Presence of erm genes among macrolide-resistant Gram-positive bacteria isolated from Danish farm soil

The presence of erm genes was investigated among macrolide-resistant Gram-positive bacteria isolated from soil samples collected from four Danish farms that had been treated with animal waste. Soil samples were collected before, a few days after spread and 1 1/2 months and 5 months later. In 33% (9/27) of these isolates, an erm gene was detected using PCR. Eight isolates were positive for erm(B) and one isolate was positive for erm(C). No isolates contained erm(A), erm(D) or erm(F). The positive isolates were identified to genus level. Two erm(B) positive isolates were identified as Enterococcus spp., and the erm(C)-positive isolate as a Streptococcus spp., probably indicating survival from animal waste. The remaining six erm(B) positive isolates all belonged to the Bacillus cereus group. The erm(B) gene has not previously been identified in B. cereus but is frequently found among enterococci. This result could indicate horizontal transfer from bacteria of animal origin to indigenous soil bacteria.     

Estrogen-, androgen- and aryl hydrocarbon receptor mediated activities in passive and composite samples from municipal waste and surface waters

Passive and composite sampling in combination with in vitro bioassays and identification and quantification of individual chemicals were applied to characterize pollution by compounds with several specific modes of action in urban area in the basin of two rivers, with 400,000 inhabitants and a variety of industrial activities. Two types of passive samplers, semipermeable membrane devices (SPMD) for hydrophobic contaminants and polar organic chemical integrative samplers (POCIS) for polar compounds such as pesticides and pharmaceuticals, were used to sample wastewater treatment plant (WWTP) influent and effluent as well as rivers upstream and downstream of the urban complex and the WWTP. Compounds with endocrine disruptive potency were detected in river water and WWTP influent and effluent. Year-round, monthly assessment of waste waters by bioassays documented estrogenic, androgenic and dioxin-like potency as well as cytotoxicity in influent waters of the WWTP and allowed characterization of seasonal variability of these biological potentials in waste waters. The WWTP effectively removed cytotoxic compounds, xenoestrogens and xenoandrogens. There was significant variability in treatment efficiency of dioxin-like potency. The study indicates that the WWTP, despite its up-to-date technology, can contribute endocrine disrupting compounds to the river. Riverine samples exhibited dioxin-like, antiestrogenic and antiandrogenic potencies. The study design enabled characterization of effects of the urban complex and the WWTP on the river. Concentrations of PAHs and contaminants and specific biological potencies sampled by POCIS decreased as a function of distance from the city.     

Passive sampling: A cost-effective method for understanding antibiotic fate,behaviour and impact

The occurrence of antibiotics in the environment has raised much concern in recent years. Understanding their release, fate and behaviour in the environment is vital to assess potential risks. In this study, a novel passive water sampler – diffusion gradients in thin-films for organics (o-DGT) – was employed to assess the occurrence and removal of antibiotics in two waste water treatment plants (WWTPs) — one in China and the other in the United Kingdom (UK). Of the targeted compounds, 11 of 19 were detected in the Chinese WWTP (ND—200 ng/L) and 10 of 40 were found in the UK plant (ND—1380 ng/L). Florfenicol, lincomycin, ofloxacin and roxithromycin were most abundant in the Chinese WWTP (influent), while anhydrous erythromycin, ciprofloxacin, trimethoprim, ofloxacin and sulfapyridine were the most abundant in the UK influent samples. Estimated Chinese and UK consumption data are used to interpret the results. Neither of the WWTPs was very effective at removing antibiotics: ~ 40–50% (overall) was removed by the two plants, with the rest being discharged into the receiving rivers. This is the first study using o-DGT to assess the occurrence and removal of antibiotics in WWTPs. o-DGT is a useful, cost-effective tool to assess WWTP performance and can highlight the effectiveness of treatment steps, which can be applied to wastewater based epidemiology studies.     

