Comment on "Toxicological relevance of emerging contaminants for drinking water quality" by M. Schriks, M.B. Heringa, M.M.E. van der Kooi, P. de Voogt and A.P. van Wezel [Water Research 44 (2010) 461-476]

This is the post-print version of the final paper published in Water Research. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2011 Elsevier B.V.No abstract available

Collecting household water usage data: telephone questionnaire or diary?

<p>Abstract</p> <p>Background</p> <p>Quantitative Microbial Risk Assessment (QMRA), a modelling approach, is used to assess health risks. Inputs into the QMRA process include data that characterise the intensity, frequency and duration of exposure to risk(s). Data gaps for water exposure assessment include the duration and frequency of urban non-potable (non-drinking) water use. The primary objective of this study was to compare household water usage results obtained using two data collection tools, a computer assisted telephone interview (CATI) and a 7-day water activity diary, in order to assess the effect of different methodological survey approaches on derived exposure estimates. Costs and logistical aspects of each data collection tool were also examined.</p> <p>Methods</p> <p>A total of 232 households in an Australian dual reticulation scheme (where households are supplied with two grades of water through separate pipe networks) were surveyed about their water usage using both a CATI and a 7-day diary. Householders were questioned about their use of recycled water for toilet flushing, garden watering and other outdoor activities. Householders were also questioned about their water use in the laundry. Agreement between reported CATI and diary water usage responses was assessed.</p> <p>Results</p> <p>Results of this study showed that the level of agreement between CATI and diary responses was greater for more frequent water-related activities except toilet flushing and for those activities where standard durations or settings were employed. In addition, this study showed that the unit cost of diary administration was greater than for the CATI, excluding consideration of the initial selection and recruitment steps.</p> <p>Conclusion</p> <p>This study showed that it is possible to successfully 'remotely' coordinate diary completion providing that adequate instructions are given and that diary recording forms are well designed. In addition, good diary return rates can be achieved using a monetary incentive and the diary format allows for collective recording, rather than an individual's estimation, of household water usage. Accordingly, there is merit in further exploring the use of diaries for collection of water usage information either in combination with a mail out for recruitment, or potentially in the future with Internet-based recruitment (as household Internet uptake increases).</p

Removal of emerging contaminants for water reuse by membrane technology

Emerging trace organic contaminants (TrOCs) are broadly defined as any synthetic or naturally occurring chemicals that have not been routinely monitored but have the potential to enter the environment and cause known or suspected adverse ecological or human health effects [1]. Most of these TrOCs are from municipal, agricultural and industrial wastewater sources (see Figure 9.1). Their release to the environment had likely occurred for a long time but was only recently recognised by new and advanced analytical methods [2]. In some cases, emerging contaminants can also result from the synthesis of new chemicals either intentionally as a chemical of industrial interest or unintentionally as a by-product. A notable example of the latter is the N-nitrosamine group that can be formed as by-products due to a range of industrial activities including the production of rocket fuel, rubber and tobacco as well as water or wastewater disinfection by chloramine [3]

Microlayer enrichment in natural treatment systems: linking the surface microlayer to urban water quality

Natural treatment systems (NTS), such as constructed wetlands and stormwater ponds, are multibenefit, multidisciplinary approaches to sustaining water resources and reducing contaminant loading to urban streams. Surficial thin films (called surface microlayers) are not well characterized in NTS, but may have important implications for ecosystems, public health, and pollutant fate and transport. We present results from a case study evaluating microlayer contaminant partitioning across 4 NTS in Melbourne, Australia. To our knowledge, this study provides the first direct evidence for microlayer formation and contaminant enrichment (total petroleum hydrocarbons and trihalomethanes) in NTS. Contaminated microlayers were detected in the three most stable NTS, with stability defined relative to wind speed. Fluorescent-dissolved organic matter profiles differed between microlayer and subsurface water in these systems, suggesting that fluorescence-based techniques are useful for microlayer detection. Although individual fluorophores were not consistently associated with specific contaminants, fluorescence ratios were useful for identifying likely contaminant source waters, including road-runoff and irrigation water from nearby green spaces. We evaluate our case study in light of what is known about surface microlayers in analogous systems (e.g., oceans, estuaries, and lakes), in order to identify existing research gaps and future opportunities. WIREs Water 2016, 3:269–281. doi: 10.1002/wat2.1128. This article is categorized under: Engineering Water > Sustainable Engineering of Water Engineering Water > Water, Health, and Sanitation Science of Water > Water Quality.</p