scholarly journals Water Quality as a Predictor of Legionella Positivity of Building Water Systems

Pathogens ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 295 ◽  
Author(s):  
David Pierre ◽  
Julianne L. Baron ◽  
Xiao Ma ◽  
Frank P. Sidari ◽  
Marilyn M. Wagener ◽  
...  
Keyword(s):  
Water Quality ◽  
Cold Water ◽  
Water Systems ◽  
Quality Parameters ◽  
Free Chlorine ◽  
Hot Water ◽  
Water Quality Parameters ◽  
Plate Count ◽  
Poor Correlation ◽  
Distal Site

Testing drinking water systems for the presence of Legionella colonization is a proactive approach to assess and reduce the risk of Legionnaires’ disease. Previous studies suggest that there may be a link between Legionella positivity in the hot water return line or certain water quality parameters (temperature, free chlorine residual, etc.) with distal site Legionella positivity. It has been suggested that these measurements could be used as a surrogate for testing for Legionella in building water systems. We evaluated the relationship between hot water return line Legionella positivity and other water quality parameters and Legionella colonization in premise plumbing systems by testing 269 samples from domestic cold and hot water samples in 28 buildings. The hot water return line Legionella positivity and distal site positivity only demonstrated a 77.8% concordance rate. Hot water return line Legionella positivity compared to distal site positivity had a sensitivity of 55% and a specificity of 96%. There was poor correlation and a low positive predictive value between the hot water return line and distal outlet positivity. There was no correlation between Legionella distal site positivity and total bacteria (heterotrophic plate count), pH, free chlorine, calcium, magnesium, zinc, manganese, copper, temperature, total organic carbon, or incoming cold-water chlorine concentration. These findings suggest that hot water return line Legionella positivity and other water quality parameters are not predictive of distal site positivity and should not be used alone to determine the building’s Legionella colonization rate and effectiveness of water management programs.

scholarly journals Negative Effect of High pH on Biocidal Efficacy of Copper and Silver Ions in Controlling Legionella pneumophila

2002 ◽  
Vol 68 (6) ◽  
pp. 2711-2715 ◽  
Author(s):  
Yu-sen E. Lin ◽  
Radisav D. Vidic ◽  
Janet E. Stout ◽  
Victor L. Yu
Keyword(s):  
Water Quality ◽  
Legionella Pneumophila ◽  
Copper Ions ◽  
Silver Ions ◽  
Water Systems ◽  
Quality Parameters ◽  
Hot Water ◽  
Water Quality Parameters ◽  
Ion Concentration ◽  
The Impact

ABSTRACT Copper-silver (Cu-Ag) ionization has effectively controlled Legionella spp. in the hot water systems of numerous hospitals. However, it was ineffective at controlling Legionella in one Ohio hospital despite the confirmation of adequate total concentrations of copper and silver ions. The pH of the water at this hospital was found to be 8.5 to 9.0. The purpose of this study was to investigate the impact of pH and other water quality parameters, including alkalinity (HCO3 −), hardness (Ca2+ and Mg2+), and amount of dissolved organic carbon (DOC), on the control of Legionella by Cu-Ag ionization. Initial concentrations of Legionella and copper and silver ions used in batch experiments were 3 × 106 CFU/ml and 0.4 and 0.08 mg/liter, respectively. Changes in bicarbonate ion concentration (50, 100, and 150 mg/liter), water hardness (Ca2+ at 50 and 100 mg/liter; Mg2+ at 40 and 80 mg/liter), and level of DOC (0.5 and 2 mg/liter) had no significant impact on the efficacy of copper and silver ions in killing Legionella at a neutral pH. When the pH was elevated to 9 in these experiments, copper ions achieved only a 10-fold reduction in the number of Legionella organisms in 24 h, compared to a millionfold decrease at pH 7.0. Silver ions were able to achieve a millionfold reduction in 24 h at all ranges of water quality parameters tested. Precipitation of insoluble copper complexes was observed at a pH above 6.0. These results suggest that pH may be an important factor in the efficacy of copper-silver ionization in controlling Legionella in water systems.

scholarly journals Is a Proactive Approach to Controlling Legionella in the Environment Justified?

