upstream site
Recently Published Documents


TOTAL DOCUMENTS

94
(FIVE YEARS 14)

H-INDEX

25
(FIVE YEARS 3)

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3172
Author(s):  
Devika Nair ◽  
K. G. Evans ◽  
Sean Bellairs ◽  
M. R. Narayan

Mining can cause environmental disturbances and thus mined lands must be managed properly to avoid detrimental impacts in the future. They should be rehabilitated in such a way that post mining landforms behave similarly as the surrounding stable undisturbed areas. A challenge for government regulators and mine operators is setting closure criteria for assessment of the stability of the elevated post-mining landforms. Stability of a landform is often measured by the number and incision depth of gullies. This can assess mass stability and bulk movement of coarse material. However, there is a need for a more sensitive approach to assess catchment disturbances using the concept of waves of fine suspended sediment and thus determine the dynamics of recovery of a post mining landform. A more environmentally meaningful approach would be to assess the fine suspended sediment (FSS, silt + clay (0.45 µm < diameter < 63 µm)) leaving the system and entering downstream waterways. We propose assessing stability through relationships between rainfall event loads of FSS and event discharge (Q) in receiving streams. This study used an innovative approach where, instead of using instantaneous FSS concentration, it used total FSS load in waves of sediment driven through the system by rainfall runoff events. High resolution stream monitoring data from 2004 to 2015 in Gulungul and Magela Creeks, Northern Territory, Australia, were used to develop a relationship between sediment wave and event discharge, ∑FSS α f(Q). These creeks are adjacent to and receive runoff from Ranger Mine. In 2008, a 10 ha elevated waste rock landform was constructed and instrumented in the Gulungul Creek catchment. The earthworks required to build the landform created a considerable disturbance in the catchment, making a large volume of disturbed soil and substrate material available for erosion. Between 2008 and 2010, in the first two wet seasons immediately after construction, the downstream monitoring site on Gulungul Creek showed elevated FSS wave loads relative to discharge, compared with the upstream site. From 2010 onwards, the FSS loads relative to Q were no longer elevated. This was due to the establishment of vegetation on the site and loose fine sediment being trapped by vegetation. Large scale disturbance associated with mining and rehabilitation of elevated landforms causes elevated FSS loads in receiving streams. The predicted FSS loads for the stream as per the relationships between FSS and event discharge may not show a 1:1 relation with the observed loads for respective gauging stations. When downstream monitoring shows that FSS wave loads relative to rainfall runoff event discharge reduce back to pre-construction catchment levels, it will indicate that the landform is approaching equilibrium. This approach to assess landform stability will increase the sensitivity of assessing post-mining landform recovery and assist rehabilitation engineers to heal the land and benefit owners of the land to whom it is bestowed after rehabilitation.


2021 ◽  
Author(s):  
Cheng-Han Liu ◽  
Yi-Lynne Chuang ◽  
Revathi Gurunathan ◽  
Chi-Ying Hsieh ◽  
Hans-Uwe Dahms

Abstract Wastewater emission to surface waters is a major pathway for antibacterials and antibacterial-resistant bacteria. Polluted waterbodies such as rivers provide a reservoir for bacterial resistance. We studied water quality and bacterial antibacterial resistance along the subtropical Qishan River in Taiwan as a case study of environmental resistance spread in a pristine to rural area. Human settlement densities increased generally from pristine mountain sites to the more polluted lowlands generally. Accordingly, as a working hypothesis, we expected antibacterial resistance level to increase towards downstream. We collected sediment samples from 8 stations along the Qishan river and where the Qishan river reaches the Kaoping river. The samples were processed in the lab for bacteriological and physicochemical analysis. Antibacterial resistance was tested by disk diffusion and micro-dilution with ten common antibacterials. A comparison was made among the sites where isolates began to occur at the upstream (site 1–6) with the downstream, including site 7 (Qishan town), site 8 (wastewater treatment plant) and site 9 (Kaoping river). The results of multivariate analysis for bacteriological and physicochemical parameters showed increasing water pollution levels downstream of the Qishan river. Ten bacteria including Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Enterobacter sp., Acinetobacter sp., Staphylococcus spp. and Bacillus spp. were analyzed and tested in the study. Their percentage of occurrence varied at each site. The resistance level was determined from the growth inhibition zone diameter (disk diffusion) and the minimum inhibitory concentration (micro-dilution). The results indicated that antibacterial resistance was related to certain environmental factors. Besides, the usage pattern of different classes of antibacterials in different places could alter trends of their resistance. Bacteria were found with increased resistance to antibacterials used in agriculture through the downstream sites according to the results. The WWTP emitting wastewater was demonstrated to be a hotspot of resistance in aquatic environments. In conclusion, bacterial resistance against antibacterials from the Qishan river has become a potential public health threat. This study could assist authorities by providing a reference for water quality risk assessment and management in Kaohsiung city and southern Taiwan.


