Defining proactive limit values.
The Basic Rule of Environmental Hygiene BREH (Dieter 1996;1998b) is a suitable starting point for proactive chemicals management.Three definitions (==> LV) for corresponding proactive LVs can be derived from the BREH: (1) Functional anthropogenic exposure of the type residues = substance group B is accepted at least at a minimal technical threshold FB > 0 to maintain desired functionality distinctly below the most sensitive adverse effect threshold Ea, (0 < FB ==> LVB < Ea). (2) Group C exposure = non functional contaminants (F c = 0) is to be tolerated only at technically low if not "zero" levels Tc, hence 0 = Fc < Tc ==> LVC < <or= Ea. (3) Group A = natural exposure with neither a technical background nor defined functionality (NA = FA >or= 0). It may be accepted or tolerated up to its upper limit NA <or= Ea, irrespective of how wide or narrow the margin of safety between both might be (0 << NA==>LVA <or= Ea). The BREH is not only a suitable starting point for finding proactive LVs, but also for sustainable environmental care by responsible management of chemicals. Additionally, it helps to minimize "adverse effects" at the level of society by motivating competing groups to follow conflicting interests in a consensual manner.
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Institute for Water, Soil and Air Hygiene of the Federal Environmental Agency, P.O. Box 330022, D-14191, Berlin, Germany.