scholarly journals Effects of plumbing systems on human exposure to disinfection byproducts in water: a case study

2015 ◽  
Vol 14 (3) ◽  
pp. 489-503 ◽  
Author(s):  
Shakhawat Chowdhury
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Tap Water ◽  
Regulatory Compliance ◽  
Disinfection Byproducts ◽  
Hot Water ◽  
Cancer Risks ◽  
Plumbing Systems ◽  
Daily Intakes ◽  
Water Tanks

Disinfection byproducts (DBPs) in water distribution systems (WDS) are monitored for regulatory compliance, while populations are exposed to DBPs in tap water that may be different due to stagnation of water in plumbing pipes (PP) and heating in hot water tanks (HWT). This study investigated the effects of water stagnation in PP and HWT on exposure and risk of DBPs to humans. Trihalomethanes (THMs) in PP and HWT were observed to be 1.1–2.4 and 1.6–3.0 times, respectively, to THMs in the WDS, while haloacetic acids (HAAs) were 0.9–1.8 and 1.2–1.9 times, respectively, to HAAs in the WDS. The chronic daily intakes of DBPs from PP and HWT were 0.6–1.8 and 0.5–2.3 times the intakes from WDS. The cancer risks from PP and HWT were 1.46 (0.40–4.3) and 1.68 (0.35–5.1) times the cancer risks from WDS. The findings may assist in regulating DBPs exposure concentrations.

scholarly journals Models for predicting heavy metal concentrations in residential plumbing pipes and hot water tanks

2021 ◽  
Author(s):  
Shakhawat Chowdhury ◽  
Fayzul Kabir ◽  
Mohammad Abu Jafar Mazumder ◽  
Khalid Alhooshani ◽  
Amir Al-Ahmed ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Distribution Systems ◽  
Water Distribution ◽  
Tap Water ◽  
Hot Water ◽  
Validation Data ◽  
Metal Concentrations ◽  
Heavy Metal Concentrations ◽  
Water Tanks

Abstract Supply water is an important source of human exposure to heavy metals through the oral pathway. Due to stagnation of water in plumbing systems, exposure concentrations of heavy metals from tap water can be higher than water distribution systems (WDS), which is often ignored by the regulatory agencies. In this study, concentrations of a few heavy metals (arsenic (As), chromium (Cr), copper (Cu), mercury (Hg), manganese (Mn), magnesium (Mg), zinc (Zn) and iron (Fe)) and water quality parameters were monitored in WDS, plumbing pipe (PP) and hot water tanks (HWT). Multiple models were trained for predicting metal concentrations in PP and HWT, which were validated. Heavy metal concentrations in HWT were 1.2–8.1 and 1.4–6.7 times the concentrations in WDS and PP respectively. Concentrations of As, Cr, Cu, Hg and Zn were in the increasing order of WDS, PP and HWT. Concentrations of Cr and Fe were higher during summer while Cu and Zn were higher in winter. The models showed variable performances for PP and HWT (R2: PP = 0.61–0.99; HWT = 0.71–0.99). The validation data demonstrated variable correlation coefficients (r: PP = 0.45–0.99; HWT = 0.83–0.99). Few models can be used for predicting heavy metals in tap water to reduce the cost of expensive sampling and analysis.

Review / SynthèseA review of drinking-water-associated endotoxin, including potential routes of human exposure

2002 ◽  
Vol 48 (7) ◽  
pp. 567-587 ◽  
Author(s):  
William B Anderson ◽  
Robin M Slawson ◽  
Colin I Mayfield
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Tap Water ◽  
Disinfection Byproducts ◽  
Potential Health ◽  
Biofilm Growth ◽  
Disinfection Byproduct ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution

In the past decade efforts have been made to reduce the formation of harmful disinfection byproducts during the treatment and distribution of drinking water. This has been accomplished in part by the introduction of processes that involve the deliberate encouragement of indigenous biofilm growth in filters. In a controlled environment, such as a filter, these biofilms remove compounds that would otherwise be available as disinfection byproduct precursors or support uncontrolled biological activity in distribution systems. In the absence of exposure to chlorinated water, most biofilm bacteria are gram negative and have an outer layer that contains endotoxin. To date, outbreaks of waterborne endotoxin-related illness attributable to contamination of water used in hemodialysis procedures have been only infrequently documented, and occurrences linked to ingestion or through dermal abrasions could not be located. However, a less obvious conduit, that of inhalation, has been described in association with aerosolized water droplets. This review summarizes documented drinking-water-associated incidents of endotoxin exposure attributable to hemodialysis and inhalation. Typical endotoxin levels in water and conditions under which substantial quantities can enter drinking water distribution systems are identified. It would appear that endotoxin originating in tap water can be inhaled but at present there is insufficient information available to quantify potential health risks.Key words: endotoxin, lipopolysaccharide, LPS, drinking water.

