Effect of river landscape on the sediment concentrations of antibiotics and corresponding antibiotic resistance genes (ARG)

The purpose of this study was to quantify antibiotic resistance genes (ARG) in the sediments of the mixed-landscape Cache La Poudre River, which has previously been studied and shown to have high concentrations of antibiotics related to urban and agricultural activities. River sediments were sampled during two events (high-flow and low-flow) from five sites with varying urban and agricultural impact levels. Polymerase-chain-reaction (PCR) detection assays were conducted for four sulfonamide resistance gene families, using newly designed primers, and five tetracycline resistance gene families, using previously published primers. Sul(I), sul(II), tet(W), and tet(O) gene families were further quantified by real-time quantitative polymerase chain reaction (Q-PCR). Resistance to four classes of antibiotics (tetracyclines, sulfonamides, ionophores, and macrolides) was also investigated using a culture-based approach. The quantities of resistance genes normalized to the 16S gene copy number were significantly different between the sites, with higher resistance gene concentrations at the impacted sites than at the pristine site. Total resistant CFUs were over an order of magnitude lower at the pristine site, but differences were less apparent when normalized to the total CFUs. Six tetracyclines and six sulfonamides were also quantified in the sediments and were found to be highest at sites impacted by urban and agricultural activity, with no antibiotics detected at the pristine sit. To the knowledge of the authors, this study is the first to demonstrate a relationship between urban and agricultural activity and microbial resistance in river sediments using quantitative molecular tools.     

Pesticides in Portuguese surface and ground waters

Pesticides used in Portuguese agricultural areas have been found in surface and ground waters. In the surface water collected in three river basins from 1983 to 1999, insecticides and herbicides were detected from the monitored pesticides, particularly atrazine, chlorfenvinphos (Z+E), alpha- and beta-endosulfan, lindane, molinate and simazine, reaching the maximum values, respectively, of 0.63, 31.6, 0.18 microg/L (alpha-endosulfan), 0.18 microg/L (beta-endosulfan), 0.24, 48 and 0.3 microg/L. In the ground water collected from the wells of seven agricultural areas from 1991 to 1998, several monitored herbicides were detected: alachlor, atrazine, metolachlor, metribuzine and simazine, reaching the maximum concentration values of 13, 30, 56, 1.4 and 0.4 microg/L, respectively. The herbicides more frequently detected were atrazine (64%), simazine (45%) and alachlor (25%). Other than these, the monitored pesticides can be present in Portuguese surface and ground waters. Therefore, to improve the analytical conditions, the use of multiresidue methods and automated techniques are desirable in future work.     

Occurrence of ionophore antibiotics in water and sediments of a mixed-landscape watershed

Analytical methods for quantifying three ionophore antibiotics, monensin, salinomycin, and narasin, were developed for water and sediment matrices. Sample preparation was based on solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS) was used to separate and detect the compounds. Recoveries ranged from 83% to 117% for water and from 51% to 105% for sediment in three different concentrations with less than 10% of relative standard deviation. The statistical detection limit was 0.001-0.003 microg/L for water and 0.4-3.6 microg/kg for sediment. Ionophore antibiotics are only used to treat coccidiostats for broilers or turkeys, and to increase growth and feed efficiency for beef and dairy cattle. Since they are not used for human purposes, these compounds can act as markers for the transport of animal pharmaceuticals to the watershed. The occurrence of three ionophore compounds was determined at five sampling sites along the Cache la Poudre River in Northern Colorado representing pristine, urban, and agriculture landscapes. Statistical analysis demonstrates that the measured concentration was significantly different among sampling sites in different sampling events for both water and sediment. In addition, significant differences were observed among different sampling times at each sampling site. Furthermore, all three ionophores were found in the sediments at much higher concentrations than in water indicating the importance of this matrix when determining environmental impacts.     

Distribution patterns of antibiotic residues in an urban river catchment

The residual patterns of 23 target antibiotics in five classes of compound in catchment sediments of a rapidly urbanizing city in east China were studied. A total of 14 antibiotics were detected in the catchment. The dominant classes were tetracyclines and fluoroquinolones and these occurred at substantial concentrations. High environmental risk at the sites sampled may be associated with antibiotics detected at high concentrations. For example, at one site chlortetracycline was found to occur at concentrations ≤ 4496 ng/g. Source traceability indicates that high intensity of urbanization (e.g. hospitals and livestock farms) had a high spatial relationship with sites of high antibiotic contaminations. Urban and suburban areas had some impacts on antibiotic residues in the catchment, especially on veterinary antibiotics such as chlortetracycline in suburban areas. Moreover, antibiotics detected at high concentrations in urban areas included fluoroquinolones associated with human medicine.     

