The annual average concentration is the simplest and most widely used state indicator for both nitrates and pesticides. The threshold values for the drinking water and groundwater are 50 mg NO3/L for nitrate, 0.1µg/L for a single pesticide, and 0.5 µg/L for the total pesticides (Table 6.2). The Drinking water Directive and Groundwater Directive set these limits.

Validity and robustness of the annual average concentration strongly depend on the quality and quantity of the monitoring data. Furthermore, this indicator does not reflect the temporal and spatial variability of the nitrate and pesticide in the water.

Table 6.2: Summary of state indicators and their threshold values and limits for water quality and regulatory compliances

Main domain Indicators Contaminants Threshold/ limit Unit
Water quality Annual average concentrations NO3 50 mg/L
Individual pesticide 0.1 µg/L
Sum of all pesticides 0.5 µg/L
Trend NO3 - upward, downward, no significant
Regulatory compliance Frequency of exceedance quality standard NO3 - %
Individual pesticide - %
Frequency of findings quality standard Individual pesticide Detection limit %
Maximal concentrations NO3 50 mg/L
Maximal concentrations Individual pesticide - µg/L
Sum of all pesticides - µg/L
All pesticides - -
Number of substances   - -


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