GLORIA CHAN GLORIA.CHAN@SCMP.COM
PUBLISHED : Wednesday, 05 August, 2015, 7:01am
UPDATED : Wednesday, 05 August, 2015, 10:28am
Contractors have agreed with the Housing Authority to buy and install an NSF 53 certified water filter for each household as a short-term measure. Photo: David Wong
Three more public housing estates have been identified as having excessive lead levels in their tap water, with more than 4,500 new families likely to be affected, raising the number of affected estates to seven.
Of the four main contractors responsible for plumbing across these estates, China State Construction Engineering (HK) and Shui On Building Contractors have agreed with the Housing Authority to buy and install an NSF 53 certified water filter for each household as a short-term measure to put residents’ minds at ease.
These are contractors for Kai Ching Estate and Hung Hom Estate, and Kwai Luen Estate Phase 2, respectively.
Yau Lee Construction Company and Paul Y Engineering Group - the main contractors for Lower Ngau Tau Kok Estate Phase 1 and Shek Kip Mei Estate Phase 2, and Wing Cheong Estate and Tung Wui Estate respectively - are still in discussion with the government about installing water filters and have yet to reach an agreement.
But what does “NSF 53 certified” mean? The South China Morning Post asked Rick Andrew, water quality expert and business development director for NSF International’s global water division, for more information.
1. What is NSF?
The National Sanitation Foundation (NSF International) is an independent global organisation, founded in 1944, that writes standards, and tests and certifies products for the building materials, food, water, health sciences, and consumer goods industries to minimise adverse health effects and protect the environment.
2. Are all NSF 53 certified water filters able to keep lead levels below the World Health Organisation standard of 0.010 mg/L?
The product must state on the label that it has been certified to reduce lead. Water filters certified to NSF 53 for lead reduction are tested to reduce the level of lead from 0.15 mg/L to 0.010 mg/L or lower. They are also tested beyond the manufacturer’s recommended lifetime for extra assurance that the filters will function effectively.
Resident Lin Siu-mui shows a glass of tap water at Shek Kip Mei Estate. Photo: David Wong
3. How do these filters work in keeping away lead and other heavy metals?
Most of the filters certified to NSF for lead reduction use a combination of activated carbon and other special metal adsorbents. In addition, these filters must have an ability to treat particles of lead in the water by having pores that are too small for the particles to fit through.
4. How does one know whether one’s current water filter is effective, especially if it doesn’t have the NSF 53 certification?
That is why certification to NSF International standards is so important – it provides assurance to consumers that the product has been tested by a credible organisation to verify that it effectively reduces the contaminants as claimed on the product’s packaging.
If a consumer is using an uncertified water filter, they are placing their trust in the product’s manufacturer and the claims made on the packaging. There is really no way that a consumer can verify that a water filter’s label claims are true without certification.
Residents collect fresh water at one of the temporary distribution points at Hung Hom Estate in Hung Hom, amid lead water scare. Photo: Sam Tsang
5. How frequently do you recommend people change the filter cartridge and why?
No matter what type of water filter you use, there is a good chance that it uses a filter media that will need to be replaced on a regular basis.
The recommended filter change cycle varies from one product to the next. Home filtration systems certified to NSF 53 for lead reduction will have a certified “service cycle”. The service cycle for these filters will be for a specific number of gallons and possibly an estimate of the number of months that a cartridge will last in the average home. To ensure the filter continues to reduce contaminants, replace it according to the manufacturer’s recommendations.
To ensure your water treatment system is performing effectively, use the proper replacement cartridge and change your filter at the recommended interval. Filter cartridges are not universal. While a filter cartridge may look similar in size and even appear to fit inside the housing of a water treatment system, even the smallest size difference could allow water to go around the cartridge rather than through it. This could result in the water not being filtered effectively.
6. Are there any particular water filter models you recommend?
The most important attribute to look for in a home water treatment device is NSF certification. See NSF’s website listing at http://info.nsf.org/Certified/DWTU/for the current list of certified home water treatment devices. Other than this, we recommend that consumers select the water filter that best suits their water concerns and product preferences.
http://m.scmp.com/news/hong-kong/health-environment/article/1846638/six-things-know-about-water-filters-more-hong-kong
