Algicidal bacterium CZBC1 inhibits the growth of Oscillatoria chlorina, Oscillatoria tenuis, and Oscillatoria planctonica.

Frequent harmful cyanobacteria blooms limit the sustainable development of aquaculture. Algicidal bacteria can efficiently control harmful algae without secondary pollution. The algicidal bacteria CZBC1 can lyse Oscillatoria spp.

Persistence of antibiotic resistance genes and bacterial community changes in drinking water treatment system: From drinking water source to tap water.

As emerging contaminants, antibiotic resistance genes (ARGs) have become a public concern. This study aimed to investigate the occurrence and diversity of ARGs, and variation in the composition of bacterial communities in source water, drinking water treatment plants, and tap water in the Pearl River Delta region, South China. Various ARGs were present in the different types of water.

Removal of antibiotics and antibiotic resistance genes from domestic sewage by constructed wetlands: Optimization of wetland substrates and hydraulic loading.

This study aimed to assess removal potential of antibiotics and antibiotic resistance genes (ARGs) in raw domestic wastewater by various mesocosm-scale horizontal subsurface-flow constructed wetlands (CWs) planted Cyperus alternifolius L. with different design parameters. Twelve CWs with three hydraulic loading rates (HLR 10, 20 and 30cm/day) and four substrates (oyster shell, zeolite, medical stone and ceramic) were set up in order to select the best optimized wetland.

Discharge of swine wastes risks water quality and food safety: Antibiotics and antibiotic resistance genes from swine sources to the receiving environments.

Swine feedlots are widely considered as a potential hotspot for promoting the dissemination of antibiotic resistance genes (ARGs) in the environment. ARGs could enter the environment via discharge of animal wastes, thus resulting in contamination of soil, water, and food. We investigated the dissemination and diversification of 22 ARGs conferring resistance to sulfonamides, tetracyclines, chloramphenicols, and macrolides as well as the occurrence of 18 corresponding antibiotics from three swine feedlots to the receiving water, soil environments and vegetables.

Tissue-specific bioaccumulation of human and veterinary antibiotics in bile, plasma, liver and muscle tissues of wild fish from a highly urbanized region.

We investigated the bioaccumulation of antibiotics in bile, plasma, liver and muscle tissues of wild fish from four rivers in the Pearl River Delta region. In total, 12 antibiotics were present in at least one type of fish tissues from nine wild fish species in the four rivers. The mean values of log bioaccumulation factors (log BAFs) for the detected antibiotics in fish bile, plasma, liver, and muscle tissues were at the range of 2.

Joint antibacterial activity of soil-adsorbed antibiotics trimethoprim and sulfamethazine.

Trimethoprim (TMP) and sulfamethazine (SMZ) are two antibiotics that are often administered in combination. We investigated the sorption and desorption behaviors of TMP and SMZ individually as single solute and in combination as co-solute in three representative soils, and evaluated joint antibacterial activity of the soil-adsorbed antibiotics to a reference strain Escherichia coli ATCC 25922. Comparative sorption tests showed that co-solute sorption of TMP and SMZ was not considerably different from their single sorption.

Dissemination of antibiotic resistance genes in representative broiler feedlots environments: identification of indicator ARGs and correlations with environmental variables.

Livestock operations are known to harbor elevated levels of antibiotic resistance genes (ARGs) that may pose a threat to public health. Broiler feedlots may represent an important source of ARGs in the environment. However, the prevalence and dissemination mechanisms of various types of ARGs in the environment of broiler feedlots have not previously been identified.

Contamination profiles of antibiotic resistance genes in the sediments at a catchment scale.

The aim of this study was to investigate the contamination profiles of tetracycline, sulfonamide, and macrolide resistance genes, as well as integrons in sediments of Dongjiang River basin of South China by real time quantitative polymerase chain reaction. sul2 was the most abundant resistance gene, with the average concentration of 6.97×10(8) copies/g and 1.

Removal of antibiotics and antibiotic resistance genes in rural wastewater by an integrated constructed wetland.

Integrated constructed wetlands (ICWs) are regarded as one of the most important removal technology for pollutants in rural domestic wastewaters. This study investigated the efficiency of an ICW consisting of a regulating pool, four surface and subsurface flow-constructed wetlands, and a stabilization unit for removing antibiotics and antibiotic resistance genes (ARGs) from rural domestic wastewaters. The results showed that antibiotics leucomycin, ofloxacin, lincomycin, and sulfamethazine, and ARGs sul1, sul2, tetM, and tetO were the predominant antibiotics and ARGs in the influent, respectively.