Determination of penicillin G and its degradation products in a penicillin production wastewater treatment plant and the receiving river

To investigate the fate of penicillin G (PEN G) in the wastewater from a PEN G production facility and the receiving river, an analytical method was developed for the simultaneous detection of PEN G and five degradation products using liquid chromatography-electrospray ionization mass spectrometry (LC-ESI/MS). PEN G had already undergone transformation before entering into the wastewater treatment plant (WWTP), with concentrations of 153+/-4 microg/L in raw wastewater. Most of the PEN G could be eliminated following successive treatments of anaerobic, hydrolysis, and two aerobic units under a hydraulic residence time (HRT) of 30 h, and the final concentrations were 1.68+/-0.48 microg/L in treated water. In the receiving river, the concentration of PEN G decreased from 0.31+/-0.04 microg/L at the discharging point to under the detection limit (0.03 microg/L) at the last sampling site (about 30 km from the discharging point). The main PEN G degradation products in surface water were found to be penilloic acid, penicilloic acid and isopenillic acid, which occupied 65.8%, 20.4% and 12.9%, respectively, of the total concentration at the last site. This is the first study on the behaviors of PEN G and its main degradation products in wastewater treatment processes and the aquatic environment.     

Pesticides in the atmosphere of the Mississippi River Valley, part II--air

Weekly composite air samples were collected from early April through to mid-September 1995 at three paired urban and agricultural sites along the Mississippi River region of the Midwestern United States. The paired sampling sites were located in Mississippi, Iowa, and Minnesota. A background site, removed from dense urban and agricultural areas, was located on the shore of Lake Superior in Michigan. Each sample was analyzed for 49 compounds; of these, 21 of 26 herbicides, 13 of 19 insecticides, and 4 of 4 related transformation products were detected during the study, with most pesticides detected in more than one sample. The maximum number of pesticides detected in an air sample was 18. Herbicides were the predominant type of pesticide detected at every site. Detection frequencies of most herbicides were similar at the urban and agricultural sites in Iowa and Minnesota. In Mississippi, herbicides generally were detected more frequently at the agricultural site. The insecticides chlorpyrifos, diazinon, and carbaryl, which are used in agricultural and non-agricultural settings, were detected more frequently in urban sites than agricultural sites in Mississippi and Iowa. Methyl parathion was detected in 70% of the samples from the Mississippi agricultural site and at the highest concentration (62 ng/m3 air) of any insecticide measured in the study. At the background site, dacthal (100%), atrazine (35%), cyanazine (22%), and the (primarily atrazine) triazine transformation products CIAT (35%) and CEAT (17%) were detected most frequently, suggesting their potential for long-range atmospheric transport.     

Occurrence of antibiotics in the aquatic environment

The recent monitoring of drug residues in the aquatic environment has gained much interest as many pharmaceutical compounds can frequently be found in sewage treatment plant (STP) effluents and river water at concentrations up to several microgram/l. This article describes the analysis of various water samples for 18 antibiotic substances, from the classes of macrolid antibiotics, sulfonamides, penicillins and tetracyclines. Samples were preconcentrated via lyophilization and quantified using HPLC-electrospray-tandem-mass spectrometry. The investigated STP effluents and surface water samples showed frequent appearance of an erythromycin degradation product, roxithromycin and sulfamethoxazole with concentrations up to 6 micrograms/l. Neither tetracyclines nor penicillins could be detected at concentration levels above 50 and 20 ng/l, respectively. From the large number of ground water samples that were taken from agricultural areas in Germany, no contamination by antibiotics was detected except for two sites. This indicates that intake from veterinary applications to the aquatic environment is of minor importance.     

滨水世博园建设与后续开发--解析澳大利亚布里斯班南岸公园

历史上,许多国家的承办城市将世界博览会选址于城市滨水地区。本文以布里斯班南岸公园为主,并结合其它案例的分析 从世博园建设与河流整治的结合,世博园建设带动城市滨水区开发,以及世博园后续开发与城市建设的关系等3个方面对滨水世博园进行了探讨。     

The distribution of oxidized nitrogen in urban air

This paper describes the distribution of oxidized nitrogen compounds in urban air. The studies reported here have focused on NO, NO2, PAN and NO-3. These species have been monitored for periods of several weeks at a nmber of locations throughout the U.S.A. Oxidized nitrogen distribution is discussed in terms of the daily patterns of nitrogen pollutant concentrations, the fractional conversion of NOx to products and the diurnal profile of the conversion fraction, and lastly, the contribution of the individual compounds to the overall oxidized nitrogen burden. Site to site variations in the distribution are explained by photochemical conversion, distance between the site and the source region, and the proximity of local NOx emission sources.     

