Abstract:Detection of N-nitrosamines in water supplies is an environmental and public health issue because many N-nitrosamines are classified as probable human carcinogens. Some analytical methods are inadequate for detecting N-nitrosodimethylamine (NDMA) at low ng/L concentrations in water due to poor extraction efficiencies and nonselective and nondistinctive GC/MS electron ionization techniques. Development of a selective, sensitive, and affordable benchtop analytical method for eight N-nitrosamines, at relevant dri… Show more
“…NPyr and NMor were first found in drinking water distribution systems from in a city in Canada that employed chloramines in combination with UV disinfection, at concentrations of 2-4 ng/L and 1 ng/L, respectively (Charrois et al, 2004). It is important to note that NPyr and NMor have not previously been found in source water and finished water.…”
Section: Factors Influencing the Formation Of Nitrosaminesmentioning
“…NPyr and NMor were first found in drinking water distribution systems from in a city in Canada that employed chloramines in combination with UV disinfection, at concentrations of 2-4 ng/L and 1 ng/L, respectively (Charrois et al, 2004). It is important to note that NPyr and NMor have not previously been found in source water and finished water.…”
Section: Factors Influencing the Formation Of Nitrosaminesmentioning
“…It has also been studied the interaction of the polymer remaining in the water and its reaction with components of water, which causes the formation of trihalomethanes (THMs) (Bolto, 2007;Hebert et al, 2010) or the disinfection by-products (Gerecke and Sedlak, 2003;Charrois et al, 2004;Bolto, 2007).…”
Section: Use Of Coagulants and Flocculants: Advantages And Drawbacksmentioning
Arnal Arnal, JM.; Sancho Fernández, MP. (2015). Alternatives to the use of synthetic organic coagulant aids in drinking water treatment: improvements in the application of the crude extract of Moringa oleifera seed. Desalination and Water Treatment. 55(13):3635-3645. doi:10.1080/19443994.2014.939487. Alternatives to the use of synthetic organic coagulant-aids in drinking water treatment: improvements in the application of the crude extract of Moringa oleifera seed
Abstract:Drinking water treatment is a process based on multiple stages that has as main objective to provide water safe enough to be consumed by humans. Coagulation-flocculation is used to remove colloidal and suspended solids. This process improves the performance of subsequent stages (as sedimentation or filtration) as well as the water quality with a desired end-use. For many years, inorganic and organic synthetic polyelectrolytes have been used in coagulationflocculation processes. However, its use has been deeply studied recently to determine the potential impact of residual concentration of these substances over human health and the environment. Strict regulations limit the concentration of free residual monomer after the addition of Polyacrylamide (PAM) in drinking water treatment and study the effect of the interaction of the residues with disinfection products. Therefore, in the last years there has been a resurgence of interest to use natural materials with the same performance that synthetic, but with lower hazard for the environment and humans. This work studies the use of the flocculant extracted from Moringa oleifera seed, in combination with Polyaluminum Chloride (PAC). The performance is compared with the combination PAC-PAM in terms of coagulant activity and physical-chemical quality of the water treated. Jar test were carried out using two types of natural water (with presence of bentonites) and different combinations of coagulant and flocculants. Results show that coagulant activity of PAC-Moringa combination is comparable with the results obtained with PAC-PAM, reducing initial turbidity up to 90% in all the tests. With regard to physical-chemical quality of the treated water, PAC-Moringa produces values under the drinking water quality standards for all the parameters analyzed. It is remarkable the decrease of 50% in the trihalomethanes formation potential rate shown for PAC-Moringa combination, observed when treating natural water with presence of bentonites. Therefore, the results obtain in this work encourage the use of Moringa oleifera extract as a natural, low cost, effective and low toxicity alternative to the use of synthetic organic polyelectrolytes as polyacrylamide for drinking water treatment.
“…The extracts were analyzed by GC/CI-MS/MS using methanol (for manual LLE and Ambersorb methods) or acetonitrile (for micro-LLE and Ambersorb-Envi-carb methods) positive chemical ionization (PCI). Charrois et al (2004) developed a SPE method using Ambersorb 572-Lichrolut EN and GC/MS ammonia positive chemical ionization, which favored the formation of adducts and increasing the selectivity compared to methanol PCI or LRMS-EI. The selectivity of [M+18] + and [M+1] + ions obtained in ammonia PCI mode were more distinctive for quantification compared to low mass fragments produced by EI that allowed for the detection of NDMA at the 1.6 ng l -1 level.…”
Chloroform and other bromochlorotrihalomethanes were first identified as disinfection byproducts (DBPs) in chlorinated water in 1970s. Since then, many other DBPs have been identified such as haloacetonitriles, haloacetaldehydes, cyanogen halides, aldehydes, ketoacids, chlorite, bromate and other organic and inorganic compounds. Due to their occurrence and potential health risks, the U.S.EPA promulgated the Stage I Disinfectants and Disinfection Byproducts (D-DBP) Rule in 1998. To assist water utilities monitoring DBPs in their finished water, the U.S. EPA published a list of approved analytical methods under the D-DBP Rule. In 1996, the U.S. EPA also promulgated the Information Collection Rule (ICR) to collect brackground information on DBPs and pathogens for the Stage II D-DBP-Rule. Actually 500 DBPs are known but few have been investigated for their quantitative occurrence and health effects. Due to the fact that their identification and quantitation have become extremely important to drinking water companies in order to reduce or remove their presence, other analytical methods different from those proposed by U.S. EPA have been optimized and are now commented in this article.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.