Using monochloramines to disinfect drinking water: the effects it has on lead content

2010 ◽  
Vol 5 (2) ◽  
Author(s):  
A.M. Rizzuti ◽  
L.N. Rogers
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Distribution System ◽  
Water Distribution ◽  
Graphite Furnace ◽  
Atomic Absorption Spectrophotometry ◽  
The Past ◽  
Graphite Furnace Atomic Absorption ◽  
Water District ◽  
Pb Concentration

Over the past ten years, several U.S. cities have switched from using free chlorine to chloramines to disinfect drinking water. Coincident with this shift have been reports by some water districts of lead (Pb) levels in drinking water that exceed the action limit of 15ppb set by the EPA. In this paper, a study was conducted on a water district that utilizes monochloramines to disinfect drinking water. The purpose of this research was to determine the Pb content of drinking water treated in this district. Water samples were collected both from homes with and from homes without Pb plumbing. The water samples were analyzed for Pb content using graphite furnace atomic absorption spectrophotometry. Samples obtained from homes without Pb plumbing had a Pb concentration range of 10.7 ppb − 20.3 ppb (average = 15.9 ppb), whereas samples obtained from homes with Pb plumbing had a Pb concentration range of 20.4 ppb − 73.9 ppb (average = 29.0 ppb). The average Pb concentrations for both types of homes were above the EPA action limit of 15ppb. The most plausible explanation for this is leaching of Pb from the water distribution system caused by the water treatment plants' use of monochloramines to disinfect water.

Phylogenetic assessment of heterotrophic bacteria from a water distribution system using 16S rDNA sequencing

2005 ◽  
Vol 51 (4) ◽  
pp. 325-335 ◽  
Author(s):  
Sima T Tokajian ◽  
Fuad A Hashwa ◽  
Ian C Hancock ◽  
Pierre A Zalloua
Keyword(s):  
Drinking Water ◽  
16S Rdna ◽  
Water Samples ◽  
Distribution System ◽  
Water Distribution ◽  
Heterotrophic Bacteria ◽  
Diagnostic Methods ◽  
Plate Count ◽  
Rdna Sequencing ◽  
Drinking Water Samples

Determination of a heterotrophic plate count (HPC) for drinking-water samples alone is not enough to assess possible health hazards associated with sudden changes in the bacterial count. Speciation is very crucial to determine whether the population includes pathogens and (or) opportunistic pathogens. Most of the isolates recovered from drinking water samples could not be allocated to a specific phylogenetic branch based on the use of conventional diagnostic methods. The present study had to use phylogenetic analysis, which was simplified by determining and using the first 500-bp sequence of the 16S rDNA, to successfully identify the type and species of bacteria found in the samples. Gram-positive bacteria α-, β-, and γ-Proteobacteria were found to be the major groups representing the heterotrophic bacteria in drinking water. The study also revealed that the presence of sphingomonads in drinking water supplies may be much more common than has been reported so far and thus further studies are merited. The intermittent mode of supply, mainly characterized by water stagnation and flow interruption associated possibly with biofilm detachment, raised the possibility that the studied bacterial populations in such systems represented organisms coming from 2 different niches, the biofilm and the water column.Key words: intermittent water supply, 16S rDNA, biofilm, water column.

scholarly journals Identification of Bacteria in Biofilm and Bulk Water Samples from a Nonchlorinated Model Drinking Water Distribution System: Detection of a Large Nitrite-Oxidizing Population Associated with Nitrospira spp

2005 ◽  
Vol 71 (12) ◽  
pp. 8611-8617 ◽  
Author(s):  
Adam C. Martiny ◽  
Hans-Jørgen Albrechtsen ◽  
Erik Arvin ◽  
Søren Molin
Keyword(s):  
Drinking Water ◽  
Organic Carbon ◽  
Water Samples ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Bulk Water ◽  
Drinking Water Distribution System ◽  
Assimilable Organic Carbon ◽  
Drinking Water Distribution

