scholarly journals Disinfection by-products and extractable organic compounds in South African tap water

2008 ◽  
Vol 4 (1) ◽  
Author(s):  
Carien Nothnagel ◽  
Karsten Kotte ◽  
J J Pienaar ◽  
P G Van Zyl ◽  
J P Beukes
Keyword(s):  
Drinking Water ◽  
South African ◽  
Tap Water ◽  
Target Range ◽  
Preliminary Results ◽  
The Us ◽  
Microbiological Parameters ◽  
Us Epa ◽  
Micro Organisms ◽  
By Products

An important step in urban purification of drinking water is disinfection by e.g. chlorination where potential pathogenic micro-organisms in the water supply are killed. The presence of organic material in natural water leads to the formation of organic by- products during disinfection. Over 500 of these disinfection by-products (DBPs) have been identified and many more are estimated to form during the disinfection step. Several DBPs such as trihalomethanes (THMs), which is carcinogenic, poses serious health risks to the community. There is very few quantitative data available which realizes the actual levels of these compounds present in drinking water. The levels of four THMs present in drinking water were measured. It included chloroform, bromodichloromethane, chlorodibromomethane and bromoform. Although microbiological parameters are considered to get more attention than disinfection by-products, the measurement of the levels of these compounds in South-African drinking water is essential together with establishing minimum acceptable concentration levels. The target range for total trihalomethanes (TTHMs) established by the US EPA at the end of 2003 is 0-0.08ug/mL. The aim of this paper is to create an awareness of the problem as well as presenting preliminary results obtained with the method of analysis. Preliminary results indicate that urgent attention must be given to the regulation and monitoring of DBPs in South African drinking water.

Towards an improved human exposure assessment for contaminants in drinking water released by products used for domestic water distribution

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Eddo J. Hoekstra
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Water Distribution ◽  
Tap Water ◽  
Domestic Water ◽  
Sampling Protocol ◽  
Human Exposure Assessment ◽  
Micro Organisms ◽  
By Products

Substances migrated from products or micro-organisms released from biofilms in the domestic distribution system may affect the quality of tap water. The approach to protect consumers against these possible contaminants and specifically the sampling protocol for compliance monitoring at the tap is not well described in the European Drinking Water Directive. Regulators of the member states like to have guidance. This paper describes the issue and proposes a possible approach.

Influence of US EPA 1622 method successive steps on the viability of Cryptosporidium oocysts

2000 ◽  
Vol 41 (7) ◽  
pp. 189-196 ◽  
Author(s):  
K. Guyot ◽  
M. F. Gireaudot-Liepmann ◽  
A. Cabon ◽  
I. Riveau-Ricard ◽  
M. Lange ◽  
...  
Keyword(s):  
Water Samples ◽  
Tap Water ◽  
High Recovery ◽  
The Us ◽  
Cryptosporidium Oocysts ◽  
Cartridge Filter ◽  
Us Epa ◽  
Cryptosporidium Parvum Oocysts ◽  
Elution Step

Viable Cryptosporidium parvum oocysts were processed by the US EPA 1622 method to determine if the procedure that requires successive filtration, elutionand centrifugation alters their integrity and viability (determined by in vitro excystation). Oocyst seeded in tap water samples were also used to evaluate recovery efficiencies and impact of the whole procedure on oocyst viability. Filtration through Envirochek Gelman cartridge was found not to damage oocysts. The use of Laureth-12 buffer during the elution step was shown to lead to greater spontaneous oocysts excystation than other phosphate buffers containing between 80 and/or SDS (like the Gelman buffer). However, this drawback was widely balanced against the best efficiency of this buffer to elute oocysts captured by the cartridge filter and therefore against its high recovery efficiency. Thus, in water samples in which the oocyst concentration is expected to be low, it is more advantageous to employ the Laureth-12 buffer for the elution through it can influence viability. Centrifugation speeds (1,000–5,000 g) did not alter oocysts.

scholarly journals Arsenic in Drinking Water and Lung Cancer Mortality in the United States: An Analysis Based on US Counties and 30 Years of Observation (1950–1979)