Occurrence and fate of antibiotics in the Seine River in various hydrological conditions

Occurrence and fate of 17 antibiotics were investigated in the aqueous phase of river water under different hydrological conditions at 5 sampling locations in the Seine River inner estuary. The target analytes belonged to 4 groups: quinolones, sulfonamides, nitro-imidazoles and diaminopyrimidines. This six-month survey (from January to June 2006) showed that different compounds were occurring at individual concentrations reaching 544 ng L(-)(1) (sulfamethoxazole). All 17 compounds were detected at least once in the survey. Sulfamethoxazole was detected in every sample, and showed the highest concentrations. Norfloxacin and flumequine were found to be the most ubiquitous quinolones, with detection frequencies of 33 and 75% respectively at the most contaminated site (Poses). Investigations concerning the origins of this contamination were made by means of a longitudinal profile along the Seine River between Paris and Poses. It showed large inputs of norfloxacin, ofloxacin, trimethoprim and sulfamethoxazole from wastewater treatment plants, with an increase in norfloxacin and sulfamethoxazole concentrations of 84% and 70% respectively, both reaching 155 ng L(-)(1) in the river, downstream from a wastewater outlet. The detected compounds showed different dissipation patterns and behaviours under different hydrological conditions. Higher inputs of norfloxacin were found in low flow conditions, which were rapidly attenuated along the stream. In contrast, sulfamethoxazole inputs were increasing in high flow conditions, and dissipation of this compound was found to be slow. Similar behaviour was observed for the synergist trimethoprim. Flumequine was also frequently detected and its input increased during flood events.     

Significance of urban and agricultural land use for biocide and pesticide dynamics in surface waters

Biocides and pesticides are designed to control the occurrence of unwanted organisms. From their point of application, these substances can be mobilized and transported to surface waters posing a threat to the aquatic environment. Historically, agricultural pesticides have received substantially more attention than biocidal compounds from urban use, despite being used in similar quantities.This study aims at improving our understanding of the influence of mixed urban and agricultural land use on the overall concentration dynamics of biocides and pesticides during rain events throughout the year. A comprehensive field study was conducted in a catchment within the Swiss plateau (25 km²). Four surface water sampling sites represented varying combinations of urban and agricultural sources. Additionally, the urban drainage system was studied by sampling the only wastewater treatment plant (WWTP) in the catchment, a combined sewer overflow (CSO), and a storm sewer (SS). High temporal resolution sampling was carried out during rain events from March to November 2007.The results, based on more than 600 samples analyzed for 23 substances, revealed distinct and complex concentration patterns for different compounds and sources. Five types of concentration patterns can be distinguished: a) compounds that showed elevated background concentrations throughout the year (e.g. diazinon >50 ng L⁻¹), indicating a constant household source; b) compounds that showed elevated concentrations driven by rain events throughout the year (e.g. diuron 100-300 ng L⁻¹), indicating a constant urban outdoor source such as facades; c) compounds with seasonal peak concentrations driven by rain events from urban and agricultural areas (e.g. mecoprop 1600 ng L⁻¹ and atrazine 2500 ng L⁻¹ respectively); d) compounds that showed unpredictably sharp peaks (e.g. atrazine 10,000 ng L⁻¹, diazinon 2500 ng L⁻¹), which were most probably due to improper handling or even disposal of products; and finally, e) compounds that were used in high amounts but were not detected in surface waters (e.g. isothiazolinones).It can be safely concluded that in catchments of mixed land use, the contributions of biocide and pesticide inputs into surface waters from urban areas are at least as important as those from agricultural areas.     

The potential of pesticides to contaminate the groundwater resources of the Axios river basin in Macedonia, Northern Greece. Part I. Monitoring study in the north part of the basin

