The interplay of suspended sediment concentration, particle size and fluid velocity on the rapid deposition of suspended iron oxide particles in PVC drinking water pipes.

The inner walls of drinking water pipes are often expected to be clean and controlled surfaces to assure safe water access to the public. However, these surfaces are typically contaminated with particulate materials and biofilms that eventually degrade water quality. While water utilities place significant efforts in identifying and flushing material deposits from compromised pipes, the development of effective preventive strategies is still limited by the lack of knowledge about material accumulation processes. The aim of this paper is to examine the interplay between suspended sediment concentration, particle size and fluid velocity and the attachment of suspended iron oxide particles in PVC drinking water pipes. For that purpose, a series of short experiments were completed, whereby water amended with a known concentration of selected and stable iron oxide particles was introduced in a full-scale pipe loop laboratory over a short period of time and both turbidity and suspended sediment concentration (SSC) were measured at the inlet and outlet of the pipe loop. Results showed that a selected fraction of the injected particles with sizes above a specific threshold in the range of 4.6 to 6.8 µm had not reached the downstream section of the pipe loop, but instead remained attached to the pipe walls. In addition, exponential decay of the SSC was observed to occur along the pipes and to cause most of the sediments to accumulate in the upstream section of the pipe loop. The research improved our understanding of the physical processes of particulate material accumulation in DWDSs, and it will help water utilities forecast and monitor material accumulation and discolouration potential.

A comprehensive review on current technologies for removal of endocrine disrupting chemicals from wastewaters.

In the recent years, endocrine disrupting compounds (EDCs) has received increasing attention due to their significant toxic effects on human beings and wildlife by affecting their endocrine systems. As an important group of emerging pollutant, EDCs have been detected in various aquatic environments, including surface waters, groundwater, wastewater, runoff, and landfill leachates. Their removal from water resources has also been an emerging concern considering growing population as well as reducing access to fresh water resources. EDC removal from wastewaters is highly dependent on physicochemical properties of the given EDCs present in each wastewater types as well as various aquatic environments. Due to chemical, physical and physicochemical diversities in these parameters, variety of technologies consisting of physical, biological, electrochemical, and chemical processes have been developed for their removal. This review highlights that the effectiveness of EDC removal is highly dependent of selecting the appropriate technology; which decision is made upon a full wastewater chemical characterization. This review aims to provide a comprehensive perspective about all the current technologies used for EDCs removal from various aquatic matrices along with rising challenges such as the antimicrobial resistance gene transfer during EDC treatment.

The role of antibiotics and heavy metals on the development, promotion, and dissemination of antimicrobial resistance in drinking water biofilms.

Antimicrobial resistance (AMR), as well as the development of biofilms in drinking water distribution systems (DWDSs), have become an increasing concern for public health and management. As bulk water travels from source to tap, it may accumulate contaminants of emerging concern (CECs) such as antibiotics and heavy metals. When these CECs and other selective pressures, such as disinfection, pipe material, temperature, pH, and nutrient availability interact with planktonic cells and, consequently, DWDS biofilms, AMR is promoted. The purpose of this review is to highlight the mechanisms by which AMR develops and is disseminated within DWDS biofilms. First, this review will lay a foundation by describing how DWDS biofilms form, as well as their basic intrinsic and acquired resistance mechanisms. Next, the selective pressures that further induce AMR in DWDS biofilms will be elaborated. Then, the pressures by which antibiotic and heavy metal CECs accumulate in DWDS biofilms, their individual resistance mechanisms, and co-selection are described and discussed. Finally, the known human health risks and current management strategies to mitigate AMR in DWDSs will be presented. Overall, this review provides critical connections between several biotic and abiotic factors that influence and induce AMR in DWDS biofilms. Implications are made regarding the importance of monitoring and managing the development, promotion, and dissemination of AMR in DWDS biofilms.

Does eating while watching television influence children's food-related behaviours?

To assess children's food-related behaviours and their relationships with eating while watching television (TV), data were collected from 534 ten-year-old French-Canadian children. A self-administered questionnaire was used. Almost 18% of girls and over 25% of boys reported eating in front of the TV every day. Although, overall, the boys' eating pattern was less healthy than the girls', all of the children's food choices deteriorated with increased frequency of eating in front of the TV. Compared with girls, boys gave more importance to coloured and attractive foods, and to selecting foods similar to those eaten by others. Over 50% of children reported always receiving negative weight-related comments from family members. For boys, significant correlations were found between the frequency of eating in front of the TV, the importance given to a food's appearance, and their requests to parents for advertised foods. Significance was at the p<0.05 level for all findings. These results suggest that gender should be considered in attempts to understand children's food motivations and behaviours. The findings also indicate the need to document children's eating environments, and to inform children and their families about eating behaviours that may be associated with a given environment.