Assessing the impact of corrosion control measures on tap drinking water of the Greater Vancouver Regional District

Knox, Gillian Frances; Mavinic, Donald S.; Atwater, James W.; MacQuarrie, Doug

doi:10.1139/l05-043

Cited by 3 publications

(5 citation statements)

References 13 publications

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“…However, small variations in pH levels did not affect the concentrations of lead present in the samples taken at the tap suggesting corrosion control did not affect the levels of lead found (26). Similarly, Deshommes et al, found extreme lead concentrations up to 2640 times greater than the MAC after an 8-hour stagnation period along with a sample reaching 186 times greater than the MAC after a 5-minute flush in buildings serviced by lead plumbing and piping along with corrosive water (11).…”

Section: Relationship Between Plumbing Water Quality and Lead Concen...mentioning

confidence: 93%

“…The highest amount of lead was found in the first and second samples after a cold-water flush at the tap compared to samples at the source of the water in each region (26). These results are indicative that corrosion of household plumbing during the delivery of water contributed to the significant increases in levels of lead and impacted the water quality (26).…”

Section: Relationship Between Plumbing Water Quality and Lead Concen...mentioning

confidence: 94%

“…The concentration of lead dissolved in drinking water from plumbing is dependent on several factors such as the corrosiveness, the duration of stagnation, and pH of the water (25). Corrosion of lead-based plumbing during the delivery of water from the source to tap is a major contributor to the amount of lead found in drinking water (26). Knox et al compared the drinking water quality at the tap of homes to the quality of water at the source by analyzing the pH, corrosion controls, and the amount of lead detected (26).…”

Section: Relationship Between Plumbing Water Quality and Lead Concen...mentioning

confidence: 99%

“…Corrosion of lead-based plumbing during the delivery of water from the source to tap is a major contributor to the amount of lead found in drinking water (26). Knox et al compared the drinking water quality at the tap of homes to the quality of water at the source by analyzing the pH, corrosion controls, and the amount of lead detected (26). The highest amount of lead was found in the first and second samples after a cold-water flush at the tap compared to samples at the source of the water in each region (26).…”

Section: Relationship Between Plumbing Water Quality and Lead Concen...mentioning

confidence: 99%

“…Knox et al compared the drinking water quality at the tap of homes to the quality of water at the source by analyzing the pH, corrosion controls, and the amount of lead detected (26). The highest amount of lead was found in the first and second samples after a cold-water flush at the tap compared to samples at the source of the water in each region (26). These results are indicative that corrosion of household plumbing during the delivery of water contributed to the significant increases in levels of lead and impacted the water quality (26).…”

Section: Relationship Between Plumbing Water Quality and Lead Concen...mentioning

