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Application of Escherichia coli antibiotic resistance patterns for contamination source identification in watershed 全文
2019
Yu, Tai-Yi | Chin, Ching-Ju Monica | Chang, Yu-Jie
Spatial correlation of pollution of the water resource in Taipei, Taiwan, were examined by analyzing the antibiotic resistance patterns (ARPs) of 96 Escherichia coli colonies, which were isolated from 7 sampling sites in 3 river sections. The ARPs were the growth patterns of isolated E. coli colonies in the medium with seven kinds of antibiotics, including ampicillin, chlortetracycline, erythromycin, oxytetracycline, streptomycin, tetracycline, and salinomycin of different concentrations. The results showed that the survival rate of E. coli decreased with increasing concentration of antibiotics; however, various ARPs under different antibiotics of different concentrations significantly increased both the useful information and complexities. Hierarchical cluster analysis (HCA) and two-stage principal component analysis (PCA) were applied to analyze the spatial correlations and interrelations of distinct ARPs among sampling sites in this study. It was found that the seven sampling sites can be categorized into three groups which may represent three possible pollution characteristics.
显示更多 [+] 显示较少 [-]Performance of a kerb side inlet to irrigate street trees and to improve road runoff water quality: a comparison of four media types 全文
2019
Sapdhare, Harsha | Myers, Baden | Beecham, Simon | Brien, Chris
Performance of a kerb side inlet to irrigate street trees and to improve road runoff water quality: a comparison of four media types 全文
2019
Sapdhare, Harsha | Myers, Baden | Beecham, Simon | Brien, Chris
The TREENET inlet is an emerging water-sensitive urban design technology that consists of a novel kerb side inlet coupled with a leaky well infiltration system. The inlets have been retrofitted to existing roads since 2006; however, there is currently little information available on the effectiveness of these inlet and leaky well systems. This study investigated the performance of the kerb side inlets and leaky well system for water quality improvement prior to infiltration to native soil. The leaky wells included four filter media types, namely gravel, water treatment solids, sandy loam and clay. To compare the performance of the four filter media types, batch and column studies were performed in the laboratory. The best performance was observed using the sandy loam as a filter media, followed by clay, water treatment solids and then gravel. The selection of effective media for removal of heavy metals is important as each media type has different pollutant removal capacity, infiltration and clogging performance.
显示更多 [+] 显示较少 [-]Performance of a kerb side inlet to irrigate street trees and to improve road runoff water quality: a comparison of four media types 全文
2019
Sapdhare, H. | Myers, B. | Beecham, S. | Brien, C.
The TREENET inlet is an emerging water-sensitive urban design technology that consists of a novel kerb side inlet coupled with a leaky well infiltration system. The inlets have been retrofitted to existing roads since 2006; however, there is currently little information available on the effectiveness of these inlet and leaky well systems. This study investigated the performance of the kerb side inlets and leaky well system for water quality improvement prior to infiltration to native soil. The leaky wells included four filter media types, namely gravel, water treatment solids, sandy loam and clay. To compare the performance of the four filter media types, batch and column studies were performed in the laboratory. The best performance was observed using the sandy loam as a filter media, followed by clay, water treatment solids and then gravel. The selection of effective media for removal of heavy metals is important as each media type has different pollutant removal capacity, infiltration and clogging performance. | Harsha Sapdhare, Baden Myers, Simon Beecham, Chris Brien
显示更多 [+] 显示较少 [-]Assessment of intermittent exposure of zinc oxide nanoparticle (ZNP)–mediated toxicity and biochemical alterations in the splenocytes of male Wistar rat 全文
2019
Singh, Neelu | Das, Monoj Kumar | Gautam, Rohit | Ramteke, Anand | Rajamani, Paulraj
Nanoparticles are being used extensively and found in applications to various fields ranging from agriculture to electronic devices, diagnosis to drug delivery, and cosmetics to food packaging. Increasing usage of engineered nanomaterials (ENM) raises potential concern for human health as well as to the environment. The present study aims to explore the effects of intermittent intraperitoneal exposure of ZNP on the spleen of male Wistar rat. Animals were divided into three groups, control and ZNP-treated groups (50 mg/kg and 250 mg/kg body weight), six in each group. Experimental animals were treated with different doses of ZNP once a week for 4 weeks, whereas control groups received water. After 28 days of exposure, animals were sacrificed, spleen tissue was excised, and various parameters such as hematological, genotoxicity, antioxidants, and histopathological were studied for changes in spleen if any. Results showed that ZNP exposure manages to induce alteration in various studied hematological parameters like neutrophils, platelets, and eosinophils which are found to increase significantly after the last treatment compared with the first treatment of ZNP. However, hemoglobin content, PCV, and MCV decrease with increasing dose of ZNP significantly in last treatment, when compared with the first treatment. DNA damage was observed in rats treated with a high dose of ZNPs compared with that in the control when analyzed through comet assay. Flow cytometric study was performed for better understanding of the underlying mechanism of the ZNP-mediated toxicity. From the present investigation, an increase in ROS production, a decrease in MMP, and increased apoptosis were exhibited. Further, altered antioxidant level (SOD, CAT, LDH, CYT P450, and CYT b5 r) has been observed in the studied splenic tissue, also histopathological changes observed in the rats exposed with high doses of ZNP. Therefore, ZNP may have the potential to induce a toxic effect even when exposed intermittently.