ABSTRACT In a model drinking water distribution system characterized by a low assimilable organic carbon content (<10 μg/liter) and no disinfection, the bacterial community was identified by a phylogenetic analysis of rRNA genes amplified from directly extracted DNA and colonies formed on R2A plates. Biofilms of defined periods of age (14 days to 3 years) and bulk water samples were investigated. Culturable bacteria were associated with Proteobacteria and Bacteriodetes, whereas independently of cultivation, bacteria from 12 phyla were detected in this system. These included Acidobacteria, Nitrospirae, Planctomycetes, and Verrucomicrobia, some of which have never been identified in drinking water previously. A cluster analysis of the population profiles from the individual samples divided biofilms and bulk water samples into separate clusters (P = 0.027). Bacteria associated with Nitrospira moscoviensis were found in all samples and encompassed 39% of the sequenced clones in the bulk water and 25% of the biofilm community. The close association with Nitrospira suggested that a large part of the population had an autotrophic metabolism using nitrite as an electron donor. To test this hypothesis, nitrite was added to biofilm and bulk water samples, and the utilization was monitored during 15 days. A first-order decrease in nitrite concentration was observed for all samples with a rate corresponding to 0.5 × 105 to 2 × 105 nitrifying cells/ml in the bulk water and 3 × 105 cells/cm2 on the pipe surface. The finding of an abundant nitrite-oxidizing microbial population suggests that nitrite is an important substrate in this system, potentially as a result of the low assimilable organic carbon concentration. This finding implies that microbial communities in water distribution systems may control against elevated nitrite concentrations but also contain large indigenous populations that are capable of assisting the depletion of disinfection agents like chloramines.

scholarly journals Prevalence of Legionella spp. and Escherichia coli in the drinking water distribution system of Wrocław (Poland)

2020 ◽  
Vol 20 (3) ◽  
pp. 1083-1090
Author(s):  
M. Wolf-Baca ◽  
A. Siedlecka
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Legionella Pneumophila ◽  
Water Samples ◽  
Distribution System ◽  
Water Distribution ◽  
Tap Water ◽  
Potential Threat ◽  
E Coli ◽  
Drinking Water Distribution

Abstract Drinking water should be free from bacterial pathogens that threaten human health. The most recognised waterborne opportunistic pathogens, dwelling in tap water, are Legionella pneumophila and Escherichia coli. Drinking water samples were tested for the presence of Legionella spp., L. pneumophila, and E. coli in overall sample microbiomes using a quantitative real-time polymerase chain reaction (qPCR) approach. The results indicate a rather low contribution of Legionella spp. in total bacteria in the tested samples, but L. pneumophila was not detected in any sample. E. coli was detected in only one sample, but at a very low level. The qacEΔ1 gene, conferring resistance to quaternary ammonium compounds, was also not detected in any sample. The results point to generally sufficient quality of drinking water, although the presence of Legionella spp. in tap water samples suggests proliferation of these bacteria in heating units, causing a potential threat to consumer health.

scholarly journals PHYSICO-CHEMICAL AND BACTERIOLOGICAL COMPOSITION IN A METROPOLITAN DRINKING WATER DISTRIBUTION SYSTEM IN KATHMANDU

2017 ◽  
Vol 22 (1) ◽  
pp. 159-164
Author(s):  
Pratima Tamrakar ◽  
Suman K. Shakya ◽  
Chitra B. Baniya
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Samples ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Drinking Water Distribution System ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Drinking Water Distribution

The study was concentrated on water quality appraisal in metropolitan drinking water distribution system in Kathmandu during 2011 to 2015 AD. The study covers 24 research areas from surface water sources, treatment plants, processing and water supply networks of public, private and community drinking water suppliers in the main city of Kathmandu valley. Water quality was analyzed under six physical, seventeen chemical and two bacteriological parameters. All tests were conducted in accordance with the procedures laid down in the Standard Methods. Total 320 samples collected during two years of periods. The physico-chemical parameters of tested water samples from sources, reservoirs and taps were found to be within the range of National Drinking Water Quality Standard (NDWQS). The turbidity and pH values for most of the tested water samples from sources, reservoirs and taps except for a few source and tap samples were found to be within the NDWQS guideline values. The chemical parameters values of majority of tested source water samples were below the maximum level. The values of iron, manganese, sodium and chloride content of some source samples were found higher than the maximum permissible level recommended by NDWQS and WHO guideline. Bacteriologically, larger proportion of water samples (sources, reservoirs and taps) were found to be unacceptable. The present study disclosed fecal contamination to be the major problem in drinking water from source to the distribution for city water supply systems in selected metropolitan areas. The physico-chemical qualities of water in most cases were within acceptable limit.Journal of Institute of Science and TechnologyVolume 22, Issue 1, July 2017, page: 159-164

scholarly journals Disinfection by-products in drinking water distribution system of Bucharest City

2021 ◽  
Vol 3 (1) ◽  
pp. 10-18
Author(s):  
Iuliana Paun ◽  
◽  
Florentina Laura Chiriac ◽  
Vasile Ion Iancu ◽  
Florinela Pirvu ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Distribution System ◽  
Water Distribution ◽  
Inorganic Ions ◽  
Residual Chlorine ◽  
Chlorination Process ◽  
Water Legislation ◽  
Drinking Water Samples ◽  
By Products

