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Effect of ultraviolet irradiation and chlorination on ampicillin-resistant

Yuchen PANG,Jingjing HUANG,Jinying XI,Hongying HU,Yun ZHU

《环境科学与工程前沿（英文）》 2016年第10卷第3期页码 522-530 doi: 10.1007/s11783-015-0779-9

摘要： Antibiotic resistance is a serious public health risk that may spread via potable and reclaimed water. Effective disinfection is important for inactivation of antibiotic-resistant bacteria and disruption of antibiotic resistance genes. Ampicillin is a widely prescribed antibiotic but its effectiveness is increasingly undermined by resistance. In this study, changes in ampicillin resistance for ( ) CGMCC 1.1595 were analyzed after exposure to different doses of ultraviolet (UV) or chlorine, and damage incurred by the plasmid encoding ampicillin resistance gene was assessed. We reported a greater stability in ampicillin-resistant CGMCC 1.1595 after UV irradiation or chlorination when compared with previously published data for other strains. UV irradiation and chlorination led to a shift in the mortality frequency distributions of ampicillin-resistant when subsequently exposed to ampicillin. The ampicillin hemi-inhibitory concentration (IC ) without disinfection was 3800 mg·L , and an increment was observed after UV irradiation or chlorination. The IC of ampicillin-resistant was 1.5-fold higher at a UV dose of 40 mJ·cm , and was 1.4-fold higher when exposed to 2.0 mg·L chlorine. These results indicate that UV irradiation and chlorination can potentially increase the risk of selection for strains with high ampicillin resistance. There was no evident damage to after 1–10 mg Cl ·L chlorination, while a UV dose of 80 mJ·cm yielded a damage ratio for of approximately 1.2-log. Therefore, high UV doses are required for effective disruption of antibiotic resistance genes in bacteria.

关键词： antibiotic resistance Escherichia coli ampicillin resistance gene ultraviolet irradiation chlorination

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Microbial responses to the use of NaClO in sediment treatment

《环境科学与工程前沿（英文）》 2022年第16卷第2期 doi: 10.1007/s11783-021-1451-1

摘要：

• Chlorine addition enhanced the release of TOC, TN from the sediment.

关键词： Sediment chlorination Substance mobility Microbial response Community composition Function

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Haloacetic acids in swimming pool and spa water in the United States and China

Xiaomao WANG,Garcia Leal M I,Xiaolu ZHANG,Hongwei YANG,Yuefeng XIE

《环境科学与工程前沿（英文）》 2014年第8卷第6期页码 820-824 doi: 10.1007/s11783-014-0712-7

摘要： The objective of this study is to investigate the occurrence of haloacetic acids (HAAs), a group of disinfection byproducts, in swimming pool and spa water. The samples were collected from six indoor pools, six outdoor pools and three spas in Pennsylvania, the United States, and from five outdoor pools and nine indoor pools in Beijing, China. Five HAAs (HAA5), including monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, and dibromoacetic acid were analyzed. Total chlorine, pH and total organic carbon concentration were analyzed as well. Results indicated that the levels of HAA5 in swimming pools and spas in the United States ranged from 70 to 3980 μg·L , with an arithmetic average at 1440 μg·L and a median level at 1150 μg·L . These levels are much higher than the levels reported in chlorinated drinking water and are likely due to organic matters released from swimmers’ bodies. The levels of HAA5 in swimming pools in China ranged from 13 to 332 μg·L , with an arithmetic average at 117 μg·L and a median level at 114 μg·L . The lower HAA levels in swimming pools in China were due to the lower chlorine residuals. Results from this study can help water professionals to better understand the formation and stability of HAAs in chlorinated water and assess risks associated with exposures to HAAs in swimming pools and spas.

关键词： chlorination disinfection byproduct haloacetic acid swimming pool trihalomethane

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Formation of disinfection byproducts from accumulated soluble products of oleaginous microalga after chlorination

Yu Liu, Qiao Zhang, Yu Hong

《环境科学与工程前沿（英文）》 2017年第11卷第6期 doi: 10.1007/s11783-017-0938-2

摘要： When microalgae are simultaneously applied for wastewater treatment and lipid production, soluble algal products (SAP) should be paid much attention, as they are important precursors for formation of disinfection byproducts (DBPs), which have potential risks for human health. sp. HQ is an oleaginous microalga that can generate SAP during growth, especially in the exponential phase. This study investigated the contribution of SAP from sp. HQ to DBP formation after chlorination. The predominant DBP precursors from SAP were identified with the 3D excitation-emission matrix fluorescence. After chlorination, a significant reduction was observed in the fluorescence intensity of five specific fluorescence regions, particularly aromatic proteins and soluble microbial by-product-like regions, accompanied with slight shifting of the peak. The produced DBPs were demonstrated to include trihalomethanes and haloacetic acids. As the algal cultivation time was extended in wastewater, the accumulated SAP strengthened the formation of DBPs. The trend for DBP formation was as follows: chloroform>dichloroacetic acid>trichloroacetic acid.

