane permeability in ceramic MBR.

The unintended formation of disinfection byproducts (DBPs) may compromise the safety of drinking water. Since no specified DBPs have been found to be responsible for the overall adverse effects and over half of total organic halogen (TOX) remains unidentified, DBP mixture toxicity is gaining increasing interest as a potential indicator of how risky drinking water might be. In this study, a new approach to evaluating the toxicity of drinking water DBP mixtures was developed by combining freeze-drying or rotoevaporation pretreatment with an in vivo high-salinity-tolerance bioassay with the embryos of a marine polychaete Platynereis dumerilii. The DBP recoveries by freeze-drying or rotoevaporation were compared with those by commonly applied liquid-liquid-extraction (LLE). For drinking water subjected to typical disinfection processes (i.e., chlorination, chloramination, chlorine dioxide treatment, and ozonation with or without postchlorination), LLE led to the lowest TOX recovery (11-18%) and the loss of all inorganic DBPs, while freeze-drying and rotoevaporation recovered 28-58% and 35-61% of TOX, respectively, and effectively recovered 81-99% and 85-104% of inorganic DBPs, respectively. Thus, LLE caused an underestimation of the toxicity of DBP mixtures compared with freeze-drying and rotoevaporation. Besides, the comparative toxicity varied significantly for water samples pretreated with different methods due to the effect of inorganic DBPs and a synergistic effect of organic and inorganic DBPs. The new approach revealed that the bromide-rich source water disinfected with ozone caused the highest developmental toxicity, followed by those disinfected with chlorine, chlorine dioxide, and chloramine in that order.

Jianping Xu, Xiaoyan Liu, Sheng Yang, Xiangru Zhang, Yuankai Shi Department of Medical Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing Key Laboratory of Clinical Study on Anticancer Molecular Targeted Drugs, Beijing, People’s Republic of China Background: Treatment failure frequently occurs in patients with epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) who respond to EGFR tyrosine kinase inhibitors initially. This retrospective study tried to investigate the efficacy and safety of apatinib plus icotinib in patients with advanced NSCLC after icotinib treatment failure.Patients and methods: This study comprised 27 patients with advanced NSCLC who had progressed after icotinib monotherapy. Initially, patients received oral icotinib (125mg, tid) alone. When the disease progressed, they received icotinib plus apatinib (500mg, qd, orally). Treatment was continued until disease progression, unacceptable toxicity or consent withdrawal.Results: Followed up to December 2016, the median time of combined therapy was 7.47months, and eight of 27 patients were dead. The median overall survival was not reached, and median progression-free survival (PFS) was 5.33months (95% CI, 3.63–7.03months). Moreover, the objective response rate (ORR) was 11.1%, and the disease control rate (DCR) was 81.5%. A total of 14 patients received combined therapy as the second-line treatment, and the ORR and DCR were 7.1% and 78.6%, respectively; 13 patients received drugs as the third- or later-line treatment, with an ORR and a DCR of 15.4% and 84.6%, respectively. In addition, 11 patients experienced icotinib monotherapy failure within 6months with median PFS of 7.37months, and 16 patients had progression after 6months with median PFS of 2.60months. The common drug-related toxic effects were hypertension (44.4%) and fatigue (37.0%).Conclusion: Apatinib plus icotinib is efficacious in treating patients with advanced NSCLC after icotinib treatment failure, with acceptable toxic effects. Keywords: epidermal growth factor receptor mutation, non-small cell lung cancer, apatinib, icotinib, efficacy

When a bromide-containing water is treated by the ultraviolet (UV)/chlorine process, hydroxyl radicals (HO) and halogen radicals such as Cl or Br are formed due to the UV photolysis of free halogens. These reactive species may induce the formation of bromate, which is a probable human carcinogen. Bromate formation in the UV/chlorine process using low pressure (LP) and medium pressure (MP) lamps in the presence of bromide was investigated in the present study. The UV/chlorine process significantly enhanced bromate formation as compared to dark chlorination. The bromate formation was elevated with increasing UV fluence, bromide concentration, and pH values under both LP and MP UV irradiations. It was significantly enhanced at pH 9 compared to those at pH 6 and 7 with MP UV irradiation, while it was slightly enhanced at pH 9 with LP UV. The formation by UV/chlorine process started with the formation of free bromine (HOBr/OBr-) through the reaction of chlorine and bromide, followed by a subsequent oxidation of free bromine and formation of BrO and bromate by reacting with radicals.