Chlorine is widely used in Romania and all over the world as a disinfectant of drinking water. During the chlorination process, the natural organic matter and inorganic ions react with chlorine forming disinfection by-products (DBPs). The predominant organic disinfection by-products are trihalomethanes (THMs) while the main inorganic disinfection by-products are chlorate and chlorite ions. THMs were detected in all investigated drinking water samples from Bucharest distribution system with values from 27.8 µg/L up to 75.1 µg/L, which are below the maximum concentration value admitted by Romanian drinking water legislation of 100 µg/L. Chloroform constitutes the major component in total THMs concentration found in all tested drinking water. Chlorate and chlorite anions were not detected in any of the investigated drinking water samples. THMs concentration was correlated with total organic carbon (TOC), residual chlorine and chloride.

Survey of pathogenic bacteria of biofilms in a metropolitan drinking water distribution system

2019 ◽  
Author(s):  
Jiang Chen ◽  
Ya Shi ◽  
Dongqing Cheng ◽  
Yan Jin ◽  
William Hutchins ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Pathogenic Bacteria ◽  
Eastern China ◽  
Flowing Water ◽  
Chromogenic Medium ◽  
Drinking Water Distribution

Abstract Bacteria, especially pathogenic bacteria, were detected in order to estimate the safety of drinking water distribution systems (DWDS). 16 biofilms and 12 water samples (6 retained and 6 flowing) were collected from a city DWDS in Eastern China. Biofilms were observed using scanning electron microscopy. Cultivable bacteria of biofilms were counted by heterotrophic plate counts, ranging from 3.61 × 101 to 1.67 × 106 CFU·cm−2. Coliforms, Salmonella, Shigella, Vibrio, and Legionella were separated by EMB agar, Salmonella chromogenic medium, Shigella chromogenic medium, TCBS agar, BCYE agar, and 13/16, 8/16, 7/16, 6/16, 0/16 biofilm samples were found positive respectively. Retained and flowing water samples were collected to estimate the influence of hydrodynamic conditions on biofilm detachment. All 6 retained water samples were positive for bacteria, count ranged from 1.2 × 103 to 2.8 × 104 CFU·mL−1 and 2/6, 3/6, 2/6, 0/6, 0/6 samples were positive for coliforms, Salmonella, Shigella, Legionella, and Vibrio, respectively. While only 3 of 6 flowing water samples were bacteria positive, counts ranged from 102 to 103 CFU·mL−1, 2/6 were coliforms positive, no pathogens under testing were detected. The results show that there are pathogens in DWDS biofilms, which can cause health related problems if detached from their surface.

scholarly journals Relationship between maternal sodium intake and blood lead concentration during pregnancy

2012 ◽  
Vol 109 (5) ◽  
pp. 853-858 ◽  
Author(s):  
Yo A. Lee ◽  
Ji-Yun Hwang ◽  
Hyesook Kim ◽  
Ki Nam Kim ◽  
Eun-Hee Ha ◽  
...  
Keyword(s):  
Sodium Intake ◽  
Graphite Furnace ◽  
Blood Lead ◽  
Atomic Absorption Spectrophotometry ◽  
Dietary Intakes ◽  
Korean Women ◽  
Dietary Recommendations ◽  
Graphite Furnace Atomic Absorption ◽  
The Relationship ◽  
Pb Concentration

Pb is released from bone stores during pregnancy, which constitutes a period of increased bone resorption. A high Na intake has been found to be negatively associated with Ca and adversely associated with bone metabolism. It is possible that a high Na intake during pregnancy increases the blood Pb concentration; however, no previous study has reported on the relationship between Na intake and blood Pb concentration. We thus have investigated this relationship between Na intake and blood Pb concentrations, and examined whether this relationship differs with Ca intake in pregnant Korean women. Blood Pb concentrations were analysed in 1090 pregnant women at mid-pregnancy. Dietary intakes during mid-pregnancy were estimated by a 24 h recall method covering the use of dietary supplements. Blood Pb concentrations in whole-blood samples were analysed using graphite furnace atomic absorption spectrophotometry. Multiple regression analysis performed after adjustment for covariates revealed that maternal Na intake was positively associated with blood Pb concentration during pregnancy, but only when Ca intake was below the estimated average requirement for pregnant Korean women (P= 0·001). The findings of the present study suggest that blood Pb concentration during pregnancy could be minimised by dietary recommendations that include decreased Na and increased Ca intakes.

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