显示更多 [+] 显示较少 [-]Occurrence, removal and environmental risk of markers of five drugs of abuse in urban wastewater systems in South Australia 全文
2019
Yadav, Meena K. | Short, Michael D. | Gerber, Cobus | van den Akker, Ben | Aryal, Rupak | Saint, Christopher P.
The occurrence and fate of five drugs of abuse in raw influent and treated effluent wastewater were investigated over a period of 1 year in the Adelaide region of South Australia. Four wastewater treatment plants were chosen for this study and monitored for five drugs which included cocaine in the form of its metabolite benzoylecgonine (BE), methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA) and two opioids (codeine and morphine) during the period April 2016 to February 2017. Alongside concentrations in raw sewage, the levels of drugs in the treated effluent were assessed and removal efficiencies were calculated. Drug concentrations were measured by mixed-mode solid phase extraction and liquid chromatography coupled to a quadrupole mass spectrometer. Drug concentrations detected in the raw wastewater ranged from 7 to 6510 ng/L and < LOD to 4264 ng/L in treated effluent samples. Drug removal rates varied seasonally and spatially. The mass loads of drugs discharged into the environment were in descending order: codeine > methamphetamine > morphine > MDMA > BE. Results showed that all the targeted drugs were on average incompletely removed by wastewater treatment, with removal performance highest for morphine (94%) and lowest for MDMA (58%). A screening-level environmental risk assessment was subsequently performed for the drugs based on effluent wastewater concentrations. Based on calculated risk quotients, overall environmental risk for these compounds appears low, with codeine and methamphetamine likely to pose the greatest potential risk to receiving environments. Given the recognised limitations of current ecotoxicological models and risk assessment methods for these and other pharmaceutical drugs, the potential for environmental impacts associated with the continuous discharge of these compounds in wastewater effluents should not be overlooked.
显示更多 [+] 显示较少 [-]Arsenic exposure intensifies glycogen nephrosis in diabetic rats 全文
2019
Sertorio, Marcela Nascimento | Souza, Ana Cláudia Ferreira | Bastos, Daniel Silva Sena | Santos, Felipe Couto | Ervilha, Luiz Otávio Guimarães | Fernandes, Kenner Morais | de Oliveira, Leandro Licursi | Machado-Neves, Mariana
It is known that either arsenic exposure or diabetes can impact renal function. However, it is unclear how these combined factors may influence kidney functions. Therefore, we evaluated morphological, functional, and oxidative parameters in the kidney of diabetic rats exposed to arsenic. Healthy male Wistar rats and streptozotocin-induced diabetic rats were exposed to 0 and 10 mg/L arsenate through drinking water for 40 days. Renal tissue was assessed using morphometry, mitosis and apoptosis markers, mineral proportion, oxidative stress markers, as well as the activity of antioxidant enzymes and membrane-bound adenosine triphosphatases. Arsenate intake altered glucose levels in healthy animals, but it did not reach hyperglycemic conditions. In diabetic animals, arsenate led to a remarkable increase of glycogen nephrosis in distal tubules. In these animals, additionally, the activity of catalase and glutathione S-transferase, besides the proportion of Fe, Cu, and K in renal tissue, was altered. Nevertheless, arsenate did not accumulate in the kidney and did not impact on other parameters previously altered by diabetes, including levels of malondialdehyde, Na, urea, creatinine, and apoptosis and mitosis markers. In conclusion, besides the intensification of glycogen nephrosis, the kidney was able to handle arsenate toxicity at this point, preventing arsenic deposition in the exposed groups and the impairment of renal function.