scholarly journals Saving cold drinking water in residential hot water distribution systems

2020 ◽  
Vol 24 ◽  
pp. e4
Author(s):  
Marcelo Dalmédico Ioris ◽  
Enedir Ghisi
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Cold Water ◽  
Solenoid Valve ◽  
Hot Water ◽  
Water Tank ◽  
Vertical Pipe ◽  
Plumbing Systems ◽  
Approximate Amount

In homes that have instantaneous gas heaters to heat water, cold water is wasted in the first seconds of using hot water fixtures. This waste is caused due to the large lengths of piping between the hot water fixtures and the heater that feeds them. The water in such pipes suffers thermal losses over time. When turning on the fixtures, this drinking water, because it is cold, is rejected by users, especially when using showers. This work deals with the conformation of a system that avoids wasting water in residential hot water services. To establish this conformation, a usual plumbing design was analysed to verify the changes proposed in order to optimise the operation of the system. The gas-heated hot water pipes are currently installed so that the pipes start at the heater and run through the entire house to the hot water fixtures furthest from the heater. It was found that the waste of water in a water fixture decreases if there is the consumption of hot water previously in one of the water fixtures of the house. To avoid this waste, according to the configuration of the current plumbing systems, it is necessary to install an additional set of electronic equipment that automatically redirects the cold water − that would be wasted − to a water tank for later use. The system proposed is composed of a solenoid valve located at the end of the hot water pipe. This valve has the function of letting flow to the water tank the approximate amount of cold water that would be wasted. Through a radio frequency signal sent when a button located near the hot water fixtures is pressed, the system recognises which water fixture was turned on and the approximate amount of cold water that must be released through the valve until the arrival of hot water from the heater. Then, there must be a pipe that collects the water that flows through the solenoid valve. Such pipe will be connected to a vertical pipe, responsible for collecting water from all flats and directing the water to the water tank. The installation of the system is based on the recommendations of the standards used in Brazil and the most frequent configuration found in homes. This work also serves as a guide for installing the system in homes other than the example shown herein.

scholarly journals Disinfection by-products in desalinated and blend water: formation and control strategy

2018 ◽  
Vol 17 (1) ◽  
pp. 1-24 ◽  
Author(s):  
Shakhawat Chowdhury
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Cancer Risks ◽  
Domestic Water ◽  
Desalinated Water ◽  
Water Demands ◽  
Product Water ◽  
And Control ◽  
Different Sources ◽  
By Products

Abstract Desalinated seawater is the major source of drinking water in many countries. During desalination, several activities including pretreatment, desalination, stabilization, mixing, storage and distribution are performed. Few disinfectants are used during these activities to control the biofouling agents and microbiological regrowth. The reactions between the disinfectants and natural organic matter (NOM), bromide and iodide form disinfection by-products (DBPs) in product water. The product water is stabilized and mixed with treated freshwater (e.g., groundwater) to meet the domestic water demands. The DBPs in desalinated and blend water are an issue due to their possible cancer and non-cancer risks to humans. In this paper, formation and distribution of DBPs in different steps of desalination and water distribution systems prior to reaching the consumer tap were reviewed. The variability of DBPs among different sources and desalination processes was explained. The toxicities of DBPs were compared and the strategies to control DBPs in desalinated water were proposed. Several research directions were identified to achieve comprehensive control on DBPs in desalinated water, which are likely to protect humans from the adverse consequences of DBPs.