The Axios river basin is an area of high agricultural importance for Macedonia, Northern Greece. High priced crops such as cotton, corn, sugarbeets, vegetables and rice are rotated with cereals and alfalfa and thus a great variety of pesticides are used annually for the control of pests and diseases. Moreover, the groundwater resources of the specific area constitute the main source of potable water for the surrounding cities and villages. Therefore, a study was initiated to investigate the probable risks of groundwater contamination with pesticides. The leaching of pesticides from agricultural soils was monitored in the phreatic horizon as well as in soil water samples collected with suction lysimeters. In parallel studies, the presence of pesticides in the irrigation water and the water of Axios river was also monitored. Pesticides like carbofuran, atrazine, alachlor and prometryne, which were regularly applied in the northern part of the basin during 1992-1994 were detected at concentrations occasionally exceeding 1 microg/l in soil water from the deeper soil layers and in the phreatic horizon. Residues of pesticides others than the ones applied in the studied area like propanil, terbufos and paraoxon-methyl were also detected at the deeper soil layers and in the phreatic horizon. The latter pesticides were also detected at significant concentrations in the irrigation water which mainly consisted of riverine water. The lack of an independent soil draining system and the use of riverine water for irrigation purposes resulted in the redistribution of residual amounts of these pesticides in the phreatic horizon beneath the agricultural area.     

Seasonal variation in drinking water concentrations of disinfection by-products in IZMIR and associated human health risks

Seasonal variation in concentrations of two different disinfection by-product groups, trihalomethanes (THMs) and haloacetonitriles (HANs), was investigated in tap water samples collected from five sampling points (one groundwater and four surface water sources) in Izmir, Turkey. Estimates of previously published carcinogenic and non-carcinogenic risks through oral exposure to THMs were re-evaluated using a probabilistic approach that took the seasonal concentration variation into account. Chloroform, bromoform, dibromochloromethane and dichloroacetonitrile were the most frequently detected compounds. Among these, chloroform was detected with the highest concentrations ranging from 0.03 to 98.4 microg/L. In tap water, at the groundwater supplied sampling point, brominated species, bromoform and dibromoacetonitrile, were detected at the highest levels most probably due to bromide ion intrusion from seawater. The highest total THM and total HAN concentrations were detected in spring while the lowest in summer and fall. The annual average total THM concentration measured at one of the surface water supplied sampling points exceeded the USEPA's limit of 80 microg/L. While all non-carcinogenic risks due to exposure to THMs in Izmir drinking water were negligible, carcinogenic risk levels associated with bromodichloromethane and dibromochloromethane were higher than one in million.     

A simple method for the measurement of organic iodine in wastewater and surface water

Total adsorbable organic iodine (TAOI) has been used as a surrogate parameter for X-ray contrast media in municipal wastewater. Available methods require specialized equipment for pyrolyzing these compounds to convert the covalently bound iodine into iodide, which is then measured by ion chromatography. In this study we describe a simple method for liberating iodide from these compounds with Cu(II) and hydrogen peroxide. Concentrations of TAOI were measured in wastewater effluent, surface waters that were expected to be impacted by wastewater, and unimpacted surface waters. TAOI concentrations ranged between 1.9 and 16.3 microg/L I in wastewater with a median of 6.5 microg/L I. The lowest TAOI concentrations consistently were detected in a wastewater treatment plant that apparently had few hospitals within its collection area. In comparison, TAOI concentrations in surface water that was unimpacted by sewage were between 0.3 and 3.5 microg/L I. TAOI concentrations in surface waters that were impacted by sewage were consistent with the expected conservative behavior of TAOI.     

Organotin survey in the Adour-Garonne basin

Organotin monitoring was performed in waters of 11 rivers of the southwest of France during a 9 months period, between February and October 2001. Surface sediments were studied during the summer. Eighteen sampling points were chosen as representative of specific industrial or agricultural activities. In most samples, organotins were detected and butyltins are the most frequently present, with concentrations ranging over 0.2-30 ng(Sn)/L. Phenyltins were detected especially in spring and at the end of summer, which corresponds to likely diffusion from agricultural sources. Some high butyl- and phenyltin concentrations up to 700 ng(Sn)/L occurred during the spring where pesticides for agricultural activities were largely used. Octyltins were present in water frequently as well, with lower concentrations, probably originating from continuous leaching of plastics. Sediments appeared contaminated by the same species, with higher monobutyltin concentrations of about 30-40 microg(Sn)/kg which shows the importance of biological degradations occurring in surface sediments. This non-pesticidal organotin compounds can also be introduced from leaching of organotin-stabilized PVC by water. Using the different organotin concentrations obtained and other physico-chemical parameters measured, such as temperature or water flow rate, a statistical study was performed by principal component analysis. The results obtained allow the main sources of organotin diffusion to be identified and the hydrological cycle of these compounds better understand.     