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Hamid Ferdosi ◽  
Elisabeth K. Dissen ◽  
Nana Ama Afari-Dwamena ◽  
Ji Li ◽  
Rusan Chen ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Drinking Water ◽  
Cancer Risk ◽  
Lung Cancer Risk ◽  
The United States ◽  
Risk Estimates ◽  
Unit Risk ◽  
The Us ◽  
Us Epa ◽  
Us Counties

Background.To examine whether the US EPA (2010) lung cancer risk estimate derived from the high arsenic exposures (10–934 µg/L) in southwest Taiwan accurately predicts the US experience from low arsenic exposures (3–59 µg/L).Methods. Analyses have been limited to US counties solely dependent on underground sources for their drinking water supply with median arsenic levels of ≥3 µg/L.Results. Cancer risks (slopes) were found to be indistinguishable from zero for males and females. The addition of arsenic level did not significantly increase the explanatory power of the models. Stratified, or categorical, analysis yielded relative risks that hover about 1.00. The unit risk estimates were nonpositive and not significantly different from zero, and the maximum (95% UCL) unit risk estimates for lung cancer were lower than those in US EPA (2010).Conclusions. These data do not demonstrate an increased risk of lung cancer associated with median drinking water arsenic levels in the range of 3–59 µg/L. The upper-bound estimates of the risks are lower than the risks predicted from the SW Taiwan data and do not support those predictions. These results are consistent with a recent metaregression that indicated no increased lung cancer risk for arsenic exposures below 100–150 µg/L.

scholarly journals The Effect of Different Boiling and Filtering Devices on the Concentration of Disinfection By-Products in Tap Water

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Glòria Carrasco-Turigas ◽  
Cristina M. Villanueva ◽  
Fernando Goñi ◽  
Panu Rantakokko ◽  
Mark J. Nieuwenhuijsen
Keyword(s):  
Drinking Water ◽  
Health Effects ◽  
Reverse Osmosis ◽  
Tap Water ◽  
Epidemiological Studies ◽  
The Other ◽  
Large Decrease ◽  
Adverse Health Effects ◽  
Before And After ◽  
By Products

Disinfection by-products (DBPs) are ubiquitous contaminants in tap drinking water with the potential to produce adverse health effects. Filtering and boiling tap water can lead to changes in the DBP concentrations and modify the exposure through ingestion. Changes in the concentration of 4 individual trihalomethanes (THM4) (chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM)), MX, and bromate were tested when boiling and filtering high bromine-containing tap water from Barcelona. For filtering, we used a pitcher-type filter and a household reverse osmosis filter; for boiling, an electric kettle, a saucepan, and a microwave were used. Samples were taken before and after each treatment to determine the change in the DBP concentration. pH, conductivity, and free/total chlorine were also measured. A large decrease of THM4 (from 48% to 97%) and MX concentrations was observed for all experiments. Bromine-containing trihalomethanes were mostly eliminated when filtering while chloroform when boiling. There was a large decrease in the concentration of bromate with reverse osmosis, but there was a little effect in the other experiments. These findings suggest that the exposure to THM4 and MX through ingestion is reduced when using these household appliances, while the decrease of bromate is device dependent. This needs to be considered in the exposure assessment of the epidemiological studies.

scholarly journals Contamination Level, Source Identification and Health Risk Assessment of Potentially Toxic Elements in Drinking Water Sources of Mining and Non-mining Areas of Khyber Pakhtunkhwa, Pakistan

2021 ◽  
Author(s):  
Zahid Imran Bhatti ◽  
Muhammad Ishtiaq ◽  
Said Akbbar Khan ◽  
javed nawab ◽  
Sardar Khan ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Surface Water ◽  
Health Risk ◽  
Toxic Elements ◽  
Water Sources ◽  
Potentially Toxic Elements ◽  
Mining Areas ◽  
The Us ◽  
Us Epa