2021 ◽  
Vol 59 (3) ◽  
Author(s):  
Daniela Glažar Ivče ◽  
Dobrica Rončević ◽  
Marina Šantić ◽  
Arijana Cenov ◽  
Dijana Tomić Linšak ◽  
...  
Keyword(s):  
Drinking Water ◽  
Legionella Pneumophila ◽  
Cold Water ◽  
Aged Care ◽  
Water Systems ◽  
Hot Water ◽  
Plate Count ◽  
Surveillance Program ◽  
Adequate Treatment ◽  
Proactive Approach

Research background. Legionella are Gram-negative bacteria that are ubiquitous in the natural environment. Contaminated water in manmade water systems is a potential source of transmission of Legionnaires’ disease (LD). The aim of this study was to explore the prevalence of Legionella pneumophila (L. pneumophila) in the drinking water distribution system (DWDS) of Primorje-Gorski Kotar County (PGK County), Croatia, for the period 2013-2019, coupled with the incidence of LD. A number of L. pneumophila-positive samples (>100 CFU/L), serogroup distribution, and the degree of contamination of specific facilities (health & aged care, tourism, sports) were assessed. Based on the results obtained, the reasoning for the implementation of a mandatory Legionella environmental surveillance program was assessed. Experimental approach. Sample testing for Legionella was carried out according to ISO 1173. A Heterotrophic Plate Count (HPC) and P. aeruginosa were analysed along with the basic physico-chemical indicators of drinking water quality. The research period was divided into two parts, namely, the 2013-2018 period (before implementation of the prevention program, after the outbreak of LD), and year 2019 (proactive approach, no LD cases recorded). Results and conclusion. During the 7-year observation period in PGK County, an increase in the number of samples tested for Legionella was found. An increase in Legionella-positive samples (particularly pronounced during the warmer part of the year) was recorded, along with a growing trend in the number of reported LD cases. In addition to hot water systems, the risk of Legionella colonization also applies to cold water systems. Health & aged care facilities appear to be at highest risk. In addition to the higher proportion of positive samples and a higher degree of microbiological load at these facilities, the highest proportion of L. pneumophila SGs 2-14 was identified. Due to the diagnostic limitations of the applied tests, the number of LD cases is underdiagnosed. Novelty and scientific contribution. The introduction of a mandatory preventive approach to monitoring Legionella in DWDS water samples, along with the definition of national criteria for the interpretation of results, will create the preconditions for diagnosis and adequate treatment of larger numbers of LD cases.

scholarly journals Legionella: A Promising Supplementary Indicator of Microbial Drinking Water Quality in Municipal Engineered Water Systems

2021 ◽  
Vol 9 ◽  
Author(s):  
Chiqian Zhang ◽  
Jingrang Lu
Keyword(s):  
Public Health ◽  
Water Quality ◽  
Drinking Water ◽  
Water Systems ◽  
Quality Parameters ◽  
Drinking Water Quality ◽  
Water Quality Parameters ◽  
Fecal Coliforms ◽  
Spatiotemporal Variations ◽  
Hydraulic Residence Time

Opportunistic pathogens (OPs) are natural inhabitants and the predominant disease causative biotic agents in municipal engineered water systems (EWSs). In EWSs, OPs occur at high frequencies and concentrations, cause drinking-water-related disease outbreaks, and are a major factor threatening public health. Therefore, the prevalence of OPs in EWSs represents microbial drinking water quality. Closely or routinely monitoring the dynamics of OPs in municipal EWSs is thus critical to ensuring drinking water quality and protecting public health. Monitoring the dynamics of conventional (fecal) indicators (e.g., total coliforms, fecal coliforms, and Escherichia coli) is the customary or even exclusive means of assessing microbial drinking water quality. However, those indicators infer only fecal contamination due to treatment (e.g., disinfection within water utilities) failure and EWS infrastructure issues (e.g., water main breaks and infiltration), whereas OPs are not contaminants in drinking water. In addition, those indicators appear in EWSs at low concentrations (often absent in well-maintained EWSs) and are uncorrelated with OPs. For instance, conventional indicators decay, while OPs regrow with increasing hydraulic residence time. As a result, conventional indicators are poor indicators of OPs (the major aspect of microbial drinking water quality) in EWSs. An additional or supplementary indicator that can well infer the prevalence of OPs in EWSs is highly needed. This systematic review argues that Legionella as a dominant OP-containing genus and natural inhabitant in EWSs is a promising candidate for such a supplementary indicator. Through comprehensively comparing the behavior (i.e., occurrence, growth and regrowth, spatiotemporal variations in concentrations, resistance to disinfectant residuals, and responses to physicochemical water quality parameters) of major OPs (e.g., Legionella especially L. pneumophila, Mycobacterium, and Pseudomonas especially P. aeruginosa), this review proves that Legionella is a promising supplementary indicator for the prevalence of OPs in EWSs while other OPs lack this indication feature. Legionella as a dominant natural inhabitant in EWSs occurs frequently, has a high concentration, and correlates with more microbial and physicochemical water quality parameters than other common OPs. Legionella and OPs in EWSs share multiple key features such as high disinfectant resistance, biofilm formation, proliferation within amoebae, and significant spatiotemporal variations in concentrations. Therefore, the presence and concentration of Legionella well indicate the presence and concentrations of OPs (especially L. pneumophila) and microbial drinking water quality in EWSs. In addition, Legionella concentration indicates the efficacies of disinfectant residuals in EWSs. Furthermore, with the development of modern Legionella quantification methods (especially quantitative polymerase chain reactions), monitoring Legionella in ESWs is becoming easier, more affordable, and less labor-intensive. Those features make Legionella a proper supplementary indicator for microbial drinking water quality (especially the prevalence of OPs) in EWSs. Water authorities may use Legionella and conventional indicators in combination to more comprehensively assess microbial drinking water quality in municipal EWSs. Future work should further explore the indication role of Legionella in EWSs and propose drinking water Legionella concentration limits that indicate serious public health effects and require enhanced treatment (e.g., booster disinfection).