On-line chemical cleaning with sodium hypochlorite (NaClO) has been extensively practiced for maintaining the stable permeability of membrane bioreactor (MBR), during which activated sludge is inevitably exposed to NaClO. The authors previously reported the NaClO-induced generation of dissolved organic matter (DOM) and halogenated byproducts, however their fate in terms of biodegradability and removability in MBR has been unknown. Therefore, this study investigated the removal mechanisms of generated DOM and byproducts in an aerobic MBR. It was found that about 39% of DOM produced was removed through biodegradation and membrane rejection. The fluorescence excitation-emission matrix (EEM) coupled with parallel factor analysis (PARAFAC) also revealed that protein-like substances were more readily biodegradable than humic-like substances. Moreover, 25 kinds of chlorinated and brominated byproducts were detected after the contact of biomass with NaClO by ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry, while nine of which were confirmed with standard compounds. 62.4–84.5% halogenated byproducts were ended up in permeate of MBR chemically cleaned with 5–20 mg/L of NaClO. This study raises a serious concern on reusing and recycling of such MBR permeate.

Chlorine dioxide (ClO2) is a widely used alternative disinfectant due to its high biocidal efficiency and low-level formation of trihalomethanes and haloacetic acids. A major portion of total organic halogen (TOX), a collective parameter for all halogenated DBPs, formed in ClO2-treated drinking water is still unknown. A commonly used pretreatment method for analyzing halogenated DBPs in drinking water is one-time liquid-liquid extraction (LLE), which may lead to a substantial loss of DBPs prior to analysis. In this study, characterization and identification of polar halogenated DBPs in a ClO2-treated drinking water sample were conducted by pretreating the sample with multiple extractions. Compared to one-time LLE, the combined four-time LLEs improved the recovery of TOX by 2.3 times. The developmental toxicity of the drinking water sample pretreated with the combined four-time LLEs was 1.67 times higher than that pretreated with one-time LLE. With the aid of ultra-performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry, a new group of polar halogenated DBPs, trihalomethanols, were detected in the drinking water sample pretreated with multiple extractions; two of them, trichloromethanol and bromodichloromethanol, were identified with synthesized standard compounds. Moreover, these trihalomethanols were found to be the transformation products of trihalomethanes formed during ClO2 disinfection. The results indicate that multiple LLEs can significantly improve extraction efficiencies of polar halogenated DBPs and is a better pretreatment method for characterizing and identifying new polar halogenated DBPs in drinking water.

Chlorine disinfection is a vital treatment process to inactivate pathogens, but it also generates numerous halogenated disinfection byproducts (DBPs) via reactions with halides and natural organic matter (NOM). Epidemiological studies have shown that consumption of chlorinated drinking water with halogenated DBPs is related to increased spontaneous abortions, stillbirth, birth defects, and bladder and colorectal cancers. To control DBPs, efforts have been devoted to minimizing the formation of DBPs by removing the major DBP precursor, NOM, or by adopting alternative disinfectants. Notably, the precursor removal may not be very effective and the application of alternative disinfectants may generate their own sets of DBPs. It has remained a grand challenge to develop a new DBP control strategy which can effectively decrease the DBP formation and reduce the health risks of chlorinated drinking water. To solve this problem, Zhang’s group reported a new approach to effectively control halogenated DBPs by removing intermediate aromatic halogenated DBPs, which were formed from chlorine disinfection, via granular activated carbon (GAC) adsorption.

Chlorination is extensively applied for disinfecting sewage effluents, but it unintentionally generates disinfection byproducts (DBPs). Using seawater for toilet flushing introduces a high level of bromide into domestic sewage. Chlorination of sewage effluent rich in bromide causes the formation of brominated DBPs. The objectives of achieving a disinfection goal, reducing disinfectant consumption and operational costs, as well as diminishing adverse effects to aquatic organisms in receiving water body remain a challenge in sewage treatment. In this study, we have demonstrated that, with the same total chlorine dosage, a three-step chlorination (dosing chlorine by splitting it into three equal portions with a 5-min time interval for each portion) was significantly more efficient in disinfecting a primary saline sewage effluent than a one-step chlorination (dosing chlorine at one time). Compared to one-step chlorination, three-step chlorination enhanced the disinfection efficiency by up to 0.73-log reduction of Escherichia coli. The overall DBP formation resulting from one-step and three-step chlorination was quantified by total organic halogen measurement. Compared to one-step chlorination, the DBP formation in three-step chlorination was decreased by up to 23.4%. The comparative toxicity of one-step and three-step chlorination was evaluated in terms of the development of embryo-larva of a marine polychaete Platynereis dumerilii. The results revealed that the primary sewage effluent with three-step chlorination was less toxic than that with one-step chlorination, indicating that three-step chlorination could reduce the potential adverse effects of disinfected sewage effluents to aquatic organisms in the receiving marine water.

