Identification Of Disinfection Byproducts Research Articles

Identification of disinfection by-products (DBP) in thermal water swimming pools applying non-target screening by LC-/GC-HRMS

The discovery of new disinfection by-products (DBPs) is still a rarely investigated research area in past studies. In particular, compared to freshwater pools, therapeutic pools with their unique chemical composition have rarely been investigated for novel DBPs. Here we have developed a semi-automated workflow that combines data from target and non-target screening, calculated and measured toxicities into a heat map using hierarchical clustering to assess the pool's overall potential chemical risk. In addition, we used complementary analytical techniques such as positive and negative chemical ionization to demonstrate how novel DBPs can be better identified in future studies. We identified two representatives of the haloketones (pentachloroacetone, and pentabromoacetone) and tribromo furoic acid detected for the first time in swimming pools. Non-target screening combined with target analysis and toxicity assessment may help to define risk-based monitoring strategies in the future, as required by regulatory frameworks for swimming pool operations worldwide.

How well does XAD resin extraction recover halogenated disinfection byproducts for comprehensive identification and toxicity testing?

Halogenated disinfection byproducts (DBPs) are an unintended consequence of drinking water disinfection, and can have significant toxicity. XAD resins are commonly used to extract and enrich trace levels of DBPs for comprehensive, nontarget identification of DBPs and also for in vitro toxicity studies. However, XAD resin recoveries for complete classes of halogenated DBPs have not been evaluated, particularly for low, environmentally relevant levels (ng/L to low µg/L). Thus, it is not known whether levels of DBPs or the toxicity of drinking water might be underestimated. In this study, DAX-8/XAD-2 layered resins were evaluated, considering both adsorption and elution from the resins, for extracting 66 DBPs from water. Results demonstrate that among the 7 classes of DBPs investigated, trihalomethanes (THMs), including iodo-THMs, were the most efficiently adsorbed, with recovery of most THMs ranging from 50%-96%, followed by halonitromethanes (40%-90%). The adsorption ability of XAD resins for haloacetonitriles, haloacetamides, and haloacetaldehydes was highly dependent on the individual species. The adsorption capacity of XAD resins for haloacetic acids was lower (5%-48%), even after adjusting to pH 1 before extraction. Recovery efficiency for most DBPs was comparable with their adsorption, as most were eluted effectively from XAD resins by ethyl acetate. DBP polarity and molecular weight were the two most important factors that determine their recovery. Recovery of trichloromethane, iodoacetic acid, chloro- and iodo-acetonitrile, and chloroacetamide were among the lowest, which could lead to underestimation of toxicity, particularly for iodoacetic acid and iodo-acetonitrile, which are highly toxic.

Identification of Disinfection By-Products (Dbp) in Thermal Water Swimming Pools Applying Non-Target Screening by Lc-/Gc-Hrms

Identification of Disinfection By-Products (Dbp) in Thermal Water Swimming Pools Applying Non-Target Screening by Lc-/Gc-Hrms

Photodecay of inorganic chloramines and disinfection by-products in synthetic and brine solution using UV irradiation

Disinfection by-products (DBPs) such as chloramines, haloacetic acids (HAAs) and trihalomethane (THMs) are frequently detected in water and wastewater systems and their excess concentration can be detrimental to human health and many industrial operations. Therefore, it is imperative to evaluate their formation and speciation and decay kinetics in subsequent disinfection processes like UV treatment. UV Photodecay of monochloramine (NH2Cl), dichloramine (NHCl2) and trichloramine (NCl3) and decay kinetics of these compounds were assessed at different environmental conditions in synthetic and brine solutions. Results showed that the chloramine fractions and speciation were strongly dependent on solution pH and chlorine to ammonia molar ratios. Among the chloramines, NCl3 showed the fastest depletion with a quantum yield of 2.16 mol E−1. Kinetics study showed that the rate of photodecay and quantum yield of NCl3 was 8-times and 13-times higher than NHCl2 and NH2Cl, respectively. Addition of natural organic matter lead to formation of DBPs like THMs and HAAs in reaction mixture and the concentration of DBPs was found to increase post UV irradiation. DBP concentrations in present study were well below the regulatory value provided by US Environmental Protection Agency (US EPA). This investigation provides a better understanding of chloramine decay kinetics and aids in identification of DBPs that can potentially discharged from treatment plants employing UV photolysis.