湖北省湖泊水环境化学特征及其与人类活动的关系

通过对湖北省近３０个湖泊水环境化学的分析，探讨了湖北省湖泊水质状况和湖水的化学稳定性，指出远离工业区和居民生活区的湖泊水质一般较好，城区或城效型湖泊在不同程度上受到了工业废水和生活污水的影响。控制，消除湖泊污染是今后经济、社会和环境建设不可忽视的重要工作。     

Does human activity impact the natural antibiotic resistance background? Abundance of antibiotic resistance genes in 21 Swiss lakes

Antibiotic resistance genes (ARGs) are emerging environmental contaminants, known to be continuously discharged into the aquatic environment via human and animal waste. Freshwater aquatic environments represent potential reservoirs for ARG and potentially allow sewage-derived ARG to persist and spread in the environment. This may create increased opportunities for an eventual contact with, and gene transfer to, human and animal pathogens via the food chain or drinking water. However, assessment of this risk requires a better understanding of the level and variability of the natural resistance background and the extent of the human impact. We have analyzed water samples from 21 Swiss lakes, taken at sampling points that were not under the direct influence of local contamination sources and analyzed the relative abundance of ARG using quantitative real-time PCR. Copy numbers of genes mediating resistance to three different broad-spectrum antibiotic classes (sulfonamides: sul1, sul2, tetracyclines: tet(B), tet(M), tet(W) and fluoroquinolones: qnrA) were normalized to copy numbers of bacterial 16S rRNA genes. We used multiple linear regression to assess if ARG abundance is related to human activities in the catchment, microbial community composition and the eutrophication status of the lakes. Sul genes were detected in all sampled lakes, whereas only four lakes contained quantifiable numbers of tet genes, and qnrA remained below detection in all lakes. Our data indicate higher abundance of sul1 in lakes with increasing number and capacity of wastewater treatment plants (WWTPs) in the catchment. sul2 abundance was rather related to long water residence times and eutrophication status. Our study demonstrates the potential of freshwater lakes to preserve antibiotic resistance genes, and provides a reference for ARG abundance from lake systems with low human impact as a baseline for assessing ARG contamination in lake water.     

The removal of uranium from mining waste water using algal/microbial biomass

We describe a three step process for the removal of uranium (U) from dilute waste waters. Step one involves the sequestration of U on, in, and around aquatic plants such as algae. Cell wall ligands efficiently remove U(VI) from waste water. Growing algae continuously renew the cellular surface area. Step 2 is the removal of U-algal particulates from the water column to the sediments. Step 3 involves reducing U(VI) to U(IV) and transforming the ions into stable precipitates in the sediments. The algal cells provide organic carbon and other nutrients to heterotrophic microbial consortia to maintain the low E(H), within which the U is transformed. Among the microorganisms, algae are of predominant interest for the ecological engineer because of their ability to sequester U and because some algae can live under many extreme environments, often in abundance. Algae grow in a wide spectrum of water qualities, from alkaline environments (Chara, Nitella) to acidic mine drainage waste waters (Mougeotia, Ulothrix). If they could be induced to grow in waste waters, they would provide a simple, long-term means to remove U and other radionuclides from U mining effluents. This paper reviews the literature on algal and microbial adsorption, reduction, and transformation of U in waste streams, wetlands, lakes and oceans.     

Antimicrobial resistance among Pseudomonas spp. and the Bacillus cereus group isolated from Danish agricultural soil

From four Danish pig farms, bacteria of Pseudomonas spp. and the Bacillus cereus group were isolated from soil and susceptibility towards selected antimicrobials was tested. From each farm, soil samples representing soil just before and after spread of animal waste and undisturbed agricultural soil, when possible, were collected. Soil from a well-characterized Danish farm soil (H?jbakkegaard) was collected for comparison. The Pseudomonas spp. and B. cereus were chosen as representative for Gram-negative and Gram-positive indigenous soil bacteria to test the effect of spread of animal waste on selection of resistance among soil bacteria. No variations in resistance levels were observed between farms; but when the four differently treated soils were compared, resistance was seen for carbadox, chloramphenicol, nalidixan (nalidixic acid), nitrofurantoin, streptomycin and tetracycline for Pseudomonas spp., and for bacitracin, erythromycin, penicillin and streptomycin for the B. cereus group. Variations in resistance levels were observed when soil before and after spread of animal waste was compared, indicating an effect from spread of animal waste.     

