Protection factors generic

In the past few years, there have been increasing efforts towards international harmonization of approaches to pesticide exposure assessment. Harmonization allows exposure assessors to share expertise and resources and develop better methods. Ongoing efforts towards international harmonization are discussed in Chapter 10. The development of generic databases has provided an impetus for harmonization of methodologies for generating the data. Further harmonization would increase the number of studies that could be included in databases, thus improving the exposure estimates derived from them. The use of harmonized factors for dermal absorption and clothing penetration, plus protective factors... 

In the prospective context, a common and simple way to handle uncertainty is the use of uncertainty factors (UFs). These may suffice to derive a safe concentration of a substance associated to a predefined protection level to be used generically — that is, it is safe even in worst-case conditions. The greater the uncertainty in models or data for the extrapolations, the larger the overall UF in the lower tiers. The UF is applied to the risk assessment to account for unquantified uncertainties. In some cases, the factor depends on the amount of available data, or UFs per extrapolation are multiplied to provide the final factor (e.g., 10 x 10 x 10 as the UF for 3 assessment steps yields an overall factor of 1000). 

Tier-1 extrapolation (mostly for protection purposes) based on simple generic approaches (usually uncertainty factor)... 

What can be said about the protective value of the ADI There is no way to be sure how close it is to the true threshold, by which is meant the threshold dose for the most sensitive members of the human population. If the generic safety factors are accurate, or are larger than they need to be, then the ADI should be adequately protective, or even more protective than it needs to be. A recent review of the available... 

As groundwater discharge is almost the only sustainable source of surface waters, dilution cannot be accounted for, but due to nitrate degrading processes at different interfaces an attenuation factor of 0.5 was established. However, despite this natural breakdown it was proved that, specifically at the Odense river basin, the generic Environmental Quality Standard for nitrates of 50mg/l is not protective to aquatic ecosystems. Specifically for this groundwater body and its interactions with surface water, a ninate threshold value less than 20 mg/1 would be necessary to decrease the nutrient load to an acceptable level. 

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