A broad range of organic compounds are known to exist in drinking water sources and serve as precursors of disinfection byproducts(DBPs).Epidemiological findings of an association of increased risk of bladder cancer with the consumption of chlorinated water has resulted in health concerns about DBPs.Peptides are thought to be an important category of DBP precursors in water.However,little is known about the actual presence of peptides and their DBPs in drinking water because of their high sample complexity and low concentrations.To address this challenge and identify peptides and non-chlorinated/chlorinated peptide DBPs from large sets of organic compounds in water,we developed a novel high throughput analysis strategy,which integrated multiple solid phase extraction(SPE),high performance liquid chromatography(HPLC)separation,and non-target identification using precursor ion exclusion(PIE)high resolution mass spectrometry(MS).After MS analysis,structures of candidate compounds,particularly peptides,were obtained by searching against the Human Metabolome Database(HMDB).Using this strategy,we successfully detected 625 peptides(out of 17,205 putative compounds)and 617 peptides(out of 13,297)respectively in source and finished water samples.The source and finished water samples had 501 peptides and amino acids in common.The remaining 116 peptides and amino acids were unique to the finished water.From a subset of 30 putative compounds for which standards were available,25 were confirmed using HPLC-MS analysis.By analyzing the peptides identified in source and finished water,we successfully confirmed three disinfection reaction pathways that convert peptides into toxic DBPs. 相似文献
Tetracycline-resistant bacteria (TRB) are of concern as emerging microbial contaminants in reclaimed water. To understand the effects of UV disinfection on TRB, both inactivation and reactivation profiles of TRB, as well as 16 tetracycline-resistant isolates from secondary effluent, were characterized in this study. The inactivation ratio of TRB was significantly lower (3.0-log) than that of heterotrophic bacteria (> 4.0-log) in the secondary effluent. Additionally, the proportion of TRB significantly increased from 1.65% to 15.51% under 20 mJ/cm2 ultraviolet (UV) exposure. The inactivation rates of tetracycline-resistant isolates ranged from 0.57/s to 1.04/s, of which tetracycline-resistant Enterobacter-1 was the most tolerant to UV light. The reactivation of TRB, tetracycline-resistant isolated strains, as well as heterotrophic bacteria commonly occurred in the secondary effluent even after 20 mJ/cm2 UV exposure. The colony forming ability of TRB and heterotrophic bacteria reached 3.2-log and 3.0-log under 20 mJ/cm2 UV exposure after 22 hr incubation. The final inactivation ratio of tetracycline-resistant Enterobacter-1 was 1.18-log under 20 mJ/cm2 UV exposure after 22 hr incubation, which is similar to those of TRB (1.18-log) and heterotrophic bacteria (1.19-log). The increased proportion of TRB and the reactivation of tetracycline-resistant enterobacteria in reclaimed water could induce a microbial health risk during wastewater reuse. 相似文献
Environmental Science and Pollution Research - Soil organic matter (SOM) and its fraction play an important role in maintaining and improving soil fertility of paddy field. However, there is still... 相似文献
Environmental Geochemistry and Health - Pharmaceutically active compounds (PhACs) released into the environment have an adverse impact on the soil and water ecosystem as well as human health.... 相似文献
Various geographical duckweed isolates have been developed for phytoremediation of lead. The Pb2+ removal efficiency of Lemna aequinoctialis, Landoltia punctata, and Spirodela polyrhiza was investigated in monoculture and polyculture at different levels of pH and initial Pb2+ concentrations. L. aequinoctialis was not sensitive to the tested pH but significantly affected by initial Pb2+ concentration, whereas synergistic effect of pH and initial Pb2+ concentration on removal efficiency of L. punctata and S. polyrhiza was found. Although the majority of polycultures showed median removal efficiency as compared to respective monocultures, some of the polycultures achieved higher Pb2+ removal efficiencies and can promote population to remove Pb2+. Besides, the three duckweed strains could be potential candidates for Pb2+ remediation as compared to previous reports. Conclusively, this study provides useful references for future large-scale duckweed phytoremediation.
This paper develops a new crop mapping method through combined utilization of both time and frequency information based on wavelet variance and Jeffries–Matusita (JM) distance (CIWJ for short). A two-dimensional wavelet spectrum was obtained from datasets of daily continuous vegetation indices through a continuous wavelet transform using the Mexican hat and the Morlet mother wavelets. The time-average wavelet variance (TAWV) and the scale-average wavelet variance (SAWV) were then calculated based on the wavelet spectrum of the Mexican hat and the Morlet wavelet, respectively. The class separability based on the JM distance was evaluated to discriminate the proper period or scale range applied. Finally, a procedure for criteria quantification was developed using the TAWV and SAWV as the major metrics, and the similarity between unclassified pixels and established land use/cover types was calculated. The proposed CIWJ method was applied to the middle Hexi Corridor in northwest China using 250-m 8-day composite moderate-resolution imaging spectroradiometer (MODIS) enhanced vegetation index (EVI) time series datasets in 2012. The CIWJ method was shown to be efficient in crop field mapping, with an overall accuracy of 83.6 % and kappa coefficient of 0.7009, assessed with 30 m Chinese Environmental Disaster Reduction Satellite (HJ-1)-derived data. Compared with methods utilizing information on either frequency or time, the CIWJ method demonstrates tremendous potential for efficient crop mapping and for further applications. This method could be applied to either coarse or high spatial resolution images for agricultural crop identification, as well as other more general or specific land use classifications. 相似文献
To fulfill the requirements of Guidelines for approval of ballast water management system (G8), a set of onshore ballast water treatment equipment utilizing micro-pore ceramic filtration (MPCF) and UV radiation
(MPCF&UV) system was designed and set up with a maximum flow rate of 80 m3·h−1. Technical feasibilities of MPCF&UV system were evaluated in three areas: removal efficiencies of indicator organism and
oceanic bacteria, perdurability of a ceramic filter, and application on native seawater. The results showed that no indicator
organism (Dunaliella) or oceanic bacteria was detected after treatment of 20 L MPCF and UV radiation at 1.3×104 μW·s·cm−2. A 20 L ceramic filter can run continuously for 5.3 h at the flow rate of 15 m3·h−1 before its pressure drop up to 0.195 MPa. The removal percentage of total plankton amounts were 91.9% at a flow rate of 70
m3·h−1 by 80 L MPCF and UV radiation at 1.3×104 μW·s·cm−2. 相似文献