基于新制度经济学视角的“河长制”评析

我国频发的水危机既是水环境作为居住地、供应站功能而引发的生态破坏问题,也是作为废物库功能而引发的环境污染问题.河长制是地方政府为了重新恢复环境三大功能协调运行而发明的一项有效的实用制度.河长制因其简单易行,很快在全国形成扩散效应.河长制是源于地方政府的制度创新,本文运用新制度经济学分析了河长制的优缺点:优点是职责归属明确,权责清晰；是合理的路径依赖基础上的制度创薪；铁腕治污提高治污效率;创新扩散机制值得提倡.河长制本身存在制度缺陷:无法根除委托-代理问题；缺乏透明的监督机制;容易出现利益合谋；忽视了社会力量；行政问责很难落实.河长制综合考虑了地方权力结构与环境现实,充分利用行政长官手中的权力带动地方政府职能转变,推动了具有中国本土特色环境制度变迁的步伐.但河长制具有应急的过渡性,应在发展中扬长避短,不断完善,应通过它形成全社会参与环境管理的机制,建立可持续发展的环境治理制度.     

Occurrence of sulfonamide residues along the Ebro River basin: removal in wastewater treatment plants and environmental impact assessment

Sulfonamides (SAs) have become one of the antibiotic families most frequently found in all kind of environmental waters. In the present work, the presence of 16 SAs and one of their acetylated metabolites in different water matrices of the Ebro River basin has been evaluated during two different sampling campaigns carried out in 2007 and 2008. Influent and effluent samples from seven wastewater treatment plants (WWTPs), together with a total of 28 river water samples were analyzed by on-line solid phase extraction-liquid chromathography-tandem mass spectrometry (on-line SPE-LC-MS/MS). Sulfamethoxazole and sulfapyridine were the SAs most frequently detected in WWTPs (96-100%), showing also the highest concentrations, ranging from 27.2 ng L(-1) to 596 ng L(-1) for sulfamethoxazole and from 3.7 ng L(-1) to 227 ng L(-1) for sulfapyridine. Sulfamethoxazole was also the SA most frequently detected in surface waters (85% of the samples) at concentrations between 11 ng L(-1) and 112 ng L(-1). In order to assess the effectiveness of the wastewater treatment in degrading SAs, removal efficiencies in the seven WWTPs were calculated for each individual SA (ranging from 4% to 100%) and correlated to the corresponding hydraulic retention times or residence times of the SAs in the plants. SAs half-lives were also estimated, ranging from to 2.5 hours (sulfadimethoxine) to 128 h (sulfamethazine). The contribution of the WWTPs to the presence of SAs depends on both the load of SAs discharging on the surface water from the WWTP effluent but also on the flow of the receiving waters in the discharge sites and the dilution exerted; WWTP4 exerts the highest pressure on the receiving water course. Finally, the potential environmental risk posed by SAs was evaluated calculating the hazard quotients (HQ) to different non-target organisms in effluent and river water. The degree of susceptibility resulted in algae>daphnia>fish. Sulfamethoxazole was the only SA posing a risk to algae in effluent water, with an HQ>7.     

A simplified method for the design and sizing of anaerobic digestion systems for smaller farms

Anaerobic digestion (AD) as a waste treatment practice has existed for nearly 200 years and has become an accepted option for many farming and small-scale residential operations. Many developing countries now encourage the use of AD in order to meet new environmental regulations and/or to provide small amounts of energy resulting from methane generated during the process. This development has been met with some difficulty due to the lack of resources and knowledge of the systems in many of the rural communities in which these digesters are placed. A properly designed AD system can help prevent soil and water pollution as well as help mitigate methane emissions by capturing them for use as a potential energy source. This paper focuses on providing guidance to the proper design and sizing of an AD system for typical small farms, which account for the majority of dairy farms worldwide. A focus was on the implementation of such systems as they might be applied in Central America, although the aspects studied here can be applied for AD systems handling animal waste streams practically anywhere. We provide a method for sizing of anaerobic digester systems based on design standards from the US National Resource Conservation Service and using field sampled data of holding pen wash water runoff. An overview of the decision process for alternative designs is given, and simple-to-use nomographs are presented for use in sizing of an anaerobic digester system for smaller (non-industrial)-scale farms.     

