Jeffrey Charrois

Which chemicals drive biological effects in wastewater and recycled water

Removal of organic micropollutants from wastewater during secondary treatment followed by reverse osmosis and UV disinfection was evaluated by a combination of four in-vitro cell-based bioassays and chemical analysis of 299 organic compounds. Concentrations detected in recycled water were below the Australian Guidelines for Water Recycling. Thus the detected chemicals were considered not to pose any health risk. The detected pesticides in the wastewater treatment plant effluent and partially advanced treated water explained all observed effects on photosynthesis inhibition. In contrast, mixture toxicity experiments with designed mixtures containing all detected chemicals at their measured concentrations demonstrated that the known chemicals explained less than 3% of the observed cytotoxicity and less than 1% of the oxidative stress response. Pesticides followed by pharmaceuticals and personal care products dominated the observed mixture effects. The detected chemicals were not related to the observed genotoxicity. The large proportion of unknown toxicity calls for effect monitoring complementary to chemical monitoring.

Simultaneous analysis of 10 trihalomethanes at nanogram per liter levels in water using solid-phase microextraction and gas chromatography mass-spectrometry.

Trihalomethanes are predominantly formed during disinfection of water via reactions of the oxidant with natural organic matter. Even though chlorinated and brominated trihalomethanes are the most widespread organic contaminants in drinking water, when iodide is present in raw water iodinated trihalomethanes can also be formed. The formation of iodinated trihalomethanes can lead to taste and odor problems and is a potential health concern since they have been reported to be more toxic than their brominated or chlorinated analogs. Currently, there is no published standard analytical method for I-THMs in water. The analysis of 10 trihalomethanes in water samples in a single run is challenging because the iodinated trihalomethanes are found at very low concentrations (ng/L range), while the regulated chlorinated and brominated trihalomethanes are present at much higher concentrations (above μg/L). An automated headspace solid-phase microextraction technique, with a programmed temperature vaporizer inlet coupled with gas chromatography-mass spectrometry, was developed for routine analysis of 10 trihalomethanes i.e. bromo-, chloro- and iodo-trihalomethanes in water samples. The carboxen/polydimethylsiloxane/divinylbenzene fiber was found to be the most suitable. The optimization, linearity range, accuracy and precision of the method are discussed. The limits of detection range from 1 ng/L to 20 ng/L for iodoform and chloroform, respectively. Matrix effects in treated groundwater, surfacewater, seawater, and secondary wastewater were investigated and it was shown that the method is suitable for the analysis of trace levels of iodinated trihalomethanes in a wide range of waters. The method developed in the present study has the advantage of being rapid, simple and sensitive. A survey conducted throughout various process stages in an advanced water recycling plant showed the presence of iodinated trihalomethanes at ng/L levels.

Formation of N-nitrosamines from chlorination and chloramination of molecular weight fractions of natural organic matter.

N-Nitrosamines are a class of disinfection by-products (DBPs) that have been reported to be more toxic than the most commonly detected and regulated DBPs. Only a few studies investigating the formation of N-nitrosamines from disinfection of natural waters have been reported, and little is known about the role of natural organic matter (NOM) and the effects of its nature and reactivity on the formation of N-nitrosamines. This study investigated the influence of the molecular weight (MW) characteristics of NOM on the formation of eight species of N-nitrosamines from chlorination and chloramination, and is the first to report on the formation of eight N-nitrosamines from chlorination and chloramination of MW fractions of NOM. Isolated NOM from three different source waters in Western Australia was fractionated into several apparent MW (AMW) fractions using preparative-scale high performance size exclusion chromatography. These AMW fractions of NOM were then treated with chlorine or chloramine, and analysed for eight species of N-nitrosamines. Among these N-nitrosamines, N-nitrosodimethylamine (NDMA) was the most frequently detected. All AMW fractions of NOM produced N-nitrosamines upon chlorination and chloramination. Regardless of AMW characteristics, chloramination demonstrated a higher potential to form N-nitrosamines than chlorination, and a higher frequency of detection of the N-nitrosamines species was also observed in chloramination. The results showed that inorganic nitrogen may play an important role in the formation of N-nitrosamines, while organic nitrogen is not necessarily a good indicator for their formation. Since chlorination has less potential to form N-nitrosamines, chloramination in pre-chlorination mode was recommended to minimise the formation of N-nitrosamines. There was no clear trend in the formation of N-nitrosamines from chlorination of AMW fractions of NOM. However, during chloramination, NOM fractions with AMW <2.5 kDa were found to produce higher concentrations of NDMA and total N-nitrosamines. The precursor materials of N-nitrosamines appeared to be more abundant in the low to medium MW fractions of NOM, which correspond to the fractions that are most difficult to remove using conventional drinking water treatment processes. Alternative or advanced treatment processes that target the removal of low to medium MW NOM including activated carbon adsorption, biofiltration, reverse osmosis, and nanofiltration, can be employed to minimise the formation of N-nitrosamines.

