Stagnant Water Samples Research Articles

Multiplex Real-Time Polymerase Chain Reaction Assay To Detect Acanthamoeba spp., Vermamoeba vermiformis, Naegleria fowleri, and Balamuthia mandrillaris in Different Water Sources.

Free-living amoebae (FLA) are widely distributed in the environment. Among these, Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris, and Vermamoeba vermiformis have been reported as human pathogens with health effects ranging from lethal encephalitis to different epithelial disorders. Despite this, FLA still present many diagnostic challenges. The aim of this study was to develop a rapid and efficient multiplex real-time quantitative polymerase chain reaction (qPCR) to simultaneously detect Acanthamoeba spp., N. fowleri, B. mandrillaris, and V. vermiformis in different water sources. For the validation of the qPCR assay, 38 samples (19 tap water and 19 stagnant water sources) were analyzed. The qPCR assay accurately identified the four types of FLA with no cross-reactivity. Considering water samples with results subsequently confirmed by conventional PCR, the multiplex qPCR assay detected 18/38 (47.4%) positive samples (Acanthamoeba spp. in 44.7% and V. vermiformis in 31.6%) and growth in nonnutritive agar (NNA) cultures identified 7/38 (18.4%) positive samples. Of the tap water samples analyzed, 26.3% of samples positive for FLA were detected by growth in NNA culture whereas 31.6% were identified by qPCR. In addition, FLA were detected in 2/19 stagnant water samples (10.5%) by growth in NNA culture and in 12/19 stagnant water samples (63.2%) by qPCR. Neither N. fowleri nor B. mandrillaris was detected in the water samples analyzed. In conclusion, the qPCR developed showed its potential as a rapid tool for detection of Acanthamoeba spp., N. fowleri, B. mandrillaris, and V. vermiformis. Moreover, FLA species were detected in half of the water sources evaluated, suggesting the importance of the surveillance of these potential infectious agents.

Analysis of particles containing alpha emitters in stagnant water in Fukushima Daiichi Nuclear Power Station’s Unit 3 reactor building

Particles containing alpha (α) nuclides were identified from sediment in stagnant water in the Unit 3 reactor building of the Fukushima Daiichi Nuclear Power Station (FDiNPS). We analyzed different concentrations of α-nuclide samples collected at two sampling sites, the torus room and the main steam isolation valve (MSIV) room. The solids in the stagnant water samples were classified, and the uranium (U) and total alpha concentrations of each fraction were measured by dissolution followed by inductively coupled plasma mass spectrometry and α-spectrometry. Most of the α-nuclides in the stagnant water samples from the torus and MSIV rooms were in particle fractions larger than 10 μm. We detected uranium-bearing particles ranging from sub-µm to 10 µm in size by scanning electron microscopy–energy-dispersive X-ray (SEM–EDX) observations. The chemical forms of U particles were determined in U–Zr oxides, oxidized UO2, and U3O8 with micro-Raman spectroscopy. Other short-lived α-nuclides (plutonium [Pu], americium [Am], and curium [Cm]) were detected by alpha track detection, and the particles with α-nuclides was characterized by SEM–EDX analysis. α-nuclide-containing particles with several tens to several 100 µm in size mainly comprised iron (Fe) oxyhydroxides. In addition, we detected adsorbed U onto Fe oxyhydroxide particles in the MSIV room sample, which indicated nuclear fuel dissolution and secondary U accumulation. This study clarifies the major characteristics of U and other α-nuclides in sediment in stagnant water in the FDiNPS Unit 3 reactor building, which significantly contribute to the consideration of removal methods for particles containing α-nuclides in the stagnant water.

IEUBK Modeling of Children's Blood Lead Levels in Homes Served by Private Domestic Wells in Three Illinois Counties.