Human recreational exposure to antibiotic resistant bacteria in coastal bathing waters

Infections caused by antibiotic resistant bacteria (ARB) are associated with poor health outcomes and are recognised globally as a serious health problem. Much research has been conducted on the transmission of ARB to humans. Yet the role the natural environment plays in the spread of ARB and antibiotic resistance genes is not well understood. Antibiotic resistant bacteria have been detected in natural aquatic environments, and ingestion of seawater during water sports is one route by which many people could be directly exposed.The aim was to estimate the prevalence of resistance to one clinically important class of antibiotics (third-generation cephalosporins (3GCs)) amongst Escherichia coli in coastal surface waters in England and Wales. Prevalence data was used to quantify ingestion of 3GC-resistant E. coli (3GCREC) by people participating in water sports in designated coastal bathing waters. A further aim was to use this value to derive a population-level estimate of exposure to these bacteria during recreational use of coastal waters in 2012.The prevalence of 3GC-resistance amongst E. coli isolated from coastal surface waters was estimated using culture-based methods. This was combined with the density of E. coli reported in designated coastal bathing waters along with estimations of the volumes of water ingested during various water sports reported in the literature to calculate the mean number of 3GCREC ingested during different water sports.0.12% of E. coli isolated from surface waters were resistant to 3GCs. This value was used to estimate that in England and Wales over 6.3 million water sport sessions occurred in 2012 that resulted in the ingestion of at least one 3GCREC.Despite the low prevalence of resistance to 3GCs amongst E. coli in surface waters, there is an identifiable human exposure risk for water users, which varies with the type of water sport undertaken. The relative importance of this exposure is likely to be greater in areas where a large proportion of the population enjoys water sports. Millions of water sport sessions occurred in 2012 that were likely to have resulted in people ingesting E. coli resistant to a single class of antibiotics (3GCs). However, this is expected to be a significant underestimate of recreational exposure to all ARB in seawater.This is the first study to use volumes of water ingested during different water sports to estimate human exposure to ARB. Further work needs to be done to elucidate the health implications and clinical relevance of exposure to ARB in both marine and fresh waters in order to fully understand the risk to public health.     

Research on whole life cycle carbon emission model of typical buildings

Based on the theory of life cycle assessment (LCA), this article analyzes the influence factors on carbon emissions from residential buildings. In the article, the life cycle of residential buildings has been divided into five stages: building materials production period, construction period, operation and maintenance period, demolition period, and solid waste recycle and disposal period. Based on this definition, the authors provide a theoretical model to calculate carbon emissions of residential building life cycle. In particular, the factor of human activities was introduced in the calculation of carbon emissions from the buildings. Furthermore, the authors put forward a model for calculation with the unit of carbon emissions for per-capita living space.     

Occurrence and fate of hormone steroids in the environment

Hormone steroids are a group of endocrine disruptors, which are excreted by humans and animals. In this paper, we briefly review the current knowledge on the fate of these steroids in the environment. Natural estrogenic steroids estrone (E1), 17beta-estradiol (E2) and estriol (E3) all have a solubility of approximately 13 mg/l, whereas synthetic steroids 17alpha-ethynylestradiol (EE2) and mestranol (MeEE2) have a solubility of 4.8 and 0.3 mg/l, respectively. These steroids have a moderate binding on sediments and are reported to degrade rapidly in soil and water. Estrogenic steroids have been detected in effluents of sewage treatment plants (STPs) in different countries at concentrations ranging up to 70 ng/l for E1, 64 ng/l for E2, 18 ng/l for E3 and 42 ng/l for EE2. E2 concentrations in river waters from Japan, Germany, Italy and the Netherlands ranged up to 27 ng/l. In addition, E2 concentrations ranging from 6 to 66 ng/l have also been measured in mantled karst aquifers in northwest Arkansas. This contamination of ground water has been associated with poultry litter and cattle manure waste applied on the land. Although hormone steroids have been detected at a number of sources worldwide, currently, there is limited data on the environmental behaviour and fate of these hormone steroids in different environmental media. Consequently, the exposure and risk associated with these chemicals are not adequately understood.     