Private drinking water supplies: challenges for public health

Compared with people in many developing areas throughout the world, Canadians are fortunate to have access to safe drinking water and adequate sanitation. Globally, most diarrheal diseases — responsible for nearly two million deaths a year — can be attributed to unsafe water supplies as well as

Determination of halonitromethanes and haloacetamides: An evaluation of sample preservation and analyte stability in drinking water

Simultaneous quantitation of 6 halonitromethanes (HNMs) and 5 haloacetamides (HAAms) was achieved with a simplified liquid-liquid extraction (LLE) method, followed by gas chromatography-mass spectrometry. Stability tests showed that brominated tri-HNMs immediately degraded in the presence of ascorbic acid, sodium sulphite and sodium borohydride, and also reduced in samples treated with ammonium chloride, or with no preservation. Both ammonium chloride and ascorbic acid were suitable for the preservation of HAAms. Ammonium chloride was most suitable for preserving both HNMs and HAAms, although it is recommended that samples be analysed as soon as possible after collection. While groundwater samples exhibited a greater analytical bias compared to other waters, the good recoveries (>90%) of most analytes in tap water suggest that the method is very appropriate for determining these analytes in treated drinking waters. Application of the method to water from three drinking water treatment plants in Western Australia indicating N-DBP formation did occur, with increased detections after chlorination. The method is recommended for low-cost, rapid screening of both HNMs and HAAms in drinking water.

Safe drinking water: Critical components of effective inter-agency relationships

The paper supports the development of evidence-based emergency management frameworks of cooperation between agencies in the area of drinking water and public health, as part of developing the overall risk management culture within water utilities. We employed a qualitative research design to understand critical gaps in inter-agency relations that aggravated past drinking water and health incidents and from these identified determinants of effective relationships. We identified six critical institutional relationship components that were deficient in past incidents, namely proactivity, communication, training, sharing expertise, trust and regulation. We then analysed how these components are addressed by reputable water utilities and public health departments to develop positive examples of inter-agency cooperation. Control of different risks (e.g. public health, business, and reputation) resulting from drinking water incidents should employ a preventive framework similar to the multiple barrier approach for management of drinking water quality.

Analysis of free amino acids in natural waters by liquid chromatography-tandem mass spectrometry.

This paper reports a new analytical method for the analysis of 18 amino acids in natural waters using solid-phase extraction (SPE) followed by liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) operated in multiple reaction monitoring mode. Two different preconcentration methods, solid-phase extraction and concentration under reduced pressure, were tested in development of this method. Although concentration under reduced pressure provided better recoveries and method limits of detection for amino acids in ultrapure water, SPE was a more suitable extraction method for real samples due to the lower matrix effects for this method. Even though the strong cation exchange resin used in SPE method introduced exogenous matrix interferences into the sample extracts (inorganic salt originating from the acid-base reaction during the elution step), the SPE method still incorporates a broad sample clean-up and minimised endogenous matrix effects by reducing interferences originating from real water samples. The method limits of quantification (MLQ) for the SPE LC-MS/MS method in ultrapure water ranged from 0.1 to 100 μg L(-1) as N for the different amino acids. The MLQs of the early eluting amino acids were limited by the presence of matrix interfering species, such as inorganic salts in natural water samples. The SPE LC-MS/MS method was successfully applied to the analysis of amino acids in 3 different drinking water source waters: the average total free amino acid content in these waters was found to be 19 μg L(-1) as N, while among the 18 amino acids analysed, the most abundant amino acids were found to be tyrosine, leucine and isoleucine.