An experimental study for chlorine residual and trihalomethane formation with rechlorination

2007 ◽  
Vol 55 (1-2) ◽  
pp. 307-313 ◽  
Author(s):  
J. Lee ◽  
D. Lee ◽  
J. Sohn
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Disinfection Byproducts ◽  
Correction Coefficient ◽  
Empirical Power ◽  
Chlorine Residual ◽  
Chlorine Decay ◽  
And Control ◽  
Large Distribution

Maintenance of adequate chlorine residuals and control of disinfection byproducts (DBPs) throughout water distribution systems is currently an important issue. In particular, rechlorination can be a powerful tool in controlling adequate chlorine residual in a large distribution system. The patterns of chlorine decay and formation of DBPs due to rechlorination are different from those of chlorination; chlorine decay is slower and trihalomethane (THM) formation is lower with rechlorination. The present study evaluates whether existing predictive models for chlorine residual and THM formation are applicable in the case of rechlorination. A parallel first-order decay model represents the best simulation results for chlorine decay, and an empirical power function model (modified Amy model) with an introduced correction coefficient (ϕ1, ϕ2) is more suitable to THM formation.

Determinants of Legionella pneumophila Contamination of Water Distribution Systems: 15-Hospital Prospective Study

1987 ◽  
Vol 8 (9) ◽  
pp. 357-363 ◽  
Author(s):  
Richard M. Vickers ◽  
Victor L. Yu ◽  
S. Sue Hanna ◽  
Paul Muraca ◽  
Warren Diven ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Cold Water ◽  
Physicochemical Characteristics ◽  
Hot Water ◽  
Environmental Study ◽  
Water Tank ◽  
One Year

AbstractWe conducted a prospective environmental study for Legionella pneumophila in 15 hospitals in Pennsylvania. Hot water tanks, cold water sites, faucets, and show-erheads were surveyed four times over a one-year period. Sixty percent (9/15) of hospitals surveyed were contaminated with L pneumophila. Although contamination could not be linked to a specific municipal water supplier, most of the contaminated supplies came from rivers. Parameters found to be significantly associated with contamination included elevated hot water temperature, vertical configuration of the hot water tank, older tanks, and elevated calcium and magnesium concentrations of the water (P < 0.05). This study suggests that L pneumophila contamination could be predicted based on design of the distribution system, as well as physicochemical characteristics of the water.

scholarly journals How Molecular Typing Can Support Legionella Environmental Surveillance in Hot Water Distribution Systems: A Hospital Experience

2020 ◽  
Vol 17 (22) ◽  
pp. 8662
Author(s):  
Luna Girolamini ◽  
Silvano Salaris ◽  
Jessica Lizzadro ◽  
Marta Mazzotta ◽  
Maria Rosaria Pascale ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Molecular Typing ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Gene Sequencing ◽  
Culture Technique ◽  
Hot Water ◽  
Environmental Surveillance ◽  
Risk Map

In this study, we aimed to associate the molecular typing of Legionella isolates with a culture technique during routine Legionella hospital environmental surveillance in hot water distribution systems (HWDSs) to develop a risk map able to be used to prevent nosocomial infections and formulate appropriate preventive measures. Hot water samples were cultured according to ISO 11731:2017. The isolates were serotyped using an agglutination test and genotyped by sequence-based typing (SBT) for Legionella pneumophila or macrophage infectivity potentiator (mip) gene sequencing for non-pneumophila Legionella species. The isolates’ relationship was phylogenetically analyzed. The Legionella distribution and level of contamination were studied in relation to temperature and disinfectant residues. The culture technique detected 62.21% of Legionella positive samples, characterized by L. pneumophila serogroup 1, Legionella non-pneumophila, or both simultaneously. The SBT assigned two sequence types (STs): ST1, the most prevalent in Italy, and ST104, which had never been isolated before. The mip gene sequencing detected L. anisa and L. rubrilucens. The phylogenetic analysis showed distinct clusters for each species. The distribution of Legionella isolates showed significant differences between buildings, with a negative correlation between the measured level of contamination, disinfectant, and temperature. The Legionella molecular approach introduced in HWDSs environmental surveillance permits (i) a risk map to be outlined that can help formulate appropriate disinfection strategies and (ii) rapid epidemiological investigations to quickly identify the source of Legionella infections.

Occurrence of disinfection by-products in tap water distribution systems and their associated health risk

2013 ◽  
Vol 185 (9) ◽  
pp. 7675-7691 ◽  
Author(s):  
Jin Lee ◽  
Eun-Sook Kim ◽  
Bang-Sik Roh ◽  
Seog-Won Eom ◽  
Kyung-Duk Zoh
Keyword(s):  
Health Risk ◽  
Distribution Systems ◽  
Water Distribution ◽  
Tap Water ◽  
Water Distribution Systems ◽  
By Products
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