Measurements of radon around closed uranium mines

There are several waste rock yards at closed uranium mines around Ningyo-toge, in the Western Honshu Island of Japan, and measurements of radon were carried out by both the passive method and the sampling method around these yards. As comparatively high radon concentrations were observed in two districts through routine measurements, more detailed measurements were made by the passive method in these districts. The impact of radon emanation from the waste rock yards was small for both residential districts and around these yards when considering the natural background level of radon. In addition, by simultaneous continuous measurements of radon and its progeny at two locations, it was estimated that the effective dose caused by the representative uranium waste rock yards was less than the public effective dose limit of 1 mSv year(-1) at the fenced boundary of the waste rock site.     

Analysis of material stock accumulation in China’s infrastructure and its regional disparity

Materials stocked in infrastructure provide necessary personal and economic services, and are also closely linked with massive resource extraction, energy consumption and waste generation. To support policy deliberations toward regional harmony and sustainable development, this paper examines the temporal change during 1978–2008 and spatial patterns of ten types of materials stocked in four major infrastructures (residential buildings, roads, railways, and water pipelines) in 31 provinces in China, and diagnoses regional disparity and driving factors by Theil index and multivariable regression based on panel data. It was found that the total material stock has boomed to 42.5 billion tons in 2008, with its per capita level increased by nine times over that in 1978. Over 90 % of materials are concentrated in residential buildings and roads, and are spatially inclined to decrease from coastal regions to inland areas. Since China has shifted its strategy from an inclined to harmonious regional development, the overall inequality of per capita material stock has been changing toward equality with its scale contributed mainly by inter-regional inequality, and downward trend affected dominantly by intra-regional inequality. To balance the growth speed across regions meanwhile, to develop economy and attract foreign investment in each region, would be a promising route towards reducing regional inequality. Moreover, the enhancement of governmental performance and construction of each sector’s share would also be effective for decreasing inter-regional gaps.     

Study on Residential Water Use in North China:Analysis of Nationwide Statistical Data and Case Study of Taiyuan City

Residential water use is gradually becoming the focus in China‘s municipal water supply planning and management in recent years. Little is known, however, about the residential water use in modem China due to the transition of economy and enhancement of management on water conservation. In order to better understand the characteristics of residential water use in North China, a model for identifying the determinants of residential water use was established and analyzed by using panel data and cross-section data methodologies. Then Taiyuan city, the capital city of Shanxi Province in Northern China was selected as a case study. Both the analyses and field investigation indicate that the relatively slow increase of residential water use in recent years may result from the implementation of strict laws and regulations on water conservation. And through the investigation,first-hand information about water consumption pattern, water reuse/conservation, people‘s attitude toward water quantity and quality, etc. have been obtained.     

Sustainability research and practices in enforced residential institutions: collaborations of ecologists and prisoners

Enforced institutional settings such as penitentiaries provide environments to raise awareness, carry out research, and implement and assess practices for sustainable living. Institutions where residence is enforced due to health, recreational, military, or legal reasons (e.g., assisted living centers, summer camps, army bases, prisons) house people who may lack scientific training but have time and need for intellectual stimulation that can be filled by supervised research. These institutions have stable populations, structured social organization, and measurable inputs and outputs of materials and energy to carry out sustainable practices in tasks that affect regional resources such as groundwater quality and landfill use. We report on three examples at a corrections center resulting from partnerships among visiting academic ecology researchers, sustainability practitioners, corrections administrators, and prisoners: (1) research on how to sustainably “farm” moss for the horticulture trade to reduce harvesting pressure on wild moss populations; (2) a vermiculture and thermophilic composting system to reduce the kitchen waste; and (3) a monthly seminar series at the prison. Over 26 months: (1) participants developed methods to optimize moss growth; (2) landfill-bound waste and particulate flow rate destined for wastewater treatment decreased by 50%, to less than 50% of permit limits; (3) resulting compost (ca. 5000 kg) fertilized institutional vegetable gardens; (4) water quality improved so that the prison could return funds allocated to upgrade the prison’s water quality. The lectures encouraged intellectual exchange among researchers, convicts, and guards. Researchers derived new perspectives and broader impacts for their work. This can be a model for other correctional facilities and other enforced residential institutions (ERIs). Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Radiosensitivity of subterranean bacteria in the Hungarian Upper Permian Siltstone Formation