2021 ◽  
Author(s):  
Cheng-Han Liu ◽  
Yi-Lynne Chuang ◽  
Revathi Gurunathan ◽  
Chi-Ying Hsieh ◽  
Hans-Uwe Dahms

Abstract Wastewater emission to surface waters is a major pathway for antibacterials and antibacterial-resistant bacteria. Polluted waterbodies such as rivers provide a reservoir for bacterial resistance. We studied water quality and bacterial antibacterial resistance along the subtropical Qishan River in Taiwan as a case study of environmental resistance spread in a pristine to rural area. Human settlement densities increased generally from pristine mountain sites to the more polluted lowlands generally. Accordingly, as a working hypothesis, we expected antibacterial resistance level to increase towards downstream. We collected sediment samples from 8 stations along the Qishan river and where the Qishan river reaches the Kaoping river. The samples were processed in the lab for bacteriological and physicochemical analysis. Antibacterial resistance was tested by disk diffusion and micro-dilution with ten common antibacterials. A comparison was made among the sites where isolates began to occur at the upstream (site 1-6) with the downstream, including site 7 (Qishan town), site 8 (wastewater treatment plant) and site 9 (Kaoping river). The results of multivariate analysis for bacteriological and physicochemical parameters showed increasing water pollution levels downstream of the Qishan river. Ten bacteria including Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Enterobacter sp., Acinetobacter sp., Staphylococcus spp. and Bacillus spp. were analyzed and tested in the study. Their percentage of occurrence varied at each site. The resistance level was determined from the growth inhibition zone diameter (disk diffusion) and the minimum inhibitory concentration (micro-dilution). The results indicated that antibacterial resistance was related to certain environmental factors. Besides, the usage pattern of different classes of antibacterials in different places could alter trends of their resistance. Bacteria were found with increased resistance to antibacterials used in agriculture through the downstream sites according to the results. The WWTP emitting wastewater was demonstrated to be a hotspot of resistance in aquatic environments. In conclusion, bacterial resistance against antibacterials from the Qishan river has become a potential public health threat. This study could assist authorities by providing a reference for water quality risk assessment and management in Kaohsiung city and southern Taiwan.


Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2122
Author(s):  
Gabriella Balasa ◽  
Enjolie S. Levengood ◽  
Joseph M. Battistelli ◽  
Rima B. Franklin

Wastewater contamination and urbanization contribute to the spread of antibiotic resistance in aquatic environments. This is a particular concern in areas receiving chronic pollution of untreated waste via combined sewer overflow (CSO) events. The goal of this study was to expand knowledge of CSO impacts, with a specific focus on multidrug resistance. We sampled a CSO-impacted segment of the James River (Virginia, USA) during both clear weather and an active overflow event and compared it to an unimpacted upstream site. Bacteria resistant to ampicillin, streptomycin, and tetracycline were isolated from all samples. Ampicillin resistance was particularly abundant, especially during the CSO event, so these isolates were studied further using disk susceptibility tests to assess multidrug resistance. During a CSO overflow event, 82% of these isolates were resistant to five or more antibiotics, and 44% were resistant to seven or more. The latter statistic contrasts starkly with the upstream reference site, where only 4% of isolates displayed resistance to more than seven antibiotics. DNA sequencing (16S rRNA gene) revealed that ~35% of our isolates were opportunistic pathogens, comprised primarily of the genera Stenotrophomonas, Pseudomonas, and Chryseobacterium. Together, these results demonstrate that CSOs can be a significant source of viable clinically-relevant bacteria to the natural environment and that multidrug resistance is an important understudied component of the environmental spread of antibiotic resistance.