Polycyclic aromatic hydrocarbons (PAHs) in agricultural soil and vegetables from Tianjin

Several types of vegetables were collected from two contaminated sites in Tianjin, China. The bulk soil and the rhizosphere soil samples were also collected from the same plots. Sixteen PAHs in the samples were measured. The total concentrations of PAH16 in the bulk soil from the two sites were 1.08 and 6.25 microg/g, respectively, with similar pattern. The concentrations of PAH16 and individual compounds in the rhizosphere were significantly higher than those in the bulk soil with mean values of 2.25 and 7.82 microg/g for the two sites, respectively. The contents of both total and dissolved organic matter in the rhizosphere were also higher than those in the bulk soil. Almost all PAH compounds studied were detected in both roots and aerial parts of the vegetables studied. Abundance of higher molecular weight PAHs in vegetable, however, was lower than that in soil. Concentrations of PAH16 in vegetable were higher than those reported in the literature for other areas. It appears that agricultural soils and vegetables in Tianjin, especially those from the site located immediately next to an urban district and irrigated with wastewater for several decades, are severely contaminated by PAHs. Among the eight types of vegetable studied, the highest concentration of PAHs was found in cauliflower. By average, the concentration of PAH16 in the aerial part of vegetables was 6.5 times higher as that in vegetable root, suggesting that foliar uptake is the primary transfer pathway of PAHs from environment to vegetables.     

Occurrence of antibiotics in wastewater treatment facilities in Wisconsin, USA

Samples from several wastewater treatment facilities in Wisconsin were screened for the presence of 21 antibiotic compounds. These facilities spanned a range of community size served (average daily flow from 0.0212 to 23.6 million gallons/day), secondary treatment processes, geographic locations across the state, and they discharged the treated effluents to both surface and ground waters (for ground water after a soil passage). A total of six antibiotic compounds were detected (1-5 compounds per site), including two sulfonamides (sulfamethazine, sulfamethoxazole), one tetracycline (tetracycline), fluoroquinolone (ciprofloxacin), macrolide (erythromycin-H(2)O) and trimethoprim. The frequency of detection of antibiotics was in the following order: tetracycline and trimethoprim (80%)>sulfamethoxazole (70%)>erythromycin-H(2)O (45%)>ciprofloxacin (40%)>sulfamethazine (10%). However, the soluble concentrations were in the parts-per-billion (ppb) range (相似文献   

Occurrence of pesticides in rain and air in urban and agricultural areas of Mississippi, April-September 1995

In April 1995, the US Geological Survey began a study to determine the occurrence and temporal distribution of 49 pesticides and pesticide metabolites in air and rain samples from an urban and an agricultural sampling site in Mississippi. The study was a joint effort between the National Water-Quality Assessment and the Toxic Substances Programs and was part of a larger study examining the occurrence and temporal distribution of pesticides in air and rain in the Mississippi River basin. Concurrent high-volume air and wet-only deposition samples were collected weekly. The air samplers consisted of a glass-fiber filter to collect particles and tandem polyurethane foam plugs to collect gas-phase pesticides. Every rain and air sample collected from the urban and agricultural sites had detectable levels of multiple pesticides. The magnitude of the total concentration was 5-10 times higher at the agricultural site as compared to the urban site. The pesticide with the highest concentration in rain at both sites was methyl parathion. The pesticide with the highest concentration in the air samples from the agricultural site was also methyl parathion, but from the urban site the highest concentration was diazinon followed closely by chlorpyrifos. More than two decades since p,p'-DDT was banned from use in the United States, p,p'-DDE, a metabolite of p,p'-DDT, was detected in every air sample collected from the agricultural site and in more than half of the air samples from the urban site.     

Atmospheric particulate mercury concentration and its dry deposition flux in Changchun City, China.

From July 1999 to January 2000, we determined the particulate mercury [Hg(p)] concentration in the atmosphere of five function sites and one contrast site in the city of Changchun, China. During non-heating season, the Hg(p) concentration in air in urban areas ranged from 0.022 to 0.398 ng m(-3) with an average of 0.145 ng m(-3), and at the contrast site with an average of 0.084 ng m(-3). During the heating season, the Hg(p) concentration in urban areas was in the range of 0.148-1.984 ng m(-3) with an average of 0.461 ng m(-3) and with an average of 0.211 ng m(-3) at the contrast site. The Hg(p) concentration during heating season is two times higher than that during non-heating time. Coal burning and wind-blown soil material are the two important sources of Hg(p). Wind-blown soil material contributes 7.9-38.5% to the Hg(p) with an average of 24.1% in urban area. A theoretical model was used to estimate the dry deposition flux, with results of 43.06 microg m(-2) a(-1) in the urban area and 21.28 microg m(-2) a(-1) at the contrast site.