The main purpose of this work was to study the radioresistance of subterranean aerobic and anaerobic isolates from the Hungarian Upper Permian Siltstone (Aleurolite) Formation, in order to assess the safety of potential sites of future underground repositories for nuclear waste. A total of 93 isolates were studied. The radiosensitivities of these aerobic and anaerobic bacteria isolates were determined: the D10 values (decimal reducing doses) of the aerobic spore-formers lay in the range 0.80 -2.44 kGy, and those of the anaerobic spore-formers lay in the range 1.86 4.93 kGy. The D10 values of the aerobic and anaerobic vegetative isolates were much lower, in the ranges 0.11 0.57 and 0.22-0.40 kGy. respectively. The variability in bacterial radioresistance indicates the biodiversity at this potential disposal site. These results can affect the construction of a future underground repository, since knowledge of the most resistant microorganism may be of importance as concerns calculation of the time required to inactivate the bacteria surrounding the containers.     

C60-DOM interactions and effects on C60 apparent solubility: a molecular mechanics and density functional theory study

Dissolved organic matter (DOM) plays a critical role in the transport of carbon nano-particles (e.g. C(60)) in the aquatic environment. However, the mechanism for C(60)-DOM interactions and its environmental implications needs further investigations. In this study, the interaction of C(60) with relevant reference compounds of DOM (DOM(R)) is computationally simulated by molecular mechanics and density functional theory (DFT). All the C(60)-DOM(R) complexes are firstly optimized by classical annealing, and then DFT using the Dmol(3) code. The adsorption energies of C(60) on DOM(R) were computed. The computed electrostatic potential indicates that DOM(R) are electron acceptors in the C(60)-DOM(R) complexes, and the thermodynamic calculations indicate that electrostatic interaction is the dominant driving force for the C(60)-gallic acid complexation process in water. The presence of DOM(R) increases the apparent water solubility of C(60). It is also observed that the C(60) apparent water solubility decrease with the increase of the energy gaps of frontier molecular orbitals (E(LUMO)-E(HOMO)) for each C(60)-DOM(R) complex. These findings indicate that computational simulation is an important tool for predicting the behavior and fate of carbon nano-particles in the aquatic environment.     

基于MCR模型的农村居民点布局适宜性分区及优化模式研究——以南京市六合区金牛湖街道为例

农村居民点布局适宜性分区是实现布局优化的基础，也是改善农村生产生活条件、实现耕地占补平衡、统筹城乡发展的重要途径。以南京市六合区金牛湖街道为例，利用GIS技术分析了研究区农村居民点分布现状，采用最小累积阻力模型（MCR）实现了农村居民点布局适宜性分区，从而为农村居民点整理项目实施和村镇建设规划提供了科学依据。研究结果表明：（1）金牛湖街道农村居民点现状在整体上存在“布局松散、面积零碎”的问题；各村（社区）之间地域差异明显、分布不均衡；在空间布局上呈现出沿“低坡度、低高程、交通便利”地带分布的显著特征；（2）按农村居民点布局适宜性程度，可将金牛湖街道划分为5种适宜性分区。其中，高度适宜区占街道总面积的165%，总体上能满足农村居民点用地需求；（3）基于农村居民点现状分析及适宜性分区结果，将各村（社区）划分为“就地城镇化”、“内部整改”、“逐步迁村并点”3种优化模式，并从宏观层面上提出优化路径