Isotope dilution liquid chromatography - tandem mass spectrometry for simultaneous identification and quantification of beta-casomorphin 5 and beta-casomorphin 7 in yoghurt

A highly selective and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous identification and quantification of beta-casomorphin 5 (BCM5) and beta-casomorphin 7 (BCM7) in yoghurt. The method used deuterium labelled BCM5-d10 and BCM7-d10 as surrogate standards for confident identification and accurate and quantification of these analytes in yoghurt. Linear responses for BCM5 and BCM7 (R(2)=0.9985 and 0.9986, respectively) was observed in the range 0.01-10ng/μL. The method limits of detection (MLDs) in yoghurt extracts were found to be 0.5 and 0.25ng/g for BCM5 and BCM7, respectively. Analyses of spiked samples were used to provide confirmation of accuracy and precision of the analytical method. Recoveries relative to the surrogate standards of these spikes were in the range of 95-106% for BCM5 and 103-109% for BCM7. Precision from analysis of spiked samples was expressed as relative standard deviation (%RSD) and values were in the range 1-16% for BCM5 and 1-6% for BCM7. Inter-day reproducibility was between 2.0-6.4% for BCM5 and between 3.2-6.1% for BCM7. The validated isotope dilution LC-MS/MS method was used to measure BCM5 and BCM7 in ten commercial and laboratory prepared samples of yoghurt and milk. Neither BCM5 nor BCM7 was detected in commercial yoghurts. However, they were observed in milk and laboratory prepared yoghurts and interestingly their levels decreased during processing. BCM5 decreased from 1.3ng/g in milk to 1.1ng/g in yoghurt made from that milk at 0day storage and <MLQ at 1 and 7days storage. BCM7 decreased from 1.9ng/g in milk to <MLQ in yoghurts immediately after processing. These preliminary results indicate that fermentation and storage reduced BCM5 and BCM7 concentration in yoghurt.

DISINFECTION BY-PRODUCTS IN SMALL ALBERTA COMMUNITY DRINKING-WATER SUPPLIES

Complacent attitudes toward drinking-water quality can lead to compromised disinfection practices, as noted in such episodes as Walkerton and North Battleford. The first priority for drinking-water providers must be to ensure microbial safety. However, it is recognized that effective disinfection may not be risk free. Consequently, drinking-water guidelines seek to balance the certain danger posed by microbial pathogens with the potential adverse health hazards that may arise from disinfection by-products (DBPs). Providers of drinking water in small communities often do not have the means to reduce concentrations of DBPs, compared to utilities in larger municipalities. A significant portion of Albertas population receives drinking water from smaller scale treatment plants or from private wells. A survey of selected DBPs was conducted in 11 rural Alberta communities, with populations ranging from 60 to 2300. The objectives were to evaluate source water quality, as measured by total organic carbon, and to measure representative concentrations of trihalomethanes (THMs) and haloacetic acids (HAAs) at a point within each distribution system as well as within each water treatment plant. During the 5-wk study, our data show: (1) averages of THM3 (chloroform, bromodichloromethane, chloro dibromomethane) concentrations often exceed 100 µg/L (Health Canadas running annual average guideline for total THMs); (2) source waters with the highest TOC concentrations (15 mg/L) had the highest average THM3 concentrations (200 µg/L); and (3) poor source water quality may necessitate using alternative disinfection options to ensure compliance with microbial and chemical drinking-water guidelines.

Review of high recovery concentrate management options

AbstractCurrent methods of inland concentrate disposal include surface water discharge, deep-well injection and evaporation ponds. These methods are unsustainable and are limited by high capital cost and non-ubiquitous applications. This paper gives an overview of potential alternatives and technologies available that can reduce the concentrate formed via reducing its volume or recycling. Potential alternatives explored have been electrodialysis, mechanical evaporation, vibratory shear-enhanced process (VSEP) and wind-aided intensification of evaporation. All technologies have potential for use in areas distant from the coast and have better performance than currents management techniques. This paper reviews multiple studies that have explored alternate technologies for concentrate disposal in terms of economics and feasibility. Of the five case studies presented, VSEP shows promise as a secondary system of treatment via enhancing percentage recovery; higher permeate flux and lower operational costs.