关键词： Chlorella sp. HQ Chlorination Disinfection byproducts Fluorescence spectroscopy Soluble algal products

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Degradation of extracellular genomic, plasmid DNA and specific antibiotic resistance genes by chlorination

Menglu Zhang, Sheng Chen, Xin Yu, Peter Vikesland, Amy Pruden

《环境科学与工程前沿（英文）》 2019年第13卷第3期 doi: 10.1007/s11783-019-1124-5

摘要：

Extracellular DNA structure damaged by chlorination was characterized.

Integrity of extracellular ARG genetic information after chlorination was determined.

Typical chlorine doses will likely effectively diminish extracellular DNA and ARGs.

Plasmid DNA/ARGs were less readily broken down than genomic DNA.

The Bioanalyzer methodology effectively documented damage incurred to DNA.

关键词： Antibiotic resistance Antibiotic resistance genes (ARGs) Extracellular DNA/ARGs Chlorination

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Biofiltration and disinfection codetermine the bacterial antibiotic resistome in drinking water: A review and meta-analysis

Kun Wan, Wenfang Lin, Shuai Zhu, Shenghua Zhang, Xin Yu

《环境科学与工程前沿（英文）》 2020年第14卷第1期 doi: 10.1007/s11783-019-1189-1

摘要： Published data was used to analyze the fate of ARGs in water treatment. Biomass removal leads to the reduction in absolute abundance of ARGs. Mechanism that filter biofilm maintain ARB/ARGs was summarized. Potential BAR risks caused by biofiltration and chlorination were proposed. The bacterial antibiotic resistome (BAR) is one of the most serious contemporary medical challenges. The BAR problem in drinking water is receiving growing attention. In this study, we focused on the distribution, changes, and health risks of the BAR throughout the drinking water treatment system. We extracted the antibiotic resistance gene (ARG) data from recent publications and analyzed ARG profiles based on diversity, absolute abundance, and relative abundance. The absolute abundance of ARG was found to decrease with water treatment processes and was positively correlated with the abundance of 16S rRNA (r2 = 0.963, p<0.001), indicating that the reduction of ARG concentration was accompanied by decreasing biomass. Among treatment processes, biofiltration and chlorination were discovered to play important roles in shaping the bacterial antibiotic resistome. Chlorination exhibited positive effects in controlling the diversity of ARG, while biofiltration, especially granular activated carbon filtration, increased the diversity of ARG. Both biofiltration and chlorination altered the structure of the resistome by affecting relative ARG abundance. In addition, we analyzed the mechanism behind the impact of biofiltration and chlorination on the bacterial antibiotic resistome. By intercepting influent ARG-carrying bacteria, biofilters can enrich various ARGs and maintain ARGs in biofilm. Chlorination further selects bacteria co-resistant to chlorine and antibiotics. Finally, we proposed the BAR health risks caused by biofiltration and chlorination in water treatment. To reduce potential BAR risk in drinking water, membrane filtration technology and water boiling are recommended at the point of use.

关键词： Drinking water treatment Antibiotic resistance gene Biofiltration Chlorination

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precursors and theoretical toxicity evaluation of byproducts driving cytotoxicity and genotoxicity in chlorination

Qian-Yuan Wu, Yi-Jun Yan, Yao Lu, Ye Du, Zi-Fan Liang, Hong-Ying Hu

《环境科学与工程前沿（英文）》 2020年第14卷第2期 doi: 10.1007/s11783-019-1204-6

摘要： • NOM formed more C-DBPs while amino acids formed more N-DBPs during chlorination • Aspartic acid and asparagine showed the highest toxicity index during chlorination • Dichloroacetonitrile might be a driving DBP for cytotoxicity and genotoxicity • Dichloroacetonitrile dominated the toxicity under different chlorination conditions Chlorination, the most widely used disinfection process for water treatment, is unfortunately always accompanied with the formation of hazardous disinfection byproducts (DBPs). Various organic matter species, like natural organic matter (NOM) and amino acids, can serve as precursors of DBPs during chlorination but it is not clear what types of organic matter have higher potential risks. Although regulation of DBPs such as trihalomethanes has received much attention, further investigation of the DBPs driving toxicity is required. This study aimed to identify the important precursors of chlorination by measuring DBP formation from NOM and amino acids, and to determine the main DBPs driving toxicity using a theoretical toxicity evaluation of contributions to the cytotoxicity index (CTI) and genotoxicity index (GTI). The results showed that NOM mainly formed carbonaceous DBPs (C-DBPs), such as trichloromethane, while amino acids mainly formed nitrogenous DBPs (N-DBPs), such as dichloroacetonitrile (DCAN). Among the DBPs, DCAN had the largest contribution to the toxicity index and might be the main driver of toxicity. Among the precursors, aspartic acid and asparagine gave the highest DCAN concentration (200 g/L) and the highest CTI and GTI. Therefore, aspartic acid and asparagine are important precursors for toxicity and their concentrations should be reduced as much as possible before chlorination to minimize the formation of DBPs. During chlorination of NOM, tryptophan, and asparagine solutions with different chlorine doses and reaction times, changes in the CTI and GTI were consistent with changes in the DCAN concentration.

关键词： Chlorination Dichloroacetonitrile Aspartic acid Asparagine Toxicity index