Multimedia distribution and release characteristics of emerging PFAS in wastewater treatment plants in Tianjin, China.

Legacy and emerging PFAS in the air, wastewater, and sludge from two wastewater treatment plants (WWTPs) in Tianjin were investigated in this study. The semi-quantified nontarget PFAS accounted for up to 99 % of Æ©PFAS in the gas phase, and aqueous film-forming foam (AFFF)-related PFAS were predominant in wastewater (up to 2250 ng/L, 79 % of Æ©PFAS) and sludge (up to 4690 ng/g, 95 % of Æ©PFAS). Furthermore, field-derived air particle-gas, air-wastewater, and wastewater particle-wastewater distribution coefficients of emerging PFAS are characterized, which have rarely been reported. The emerging substitute p-perfluorous nonenoxybenzenesulfonate (OBS) and AFFF-related cationic and zwitterionic PFAS show a stronger tendency to partition into particle phase in air and wastewater than perfluorooctane sulfonic acid (PFOS). The estimated total PFAS emissions from the effluent and sludge of WWTP A were 202 kg/y and 351 kg/y, respectively. While the target PFAS only accounted for 20-33 % of the total emissions, suggesting a significant underestimation of environmental releases of the nontarget PFAS and unknown perfluoroalkyl acid precursors through the wastewater and sludge disposal. Overall, this study highlights the importance of comprehensive monitoring and understanding the behavior of legacy and emerging PFAS in wastewater systems, and fills a critical gap in our understanding of PFAS exposure.

Nontarget Screening and Fate of Emerging Per- and Polyfluoroalkyl Substances in Wastewater Treatment Plants in Tianjin, China.

Wastewater treatment plants (WWTPs) are typical point sources of per- and polyfluoroalkyl substances (PFAS) released into the environment. The suspect and nontarget screening based on gas chromatography or liquid chromatography-high resolution mass spectrometry were performed on atmosphere, wastewater, and sludge samples collected from two WWTPs in Tianjin to discover emerging PFAS and their fate in this study. A total of 40 PFAS (14 neutral and 26 ionic) and 64 PFAS were identified in the atmosphere and wastewater/sludge, respectively, among which 5 short-chain perfluoroalkyl sulfonamide derivatives, 4 ionic PFAS, and 15 aqueous film-forming foam-related cationic or zwitterionic PFAS have rarely or never been reported in WWTPs in China. Active air sampling is more conducive to the enrichment of emerging PFAS, while passive sampling is inclined to leave out some ultrashort-chain PFAS or unstable transformation intermediates. Moreover, most precursors and intermediates could be enriched in the atmosphere at night, while the PFAS associated with aerosols with high water content or particles enter the atmosphere easily during the day. Although most emerging PFAS could not be eliminated efficiently in conventional treatment units, deep bed filtration and advanced oxidation processes could partly remove some emerging precursors.

Target and nontarget analysis of per- and polyfluoroalkyl substances in surface water, groundwater and sediments of three typical fluorochemical industrial parks in China.

The objectives of this study were to identify both legacy and emerging per- and polyfluoroalkyl substances (PFAS) from three typical fluoridated industrial parks (FIPs) in China, and to assess their environmental occurrence and fate. Complementary suspect target and nontarget screening were implemented, and a total of 111 emerging PFAS were identified. Based on the multi-mass scale analysis, 25 emerging PFAS were identified for the first time, including 24 per- and polyfluoroalkyl ether carboxylic acids (PFECAs) and 1 ultra-short chlorinated perfluoroalkyl carboxylic acids (Cl-PFCAs, C2), with a maximum percentage of 48.2 % in nontarget PFAS (exclude target PFAS). The composition of PFAS identified in different media was influenced by functional groups, carbon chain length, substituents and ether bond insertion, with poly-hydrogen substituted being preferably in water and a more diverse pattern of PFECAs in sediments. The patterns of PFAS homologs revealed distinct differences among the three typical FIPs in the shift of PFAS production patterns. The C4-PFAS and short-chain carboxylic acids (≤C6) were the main PFAS in the Fuxin and Changshu, respectively. In contrast, perfluorooctanoic acid (PFOA, C8) remained dominant in Zibo, and the highest point concentrations in water and sediment were up to 706 µg/L and 553 µg/g, respectively.