Antibiotic resistance, plasmid-mediated quinolone resistance (PMQR) genes and ampC gene in two typical municipal wastewater treatment plants.

Antibiotic resistant bacteria and plasmid-mediated quinolone resistance genes and ampC gene were investigated for Escherichia coli isolates from two typical municipal wastewater treatment plants in both dry and wet seasons by using the antibiotic susceptibility test and PCR assay, respectively. The results showed that 98.4% of the isolates (1056) were found resistant to antibiotic(s) tested and 90.

Antibiotic resistance and genetic diversity of Escherichia coli isolates from traditional and integrated aquaculture in South China.

This study investigated antibiotic resistance profiles including antibiotic resistance frequencies, resistance genes and resistance patterns in Escherichia coli strains isolated from traditional and integrated aquaculture systems in South China by using antibiotic susceptibility testing and real time polymerase chain reaction (PCR) technique. The E. coli isolates were found to be resistant to at least one antibiotic among 12 antibiotics.

Evaluation of triclosan and triclocarban at river basin scale using monitoring and modeling tools: implications for controlling of urban domestic sewage discharge.

Triclosan (TCS) and triclocarban (TCC) are two commonly used personal care products. They may enter into aquatic environments after consumption and pose potential risks to aquatic organisms. We investigated the occurrence and fate of TCS and TCC in five large rivers (the Liao River, Hai River, Yellow River, Zhujiang River and Dongjiang River) in China, and compared the monitoring data with the predicted results from Level III fugacity modeling.

Determination of biocides in different environmental matrices by use of ultra-high-performance liquid chromatography-tandem mass spectrometry.

A sensitive and robust method using solid-phase extraction and ultrasonic extraction for preconcentration followed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS-MS) has been developed for determination of 19 biocides: eight azole fungicides (climbazole, clotrimazole, ketoconazole, miconazole, fluconazole, itraconazole, thiabendazole, and carbendazim), two insect repellents (N,N-diethyl-3-methylbenzamide (DEET), and icaridin (also known as picaridin)), three isothiazolinone antifouling agents (1,2-benzisothiazolinone (BIT), 2-n-octyl-4-isothiazolinone (OIT), and 4,5-dichloro-2-n-octyl-isothiazolinone (DCOIT)), four paraben preservatives (methylparaben, ethylparaben, propylparaben, and butylparaben), and two disinfectants (triclosan and triclocarban) in surface water, wastewater, sediment, sludge, and soil. Recovery of the target compounds from surface water, influent, effluent, sediment, sludge, and soil was mostly in the range 70-120%, with corresponding method quantification limits ranging from 0.01 to 0.

Class 1 and 2 integrons, sul resistance genes and antibiotic resistance in Escherichia coli isolated from Dongjiang River, South China.

Antibiotic susceptibility, detection of sul gene types and presence of class 1, 2 and 3 integrons and gene cassettes using PCR assays were investigated in 3456 Escherichia coli isolates obtained from 38 sampling sites of the Dongjiang River catchment in the dry and wet seasons. 89.1% of the isolates were resistant and 87.

Use of TIE techniques to characterize industrial effluents in the Pearl River Delta region.

We investigated the acute toxicity of various industrial effluents in the Pearl River Delta region using lux bacteria, duckweed, green algae, crustaceans and zebrafish. The potential toxicants in the industrial effluents were identified and evaluated by lux bacteria bioassay and chemical analysis. The results show that green algae (Pseudokirchneriella subcapitata) and crustacean (Ceriodaphnia dubia) were more sensitive to the effluents from electronic and electroplate factories than other test species, while lux bacteria were more sensitive to all the other effluents.

Occurrence of antibiotic resistance and characterization of resistance genes and integrons in Enterobacteriaceae isolated from integrated fish farms in South China.

Antibiotics are still widely applied in animal husbandry to prevent diseases and used as feed additives to promote animal growth. This could result in antibiotic resistance to bacteria and antibiotic residues in animals. In this paper, Enterobacteriaceae isolated from four integrated fish farms in Zhongshan, South China were tested for antibiotic resistance, tetracycline resistance genes, sulfonamide resistance genes, and class 1 integrons.

4-Nonylphenol, bisphenol-A and triclosan levels in human urine of children and students in China, and the effects of drinking these bottled materials on the levels.

