Identifying the Gaps in Practice for Combating Lead in Drinking Water in Hong Kong
Abstract
:1. Introduction
2. Methods
2.1. Governing Ordinances and Regulations
2.1.1. International Practices
2.1.2. Hong Kong Practice
2.2. Products and Materials
2.2.1. Allowable Lead Content
2.2.2. Leaching Limit
2.2.3. Testing and Commissioning
3. Results
3.1. Governing Ordinances and Regulations
3.2. Products and Materials
3.3. Testing and Commissioning
4. Conclusions
- A 3-tier quality control system is proposed to ensure that design, installation and materials used are in accordance with requirements specified in various governing ordinances and regulations.
- Performance-based approach should be adopted for specifying the allowable lead content in products and materials used.
- Leaching limit and leaching test for products and materials used should be introduced to align with US requirements.
- Two tiers sampling protocol should be adopted to ensure the quality of water on both the supply side and the plumbing installations.
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Geographic Entity | Enforcing Authority | Regulation | Standards & Guidelines | Installation |
---|---|---|---|---|
US | Environmental Protection Agency | Safe Drinking Water Act (SDWA) | Simultaneous Compliance Guidance Manual | Licensed Plumber |
Canada | Health Canada | SDWA | Guidance on Controlling Corrosion in Drinking Water Distribution Systems | |
Australia | Department of Health & Medical Research Council | SDWA | Australian Drinking Water Guidelines | |
New Zealand | Ministry of Health | SDWA | Guidelines for Drinking-Water Quality Management for New Zealand | |
UK | Secretary of State for the Environment, Transport and the Regions | Water Industry Act and Water Supply (Water Quality) Regulations | Guidance on the Implementation of the Water Supply (Water Quality) Regulations | |
Hong Kong | Water Supplies Department | Waterworks Ordinance and the Sub-Legislature Waterworks Regulations | Plumbing Installation for Buildings Specific to Hong Kong |
Geographic Entity | US * | Canada * | Australia | New Zealand | UK | Hong Kong |
---|---|---|---|---|---|---|
Copper Pipes | 0.25% | 0.25% | 0.05% | 0.085% | ||
Copper Alloy Gate Valves | 0.25% | 0.25% | 4.5% | 8% | ||
Facuets | 0.25% | 0.25% | 4.5% | not specified | ||
Solder | 0.2% | 0.2% | 0.1% | 0% | ||
Other Copper Alloy Valves and Fittings | 0.25% | 0.25% | 4.5% | 3% | ||
Weighted-Average | ≤0.25% | ≤0.25% | Nil | Nil |
Description | US | Canada | Australia | New Zealand | UK | |
---|---|---|---|---|---|---|
Test Sample | Materials or Finished Products | Only for Non-Metallic Products | ||||
Test Method | in-the-Product (all Samples except Solder); Immersion (Solder) | |||||
Sample Size | in-the Product | Smallest Inner Diameter | ||||
Immersion (Minimum Surface Area to Volume Ratio) | 5000 mm2/L | 1000 mm2/L | ||||
Sample Pre-Test | Cleaning | Rinsed with Contaminate-Free Water | Rinsed in Flowing Tap Water | |||
Conditioning in Test Water | for Minimum 2 days | for 24 h | ||||
