Qualified drinking water standards must meet microbial indicators (bacterial count), toxicological indicators (plasma concentration of heavy metals), sensory characteristics (color, smell and taste visible to the naked eye), general chemical indicators and radioactive indicators. Healthy and clean domestic water must not contain pathogenic microorganisms, and chemicals and radioactive substances in the water must not endanger human health and have good sensory characteristics.
Excessive concentration of heavy metal ions in drinking water will pose a great threat to human health, such as lead, arsenic, chromium, cadmium and mercury. The allowable safe concentration is1-10 mg/l (1μ g is equal to one thousandth of mg).
Reference value of corresponding water sample of TDS value:
0~9 pure water
10~60 mountain spring water and mineralized water
60~ 100 purified water
Extended data:
TDS value can not accurately reflect water quality. The TDS test value exceeding 1000 definitely does not meet the standard, indicating that the tap water may be polluted. But below 1000, such as water with detection values of 200 and 300, it cannot be said that the water quality of 200 is better than that of 300.
Because on the one hand, some minerals needed by human body in water will also be detected by TDS, on the other hand, fungi such as Escherichia coli harmful to human body in water can not be detected by TDS. Therefore, it is not accurate to judge water quality only by TDS value within the scope of national standards.
The internal control standards of TDS value in major water plants are not exactly the same. If groundwater is used as water source, the TDS value will be higher because of the high calcium and magnesium ions in groundwater. When surface water is used as water source, TDS value is low.
Baidu encyclopedia -TDS test
People's Network -TDS pen is not necessarily accurate in measuring water quality.