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Background China is a big country in the production and use of antibiotics. The abuse of antibiotics enables bacteria in water environment to acquire resistance, and promotes the generation and spread of antibiotics resistance genes (ARGs). The problem of antibiotic-resistant bacteria is increasingly serious and has become a public security issue of global concern. Water environment is a huge reservoir of antibiotics and ARGs. It is of great significance to study the pollution of antibiotics and ARGs in water to protect water sources and optimize the biosecurity of drinking water. Objective To evaluate the detection of antibiotics and ARGs in typical water sources, and to explore the relationship between antibiotics and ARGs. Methods Water samples were collected in Heilongjiang, Liaoning, and Hubei provinces during the wet season (from August to October) in 2020. Ten water samples were collected from each of the three places, and a total of 30 water samples were collected in this study. Five kinds of antibiotics, including macrolides, quinolones, sulfonamides, tetracycline, and β-lactam, were detected by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The integron (Intl1), 16S rRNA, and 6 kinds of ARGs were detected by quantitative real-time PCR (qPCR). The ARGs include one macrolide ARGs (ermB), one β-lactam ARGs (blaTEM), two tetracycline ARGs (tetC, tetQ), and two sulfonamide ARGs (sul1, sul2). Results The types of detected antibiotics varied by the three regions, and the concentration ranges of the same antibiotics varied by the three regions (P<0.05). The concentration ranges of selected five kinds of antibiotics were 0.11-418.80 ng·L−1 in region A, 0.12-23.23 ng·L−1 in region B, and 4.69-285.75 ng·L−1 in region C, respectively. The detection rates of all six ARGs were 100%. The absolute abundance of ARGs in region A ranged from 22.56 to 94355.91 copies·mL−1, that in region B ranged from 27.99 to 80584.32 copies·mL−1, and that in region C ranged from 41.99 to 111068.19 copies·mL−1. The absolute abundance of blaTEM was higher among the ARGs, followed by sul1 and sul2. In addition, the absolute abundance of Intl1 was also at a high level. The results of correlation analysis showed that the abundance of ARGs was positively correlated with each other. There was no correlation between specific antibiotics and corresponding ARGs. There was a positive correlation between Intl1 and sul1 or sul2 (P<0.05). Conclusion The types and concentrations of antibiotics and the abundance of ARGs in source water vary greatly in the study areas. The association between antibiotics and ARGs is uncertain. Intl1 may play an important role in the horizontal transfer of sulfonamide resistance genes.
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Objective To obtainthe baseline data of the gross α and gross β radioactivity levels in environmental samples and foods by the monitoring and analyzing the radioactivity levels in drinking water, aerosols and commercial foods in Nanjing City. Methods 15 types of samples, including water source, produced water, aerosol, chicken, pork, stalk vegetable, root vegetable, fresh milk, leafy vegetable, flour, fruits, rice, tea, fish and crab were collected. After pretreatment, LB4008 four-channel low background α and β measuring instrument was used to measure the gross α and gross β radioactivity concentrations. Results The gross α and gross β activity concentrations of source water and produced water in Nanjing from 2016 to 2019 were lower than the national limits. The gross α and gross β activity concentrations in the source water were significantly higher than those of the produced water (P < 0.05). The mean activity concentration range of gross α and gross β in aerosol were 0.16～0.98 mBq/m3 and 0.14～2.15 mBq/m3 from 2016 to 2019, and with no statistical difference in difference samples (P > 0.05). The gross α and gross β activity concentration range of foods were 0.10～17.00 Bq/kg and 22.20～187.20 Bq/kg, of which the gross α and gross β activity concentration in tea were significantly higher than that of other kinds of foods (P < 0.05). Conclusion The radioactivity level in drinking water, atmospheric aerosols and foods in Nanjing were not contaminated by radioactive substances, and the gross α and gross β were relatively stable.