Abstract Accelerated mining activities have increased water contamination with potentially toxic elements (PTEs) and their associated human health risk in developing countries. The current study investigated the distribution of PTEs, their potential sources and health risk assessment in both ground and surface water sources in mining and non–mining areas of Khyber Pakhtunkhwa, Pakistan. Water samples (n=150) were taken from selected sites and were analyzed for six PTEs (Ni, Cr, Zn, Cu, Pb and Mn). Among PTEs, Cr showed high mean concentration (497) μg L–1, followed by Zn (414) μg L–1 in mining area, while Zn showed lowest mean value (4.44) μg L–1 in non-mining areas. Elevated concentrations of Ni, Cr and moderate level of Pb in ground and surface water of Mohmand District exceeded the permissible limits set by WHO (2017). Multivariate statistical analyses showed that pollution sources of PTEs were mainly from mafic-ultramafic rocks, acid mine drainage, open dumping of mine-wastes and mine tailings. The hazard quotient (HQ) was highest for children relatively to adults, but not higher than the US-EPA limits. The hazard index (HI) for ingestions of all selected PTEs were lower than the threshold value (HIing <1), except Mohmand District which showed (HI >1) in mining areas through ingestion. Moreover, the carcinogenic risk (CR) values exceeded the threshold limits for Ni and Cr set by the US-EPA (1.0E−04 to 1.0E−06). In order to protect the drinking water sources of the study areas from more contamination, the management techniques and policy for mining operations need to be implemented.

scholarly journals Deactivation of Caenorhabditis elegans nematodes in drinking water by PMS/UV-C: Efficiency and mechanisms

2021 ◽  
Author(s):  
Taoqin Chen ◽  
Jinzhe Li ◽  
Longqian Xu ◽  
Dong Zhang ◽  
Zheng Wang ◽  
...  
Keyword(s):  
Drinking Water ◽  
Caenorhabditis Elegans ◽  
Tap Water ◽  
Water Tank ◽  
Mechanism Study ◽  
Nematode Caenorhabditis Elegans ◽  
Chlorine Disinfection ◽  
Promising Strategy ◽  
Uv C ◽  
By Products

Abstract The occurrence an d infestations of chlorine-resistant invertebrates in drinking water distributions have attracted concerns on water quality in China, making effective deactivation imperative. This study presents a no vel strategy for nematode ( Caenorhabditis elegans ) deactivation using peroxymonosulfate (PMS)/UV-C. The results indicated that 100% deactivation efficiency was obtained under optimal conditions. An acidic pH and 0.25 mg/L Fe(II) were beneficial to the PMS/UV-C-triggered deactivation of nematodes. A mechanism study demonstrated that was activated by UV-C to produce · OH and · SO 4 - , which resulted in oxidative stress and stimulated the occurrence of cell apoptosis, leading to nematode deactivation. The results reveal PMS/UV-C as an alternative to chlorination in water treatment plants (WTP) or an emergency application when chlorine-resistant invertebrates breed in a second-supply water tank, is a promising strategy for disinfection. This approach afforded the advantages of avoiding the production of chlorine disinfection by-products (DBP) and greater efficacy of nematode deactivation. This work will provide ideas for on-going research efforts into chlorine-resistant invertebrate deactivation, and eventually achieve the direct drinking of municipal tap water.

scholarly journals Low copper-2 intake in Switzerland does not result in lower incidence of Alzheimer’s disease and contradicts the Copper-2 Hypothesis

2020 ◽  
Vol 245 (3) ◽  
pp. 177-179 ◽  
Author(s):  
Marc Solioz
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Drinking Water ◽  
Dietary Supplements ◽  
Tap Water ◽  
Anthropogenic Factors ◽  
Western World ◽  
Formidable Challenge ◽  
Slow Progression ◽  
The Us