scholarly journals Legionella Colonization of Hotel Water Systems in Touristic Places of Greece: Association with System Characteristics and Physicochemical Parameters

2018 ◽  
Vol 15 (12) ◽  
pp. 2707 ◽  
Author(s):  
Maria A. Kyritsi ◽  
Varvara A. Mouchtouri ◽  
Antonis Katsioulis ◽  
Elina Kostara ◽  
Vasileios Nakoulas ◽  
...  
Keyword(s):  
Water Samples ◽  
Physicochemical Parameters ◽  
Cold Water ◽  
Protective Role ◽  
Water Systems ◽  
Free Chlorine ◽  
Hot Water ◽  
Chlorine Concentration ◽  
P Value ◽  
European Guidelines

This study aimed to assess the colonization of hotel water systems in central Greece and Corfu by Legionella, and to investigate the association between physicochemical parameters and Legionella colonization. Standardized hygiene inspection was conducted in 51 hotels, and 556 water samples were analyzed for Legionella spp. Free chlorine concentration, pH, hardness, conductivity, and trace metals were defined in cold water samples. The results of inspections and chemical analyses were associated with the microbiological results using univariate and logistic regression analysis. According to the score of the checklist used for the inspections, 17.6% of the hotels were classified as satisfactory, 15.7% as adequate, and 66.7% as unsatisfactory. Moreover, 74.5% of the hotels were colonized by Legionella spp. and 31.4% required remedial measures according to the European guidelines. Legionella spp. were isolated in 28% of the samples. Unsatisfactory results of inspections were associated with Legionella presence (relative risk (RR) = 7.67, p-value = 0.043). In hot-water systems, <50 °C temperatures increased the risk of Legionella colonization (RR = 5.36, p-value < 0.001). In cold-water systems, free chlorine concentration <0.375 mg/L (odds ratio (OR) = 9.76, p-value = 0.001), pH ≥ 7.45 (OR = 4.05, p-value = 0.007), and hardness ≥321 mgCaCO3/L (OR = 5.63, p-value = 0.003) increased the risk, whereas copper pipes demonstrated a protective role (OR = 0.29, p-value = 0.0024). The majority of the hotels inspected were colonized with Legionella. Supplementary monitoring of the risk factors that were identified should be considered.

scholarly journals Computational and Numerical Modeling for Classification of Water Quality of Lake

2020 ◽  
Vol 11 (9) ◽  
pp. 425-431
Author(s):  
Jonalyn G. Ebron ◽  
◽  
Rommel Ivan D. De Leon ◽  
Arviejhay D. Alejandro ◽  
Basaron A. Amoranto
Keyword(s):  
Water Quality ◽  
Linear Regression ◽  
Water Quality Monitoring ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Water Quality Parameter ◽  
Support Vector ◽  
Poor Correlation ◽  
Study Results

In this study, the Multivariate Linear Regression (MLR), Artificial Neural Network (ANN), k-Nearest Neighbour (kNN), and Support Vector Machine (SVM) models had been developed to simulate and to predict the water quality of Laguna Lake. The input variables for the MLR model had been determined through linear regression. The ANN, kNN, and SVM had been modelled per water quality parameter with cross validation and evaluated through its accuracy. The performance of the MLR models had been evaluated with the statistical metrics R-squared, Mean Absolute Error, and Root Mean Square Error. A web-based water quality monitoring had been developed to incorporate in their monitoring. The results had indicated that the performance of SVM is superior in the prediction of classes in most water quality parameters. The study results had shown that the poor correlation between the water quality parameters indicated that the data cannot be modelled. The results had shown that the correlation had not reached the threshold to be significant of 60% for R-squared. As per the classification models, the results of the comparison had shown that SVM had been the best model in the majority of parameters.