4-Nonylphenol (4-NP), bisphenol-A (BPA) and triclosan (TCS) are three industrial chemicals used widely in daily products. This study investigated 4-NP, BPA and TCS levels in urine samples of 287 children and students aged from 3 to 24 years old in Guangzhou, China. Total (free and conjugated) amounts of 4-NP, BPA and TCS in the urine samples were detected using gas chromatography-mass spectrometry with negative chemical ionization.

Spatial and seasonal distribution of selected antibiotics in surface waters of the Pearl Rivers, China.

The distribution and occurrence of 15 antibiotics in surface water of the Pearl River System (Liuxi River, Shijing River and Zhujiang River) and effluents of four wastewater treatment plants (WWTPs) were investigated in two sampling events representing wet season and dry season by using rapid resolution liquid chromatography-electrospray tandem mass spectrometry (RRLC-MS/MS) in positive ionization mode. Only eight antibiotics (sulfadiazine, sulfapyridine, sulfamethazine, sulfamethoxazole, trimethoprim, roxithromycin, erythromycin-H₂O and norfloxacin) were detected in the water samples of the three rivers and the effluents. The detection frequencies and levels of antibiotics in the dry season were higher than those in the wet season.

Assessing estrogenic activity in surface water and sediment of the Liao River system in northeast China using combined chemical and biological tools.

This paper investigated some selected estrogenic compounds (4-t-octylphenol: 4-t-OP; 4-nonylphenols: 4-NP; bisphenol-A: BPA; diethylstilbestrol: DES; estrone: E1; 17β-estradiol: E2; 17α-Ethinylestradiol: EE2; triclosan: TCS) and estrogenicity in the Liao River system using the combined chemical and in vitro yeast screen bioassay and assessed their ecological risks to aquatic organisms. The estrogenic compounds 4-t-OP, 4-NP, BPA, E1, E2 and TCS were detected in most of the samples, with their concentrations up to 52.1 2065.

Simultaneous determination and assessment of 4-nonylphenol, bisphenol A and triclosan in tap water, bottled water and baby bottles.

This study investigated the levels of 4-nonylphenol (4-NP), bisphenol A (BPA) and triclosan (TCS) in bottled water and tap water in Guangzhou and release of these chemicals from baby bottles using gas chromatography-mass spectrometry with negative chemical ionization. Results show that 4-NP was present in all the bottled water while 17 out of 21 contained BPA and 18 out of 21 contained TCS. Their concentrations in bottled water ranged from 108 to 298 ng/L, 17.

Simultaneous determination of four classes of antibiotics in sediments of the Pearl Rivers using RRLC-MS/MS.

A simultaneous extraction and analysis method was developed for four classes of antibiotics: sulfonamides (SAs), macrolides (MLs), fluoroquinolones (FQs) and tetracyclines (TCs) in sediment. The antibiotics in the sediment were extracted by using an optimized mixed solution (citric buffer: acetonitrile, 50:50 v/v), and analyzed by rapid resolution liquid chromatography-tandem mass spectrometry (RRLC-MS/MS) equipped with electrospray ionization source in the positive mode. The recoveries for the antibiotics in the spiked sediment were: 66.

Detection of antibiotic resistance and tetracycline resistance genes in Enterobacteriaceae isolated from the Pearl rivers in South China.

This study investigated antibiotic resistance profiles and tetracycline resistance genes in Enterobacteriaceae family isolates from the Pearl rivers. The Enterobacteriaceae isolates were tested for susceptibility to seven antibiotics ampicillin, chloramphenicol, ciprofloxacin, levofloxacin, sulphamethoxazole/trimethoprim, tetracycline and trimethoprim. In Liuxi reservoir, with an exception to ampicillin resistant strains (11%) no other antibiotic resistance bacterial strains were detected.

[Effects of antimicrobial drugs on soil microbial respiration].

The effects on soil microbial respiration of sulfonamides, tetracyclines, macrolides and so on were studied using the direct absorption method. The results show sulfamethazine, sulfamethoxazole, chlortetracycline, tetracycline, tylosin and trimethoprim inhibit soil respiration 34.33%, 34.

Growth-inhibiting effects of 12 antibacterial agents and their mixtures on the freshwater microalga Pseudokirchneriella subcapitata.

The growth-inhibiting and binary joint effects of 12 antibacterial agents on the freshwater green alga Pseudokirchneriella subcapitata (Korschikov) Hindák were investigated over 72-h exposures. The toxicity values (the median inhibitory concentration value, in micromoles) in decreasing order of sensitivity were triclosan (0.0018)>triclocarban (0.