2021 ◽  
Author(s):  
Li Xu ◽  
Chao Liu ◽  
Changpeng Xin ◽  
Wenqing Wang

Abstract Background: Mangrove environments are often characterized by large fluctuations in salinity, ranging from freshwater to hypersaline conditions. Most reports have focused on the mechanisms by which mangroves adapt to high salinity. However, how mangroves cope with seasonal freshwater habitats has seldom been studied. To address this question, we surveyed the river salinity and leaf traits (chlorophyll fluorescence, ion concentrations, carbon isotope ratios and osmolality) of Aegiceras corniculatum (L.) Blanco (river mangrove) along a freshwater-dominated river.Results: Aegiceras corniculatum at the upstream site was subjected to low salinity, being in fresh water for a long period (up to 310 h) in the wet season and experiencing a short term of low salinity in the dry season. The actual photosystem II efficiency (ФPSII) and electron transport rates (ETR) of the leaves at the upstream site decreased in the wet season, and recovered substantially in the dry season. Quenching analysis indicated that there was only a down-regulation of photoprotection, but no photoinhibition at the upstream site in the wet season. An explanation for this is that high levels of Na+ and Cl- were maintained in the leaves in the wet season.Conclusions: Long-term freshwater is a stressful environment for A. corniculatum. Aegiceras corniculatum maintains certain level Na+ and Cl- to adapt the seasonal freshwater.


Antibiotics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 575
Author(s):  
Emi Nishimura ◽  
Masateru Nishiyama ◽  
Kei Nukazawa ◽  
Yoshihiro Suzuki

Information on the actual existence of antibiotic-resistant bacteria in rivers where sewage, urban wastewater, and livestock wastewater do not load is essential to prevent the spread of antibiotic-resistant bacteria in water environments. This study compared the antibiotic resistance profile of Escherichia coli upstream and downstream of human habitation. The survey was conducted in the summer, winter, and spring seasons. Resistance to one or more antibiotics at upstream and downstream sites was on average 18% and 20%, respectively, and no significant difference was observed between the survey sites. The resistance rates at the upstream site (total of 98 isolated strains) to each antibiotic were cefazolin 17%, tetracycline 12%, and ampicillin 8%, in descending order. Conversely, for the downstream site (total of 89 isolated strains), the rates were ampicillin 16%, cefazolin 16%, and tetracycline 1% in descending order. The resistance rate of tetracycline in the downstream site was significantly lower than that of the upstream site. Furthermore, phylogenetic analysis revealed that many strains showed different resistance profiles even in the same cluster of the Pulsed-Field Gel Electrophoresis (PFGE) pattern. Moreover, the resistance profiles differed in the same cluster of the upstream and the downstream sites. In flowing from the upstream to the downstream site, it is plausible that E. coli transmitted or lacked the antibiotic resistance gene.


2020 ◽  
Vol 8 (8) ◽  
pp. 1248
Author(s):  
Yo-Jin Shiau ◽  
Chiao-Wen Lin ◽  
Yuanfeng Cai ◽  
Zhongjun Jia ◽  
Yu-Te Lin ◽  
...  