显示更多 [+] 显示较少 [-]Chemical composition and health risk indices associated with size-resolved particulate matter in Pearl River Delta (PRD) region, China 全文
2019
Fang, Dongqing | Huang, Wei | Antkiewicz, Dagmara S. | Wang, Yuqin | Khuzestani, Reza Bashiri | Zhang, Yang | Shang, Jing | Shafer, Martin M. | He, Lingyan | Schauer, James J. | Zhang, Yuanxun | Zhao, Shuo
Size-resolved particulate matter (PM) was collected at the Heshan Super-Station in the Pearl River Delta (PRD) region, China, to evaluate their chemical characteristics and potential health risks. The chemical mass closures illustrate that the dominant fraction in coarse (2.5 μm < Dₚ < 10 μm) PM was dust, while organic matter made up a substantial portion of both fine (0.1 < Dₚ < 2.5 μm) and ultra-fine (Dₚ < 0.10 μm) PM fractions. The size distribution of most PM components varied substantially. PM, NO₃⁻, K⁺, Cl⁻, Na⁺ and most of the transition/redox metals displayed bimodal size distributions with the dominant peak at 0.32–0.56 μm plus a small peak at 1.8–3.2 μm. In contrast, unimodal size distributions were found for the rest of the species, such as water-soluble organic carbon (WSOC), NH₄⁺, and SO₄²⁻ and the majority of oxyanion metals with a single peak at 0.32–0.56 μm, and Mg²⁺, Ca²⁺, and dust tracer elements which mainly accumulated in coarse particles. Based on the crustal enrichment factor (CEF) analysis, Cd, Zn, Sb, Sn, As, Pb, Mo, Cu, and Cr primarily originated from anthropogenic activities, while Ti in all size fractions and Sr, Mg, Na, and Fe in fine and ultra-fine particles were mainly emitted from natural sources. The potential health risk assessment of trace metals was performed using the hazard quotient (HQ) and excess lifetime cancer risk (ELCR) indices. Although the adverse health effects of most metals were limited, significant potential carcinogenic risks were found for As and Cr in both fine and coarse particle size fractions, which contributed more than 95% of total ELCR. Therefore, considering that these two elements were mainly emitted from industrial processes, improvements in air quality and health risks in the PRD region can be largely achieved by reducing the emissions of local industrial sources.
显示更多 [+] 显示较少 [-]Who cares what parents think or do? Observational learning and experience-based learning through communication in rice farmers’ willingness to adopt sustainable agricultural technologies in Hubei Province, China 全文
2019
Zeng, Yangmei | Zhang, Junbiao | He, Ke | Cheng, Linlin
Sustainable agricultural technologies are of great significance in fully utilizing agricultural resources and promoting agricultural production. However, the adoption rates of these technologies are often characterized as low in rural areas in China. To figure out the potential salient determinants of rice farmers’ willingness to adopt sustainable agricultural technologies, this paper, by employing the multivariate probit model and ordered probit model, particularly and firstly explores the roles of observational learning and experience-based learning through communication from parents within the household on rice farmers’ willingness to adopt these technologies. Results show that there are strong complementarities and substitutabilities between sustainable agricultural technologies that rice farmers are willing to adopt, and that observational learning and experience-based learning through communication within the household do have pronounced effects on rice farmers’ willingness to adopt some sustainable agricultural technologies and on their intensive use intentions. Therefore, while formulating policies to improve the adoption rates and adoption intensity of these technologies, relevant government agencies should take the complementarities and substitutabilities between sustainable agricultural technologies as well as observational learning and experience-based learning through communication from parents into consideration.
