Water treatment equipment identifies and treats chemicals
a. For non-carcinogens, there is a clear dose-response relationship for their toxic effects, and no harmful effects will be caused below a certain dose level, which is called the "threshold value". Water Treatment Equipment When limits for these chemicals are established, they are calculated based on the Tolerable Daily Intake (TDI).
b. Tolerable Daily Intake (TDI). When a chemical substance is ingested from food or drinking water during a lifetime without causing obvious health hazards, the estimated daily intake is the daily tolerable intake, in mg/kg.
c. No observed adverse effect dose level (NOAEL). In animal studies, the highest dose (or concentration) at which no adverse effects were observed was the NOAEL. The lowest dose (or concentration) at which an adverse effect is observed is the LOAEL.
d. Uncertainty factor. As mentioned earlier, the limit is largely based on the data obtained from animal experiments. Obviously, there are many uncertainties when extrapolating from animal experimental data to humans. In order to ensure that the established limits of chemical substances are sufficient to protect human health, it is necessary to fully consider uncertain factors when calculating the limits. Therefore, the uncertainty factor is often used, which can also be understood as a "safety factor", so that the established limits have sufficient safety boundaries.
In general, the sources and values of uncertainty coefficients are considered as follows:
The uncertainty coefficient due to interspecific differences (extrapolated from animal data to humans) is generally 100 days, and the uncertainty coefficient due to intraspecific differences (individual differences) is generally 10. The uncertainty factor due to the suitability (availability) of the experiment is determined according to the specific situation, and the maximum is 10. The uncertainty factor due to the nature and severity of toxic effects is determined on a case-by-case basis, with a maximum of 10. The uncertainty coefficient of each source is determined according to the source of the above uncertainty factors and the degree of uncertainty, but the overall uncertainty coefficient should not exceed 10,000, otherwise, such a huge uncertainty will make the calculated TDI value Extremely inaccurate
Exactly. Generally speaking, the uncertainty coefficient is 100~1000.
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