Mangrove forests are one of the important ecosystems in tropical coasts because of their high primary production, which they sustain by sequestering a substantial amount of CO2 into plant biomass. These forests often experience various levels of inundation and play an important role in CH4 emissions, but the taxonomy of methanotrophs in these systems remains poorly understood. In this study, DNA-based stable isotope probing showed significant niche differentiation in active aerobic methanotrophs in response to niche differentiation in upstream and downstream mangrove soils of the Tamsui estuary in northwestern Taiwan, in which salinity levels differ between winter and summer. Methylobacter and Methylomicrobium-like Type I methanotrophs dominated methane-oxidizing communities in the field conditions and were significantly 13C-labeled in both upstream and downstream sites, while Methylobacter were well adapted to high salinity and low temperature. The Type II methanotroph Methylocystis comprised only 10–15% of all the methane oxidizers in the upstream site but less than 5% at the downstream site under field conditions. 13C-DNA levels in Methylocystis were significantly lower than those in Type I methanotrophs, while phylogenetic analysis further revealed the presence of novel methane oxidizers that are phylogenetically distantly related to Type Ia in fresh and incubated soils at a downstream site. These results suggest that Type I methanotrophs display niche differentiation associated with environmental differences between upstream and downstream mangrove soils.


2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
W. M. Dimuthu Nilmini Wijeyaratne ◽  
P. G. Minola Udayangani Wickramasinghe

Appropriate effluent treatment processes are expected to significantly reduce the toxicity of effluents before they are released to the natural environment. The present study was aimed to assess the spatial and temporal variations of the physical and chemical water quality parameters of a natural water body receiving treated textile effluents and to assess the chromosomal abnormalities induced by the treated textile effluents. Four sampling sites (A: effluent discharge point; B: 100 m downstream from site A along the tributary; C: 200 m downstream from site A along the tributary; D: 100 m upstream from site A along the tributary) were selected associated to a tributary that received treated textile effluent. The physical and chemical water quality parameters were measured in the composite water samples collected from the study sites, and Allium cepa bioassay was conducted using aged tap water as the control. Sampling was conducted in both rainy and dry seasons. The conductivity, TDS, COD, and colour intensity of the water samples collected from the study sites were significantly higher during the dry season compared to those in the rainy season. Allium cepa root meristematic cells exposed to water samples from sites A, B, and C showed a significantly high interphase and prophase indices compared to those exposed to aged tap water and upstream site during both rainy and dry seasons. The mitotic index of the root tip cells of Allium cepa bulbs exposed to the water samples collected from the effluent discharge point (site A) and from the 100 m downstream site from site A (site B) was significantly lower than that of the other sites in both rainy and dry seasons. However, the mitotic index of the root tip cells of Allium cepa bulbs exposed to the water samples from the upstream site was not significantly different from that of the control treatment during both sampling seasons. The bioassay indicated that the mitotic index and phase index of the root meristematic cells of Allium cepa can be affected by the treated textile effluents released to the water body and the occurrence of C metaphase, chromosomal adherence, bridges, disturbed anaphase, vagrant chromosomes, and chromosomal breaks indicated that the treated textile effluent receiving tributary can possibly contain genotoxic and mutagenic compounds which can induce chromosomal abnormalities.


2020 ◽  
Vol 42 (7) ◽  
pp. 327-338
Author(s):  
Haeran Moon ◽  
Da-Hye Kim ◽  
Ki Yong Kim ◽  
Wonjin Sim ◽  
Jeong-Eun Oh