confidence: 99%

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Lead in drinking water

Zhang¹,

Chen²,

Heacock³

et al. 2021

ephj

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Background: Lead is a systemic toxin that affects multiple organs and impairs physical and mental development. Although lead is ubiquitous in the environment, majority of exposures to lead is through drinking water. Lead-based plumbing components are the primary reason. Flushing is a lead reduction technique commonly used to reduce lead in drinking water, but the efficacy of the technique has been questioned. The purpose of this research project was to determine if there were significant levels of lead found in the drinking water of 12 buildings (sites) owned and operated by a Health Authority before and after 30-second flush and to determine if flushing is an effective measure to reduce lead concentrations.Materials and Methods: Lead in drinking water data was provided by Dr. Tom Kosatsky in an Excel spreadsheet. The data contained 184 pre-flush (≥ 8-hour stagnation period) samples paired to 184 post-flush (30-second duration) samples collected at locations within the 12 different sites. The sites were labelled A to L due to confidentiality. This data was then exported to NCSS, and statistical analysis in the forms of a two tailed t-test, one tailed one sample t-test, and repeated measures ANOVA was performed to determine if a statistically significant relationship between flushing and reduced lead concentrations exists.Results: Out of 368 samples, 28% of stagnation samples contained lead concentrations greater than the MAC (n = 103) whereas, 9% of post 30-second flush samples contained lead concentration greater than the MAC (n = 33). Lead concentrations in the drinking water samples after flushing were significantly reduced below the MAC (p = 0.00000). However, lead concentrations from samples collected at sites A, C, and G were equal to or greater than the MAC. Statistical analysis failed to reject the null hypothesis that post-flush lead concentrations for samples collected at sites A, C, and G is greater to or equal to the MAC (A: p = 0.22708, C: p = 0.06866, and G: p = 0.70589).Conclusion: Flushing is an effective measure in reducing lead concentrations at the tap to safe levels. However, the effectiveness of flushing and flushing duration is dependent on numerous factors such as the stagnation period, amount of lead-based plumbing supplying the drinking water and building size. Longer stagnation periods, increased lead-based plumbing, and large buildings all require longer flushing times to reduce lead concentrations to below 0.005 mg/L. The results of this can study can aid governments in developing polices that will eliminate existing lead infrastructure in British Columbia and Canada. Flushing is not a long-term solution in reducing lead concentrations at the tap to below 0.005 mg/L.

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Section: Relationship Between Plumbing Water Quality and Lead Concen...mentioning

confidence: 93%

Section: Relationship Between Plumbing Water Quality and Lead Concen...mentioning

confidence: 94%

Section: Relationship Between Plumbing Water Quality and Lead Concen...mentioning

confidence: 99%

Section: Relationship Between Plumbing Water Quality and Lead Concen...mentioning

confidence: 99%

Section: Relationship Between Plumbing Water Quality and Lead Concen...mentioning

confidence: 99%

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Lead in drinking water

Zhang¹,

Chen²,

Heacock³

et al. 2021

ephj

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show abstract

Comparison of Chlorine and Chloramines on Lead Release from Copper Pipe Rigs

2013

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Comparison of sodium silicate and phosphate for controlling lead release from copper pipe rigs

et al. 2015

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This study compared sodium silicate and zinc orthophosphate for their ability to decrease lead and copper release from pilot-scale premise plumbing in low alkalinity (<5 mg/L CaCO3) water. The study used pipe loops (to age the water) connected to copper pipe rigs. The copper pipe rigs were constructed using 50:50 lead:tin solder, which provided the only source of lead. Three different treatments were compared, using the same source water: phosphate (0.8 mg-PO4/L at pH 7.3), sodium silicate with pH control (18 mg-Si/L at pH 7.3), and sodium silicate (18 mg-Si/L at pH 6.3). Lead and copper levels (both total and dissolved) were measured following the copper pipe rig after two different stagnation times (24 h, 30 min). The phosphate treatment consistently resulted in significantly lower lead release compared to sodium silicate at the same pH of 7.3. The phosphate treated pipe rigs released 12 μg/L and 2 μg/L lead following the 24 h and 30 min stagnation times, respectively. The sodium silicate with pH control system released 46 μg/L and 6.7 μg/L lead following 24 h and 30 min stagnation time, respectively. The sodium silicate treated pipe rigs released 27.4 and 4.6 μg/L lead following the 24 h and 30 min stagnation time, respectively. The phosphate treatment also consistently released less copper than both the sodium silicate with pH control treatment and the sodium silicate treatment. However, more lead particles were observed in the phosphate treatment compared to either of the sodium silicate treatments. The difference in performance between the sodium silicate corrosion inhibitor at two different pH levels, suggests that the performance of sodium silicate could be further optimized.

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Assessing the impact of corrosion control measures on tap drinking water of the Greater Vancouver Regional District

Cited by 3 publications

References 13 publications

Lead in drinking water

Lead in drinking water

Comparison of Chlorine and Chloramines on Lead Release from Copper Pipe Rigs

Comparison of sodium silicate and phosphate for controlling lead release from copper pipe rigs

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