Lead is known to impair neurocognitive development in children. Drinking water is routinely monitored for lead content in municipal systems, but private well owners are not required to test for lead. The lack of testing poses a risk of lead exposure and resulting health effects to rural children. In three Illinois counties, we conducted a cross-sectional study (n = 151 homes) examining water lead levels (WLLs), water consumption, and water treatment status to assess risk of lead exposure among residents using private water wells. Since blood lead levels (BLLs) were not available, EPA's Integrated Exposure Uptake Biokinetic (IEUBK) modeling was used to estimate the incremental contribution of WLL to BLL, holding all other sources of lead at their default values. Nearly half (48.3%) of stagnant water samples contained measurable lead ranging from 0.79 to 76.2 µg/L (median= 0.537 µg/L). IEUBK modeling showed BLLs rose from 0.3 to 0.4 µg/dL when WLLs rose from 0.54 µg/L (the tenth percentile) to 4.88 µg/L (the 90th percentile). Based on IEUBK modeling, 18% of children with a WLL at the 10th percentile would have a BLL above 3.5 µg/dL compared to 27.4% of those with a WLL at the 90th percentile. These findings suggest that the consumption of unfiltered well water likely results in increased blood lead levels in children.

High-risk clonal lineages among extended-spectrum β-lactamase producing Escherichia coli and Klebsiella pneumoniae from urban and rural stagnant water samples in Tunisia

AbstractThis study sought to investigate the occurrence and subsequently to characterize extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae from urban and rural stagnant water samples during the wet season (December to February) in several regions of northern Tunisia. From 56 stagnant water samples, 14 ESBL-producing Enterobacteriaceae were recovered, including 9 Escherichia coli, 3 Klebsiella pneumoniae, and 2 K. oxytoca. Most isolates were multidrug-resistant, with ESBL production primarily encoded by blaCTX-M-15 (n = 8) and blaCTX-M-1 (n = 4) followed by blaCTX-M-55 (n = 1) and blaTEM-26 (n = 1). One K. pneumoniae isolate co-harbored blaKPC and blaCTX-M-15 genes. Class 1 integrons were detected in 4 isolates, however, sul1, sul2, and aac(6′)-Ib-cr genes were detected in eleven, two, and four isolates, respectively. The nine E. coli isolates belonged to seven sequence types namely, B2/ST131 (3 isolates), A/ST164, A/ST10, A/ST224, A/ST38, A/ST155, and A/ST69 (each of them one isolate). The three K. pneumoniae isolates were assigned to three sequence types: ST101, ST405 (harboring CTX-M-15 and KPC), and ST1564. Overall, the phenotypic and genotypic traits of collected isolates mirror the molecular epidemiology of ESBL-producing enterobacteria in Tunisia and highlight the potential role of stagnant water in both urban and rural areas as a reservoir of ESBL-producing Enterobacteriaceae.

Bisphenol A acts as developmental agonist in Culex quinquefasciatus Say.

Plastic wastes deposited in canals running through Thiruvananthapuram city have created stagnant waters providing breeding sites for mosquitoes. In the present study, plastic waste-derived bisphenol A (BPA) was quantified from four mosquito breeding sites. During summer rain, the concentration of BPA in the stagnant water samples was found to be between 0.86 and 1.14mg/L, and hence 1mg/L BPA was considered as the environmentally relevant concentration. In the present study, the effect of BPA on the life cycle and metamorphosis of filarial vector, Culex quinquefasciatus Say was elucidated by rearing larvae in water added with BPA at and above the environmentally relevant concentration viz., 1, 2, and 4mg/L. The duration required for adult emergence was reduced from 10 to 8.5days, when the concentration of BPA was increased from 1 to 4mg/L respectively. Our study revealed that embryonic and larval developments were shortened by BPA treatment. BPA also caused a dose-dependent advancement of 20-hydroxyecdysone (20-E) peaks; phospholipase A2 induction; and upregulation of ecdysone receptor gene, EcRA, and ecdysone inducible gene E75A, which culminated in early pupation. No significant difference in sanguivory and fecundity was observed in adult mosquitoes treated with 1mg/L of BPA. Our study reveals that BPA is a developmental agonist of C. quinquefasciatus.