Test Water | pH value | Minimum 6.5 (Pipings) and 5 (Valves and Fittings) | Minimum 6.5 | |||
Temperature | 23 ± 2 °C | 20 ± 2 °C | ||||
Exposure Time | 24 ± 1 h | 24 ± 2 h | ||||
Container | in-the Product | Capped with Inert Materials | ||||
Immersion Test | Materials Inert to the Test Water | Glass or Polyethylene Ware | ||||
Single Product Allowable Leaching Limit | ≤0.5 µg/L | ≤10 µg/L (Duplicate Samples) |
Description | US | Canada 1 | Australia | New Zealand | UK 2 | Hong Kong | |
---|---|---|---|---|---|---|---|
Number of Draws | Two-Tier | One-Tier | |||||
Drawing Method | Unflushed | after a Stagnation Period of 6–12 h | 30 min | not Specified | |||
Flushed | Flush for a While to 5 min | Flush for 2–5 min | |||||
Sample Volume (L) | 1 | 1 | 0.1 | 0.15 | 1 | 0.25 | |
Sampling Location | Random | Drinking or Cooking Taps | Representative Points | Consumer Taps | Determined by WSD | ||
Sampling Size Confidence Level | 95% | not Specified | 95% | not Specified | Exact Number of Sampling Points Specified | ||
Container | Fully Filled | not Specified | Thoroughly Rinsed | ||||
Sample Holding Time | not Specified | 28 Days | within the Same Day | 7 Days | within the Same Day | ||
Sampling Water Temperature | Cold | Cold | Constant | Cold | Constant | Cold | |
Compliance | unflushed | 90% | 90% | 95% | 100% | not Specified | |
≤15 µg/L | ≤10 µg/L | ≤10 µg/L | ≤10 µg/L | ||||
flushed | 100% | 100% | |||||
≤15 µg/L | ≤10 µg/L |
Description | Unflushed | Flushed |
---|---|---|
Drawing Method | after a Period of Stagnation of 30 min to 12 h | Flush at a Uniform Rate for 2 to 5 min |
Sample Volume | 0.1 L | |
Sample Location | Sample Sites throughout the System and High Risk Areas | High Risk Areas |
Sample Size | 95% Confidence Level Related to Population Size | 10% of the Tier-1 Sample Sites including the Problematic Sites |
Compliance | 95% Non-Exceedance | 100% Non-Exceedance |
Container | thoroughly Rinsed Container Provided by Recognized Laboratory | |
Sample Holding Time | Deliver to Recognized Laboratory within a Day | |
Sampling Water Temperature | Cold Water Pipeline at Constant Temperature | |
Compliance | 10 µg/L |
Item | Diameter | Pipe/Fitting | Length (m) | Wetted Surface Area (m2) | Ratio Wetted Surface Area | UK/Hong Kong | Australia/New Zealand | US/Canada | |||
---|---|---|---|---|---|---|---|---|---|---|---|
% Lead Content | % Lead Contribution | % Lead Content | % Lead Contribution | % Lead Content | % Lead Contribution | ||||||
AB | 150 | Pipe | 152 | 71,628.5 | 0.5421 | 0.085 | 0.0461 | 0.05 | 0.0271 | 0.25 | 0.1355 |
A1 | 150 | Elbow | 0.267 | 125.8 | 0.0010 | 3 | 0.0029 | 4.5 | 0.0043 | 0.25 | 0.0002 |
CD | 150 | Pipe | 15 | 7068.6 | 0.0535 | 0.085 | 0.0045 | 0.05 | 0.0027 | 0.25 | 0.0134 |
C1 | 150 | Elbow | 0.3 | 141.4 | 0.0011 | 3 | 0.0032 | 4.5 | 0.0048 | 0.25 | 0.0003 |
C2 | 150 | Elbow | 0.3 | 141.4 | 0.0011 | 3 | 0.0032 | 4.5 | 0.0048 | 0.25 | 0.0003 |
DE | 150 | Pipe | 4 | 1885.0 | 0.0143 | 0.085 | 0.0012 | 0.05 | 0.0007 | 0.25 | 0.0036 |
D1 | 150 | Valve | 0.267 | 125.8 | 0.0010 | 8 | 0.0076 | 4.5 | 0.0043 | 0.25 | 0.0002 |