Toxicity-directed identification of disinfection by-products with high risk

Disinfection unit in water treatment process can effectively prevent the spread of water-borne diseases. However, disinfection by-products (DBPs) may cause adverse effects on human health and ecological security. The species number of DBPs are large, and properties and concentrations of DBPs are quite different. Among them, those DBPs with high risk should be identified and controlled effectively. The exposure dose and toxicity effects are two important factors for screening DBPs with high risk. Lots of current studies on DBPs focused on the identification of unknown DBPs, while the aimless identification was usually low efficiency on screening DBPs with high risk. Toxicity-directed identification of DBPs with high risk is an innovative method, and in which the toxicity assay plays a key role. According to this method, firstly researchers can screen out the components containing highly toxic DBPs, and then purposively identify the specific molecular structure of DBPs with high risk. The toxicity-directed method is helpful to efficiently identify DBPs with high risk. This review briefly summarizes the methods of identify the molecular structure and toxicity assay of DBPs, and introduces the characteristics and procedures of this method, which may provide reference for controlling water quality after disinfection treatment.

Identification of disinfection by-products (DBPs) halo phenols in drinking water

The Bureau of Indian Standard (BIS, New Delhi) has framed a set of standards for drinking water description (IS 10500:1991-http://www.indiawaterportal.org), which has specifications drawn up in 1983 with the most current amendment (July, 2010), and the US Environmental Protection Agency (USEPA 2003) has also developed policy for different drinking water disinfection by-products (DBPs). This study examined the quality of metropolitan drinking water by monitoring the physicochemical parameters, and DBPs study such as the effects of halide ions, natural organic matter, and drinking water characterization were investigated. The sampled water had halo phenols DBPs as a result of disinfection, during chlorination. The water was alkaline in nature, and the water temperature varied from 33 to 37 °C. The major ions, namely bromate, iodate, chlorite, chromate, sulfate and phosphate, have been investigated in the municipality drinking water, Tiruchirappalli and Srirangam in Tamil Nadu, India. Here, three solvents such as hexane, petroleum ether and pentane were used for the liquid–liquid extraction of target compounds. The gas chromatographs equipped with capillary columns (DB-WAX) were employed for the determination of DBPs and 2-bromo-4-chlorophenol was predominantly identified.

Identification of disinfection by-products in freshwater and seawater swimming pools and evaluation of genotoxicity

Exposure to disinfection byproducts (DBPs) in swimming pools has been linked to adverse health effects. Numerous DBPs that occur in swimming pools are genotoxic and carcinogenic. This toxicity is of a greater concern in the case of brominated DBPs that have been shown to have substantially greater toxicities than their chlorinated analogs. In chlorinated seawater swimming pools, brominated DBPs are formed due to the high content of bromide. Nevertheless, very little data is reported about DBP occurrence and mutagenicity of water in these pools. In the present study, three seawater and one freshwater swimming pools located in Southeastern France were investigated to determine qualitatively and quantitatively their DBP contents. An evaluation of the genotoxic properties of water samples of the freshwater pool and a seawater pool was conducted through the Salmonella assay (Ames test). The predominant DBPs identified in the freshwater pool were chlorinated species and included trichloroacetic acid, chloral hydrate, dichloroacetonitrile, 1,1,1-trichloropropanone and chloroform. In the seawater pools, brominated DBPs were the predominant species and included dibromoacetic acid, bromoform and dibromoacetonitile. Bromal hydrate levels were also reported. In both types of pools, haloacetic acids were the most prevalent chemical class among the analyzed DBP classes. The distribution of other DBP classes varied depending on the type of pool. As to genotoxicity, the results of Ames test showed higher mutagenicity in the freshwater pool as a consequence of its considerably higher DBP contents in comparison to the tested seawater pool.