Combined effects of seasonality and stagnation on tap water quality: Changes in chemical parameters, metabolic activity and co-existence in bacterial community

In drinking water distribution pipeline systems, the tap water quality is regulated by several biotic and abiotic factors, which can threaten the health of consumers. Stagnation is inevitable in the water distribution pipeline however, the combined effects of seasonal changes and stagnation on tap water quality are not well understood. Here, we investigated the seasonal variations in the chemical and biological quality of water after overnight stagnation for a period of one year. The results showed that the tap water quality deteriorated after overnight stagnation, with up to a 2.7-fold increase in the total iron concentrations. The total bacterial cell concentrations increased by 59–231% after overnight stagnation. The total cell and cell-bound adenosine triphosphate (ATP) of the stagnant water samples peaked in summer. In addition, Biolog analysis showed that the metabolic activities of microbes were higher in spring. The bacterial community based on Illumina Miseq DNA sequence analysis found that Proteobacteria dominated the drinking water bacterial community. The bacterial community structure varied significantly among different seasons, where the diversity and richness of the community were much higher in spring. Structural equation modeling (SEM) was constructed to determine the correlations between bacterial metabolic functions and the community structure. The redundancy analysis (RDA) indicated that the residual chlorine played a critical role in the construction of the bacterial community. Altogether, the overall findings from the present work provide novel insights into how the quality of tap water quality impacted by the seasonal changes and overnight stagnation.

Development of real-time loop-mediated isothermal amplification (RealAmp) method for sensitive and rapid detection of pathogenic and nonpathogenic Leptospira.

Leptospirosis is a zoonotic disease that is spread through water contaminated with the spirochete Leptospira. In our study, RealAmp (real-time loop-mediated isothermal amplification) was developed to distinguish between pathogenic and nonpathogenic Leptospira spp. Melt curve analysis of RealAmp showed two distinct melt curves for pathogenic and nonpathogenic Leptospira spp with a Tm value of 90±2 and 88±2°C. The sensitivity of the developed method is as low as 1pgμl-1 of Leptospira DNA. Specificity was achieved to distinguish Leptospira species using the marker genes (lipL32 and lipL21). Different environmental water samples collected from cattle shelter, pisciculture and stagnant water were tested using this RealAmp method. Pisciculture water samples were found to be highly contaminated with both pathogenic and nonpathogenic Leptospira spp (50%), followed by cattle shelter and stagnant water samples (15%). SIGNIFICANCE AND IMPACT OF THE STUDY: The occurrence of pathogenic Leptospira in the environment is a threat to humans and animals. Molecular-based differentiation of the pathogenic and nonpathogenic Leptospria is essential for environmental monitoring; however, the currently available detection methods fail to distinguish between these species. We report here a real-time loop-mediated isothermal amplification-based method that differentiates between the pathogenic and nonpathogenic Leptospira based on the melt curve analysis of the marker genes lipL32 and lipL21. The method was successfully tested with a variety of environmental water samples to study the prevalence of Leptospira in the environment.

Molecular Identification and Genotyping of Acanthamoeba Isolated from Environmental Sources in Kashan, Central Iran

Background: Acanthamoeba is one of the most common opportunistic free-living amoebae, with ubiquitous presence in various en- vironmental sources. Pathogenic strains of Acanthamoeba are the causative agents of amoebic keratitis and granulomatous amoebic encephalitis. Objectives: The aim of the present study was to identify Acanthamoeba genotypes in soil, hospital dust, and stagnant water samples from Kashan, Central Iran. Methods: In this cross sectional study, a total of 122 samples from soil (n, 32), hospital dust (n, 40), and stagnant water (n, 50) were collected and examined for the presence of free-living amoebae and Acanthamoeba species. All the samples were cultured onto non-nutrient agar plates for detection of free-living amoebae. Acanthamoeba species was identified by polymerase chain reaction (PCR) assay, using specific primers. A total of 29 Acanthamoeba isolates were sequenced, and different genotypes were detected via sequence analysis. Results: The results showed that 82.8% (101/122) of samples were positive for free-living amoebae. The PCR assay revealed that 62.5%, 52.5%, and 50% of soil, hospital dust, and stagnant water samples were positive for Acanthamoeba species, respectively. Moreover, T4, T5, T2, T7, and T11 genotypes were identified. The most common genotype was T4 (76%), isolated from stagnant water. Conclusions: Acanthamoeba is a prevalent species in the soil, hospital dust, and stagnant water of Kashan. As this protozoon can cause severe infections, health education and improvement of sanitation services are recommended for prevention of infection. Keywords: Acanthamoeba, Soil, Hospital Dust, Stagnant Water, Genotype, Iran

