A value proposed by experts, which approximates the risk threshold (and should be
strictly
adhered to). The guideline value is usually significantly lower than the legal limit and is based on
the principle of minimizing potential adverse effects as much as possible.
Explanation / Context:
This describes a guideline value (Richtwert) or precautionary threshold, a common
concept in
environmental and food safety regulations.
Purpose:
It serves as a precautionary, operational target for risk management, designed to
keep exposure or concentrations well below levels where harm is legally defined or likely to
occur.
Relation to Legal
Limits: It is stricter than the official limit (Grenzwert). The legal limit is
the maximum allowable concentration, often set with a safety margin below acute toxicity
levels. The guideline value adds an extra safety buffer, following the precautionary principle
(Vorsorgeprinzip).
Application Examples:
Nitrate in Drinking
Water: The EU limit is 50 mg/L. A national or advisory guideline
value might be set at 25 mg/L to ensure long-term safety and account for vulnerable
groups.
Cadmium in Soil:
A legal limit might be based on protecting crop yield. A stricter
guideline value for sensitive land uses (e.g., vegetable gardens) aims to minimize
human dietary exposure over a lifetime.
Nutrient Surpluses:
A guideline for nitrogen surplus (e.g., 50 kg N/ha) is set well
below levels known to cause groundwater pollution, to proactively protect water
quality.
In essence, the Richtwert is a conservative, science-based recommendation for best
practice,
aiming to prevent problems before they reach the legal limit. It is a key tool for sustainable
management in agriculture and environmental protection.
