For public health or business 'trick'?!

(Baonghean.vn) - Currently, in the province, there are some organizations using a tool called TDS pen to "test" drinking water in residential areas, then "recommend" people to buy RO water purifiers. Is their behavior for the sake of public health? Engineer Nguyen Van Hieu - Deputy Head of Technical Department, Center for Technical Standards and Quality Measurement (Department of Science and Technology) analyzed this content.

The TDS test pen of Hong Ha Technology Development Joint Stock Company is used to test drinking water samples for people in Dinh Son commune, Anh Son.

- Engineer Nguyen Van Hieu, what do you know about the tool called TDS water tester?

Engineer Nguyen Van Hieu:TDS is the total dissolved solids in water. TDS pen is a tool to test water samples to quickly give the results of total dissolved solids in the water sample. There are many types of TDS pens on the market with many different designs and origins. The expensive ones cost a few million VND; the cheap Chinese ones cost only a few hundred thousand VND/piece.

- Some people who had their water samples tested with a TDS pen said that the testers told them that the TDS index in the water sample was high, showing that the water had many impurities and pollution... Therefore, they were very worried. So I would like to ask you, is testing water with a TDS pen to evaluate water quality guaranteed?

Engineer Nguyen Van Hieu.

Engineer Nguyen Van Hieu:There is absolutely no basis. To accurately assess water quality, especially for drinking water quality, according to the national technical regulation QCVN 01:2009/BYT, it is necessary to check up to 109 indicators; of which, there are 15 level A indicators (regular monitoring level). TDS is only 1 of those 109 indicators and is a sensory indicator.

It must be understood that high total dissolved solids does not mean poor water quality. A simple example is this: natural mineral water is very good for the human body because it contains many beneficial minerals. If we use a TDS pen to test any mineral water sample, the TDS index will be very high. Furthermore, it must be known that the TDS pen only shows the total dissolved solids content in water, but cannot indicate what solids are dissolved in the water, thereby determining whether it is beneficial or harmful to human health.

According to national technical regulation QCVN 01:2009/BYT issued by the Ministry of Health, in drinking water, the TDS index must not exceed 1000mg/liter.

- After Nghe An Newspaper got involved in the case of Hong Ha Technology Development Joint Stock Company assembling and selling Maxken brand water purifiers, people in Dinh Son commune, Anh Son district proposed to tighten management, not allowing organizations and individuals to go to the locality to organize "conferences" to test drinking water samples, causing panic among the people. We think this is a very correct recommendation. On this occasion, I would like to ask you, which agencies and units are qualified to test water samples of all kinds?

Engineer Nguyen Van Hieu:To test water samples for state management purposes (in inspection and testing), only units with laboratories with adequate equipment and qualified human resources must be designated by the Ministry of Health. We call this a designated laboratory. As far as I know, there are not many laboratories like this in Vietnam.

For drinking water samples that organizations and businesses request to be tested for annual monitoring, they must be performed at accredited laboratories that meet ISO/IEC 17025:2005 standards (also known as accredited laboratories) or laboratories designated by the Ministry of Health.

For households and individuals who want to test drinking water samples, depending on their understanding, they can go to any unit or facility they trust to have it tested.

However, it must be affirmed that in order to draw conclusions on a drinking water sample, any laboratory must comply with the testing process, from the stage of water sampling, water sample preservation, etc. That is, it must ensure that the testing is methodical, scientific and objective.

As in the recent past, to serve the interdisciplinary inspection team established by the Provincial People's Committee to inspect bottled water production facilities in the area, we had to take samples according to regulations and then send them to the laboratory of the National Institute of Food Safety and Hygiene for testing.

Laboratory of the Center for Technical Standards, Measurement and Quality (Department of Science and Technology)

- According to your analysis, it is not allowed for organizations and businesses that sell water purifiers to use TDS test pens to test water samples?

Engineer Nguyen Van Hieu:As I discussed above, the results of total dissolved solids in water do not say anything about water quality. The fact that some organizations and businesses use TDS pens to test drinking water samples and then make recommendations is clearly aimed at influencing people's psychology, making them confused and worried about their health and that of their family members, so that they have to buy their products. To put it bluntly, this is a "trick" in business. In my opinion, it is necessary to warn local authorities and people about this "trick" to avoid being taken advantage of.

Thank you!

Nhat Lan(perform)