The use of pesticides in Belgian illicit indoor cannabis plantations

Cannabis (Cannabis spp.) use and cultivation continue to increase in many (European) countries. The illicit indoor cannabis plantations that supply Belgian and European cannabis markets create problems and concerns about health and safety of intervention staff, dismantling companies, the direct environment of cannabis plantations and, eventually, of cannabis users. Main risks may come from pesticide residues on plants, cultivation infrastructure and materials; left-over plant growth-promoting substances; mycotoxins from fungal pathogens on harvested plants; and/or high levels of cannabinoids in cannabis plant parts for consumption. In the present research, we report on pesticides found in illicit indoor cannabis plantations in Belgium. EN15662 QuEChERS extraction method and LC–MS/MS analysis were used to identify pesticides in indoor cannabis plantations and thus to evaluate the hazards associated with the use, cultivation and removal of cannabis plants in plantations as well as with dismantling activities in the cultivation rooms. We found pesticides in 64.3% of 72 cannabis plant samples and in 65.2% of 46 carbon filter cloth samples. Overall, 19 pesticides belonging to different chemical classes were identified. We found o-phenylphenol, bifenazate, cypermethrin, imidacloprid, propamocarb, propiconazole and tebuconazole, which is consistent with the commonly reported pesticides from literature. In only a few cases, pesticides found in bottles with a commercial label, were also identified in plant or stagnant water samples collected from the growth rooms where the bottles had been collected. We further revealed that, even though most pesticides have a low volatility, they could be detected from the carbon filters hanging at the ceiling of cultivation rooms. As a result, it is likely that pesticides also prevail in the plantation atmosphere during and after cultivation. The risk of inhaling the latter pesticides increases when plants sprayed with pesticides are intensively manipulated during dismantling activities. We conclude that pesticides represent an underestimated and under-documented health risk for intervention staff. The standard procedure for dismantling illicit indoor cannabis cultivation sites should be improved by including guidelines for appropriate personal protection equipment and dismantling protocols that take into account all possible hazards.

Superparamagnetic nanoparticles in tap water

Magnetization measurements are a useful tool in the characterization of corrosion products formed in municipal water pipes made of iron or steel. Fine particles formed in corrosion processes exhibit superparamagnetic behavior. The size of such particles, which determines their capacity to adsorb hazardous species, can therefore be found from magnetic measurements. Application of this methodology to samples extracted from flowing and stagnant tap water, respectively, has shown that the flowing water samples contained multidomain (>100 nm) ferromagnetic particles as well as aggregates of very fine superparamagnetic subdomain particles. The sizes of the fine particles are of the order of 3.2–5.6 nm. In addition to small subdomain superparamagnetic particles stagnant water samples also contained larger subdomain particles with average dimensions of 59–67 nm. Both large and small subdomain particles were trapped by the fine charcoal in household filters.

Temporal variation of airborne fungi concentrations and related factors in subway stations in Seoul, Korea

This study was performed to assess the levels of fungi concentration in subway stations in Seoul, Korea, and to investigate factors contributing to these concentrations. Ninety air samples were collected hourly over the course of a day from five different subway stations. In addition, five settled dust samples and 12 stagnant water samples were collected to investigate these as potential sources of fungi contamination. The number of passengers and frequency of passing trains were also determined during the sampling periods, as they were considered potential factors influencing the airborne fungi concentrations at a given time during the day. The airborne fungi concentrations, as a function of time, were log-normally distributed. The airborne fungi concentrations measured during the morning and evening commute hours (during which the number of passengers and frequency of passing trains was highest) were significantly higher than those measured during non-commute hours. High concentrations of fungi were found in the settled dust samples, suggesting that the settled dust may have been the main source of airborne fungi concentration. The air movement generated mainly by passengers and additionally by trains might have played a role in suspending the fungi from the settled dust. It was also found that stagnant water might be a potential source of airborne fungi.

