VietNamNet Bridge – Three months after young scientists of Hoa Lac High Tech Park used LTH 100 to clean the water of Van Lake in Hanoi, scientists have raised doubts about the effectiveness of the chemical substance.

Associate Prof Dr Le Van Cat, a chemist from the Vietnam Institute of Sciences and Technologies, said that he applauded the idea by the team of young scientists to clean the water of Van Lake but he ‘does not highly rate LTH 100 as a substance to clean water’, and that he can identify thirty substances with can be used for the same purpose.

“There are a lot of substances which can kill seaweed. In swimming pools, seaweed is killed with sulfate. LTH 100 is like any other pasteurised substance,” Cat said, adding that the method of cleaning water at Van Lake is, in fact, a kind of killing seaweed.

“Seaweed can float right after dying, but it will fall to the bottom of a lake if people do not remove it soon enough. The young scientists, I think, tried to remove the seaweed right after it died. However, how could we be sure they removed the seaweed before it fell to the bottom of the lake?” Cat asked.

Cat also denied the fact that LTH 100 can oxygenate organic substances, get rid of nitrogen, phosphorus and heavy metals as the young scientists said, emphasising that no tool can do all those things.

Meanwhile, Duong Duc Tien, PhD from Hanoi National University, said that if drastic measures were taken, Van Lake could become so clean that its bottom could be seen. However, he said that the value of the lake, as well as other lakes, is in its diversified ecosystem, and that cleaning the water of the lake does not mean turning the lake into a swimming pool.

Ha Dinh Duc, who has been famous for his researches on tortoises, is worried about if the young scientists learnt before about the historical characteristics of Van Lake. Duc said that every lake has its own characteristics and biological diversification which the current generation still cannot assess. It took hundreds or thousands of years for the current ecosystem of Van Lake today to be formed, but the ecosystem could be destroyed in a day.

Prof Dr Dang Dinh Kim, Deputy Head of the Science and Technology Institute under the Vietnam Institute for Sciences and Technologies, also affirmed that LTH 100 must not be used to clean the water of all lakes in Hanoi.

Kim and his colleagues said that the announcement by a deputy minister of science and technology recently that LTH 100 would be used to clean the water of To Lich River proves to be a hasty announcement.

(Source: Tien phong)