显示更多 [+] 显示较少 [-]The effects of tetracycline concentrations on tetracycline resistance genes and their bacterial hosts in the gut passages of earthworms (Eisenia fetida) feeding on domestic sludge 全文
2019
Wang, Yue | Yin, Zhifeng | Zhao, Haitao | Hu, Jian | Kang, Yijun
Vermi-composting is considered to be a feasible method for reducing tetracycline resistance genes (TRGs) in the sludge. Nevertheless, the way different gut passages of earthworm might affect the fates of TRGs and whether this process is affected by tetracycline (TC) concentrations need to be further investigated. In this study, we examined the effects of TC concentrations on changes in TRGs and bacterial communities in gut passages of earthworm were determined by using quantitative PCR and Illumina high-throughput sequencing. TRGs and intI1 were mainly reduced in the hindgut under the TC concentrations ranging from 0 to 25 mg/kg, while they were enriched under higher TC stress exposure. Consequently, we suggest the TC limitation of 25 mg/kg in the domestic sludge (DS) for vermi-composting. Although the predominant genera were TC sensitive under TC stress, many bacterial hosts harboring multiple TRGs (especially those in the hindgut) should be paid further attention to. In the foregut, five genera with abundant tetracycline-resistant bacteria (TRB) were specialized taxa. Among these genera, Unclassified_Solirubrobacterales and Pirellulaceae were probably related to the digestion processes. Other unclassified taxa related to the TRGs were probably derived from the DS. Five genera with abundant TRB were shared in the gut passages, and three specialized genera in the hindgut. These genera could spread TRGs and intI1 to the environment. These results suggest that vermi-composting is a feasible approach for TRG control in the DS containing TC concentration that does not exceed 25 mg/kg. Fates of TRGs and intI1 widely differ in the gut passages, showing inevitable connections with bacterial communities.
显示更多 [+] 显示较少 [-]Anaerobic degradation of 2,4,5-trichlorophenoxyacetic acid by enrichment cultures from freshwater sediments 全文
2019
Al-Fathi, Hassan | Koch, Mandy | Lorenz, Wilhelm G. | Lechner, Ute
The anaerobic biodegradation of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) was investigated using enrichment cultures from freshwater sediments at two different sites in the region of Halle, central Germany. 2,4,5-T and different organic acids or hydrogen were added as possible electron acceptor and electron donors, respectively. The primary enrichment cultures from Saale river sediment completely degraded 2,4,5-T to 3-chlorophenol (3-CP) (major product) and 3,4-dichlorophenol (3,4-DCP) during a 28-day incubation period. Subcultures showed ether cleavage of 2,4,5-T to 2,4,5-trichlorophenol and its stoichiometric dechlorination to 3-CP only in the presence of butyrate. In contrast, the primary enrichment culture from sediment of Posthorn pond dechlorinated 2,4,5-T to 2,5-dichlorophenoxyacetic acid (2,5-D), which, in the presence of butyrate, was degraded further to products such as 3,4-DCP, 2,5-DCP, and 3CP, indicating ether cleaving activities and subsequent dechlorination steps. Experiments with pure cultures of Dehalococcoides mccartyi and Desulfitobacterium hafniense demonstrated their specific dechlorination steps within the overall 2,4,5-T degradation pathways. The results indicate that the route and efficiency of anaerobic 2,4,5-T degradation in the environment depend heavily on the microorganisms present and the availability of slowly fermentable organic compounds.
显示更多 [+] 显示较少 [-]Evaluating gas chromatography with a halogen-specific detector for the determination of disinfection by-products in drinking water 全文
2019
Andersson, Anna | Ashiq, Muhammad Jamshaid | Shoeb, Mohammad | Karlsson, Susanne | Bastviken, David | Kylin, Henrik
The occurrence of disinfection by-products (DBPs) in drinking water has become an issue of concern during the past decades. The DBPs pose health risks and are suspected to cause various cancer forms, be genotoxic, and have negative developmental effects. The vast chemical diversity of DBPs makes comprehensive monitoring challenging. Only few of the DBPs are regulated and included in analytical protocols. In this study, a method for simultaneous measurement of 20 DBPs from five different structural classes (both regulated and non-regulated) was investigated and further developed for 11 DBPs using solid-phase extraction and gas chromatography coupled with a halogen-specific detector (XSD). The XSD was highly selective towards halogenated DBPs, providing chromatograms with little noise. The method allowed detection down to 0.05 μg L⁻¹ and showed promising results for the simultaneous determination of a range of neutral DBP classes. Compounds from two classes of emerging DBPs, more cytotoxic than the “traditional” regulated DBPs, were successfully determined using this method. However, haloacetic acids (HAAs) should be analyzed separately as some HAA methyl esters may degrade giving false positives of trihalomethanes (THMs). The method was tested on real water samples from two municipal waterworks where the target DBP concentrations were found below the regulatory limits of Sweden.
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