Fish assemblage changes relative to environmental factors and time in the Warta River, Poland, and its oxbow lakes

Four oxbow lakes and two neighbouring sections of their parent Warta River (Odra River system, Poland) were sampled to investigate differences in fish assemblages between habitats in 1999–2000. Additional comparisons were made with 12 other oxbow lakes in this section of the river that were sampled 30–40 years ago. Downstream of a man‐made reservoir, higher species number, diversity and evenness were recorded in oxbow lakes than in the river channel. Upstream of the reservoir, differences in these variables from both habitats were insignificant. Fluvial and stagnant water samples were clearly separated in the multivariate space of a detrended correspondence analysis (DCA). For two oxbow lakes and two neighbouring sections of the Warta River, 12 abiotic and biotic environmental variables were available, and only velocity, water temperature and conductivity were significantly correlated with canonical correspondence analysis (CCA) axes. Fish assemblages of four recently investigated oxbow lakes were clearly separated in the multivariate space of DCA from other neighbouring oxbows sampled 30–40 years ago. Species previously subdominant were becoming rare. Oxbow lakes that are continuously or at least periodically connected with the channel are indispensable for maintaining high biodiversity and a sustainable fishery in the river system.

Denitrification in the vadose zone and in surficial groundwater of a sandy entisol with citrus production

A portion of nitrate (NO 3 − ), a final breakdown product of nitrogen (N) fertilizers, applied to soils and/or that produced upon decomposition of organic residues in soils may leach into groundwater. Nitrate levels in water excess of 10 mg L−1 (NO3–N) are undesirable as per drinking water quality standards. Nitrate concentrations in surficial groundwater can vary substantially within an area of citrus grove which receives uniform N rate and irrigation management practice. Therefore, differences in localized conditions which can contribute to variations in gaseous loss of NO 3 − in the vadose zone and in the surficial aquifer can affect differential concentrations of NO3–N in the groundwater at different points of sampling. The denitrification capacity and potential in a shallow vadose zone soil and in surficial groundwater were studied in two large blocks of a citrus grove of ‘Valencia’ orange trees (Citrus sinensis (L.) Obs.) on Rough lemon rootstock ( Citrus jambhiri (L.)) under a uniform N rate and irrigation program. The NO3–N concentration in the surficial groundwater sampled from four monitoring wells (MW) within each block varied from 5.5- to 6.6-fold. Soil samples were collected from 0 to 30, 30 to 90, or 90 to 150 cm depths, and from the soil/groundwater interface (SGWI). Groundwater samples from the monitoring wells (MW) were collected prior to purging (stagnant water) and after purging five well volumes. Without the addition of either C or N, the denitrification capacity ranged from 0.5 to 1.53, and from 0.0 to 2.25 mg N2O–N kg−1 soil at the surface soil and at the soil/groundwater interface, respectively. The denitrification potential increased by 100-fold with the addition of 200 mg kg−1 each of N and C. The denitrification potential in the groundwater also followed a pattern similar to that for the soil samples. Denitrification potential in the soil or in the groundwater was greatest near the monitor well with shallow depth of vadose zone (MW3). Cumulative N2O–N emission (denitrification capacity) from the SGWI soil samples and from stagnant water samples strongly correlated to microbial most probable number (MPN) counts (r2 = 0.84 – 0.89), and dissolved organic C (DOC) (r2 = 0.96 – 0.97). Denitrification capacity of the SGWI samples moderately correlated to water-filled pore space (WFPS) (r2 = 0.52). However, extractable NO3-N content of the SGWI soil samples poorly (negative) correlated to denitrification capacity (r2 = 0.35). However, addition C, N or both to the soil or water samples resulted in significant increase in cumulative N2O emission. This study demonstrated that variation in denitrification capacity, as a result of differences in denitrifier population, and the amount of readily available carbon source significantly (at 95% probability level) influenced the variation in NO3–N concentrations in the surficial groundwater samples collected from different monitoring wells within an area with uniform N management.