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A method of direct injection and liquid chromatography coupled with tandem mass spectrometric (LC-MS / MS) was developed for simultaneous determination of 5 aniline compounds including aniline, 3-nitroaniline, 4-nitroaniline, 2,6-dichloro-4-nitroaniline and hexanitrodiphenylamine in drinking water and source water. The samples were filtered using a 0. 22-μm polyethersulfone membrane prior to HPLC analysis. Five target compounds were chromatographically separated on an HSS T3 column with gradient elution. Chromatographic data were acquired by tandem mass spectrometric detection in multiple reaction monitoring (MRM) mode, and thus favorable resolutions of all target compounds were achieved within 4 min. Under the optimal analytical conditions, the peak area of each analyte and its concentration had a good correlation within the linear range (R≥0. 995). The limit of detection (LOD) and limit of quantification (LOQ) of the method were 0. 773-1. 88 μg / L (S / N=3) and 2. 58-6. 27 μg / L (S / N=10), respectively. The intra- and inter-day relative standard deviations ( RSDs) of the mix standard solution were 0. 8% -1. 9% and 3. 3% -4. 9% , respectively. The spiked recoveries of the analytes were 84. 1% -105% and the RSDs of the spiked samples were 1. 0% -3. 1% . This proposed method was applied in the analysis of 35 samples from drinking water, source water and surface water, which indicated that the novel LC-MS / MS method could detect 5 aniline compounds in water without any complicated sample pretreatment in an accurate, sensitive and rapid way, and it also could provide technique support for evaluation of the contamination caused by aniline compounds.
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En la provincia del Chaco, el agua subterránea representa una fuente alternativa, y muchas veces única, para el consumo humano; esta es utilizada en el 14 % de los hogares. A pesar de que se reconoce el riesgo de la exposición al agua contaminada, la prevalencia de los diferentes patotipos de Escherichia coli en ambientes acuáticos no ha sido bien caracterizada. E. coli enteroagregativo (ECEA) es un patógeno emergente cuya importancia en la salud pública mundial se incrementó y quedó claramente establecida en los últimos años. El objetivo del presente trabajo fue detectar la presencia de ECEA típico mediante el reconocimiento de los factores de virulencia aap, AA probe y aggR por reacción en cadena de la polimerasa, en fuentes de agua subterráneas de la provincia del Chaco. Se identificó E. coli en 36 (38,7 %) de las 93 muestras estudiadas, provenientes de diferentes localidades. De esos 36 aislamientos, se identificaron 6 (16,7 %) portadores de los genes de ECEA, lo que representa una prevalencia del 6,4 % considerando las 93 fuentes de agua subterránea estudiadas. De esos 6 aislamientos, 3 eran portadores del gen aap, 2 del gen AA probe y uno de la combinación aggR/aap. El presente trabajo representa el primer aporte en el estudio de la presencia y distribución de genes de virulencia de ECEA en fuentes de agua subterránea de la región.
Groundwater is an important source of drinking water for many communities in Northern Argentina; particularly, in the province of Chaco, where about 14 % of households use this natural resource. Enteroaggregative Escherichia coli is an emerging pathogen whose global importance in public health has increased in recent years. Despite the significant risk of disease linked to contaminated water exposure, the prevalence of E. coli pathotypes in aquatic environments is still not so well defined. The aim of the present study was to detect the presence of typical enteroaggregative E. coli through the recognition of its virulence factors aap, AA probe and aggR by molecular techniques. A total of 93 water samples from different small communities of Chaco were analyzed. E. coli was identified in 36 (38.7 %) of the tested samples. Six strains isolated from different samples harbored the studied genes. Of these 6 isolates, 3 carried the aap gene, 2 the AA probe and the last one the combination of aap/aggR genes. The prevalence of E. coli isolates harboring enteroaggregative virulence genes in groundwater sources was 6.4 %. This work represents the first contribution to the study of the presence and distribution of virulence genes of EAEC in groundwater sources in this region of Argentina.
