A 12-month pilot plant study was conducted to evaluate a number of corrosion control treatments to reduce metal leaching from typical household plumbing materials. A pipe loop system was used to test six treatment options, with a control loop of the characteristically soft, acidic, Greater Vancouver Water District (GVWD) water. Four pH- alkalinity combinations and two concentrations of zinc orthophosphate (0.37 mg/L and 1.0 mg/L as Zn) were studied. at regular intervals, the flowing, treated, and control waters were allowed to stagnate in the pipe loop system for 8- and 16-h periods. Following the designated standing time, water samples taken from the lead/tin solder jointed, soft copper plumbing coils, the submerged, free standing coils of 50/50 lead/tin solder, and the brass faucets, were measured for lead, copper, and zinc levels. Overall, when compared to the control loop, the pH-alkalinity treatments appeared to exacerbate metal leaching in standing samples. The zinc orthophosphate treated loops were both effective at reducing lead and copper leaching to below control levels. In general, the two standing times showed little difference in the levels of leached metals. The exception to this occurred in the higher dose zinc orthophosphate loop, which had higher copper and zinc levels at the longer standing time. Key words: copper, corrosion, drinking water, lead, zinc orthophosphate.

This study was initiated to evaluate, in Greater Vancouver Water District water, the effectiveness of zinc orthophosphate, type N sodium silicate, and a commercial blend of the two as corrosion inhibitors within the limitations that a seven-loop pilot plant would allow. In all but the raw water control loop, pH and alkalinity were adjusted, and the water was disinfected with 2.5 mg/L of chloramine (NH 2 Cl). Copper and cast iron corrosion rates were measured over the course of 12 months on pipe inserts removed at 3-month intervals and via weekly monitoring using an electrical resistance measuring device. Standing water samples taken regularly from lead/tin solder jointed, soft copper plumbing coils, from submerged free standing coils of 50/50 lead/tin solder, and from faucets on each loop were measured for lead, zinc, and copper levels. The results of the weight loss determinations from the pipe inserts indicated that all of the inhibitors, particularly the zinc orthophosphate, worked very favorably with copper, but they offered no additional benefit over that obtained from the pH and alkalinity adjustments alone, in the case of the cast iron coupons. However, some very high metal levels were measured in the standing water samples from some of the inhibitor loops. Generally, both the coupon and leaching results confirmed that pH and alkalinity adjustment and disinfection with chloramine, instead of chlorine, will reduce pipe metal corrosion.Résumé : Cette étude a été entreprise afin d'évaluer, dans l'eau du Greater Vancouver Water District, l'efficacité de l'othophosphate de zinc, du silicate de sodium de type N et d'un mélange commercial des deux produits comme agents anticorrosifs dans les limites qu'un système pilote ayant sept boucles pourra permettre. Dans toutes les boucles, à l'exception de la boucle de contrôle contenant de l'eau brute, le pH et l'alcalinité ont été ajustés, et l'eau a été désinfectée avec 2,5 mg/L de chloramine (NH 2 Cl). Les taux de corrosion du cuivre et du fer fondu ont été mesurés pendant 12 mois sur des pièces de conduites, enlevées à des intervalles de trois mois, et aussi en utilisant un instrument qui mesure la résistance électrique des conduites. Des échantillons d'eau stagnante récoltés des soudures articulées de plomb/étain, de rouleaux de cuivre tendre de plombage, de rouleaux submergés de soudure 50/50 plomb/étain, et des robinets utilisés dans chaque boucle ont été régulièrement analysés pour le niveau de plomb, zinc et cuivre. Les résultats de perte de masse des pièces de conduites indiquent que tous les agents anticorrosifs, en particulier l'orthophosphate de zinc, ont agit favorablement avec le cuivre, mais n'ont fourni aucun effet bénéfique additionnel à celui obtenu uniquement de l'ajustement du pH et de l'alcalinité pour le cas du fer fondu. Cependant, quelques niveaux très élevés de métal ont été mesurés dans des échantillons d'eau stagnante obtenus des boucles contenant des agents anticorrosifs. Généralement, les résultats ont confirmé que l'ajustement du pH et de l...

This paper summarizes existing evidence on the impact of food information programs. Published and unpublished literature produced within the past decade was searched and reviewed. Relevant data were tabulated and key findings summarized. Food information programs are becoming increasingly popular as tools to help consumers select a healthy diet. The key feature of a food information program is a package logo on foods meeting nutrition criteria set by the program s administering body. The logo acts as a health message. Several countries, including Canada, have adopted food information programs. Critics believe that these programs oversimplify the concept of healthy eating, that consumers misinterpret the logo s meaning, that licensing fees prohibit small companies from participating, and that the programs are limited to purchase behaviour and do not necessarily have an impact on dietary intake. Consumers report support for the programs and are able to interpret a logo s meaning accurately. In addition, evidence shows the programs have had a positive impact on the nutrient composition of foods. Research is still needed, however, to establish the impact of such programs on food purchases and dietary intake, and the overall and long-term effectiveness of the programs as a nutrition intervention.

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A study on the quality of water distributed within the Greater Vancouver Regional District (GVRD) was carried out to evaluate the effectiveness of previously implemented corrosion controls. In addition, the effect of temperature fluctuations was investigated to determine if it influenced the efficacy of the control measures. The GVRD was divided into four distribution areas. The Capilano water had no corrosion control treatment. Seymour, Coquitlam, and Newton waters were treated with soda ash, resulting in a pH of 6.8, 6.9, and 8.1, respectively. Standing cold water and running hot and cold water samples were collected from the four zones and analyzed for lead, copper, and zinc concentrations. The source water did not influence the amount of lead at the tap. The source water did influence the amount of copper and zinc at the tap. The highest copper and zinc concentrations were found in the water with the lowest pH (Capilano) and the lowest concentrations in the water with the highest pH (Newton). Seasonal temperature fluctuations of distributed GVRD water did not affect the metal concentrations in the water.Key words: corrosion control, GVRD drinking water, copper, lead, zinc, pH adjustment.