Degradation of Perfluorooctanoic Acid by Chlorine Radical Triggered Electrochemical Oxidation System.

Electrochemical oxidation (EO) has been shown to have the unique ability to degrade perfluorooctanoic acid (PFOA), although the radical chemistry involved in this degradation is unclear, particularly in the presence of chloride ions (Cl-). In this study, reaction kinetics, free radical quenching, electron spin resonance, and radical probes were used to examine the roles of ·OH and reactive chlorine species (RCS, including Cl·, Cl2•-, and ClO·) in the EO of PFOA. Using EO in the presence of NaCl, PFOA degradation rates of 89.4%-94.9% and defluorination rates of 38.7%-44.1% were achieved after 480 min with PFOA concentrations ranging from 2.4 to 240 µM. The degradation occurred via the synergistic effect of ·OH and Cl· rather than through direct anodic oxidation. The degradation products and density functional theory (DFT) calculations revealed that Cl· triggered the first step of the reaction, thus the initial direct electron transfer was not the rate-limiting step of PFOA degradation. The change in Gibbs free energy of the reaction caused by Cl· was 65.57 kJ mol-1, which was more than two times lower than that triggered by ·OH. However, ·OH was involved in the subsequent degradation of PFOA. The synergistic effect of Cl· and ·OH in PFOA degradation is demonstrated for the first time in this study, which is promising for the development of electrochemical technology to remove perfluorinated alkyl substances from the environment.

Glucose facilitates the acclimation of organohalide-respiring bacteria.

Organohalide respiring bacteria (OHRB) are the mainstay for bioremediation of organohalide contaminated sites. Enrichment screening of OHRB is prerequisite for the development of high performance dehalogenating bacterial agents. Herein, different domestication strategies were formulated for the main factors (nutrients and inocula) affecting the enrichment of OHRB, and the dehalogenation effect was verified with 2-chlorophenol and per/polyfluoroalkyl substances. The nutrients had a greater impact on the dehalogenation of the systems relative to the inocula, where the combination of glucose and anaerobic sludge (Glu-AS) had a faster degradation rate (26 ± 2.5 µmol L-1 d-1) and more complete dechlorination effectiveness. Meanwhile, the dehalogenation results for perfluorooctanoic acid and trifluoroacetic acid showed the biological defluorination was closely related to the position of fluoride. Further, the microbial community structure profiled the resource competition, metabolic cross-feeding and nutrient dynamic exchange among fermenting bacteria, OHRB and methanogenic bacteria under different domestication strategies as endogenous factors affecting the dehalogenation performance, and speculated a hypothetical model for the interaction of different functional bacteria. Our research contributed guidelines and references for the development of efficient dehalogenating bacterial agents, and provided scientific theoretical and technical support for promoting the maximum efficiency of bioremediation of organohalogenated sites.

Sulfidated zero valent iron as a persulfate activator for oxidizing organophosphorus pesticides (OPPs) in aqueous solution and aged contaminated soil columns.