Objectives:This study aimed to investigate distributions of three nitrophenols (4-nitrophenol, 2,4-dinitrophenol, 2-methyl-4,6-dinitrophenol) and five insecticides (acetamiprid, dinotefuran, thiacloprid, triflumuron, chlorfluazuron) in the Daecheong lake that is primary water resources for the central area in Korea including Daejeon. Furthermore, the effect of land use type and monthly precipitation on the concentration trends of nitrophenols and insecticides were assessed.Methods:River water samples were obtained for once in a month for five months (June to October in 2016) in seven sites of the Daecheong lake. All residues were analyzed by LC-ESI/MSMS after extraction using solid phase extraction cartridge. Method detection limit (MDL) of nitrophenols and insecticides were 0.4-1.2 ng/L and 0.2-5.0 ng/L, respectively. Average recoveries were 93.1% for nitrophenols (2,4,6-Tribromophenol), 68.7% and 41.3% for insecticides (Acetamiprid-d3, Thiacloprid-d4, respectively).Results and Discussion:Detection frequencies (DF) and total concentrations of three nitrophenols were 71.4 to 100%, and not detected (ND) to 487 ng/L, respectively. Among insecticides, DF of neonicotinoids (acetamiprid, dinotefuran, thiacloprid) and benzoylureas (triflumuron, chlorfluazuron) ranged 28.6 to 100%, and 0 to 28.6%. Total concentrations of insecticides were ND to 253 ng/L. Total concentrations of all target compounds showed a significant difference between upstream and downstream, and adjacent lake by Mann-whitney U test. According to raising precipitation, an increasing pattern of three nitrophenols was revealed in tributaries and lakes but not observed three neonicotinoids in three lake sites. In June, dinotefuran was not detected at the Juwon upstream site with a forest land coverage, however the concentrations rapidly increased from July to August, followed by a sharp decrease in September. For the other four sites (Daecheong dam, Munui, Chudong, and Pumgok streams), dinotefuran concentrations increased by over 20 times between July and October.Conclusions:In the Daecheong lake, which is used as a water supply source for over 3,470,000 personnel, three nitrophenol levels indicated 1,000 times lower than US EPA water quality criteria (WQC) unless high detection frequency (up to 70%). Similarly, there is only WQC among insecticides, acetamiprid showed under 1% of those of guideline. These results are acceptable as a drinking water supply source. To assess the correlation between characteristics of potential origin sources by land coverage and pollutant distributions, and relative monthly precipitation, it is indicated to be increased levels along with upstream surrounding with shrubland to downstream and adjacent lake covered with mixed land coverage (i.g. shrub, and human activities such as rice paddy, farm, transportation, and living). Besides, precipitation was higher as much as increasing concentration. It might be assumed that nitrophenols and insecticides spilled as non-target contamination sources with rainfall. Dinotefuran concentrations in Juwon upstream and three-site of lakes were massively increased in summer and autumn season considered as a pesticide spraying season for bug control such as Japanese pine sawyer, fruit moth, lace bug, and mites. These results implicated the possibility of using insecticides in a sanctuary where use of pesticides is prohibited.


Author(s):  
Bilyaminu Garba Jega ◽  
O. O. Adebisi ◽  
S. S. Manga ◽  
A. Muhammad

The physicochemical parameters of the thirty water samples collected at the point of discharge of abattoir wastewater as site A (upstream), site B  (downstream) and site C (the irrigation space) of the seasonal River Tagangu were analyzed. The parameters tested include: pH, temperature, turbidity, conductivity, dissolved oxygen (DO), biological oxygen demand (BOD), nitrate, sulphate, phosphate and ammonium. All the parameters were tested following the standard procedures. The pH values obtained ranged from 6.5–7.9; suggestive of suitability of the water for bacterial growth. The temperature values ranged from 21.2–31.2oC; falling within the WHO standard. The turbidity of the water samples ranged from 520–627 NTU, which are exceedingly higher than WHO limit. The conductivity of the water samples ranged from 42.9–624.0 mS/cm; values were far higher than 400.0 mS/cm of WHO standard. The dissolved oxygen (DO) measured between 6.9-19.0 mg/l; which is also greater than WHO standard (6.0 mg/l). Biological oxygen demand (BOD) measured between 312–527.9 mg/l; greater than WHO threshold of 10.0 mg/l. The nitrate contents varied between 39.2–72.3 mg/l; greater than WHO standard (10 mg/l). The sulphate values varied between 45.6–93.9 mg/l; falling within the WHO threshold. However, values greater than 10 mg/l, suggests that the water has been polluted. The phosphate contents observed ranged from 0.435–0.849 mg/l across the three sites, values were higher than 0.3 mg/l of WHO standard. The ammonia contents of the water samples ranged from 27.7–948.5 mg/l; far greater than 0.5 mg/l of WHO standard. The physicochemical study across the three (3) sites shows the typical pollution of the river and rendered the quality of the water hazardous to humans, animals and aquatic lives that could be the users of the water.


Sign in / Sign up

Export Citation Format

Share Document