Water disinfection can result in the unintended formation of halogenated disinfection byproducts (DBPs), which have been the subject of intensive investigation over the past 40 years. Robust methods for evaluating and characterizing the formation of halogenated DBPs are prerequisites for ultimately controlling the formation of DBPs and ensuring quality and safe disinfected water. Only a fraction of the total organic halogen (TOX) formed during disinfection has been chemically identified or even well characterized by the classical (derivatization-)gas chromatography/mass spectrometry (GC/MS) method. Such a method may not be amenable to the detection of polar halogenated DBPs, which constitute a major portion of the TOX that is still unaccounted for. Accordingly, a novel precursor ion scan (PIS) method using (liquid chromatography/) electrospray ionization-triple quadrupole mass spectrometry was developed for the rapid selective detection of all polar halogenated DBPs-no matter whether the DBPs are known or unknown-in water. This article reviews recent literature on the application of the PIS method for evaluating the occurrence, formation and control of polar halogenated DBPs in disinfected waters. The challenges in developing the PIS method were briefly summarized. Application of the powerful method pinpointed >150 previously unknown DBPs and revealed the formation, speciation and transformation of halogenated DBPs in disinfected drinking water, wastewater effluents, and swimming pool water. For the same source water, positive correlations were found between the total ion intensity (TII) levels in the PIS spectra of m/z 35/79/126.9 and the total organic chlorine/bromine/iodine levels in the disinfected water sample, and a disinfected sample with a higher TII level generally showed a higher toxic potency. Accordingly, the TII value can be used as a surrogate to comparatively reflect the water quality and assess the efficiency of a DBP control approach. To achieve a more comprehensive and systematic understanding of the DBP compositions in different waters and thus better control the DBP formation and reduce their overall toxicity, topics for future work were discussed.

Edible salt is essential to the health of humans and serves as a seasoning universally. Besides chloride, edible salt also contains other anions such as bromide, fluoride, sulfate, and carbonate due to incomplete removal during raw salt refinement. In a household cooking (e.g., soup making) process, a chlorine/monochloramine residual in tap water could react with bromide in edible salt and organic matter in food (e.g., rice, wheat) to form numerous brominated disinfection byproducts (Br-DBPs) at significant levels, which might induce adverse health effects to human beings. In this study, we solicited 20 edible salts of different types (i.e., sea salts, well and rock salts, lake salts, and bamboo salts) from nine countries and determined their bromide levels to be 67–375 mg/kg, with an average level of 173 mg/kg. A total of 25 polar Br-DBPs were detected and identified with structures/formulae in cooking water samples using ultra performance liquid chromatography/electrospray ionization-triple quadruple mass spectrometry (UPLC/ESI-tqMS) and high-resolution mass spectrometry. Effects of cooking conditions (e.g., disinfectant type and level, edible salt dose, organic matter type and dose, sequence and time interval of adding organic matter and salt, etc.) on the formation of polar Br-DBPs were investigated, and optimized cooking conditions with minimized formation of polar Br-DBPs were determined. Further aided with an Hep G2 cell cytotoxicity assay, it was found that the overall cytotoxicity of chlorinated and chloraminated cooking water samples prepared after cooking condition optimization was reduced by 57% and 22%, respectively, compared with those prepared before cooking condition optimization.

The Qarhan Salt Lake (QSL) in the Qaidam Basin in western China is the largest brine potash deposit in the world. The formation of MgSO4-deficient evaporites in the QSL, whether from the evaporation of river waters with high Na+ and Cl− levels, bacterial sulfate reduction (BSR) in brines resulting in SO42− depletion, or the mixing of the river and spring waters, remains controversial. The δ34S values of 33 intercrystalline brines and 10 gypsum samples from a sediment core (ISL1A) collected in the QSL were presented in this study. Combining these results with previously reported major ionic concentrations, total dissolved solids (TDS) and δ34S values of different waters, and 87Sr/86Sr ratios of sediments, it was concluded that (1) δ34S values of the intercrystalline brines (+6.7‰ to +12.1‰) and gypsum (+8.1‰ to +10.1‰) suggested that the BSR was insignificant in the QSL. These values were dominated by those of inflowing waters and the evaporation process; (2) river waters with high Na+ and Cl− levels were unable to form MgSO4-deficient evaporites in the QSL. A strong positive correlation of Na and Cl equivalents coupled with high (Na+ + Cl−)/TDS ratios suggested that the large amount of solutes in Golmud River waters results from the dissolution of halite rather than the chemical weathering of rocks; and (3) the flowing system of the river and spring in the past 50 kyr was similar to the modern supplying system, and mixing of river and spring waters was responsible for the precipitation of evaporites in the QSL.