Sulfidation treatment is an effective method of improving the catalytic performance of zero-valent iron (ZVI). Here, we prepared sulfidated, micro-sized ZVI (S-mZVI) using ball milling technology to activate persulfate (PS) with the goal of oxidizing organophosphorus pesticides (OPPs) in aqueous solution and aged OPP-contaminated soil columns. Energy dispersive spectroscopy (EDS), X-ray powder diffraction (XRD) and X-ray photoelectron spectrometry (XPS) analyses uncovered the formation of Fe2O3, FeOOH, FeS and FeS2 in the S-mZVI prepared by ball milling with different proportions of elemental S powder to make micro-sized ZVI particles. The presence of sulfur can regulate the morphology of S-mZVI with a dispersed and spherical shape, and it can improve the activation performance of PS. In aqueous solution, 11.2 mg of S-mZVI activated 2.5 mM PS (S-mZVI-PS) with an S/Fe molar ratio of 0.100, and it was the best at activating PS, leading to oxidation-rate constants of 0.030 s-1 for 10 mg/L phorate and 0.026 s-1 for 10 mg/L terbufos, which were much greater than those of the other S-mZVI and mZVI. The results of the soil column experiment showed that the PS, which had a low consumption for the total dosage, achieved higher degradation percentages among the three OPPs in the S-mZVI-PS treatment than those in the mZVI-PS treatment over 120 h, with the best performance achieved by oxidizing 69.7% phorate, 48.0% terbufos and 60.6% aminoparathion. The effluent concentrations of the three OPPs in the S-mZVI-PS treatment were significantly lower than those in the mZVI-PS treatment, while dissolved total iron and Fe(II) displayed the opposite results. These results indicate that S-mZVI prepared by ball milling can effectively activate PS and be applied to remediate OPP-contaminated soil.

A review of Deuterixys Mason from China, with description of three new species (Hymenoptera, Braconidae, Microgastrinae).

The genus Deuterixys Mason, 1981 (Hymenoptera, Braconidae, Microgastrinae) is revised for China, with three new species described: D. jilinensis Zheng Song, sp. nov., D. longitarsus Zheng Song, sp. nov. and D. shennongensis Zheng Song, sp. nov. A key to the Old World species of Deuterixys is presented.

A new species of Glyptapanteles Ashmead (Hymenoptera, Braconidae, Microgastrinae) within Macrobrochis gigas (Lepidoptera, Arctiidae, Lithosiidae) in Fujian, China.

The south-east coastal area of Fujian, China, belongs to the Oriental Realm, and is characterized by a high insect species richness. In this work, a new species of Hymenopteran parasitoid, Glyptapanteles gigas Liang & Song, sp. nov. found in Jinjiang within hosts of caterpillars Macrobrochis gigas (Lepidoptera: Arctiidae), is described and illustrated, with differences from similar species. Additionally, we presumed that both parasitoid and host species play very important role in the coevolution and tritrophic interaction between plants, phytophagous insects, and their parasitoids, because these insects probably broke the sporangia and made contributions to their colonization, or some spores were spread for long distances by adult moths after their emergence, or some parasitoids were attracted by the eggs and larvae of these caterpillars, which was also thought to be helpful to spread of spores.

Two new species of the genus Microplitis Förster, 1862 (Hymenoptera, Braconidae, Microgastrinae) from China.

Two new species of Microplitis Förster, 1862, M.bomiensis Zhang, sp. nov., and M.paizhensis Zhang, sp. nov. from Tibet, China are described and illustrated. A key to the species of the genus Microplitis Förster from China is added.

Performance of graphite felt as a cathode and anode in the electro-Fenton process.

Choosing an electrode material with good performance and low cost is of great significance for the practical application of the electro-Fenton process. In this study, graphite felt was systematically studied to determine its application performance in an electro-Fenton system. The influence of operating parameters, pH and voltage, on the H2O2 yield and the evolution of iron ions was investigated, which helped to select the optimal parameter values. The removal rate of methylene blue was 97.8% after 20 min electrolysis under the conditions of 7 V voltage and pH 3. Inhibition experiments showed the graphite felt E-Fenton system mainly relied on the indirect oxidation of ·OH and the direct oxidation of the graphite felt anode to degrade the methylene blue. The graphite felt showed good stability as a cathode during repeated use, but the anode conductivity and catalytic performance were decreased, and the adsorption performance was enhanced. Finally, the graphite felt electrode was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and X-ray photoelectron spectroscopy (XPS) to preliminarily analyze the reason for the change in anode performance.

Revision of Microplitis species from China with description of a new species.

Microplitis bicoloratus Chen 2004 is a synonym of Microplitis prodeniae Rao & Kurian 1950, and is also the junior homonym of Microplitis bicoloratus Xu & He 2003. A new species, Microplitis fujianica sp. nov. is described and illustrated. The new species is compared with its related species from the Oriental region.