EF | 150 | Pipe | 10 | 4712.4 | 0.0357 | 0.085 | 0.0030 | 0.05 | 0.0018 | 0.25 | 0.0089 |
E1 | 150 | Valve | 0.267 | 125.8 | 0.0010 | 8 | 0.0076 | 4.5 | 0.0043 | 0.25 | 0.0002 |
E2 | 150 | Elbow | 0.3 | 141.4 | 0.0011 | 3 | 0.0032 | 4.5 | 0.0048 | 0.25 | 0.0003 |
FG | 150 | Pipe | 38 | 17,907.1 | 0.1355 | 0.085 | 0.0115 | 0.05 | 0.0068 | 0.25 | 0.0339 |
F1 | 150 | Valve | 0.267 | 125.8 | 0.0010 | 8 | 0.0076 | 4.5 | 0.0043 | 0.25 | 0.0002 |
F2 | 150 | Socket | 0.267 | 125.8 | 0.0010 | 3 | 0.0029 | 4.5 | 0.0043 | 0.25 | 0.0002 |
GH | 100 | Pipe | 38 | 11,938.1 | 0.0904 | 0.085 | 0.0077 | 0.05 | 0.0045 | 0.25 | 0.0226 |
G1 | 100 | Elbow | 0.2 | 62.8 | 0.0005 | 3 | 0.0014 | 4.5 | 0.0021 | 0.25 | 0.0001 |
HI | 100 | Pipe | 38 | 11,938.1 | 0.0904 | 0.085 | 0.0077 | 0.05 | 0.0045 | 0.25 | 0.0226 |
H1 | 100 | Elbow | 0.2 | 62.8 | 0.0005 | 3 | 0.0014 | 4.5 | 0.0021 | 0.25 | 0.0001 |
IJ | 100 | Pipe | 4 | 1256.6 | 0.0095 | 0.085 | 0.0008 | 0.05 | 0.0005 | 0.25 | 0.0024 |
I1 | 100 | Elbow | 0.2 | 62.8 | 0.0005 | 3 | 0.0014 | 4.5 | 0.0021 | 0.25 | 0.0001 |
I2 | 100 | Valve | 0.203 | 63.8 | 0.0005 | 8 | 0.0039 | 4.5 | 0.0022 | 0.25 | 0.0001 |
I3 | 100 | Socket | 0.203 | 63.8 | 0.0005 | 3 | 0.0014 | 4.5 | 0.0022 | 0.25 | 0.0001 |
JK | 25 | Pipe | 15 | 1178.1 | 0.0089 | 0.085 | 0.0008 | 0.05 | 0.0004 | 0.25 | 0.0022 |
J1 | 25 | Valve | 0.165 | 13.0 | 0.0001 | 8 | 0.0008 | 4.5 | 0.0004 | 0.25 | 0.0000 |
J2 | 25 | Elbow | 0.05 | 3.9 | 0.0000 | 3 | 0.0001 | 4.5 | 0.0001 | 0.25 | 0.0000 |
J3 | 25 | Elbow | 0.05 | 3.9 | 0.0000 | 3 | 0.0001 | 4.5 | 0.0001 | 0.25 | 0.0000 |
KL | 25 | Pipe | 15 | 1178.1 | 0.0089 | 0.085 | 0.0008 | 0.05 | 0.0004 | 0.25 | 0.0022 |
K1 | 25 | Valve | 0.165 | 13.0 | 0.0001 | 8 | 0.0008 | 4.5 | 0.0004 | 0.25 | 0.0000 |
K2 | 25 | Elbow | 0.05 | 3.9 | 0.0000 | 3 | 0.0001 | 4.5 | 0.0001 | 0.25 | 0.0000 |
K3 | 25 | Elbow | 0.05 | 3.9 | 0.0000 | 3 | 0.0001 | 4.5 | 0.0001 | 0.25 | 0.0000 |
K4 | 25 | Cold water faucet | 0.165 | 13.0 | 0.0001 | 4.5 | 0.0004 | 4.5 | 0.0004 | 0.25 | 0.0000 |
Misc | 87 | Solder | 0.058 | 15.9 | 0.0001 | 0 | 0 | 0.1 | 0.0000 | 0.2 | 0.0000 |
WLC (%) | 0.1342 | 0.098 | 0.25 |
Item | Diameter | Pipe/Fitting | Length (m) | Wetted Surface Area (m2) | Ratio Wetted Surface Area | US/Canada | Australia/New Zealand | ||||
---|---|---|---|---|---|---|---|---|---|---|---|
N × NF | LLi | LLi × Ratio Wetted Surface Area | N × NF | LLi | LLi × Ratio Wetted Surface Area | ||||||
AB | 150 | Pipe | 152 | 71,628.5 | 0.5421 | 4.18 | 2.09 | 1.1330 | 47.752 | 47,752.3 | 258.868 |
A1 | 150 | Elbow | 0.267 | 125.8 | 0.0010 | 1 | 0.50 | 0.0005 | 0.084 | 83.9 | 0.001 |
CD | 150 | Pipe | 15 | 7068.6 | 0.0535 | 0.41 | 0.21 | 0.0110 | 4.712 | 4712.4 | 2.521 |
C1 | 150 | Elbow | 0.3 | 141.4 | 0.0011 | 1 | 0.50 | 0.0005 | 0.094 | 94.2 | 0.001 |
C2 | 150 | Elbow | 0.3 | 141.4 | 0.0011 | 1 | 0.50 | 0.0005 | 0.094 | 94.2 | 0.001 |
DE | 150 | Pipe | 4 | 1885.0 | 0.0143 | 0.11 | 0.06 | 0.0008 | 1.257 | 1256.6 | 0.179 |
D1 | 150 | Valve | 0.267 | 125.8 | 0.0010 | 1 | 0.50 | 0.0005 | 0.084 | 83.9 | 0.001 |