Subject(s)
Escherichia coli Proteins/genetics , Escherichia coli/genetics , Genes, Bacterial , Groundwater/microbiology , Trans-Activators/genetics , Water Pollution , Argentina , Escherichia coli Proteins/physiology , Escherichia coli/isolation & purification , Escherichia coli/pathogenicity , Trans-Activators/physiology , Virulence/genetics , Water SupplyABSTRACT
Objective To realize the contamination status of dental unit waterlines (DUWL)in general hospitals, and provide scientific evidence for making preventive measures.Methods Three hospitals were selected for study, water source adopted by hospital A,B and C was running water,reservoir water,and filtered water through reverse osmosis filtration system respectively,specimens of dental handpiece spray water and flushing water of dental chair units were collected quarterly,total bacterial colony in water were detected.Results The qualified rate of source wa-ter,handpiece spray water,and flushing water in hospital A was 75.00%(3/4),0 (0/40)and 0 (0/40)respectively,col-ony count of handpiece spray water and flushing water was (1.20×103 -5.53×104 )CFU/mL(M=3.80×104 CFU/mL) and (2.11×104 -1.66×105 )CFU/mL(M=4.80×104 CFU/mL)respectively.The qualified rate of source water,hand-piece spray water,and flushing water in hospital B was 50.00%(2/4),60.00%(24/40)and 72.50%(29/40)respectively, colony count of handpiece spray water and flushing water was (0.00 -3.71 ×106 )CFU/mL(M=83.00 CFU/mL)and (0.00-2.39×106 )CFU/mL(M=72.00 CFU/mL)respectively.The qualified rate of source water,handpiece spray wa-ter,and flushing water in hospital C was 100.00%(4/4),55.00%(22/40)and 65.00%(26/40)respectively,colony count of handpiece spray water and flushing water was (0.00-6.20×103 )CFU/mL(M=96.00 CFU/mL)and(0.00-1.63×103 )CFU/mL(M=87.50 CFU/mL)respectively.Conclusion Water of DUWL in general hospitals is seriously con-taminated,disinfection and standardized management of source water and DUWL must be strengthened.
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Antibiotic resistance genes (ARGs) are emerging microbial hazards threatening human health. Many factors, including urban and agricultural activities and water environment changes, can significantly impact the variations of ARGs. An investigation on the occurrence and variations of ARGs in the Jiulong River was done in this study. The water samples were collected from 16 sites ranging from the upper branch to the river mouth of the Jiulong River, in both low- and high-flow periods. Eleven ARG families were tested and quantified by real-time PCR (SYBR Green) methods, and detection assays were conducted for tetA, tetG, aacC1, strA, ermB, cmlA5, vanA, dfrA1, sulII, blaTEM-1 and blaoxa-1 genes. Results showed that nine ARG families were found, then the swine industry and urban activities, including sewage discharge, might be responsible for the high levels of concentrations and relative abundances of ARGs, and the increase of salinity might decrease the relative abundances of ARGs. In addition, some ARG abundances were significantly correlated to the concentrations of NH4+ and PO4-3, particularly in the high-flow period. The human activities were important sources for ARGs in the Jiulong River, which have already become a threat to the safety of drinking water for the nearby cities.
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To understand the distribution of Giardia cysts in drinking water supplies in Seoul, Korea, we collected water samples quarterly at 6 intakes in the Han River, its largest stream and 6 conventional water treatment plants (WTPs) serving drinking water, from 2000 to 2009. Giardia cysts in each of 10 L water were confirmed in 35.0% of intake water samples and the arithmetic mean was 1.65 cysts/10 L (range 0-35 cysts/10 L). The lowest cyst density was observed at Paldang and Kangbuk intakes, and the pollution level was higher at 4 intakes downstream. It seemed that these 4 intakes were under influence of Wangsuk stream at the end of which cysts were found in all samples with the mean of 140 cysts/10 L. The annual mean number of cysts was 0.21-4.21 cysts/10 L, and the cyst level at the second half of the 10 years was about 1/5 of that at first half on average. The cysts were more frequently found in winter, and their mean density was 3.74 cysts/10 L in winter and 0.80-1.08 cysts/10 L in other seasons. All finished water samples collected at 6 WTPs were negative for Giardia in each of 100 L sample for 10 years and cyst removal by physical process was average 2.9-log. It was concluded that conventional water treatment at 6 WTPs of Seoul appears to remove the cysts effectively under the present level of their source water. Domestic wastewater from the urban region could be an important source of Giardia pollution in the river.
Subject(s)
Fresh Water/parasitology , Giardia/growth & development , Republic of Korea , Rivers/parasitology , Seasons , Water Supply/analysisABSTRACT
Objective To develop a new method for the determination of inorganic sulfide in source water by ion chromatography combined with pulsed amperometric detector.Methods The source water samples were injected into ion chromatography system after being filtrated with 0.22 ?m nylon membrane.100 mmol/L of NaOH-250 mmol/L of the NaOAc-0.5% (V/V) ethylenediamine was used as the eluent,special polarizable anions separation column IonPac 3AS7 was selected and sulfide was separated from other anions by isocratic eluent following by three-waveform pulsed amperometric detection.Results The liner range of determination for sulfide was 5-1 000 ?g/L,the equation of linear regression was y=0.325 4x-1.305 3.The detection limit was 0.5 ?g/L,the recovery rates were in the range of 90.8%-96.7%,and the relative standard deviation was 1.32%.Conclusion The method is simple with good selectivity,high sensitivity and good reproducibility and is applicable to the determination of inorganic sulfide in source water.