State of well-water quality in Kakua Chiefdom, Sierra Leone

2016 ◽  
Vol 16 (5) ◽  
pp. 1243-1254
Author(s):  
John P. Kaisam ◽  
Yahaya K. Kawa ◽  
Juana P. Moiwo ◽  
Umu Lamboi
Keyword(s):  
Water Quality ◽  
Sierra Leone ◽  
Open Water ◽  
Water Systems ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Critical Parameters ◽  
Well Water ◽  
Drinking Water Standard ◽  
Industrial Sectors

Water is the difference between living and non-living and water for drinking should be pollutant free. Thus, in supplies for urban and rural consumption, water quality is one of the most critical parameters to verify. Well and/or open-water systems are easily liable to anthropogenic contaminations, the source of most water-borne epidemics especially in developing countries like Sierra Leone. This study analyses 10 representative well-water systems for 18 water quality parameters in Kakua Chiefdom of Bo District, Sierra Leone. The study notes that well-water quality parameters such as total dissolved solids (TDS), turbidity, electrical conductivity, coliform and nitrate (NO3−) are fairly high above safe drinking water standard. The incidence of coliform in the well waters is highest in April and that of iron (Fe2+) and nitrate is highest in May. The Dipha Street well is amongst the most contaminated and has the highest scores for TDS, non-faecal coliform and fluoride (F−). Correlation analysis shows an interesting bond among the water quality parameters, ranging from strongly positive (R = 1.0) to strongly negative (R = −1.0). Fe2+ is strongly positively correlated with most of the well-water quality parameters. Irrespectively, the use of contaminated water in domestic and/or agro-industrial sectors could pose various health risks and epidemic outbreaks of different intensities.

scholarly journals STUDI IDENTIFIKASI KUALITAS AIR DAN JENIS IKAN AIR TAWAR DI SUMBER AIR PANAS DESA NYELANDING KABUPATEN BANGKA SELATAN SEBAGAI DASAR PENGELOLAAN POTENSI KAWASAN AIR PANAS UNTUK KEGIATAN PERIKANAN DAN WISATA

2019 ◽  
Vol 13 (2) ◽  
pp. 142-148 ◽  
Author(s):  
Andi Gustomi ◽  
M. Rizza Muftiadi ◽  
Wahyu Adi ◽  
Arthur M Farhaby
Keyword(s):  
Water Quality ◽  
Freshwater Fish ◽  
Natural Waters ◽  
Hot Springs ◽  
Hot Spring ◽  
Quality Parameters ◽  
Growth Patterns ◽  
Hot Water ◽  
Fish Growth ◽  
Water Quality Parameters

Hot springs in Nyelanding Village, South Bangka Regency, have the potential of geothermal resources that can be used as a potential energy source, moreover found several types of freshwater fish that utilize these hot springs as their natural habitat. The objectives of this study are to identify the water quality and diversity of freshwater fish species in the hot spring area of Nyelanding Village, South Bangka Regency; analyze the feasibility of water quality for fisheries and tourism activities; and analyzing fish growth patterns found at these locations. The results showed that there were two types of fish found in the hot springs of Nyelanding Village, which were Gabus Fish (Channa striata) and Sepat Fish (Trichogaster trichopterus). There are 6 hot water quality parameters Village Nyelanding included in standard class II PP 82 of 2001 include pH, COD, TSS, TDS, Nitrate and Total fospat, two parameters are not required (depth and ammonia), one parameter (temperature ) not in normal natural waters. The growth pattern of Gabus Fish in the hot water of Nyelanding Village is negative allometric with a growth coefficient of 2.076. In general, based on the analysis of water quality parameters, the Nyelanding Village hot water is suitable for biota life as well as aquaculture activities and tourist areas. For aquaculture, the recommended type of fish is eurythermal. However, their habit of draining the hot water pool Village Nyelanding made towards development of the area is less recommended for fishing activity, but preferably as a tourist area.

Framework for cost-effective prediction of unregulated disinfection by-products in drinking water distribution using differential free chlorine

2018 ◽  
Vol 4 (10) ◽  
pp. 1564-1576 ◽  
Author(s):  
Gyan Chhipi-Shrestha ◽  
Manuel Rodriguez ◽  
Rehan Sadiq
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Distribution ◽  
Cost Effective ◽  
Quality Parameters ◽  
Free Chlorine ◽  
Water Quality Parameters ◽  
Drinking Water Distribution ◽  
By Products

A framework for estimating the concentration of unregulated disinfection by-products in water distribution using ΔCl2 and other basic water quality parameters.

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