EF | 150 | Pipe | 10 | 4712.4 | 0.0357 | 0.28 | 0.14 | 0.0049 | 3.142 | 3141.6 | 1.120 |
E1 | 150 | Valve | 0.267 | 125.8 | 0.0010 | 1 | 0.50 | 0.0005 | 0.084 | 83.9 | 0.001 |
E2 | 150 | Elbow | 0.3 | 141.4 | 0.0011 | 1 | 0.50 | 0.0005 | 0.094 | 94.2 | 0.001 |
FG | 150 | Pipe | 38 | 17,907.1 | 0.1355 | 1.05 | 0.52 | 0.0708 | 11.938 | 11,938.1 | 16.179 |
F1 | 150 | Valve | 0.267 | 125.8 | 0.0010 | 1 | 0.50 | 0.0005 | 0.084 | 83.9 | 0.001 |
F2 | 150 | Socket | 0.267 | 125.8 | 0.0010 | 1 | 0.50 | 0.0005 | 0.084 | 83.9 | 0.001 |
GH | 100 | Pipe | 38 | 11,938.1 | 0.0904 | 1.05 | 0.52 | 0.0472 | 7.959 | 7958.7 | 7.191 |
G1 | 100 | Elbow | 0.2 | 62.8 | 0.0005 | 1 | 0.50 | 0.0002 | 0.042 | 41.9 | 2.0 × 10−4 |
HI | 100 | Pipe | 38 | 11,938.1 | 0.0904 | 10.64 | 5.32 | 0.4808 | 7.959 | 7958.7 | 7.191 |
H1 | 100 | Elbow | 0.2 | 62.8 | 0.0005 | 1 | 0.50 | 2.4 × 10−4 | 0.042 | 41.9 | 2.0 × 10−4 |
IJ | 100 | Pipe | 4 | 1256.6 | 0.0095 | 0.11 | 0.06 | 5.2 × 10−4 | 0.838 | 837.8 | 8.0 × 10−2 |
I1 | 100 | Elbow | 0.2 | 62.8 | 0.0005 | 1 | 0.50 | 2.4 × 10−4 | 0.042 | 41.9 | 2.0 × 10−4 |
I2 | 100 | Valve | 0.203 | 63.8 | 0.0005 | 1 | 0.50 | 2.4 × 10−4 | 0.043 | 42.5 | 2.1 × 10−4 |
I3 | 100 | Socket | 0.203 | 63.8 | 0.0005 | 1 | 0.50 | 2.4 × 10−4 | 0.043 | 42.5 | 2.1 × 10−4 |
JK | 25 | Pipe | 15 | 1178.1 | 0.0089 | 0.08 | 0.04 | 3.7 × 10−4 | 0.785 | 785.4 | 7.0 × 10−2 |
J1 | 25 | Valve | 0.165 | 13.0 | 0.0001 | 1 | 0.50 | 4.9 × 10−5 | 0.009 | 8.6 | 8.5 × 10−6 |
J2 | 25 | Elbow | 0.05 | 3.9 | 0.0000 | 1 | 0.50 | 1.5 × 10−5 | 0.003 | 2.6 | 7.8 × 10−7 |
J3 | 25 | Elbow | 0.05 | 3.9 | 0.0000 | 1 | 0.50 | 1.5 × 10−5 | 0.003 | 2.6 | 7.8 × 10−7 |
KL | 25 | Pipe | 15 | 1178.1 | 0.0089 | 0.41 | 0.21 | 1.8 × 10−3 | 0.785 | 785.4 | 0.070 |
K1 | 25 | Valve | 0.165 | 13.0 | 0.0001 | 1 | 0.50 | 4.9 × 10−5 | 0.009 | 8.6 | 8.5 × 10−6 |
K2 | 25 | Elbow | 0.05 | 3.9 | 0.0000 | 1 | 0.50 | 1.5 × 10−5 | 0.003 | 2.6 | 7.8 × 10−7 |
K3 | 25 | Elbow | 0.05 | 3.9 | 0.0000 | 1 | 0.50 | 1.5 × 10−5 | 0.003 | 2.6 | 7.8 × 10−7 |
K4 | 25 | Cold Water Faucet | 0.165 | 13.0 | 0.0001 | 1 | 0.50 | 4.9 × 10−5 | 0.009 | 8.6 | 8.5 × 10−6 |
Misc | 87 | Solder | 0.058 | 15.9 | 0.0001 | 1 | 0.50 | 6.0 × 10−5 | 0.011 | 10.6 | 1.3 × 10−5 |
LCC (ug/L) | 1.76 | - | 293.5 |
© 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).
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Lee, W.L.; Jia, J.; Bao, Y. Identifying the Gaps in Practice for Combating Lead in Drinking Water in Hong Kong. Int. J. Environ. Res. Public Health 2016, 13, 970. https://doi.org/10.3390/ijerph13100970
Lee WL, Jia J, Bao Y. Identifying the Gaps in Practice for Combating Lead in Drinking Water in Hong Kong. International Journal of Environmental Research and Public Health. 2016; 13(10):970. https://doi.org/10.3390/ijerph13100970
Chicago/Turabian StyleLee, Wai Ling, Jie Jia, and Yani Bao. 2016. "Identifying the Gaps in Practice for Combating Lead in Drinking Water in Hong Kong" International Journal of Environmental Research and Public Health 13, no. 10: 970. https://doi.org/10.3390/ijerph13100970