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Objective To know the pollution level of phthalates in Jiulong River source water and the purification efficiency by conventional water treatment processes. Methods The samples of Jiulong River source water and treated water from two waterworks were collected and analyzed with GC-MS during Aug.-Sep.2006. Results Jiulong River had been polluted by phthalates. The prominent phthalates pollutants were dibutyl phthalate (DBP) and diethyl phthalate(DEP). The maximum concentrations reached 17.238 ?g/L and 11.701 ?g/L, respectively. PAEs content in tap-water was lower than the standard limits. Conclusion The conventional water treatment processes, preoxidation, coagulation, sedimentation, filtration and disinfection, could remove phthalates from the drinking water to a certain degree, but the risk of phthalates pollution in drinking water still exists.
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Objective To investigate a water contamination accident caused by industrial wastewater during Feb 27th-29th ,2004,in Tuojiang river, analyze the variation of sanitary quality of drinking water during and after the accident. Methods After the occurrence of the accident,consecutive surveillance and analyses were done to discover the variation of the levels of amino-nitrogen,nitrite and nitrate in source water and finished water of Jianyang Water Works and Neijiang No 2 Water Works,which located at the lower reaches of Jianyang. Results The levels of amino-nitrogen in source water and finished water of Jianyang Water Works reached the first peak [(47.04?2.48)?(45.97?2.37)mg/L]at the 3rd day(March 3rd) after the end of discharge of industrial wastewater from contamination source,decreased at the 4th day ,reached the second peak at the 5th day[(42.26?2.88)?(39.50?2.64)mg/L], then decreased gradually, presented the normal levels at the 11th day[(0.54?0.10)?(0.30?0.12)mg/L]. The levels of nitrite in source water and finished water of Jianyang Water Works reached the first peak [(2.09?0.23)?(0.91?0.15)mg/L] at the 2 nd-3rd day after the end of discharge of industrial wastewater from contamination source,decreased at the 4th day ,reached the second peak at the 5th day[(2.18?0.33),(0.61?0.16)mg/L], then decreased gradually,presented the normal levels at the 11th day[(0.16?0.07)?(0.02?0.01)mg/L]. The levels of nitrate in source water and finished water of Jianyang Water Works(3.56～9.15 mg/L) didn't exceed the standard ruled the Sanitary Standard for Drinking Water (2001) throughout the duration of accident. The levels of amino-nitrogen and nitrite in source water and finished water of Neijiang No.2 Water Works both exceeded the related standards, the levels of nitrate met the requirement of the Sanitary Standard for Drinking Water (2001) during the period from the first day to the third day after the end of discharge of industrial wastewater from contamination source. From the forth day to the 25 th day, Neijiang No.2 Water Works was changed to be supplied by the Five-star reservoir,and produced safe and sanitary finished water meeting the requirement of the Sanitary Standard for Drinking Water (2001). Conclusion This wastewater contamination accident seriously deteriorates the quality of drinking water in Jianyang and Neijiang.
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Objective To analyze the kinds of organic compounds in source water and finished water. Methods The organic pollutants in water samples collected from source water and finiched water and enriched by GDX resin, were analyzed by GC/ MS. Results 48 organic compounds including phthalates, phenols, terpanes and aromatic compounds were detected in water samples. Similar kinds of organic compounds were found in source water samples and finished water samples. The main pollutants were phthalates, phenols and cyclic compound which had a high percentages (85%-94% ). Conclusion Many kinds of organic compounds in source water still existed in the finished water.
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Objective To provide scientific basis for prevention of source water pollution and minimization of impacts of biological pollution on drinking water quality.Methods The source water and finished water were determined based on the National Sanitary Method for Determination of Drinking Water(GB5750-1985),the sanitary quality of source water was classified based on the National Standard for Environmental Quality of Surface Water(GHZB1-1999),the sanitary quality of finished water was evaluated based on the National Sanitary Standard for Drinking Water(GB5749-1985).Results 36.8% of the accidents of source water pollution were induced by biological pollution,which mainly occured in rivers and lakes. Conclusion The important countermeasures for the minimization of source water biological pollution were to improve the process of water treatment and to develop the deep water treatment for conventional water treatment.