In recent years, the “Copper-2 Hypothesis” has been put forth in an attempt to explain the epidemic of Alzheimer’s disease (AD) in the Western world. According to this hypothesis, “free” copper (copper-2) in drinking water, dietary supplements, and meat is the chief cause of the increased incidence of AD in recent decades. In contrast to the US, copper plumbing for drinking water is not used in Switzerland and tap water is very low in copper. Other “risk” factors including dietary supplements and meat consumption are also lower in Switzerland than in the US. Yet, the incidence of AD is closely similar in the two countries. This contradicts the Copper-2 Hypothesis. Impact statement The Western world is faced with an Alzheimer’s epidemic. Identifying the life style and anthropogenic factors involved has become a priority. This is a formidable challenge due to the complexity and the slow progression of the disease. A hypothesis put forth by George Brewer postulates divalent copper (copper-2), chiefly present in drinking water from copper pipes, to be a major risk factor for Alzheimer’s disease. In Switzerland, copper pipes are not used for drinking water, but the frequency of Alzheimer’s disease is similar to that of other Western countries. This contradicts Brewer’s hypothesis and suggests that other factors are responsible for today’s Alzheimer’s epidemic.

Monitoring of hazardous substances at Alcantarilha's water treatment plant, Portugal

2004 ◽  
Vol 4 (5-6) ◽  
pp. 343-353 ◽  
Author(s):  
M.J. Rosa ◽  
T. Cecílio ◽  
M. Ribau Teixeira ◽  
M. Viriato ◽  
R. Coelho ◽  
...  
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Hazardous Substances ◽  
Legal Standards ◽  
Guideline Values ◽  
Microbiological Parameters ◽  
By Products

A monitoring programme of hazardous substances was implemented in Alcantarilha's water treatment plant (Algarve, Portugal) since 2002, in addition to the legally established monitoring of standard physical, chemical and microbiological parameters. The objective of this programme was to ensure the drinking water quality regarding the waterborne disease organisms Cryptosporidium, Giardia, Salmonella, Pseudomonas aeruginosa, enterovirus and cyanobacteria, and the potentially harmful chemicals aluminium, cyanotoxins, and disinfection by-products (THM) and their precursors (TOC, DOC, UV254 nm, SUVA). Most of these parameters are new and still not regulated by the Portuguese and the European legislation. Data presented in this study refer to the period of August 2002 to October 2003. Results show that, despite the seasonal variations of the raw water quality, concentrations of the hazardous substances in the supplied drinking water were far below the legal standards and the WHO's and EPA guideline values, demonstrating the high removal efficiencies of this treatment plant.

scholarly journals Detection of Giardia and Cryptosporidium cysts/oocysts in watersheds and drinking water sources in Brazil urban areas

2009 ◽  
Vol 8 (2) ◽  
pp. 399-404 ◽  
Author(s):  
Maria Tereza Pepe Razzolini ◽  
Thaís Filomena da Silva Santos ◽  
Veridiana Karmann Bastos
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Urban Areas ◽  
Water Sources ◽  
Raw Water ◽  
Protozoan Parasites ◽  
The Us ◽  
Cryptosporidium Oocysts ◽  
Us Epa ◽  
Giardia Cysts

The protozoan parasites Giardia and Cryptosporidium have been described as important waterborne disease pathogens, and are associated with severe gastrointestinal illnesses. The objective of this paper was to investigate the presence of Giardia cysts and Cryptosporidium oocysts in samples from watershed catchments and treated water sources. A total of 25 water samples were collected and examined according to the US EPA—Method 1623, 2005, consisting of 12 from drinking water and 13 from raw water. Positive samples from raw water for Giardia cysts and Cryptosporidium oocysts were 46.1 and 7.6%, respectively. In finished water, positive samples were 41.7% for Giardia cysts and 25.0% for Cryptosporidium oocysts. Concentrations of Giardia cysts found in raw water samples ranged from “not detected” to 3.4 cysts/L, whereas concentrations of Cryptoporidium oocysts ranged from “not detected” to 0.1 oocysts/L. In finished water, Giardia concentrations ranged from “not detected” to 0.06 cysts/L, and Cryptosporidium, from “not detected” to 0.01 oocysts/L. Concentrations of Giardia cysts and Cryptosporidium oocysts were not high in the samples analyzed. Nevertheless, the results of this study highlight the need to monitor these organisms in both raw and drinking water.

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