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The nutrient and heavy metal emissions by point and diffuse sources were estimated for 45
sub catchments of the Odra basin for the period 1993-1997 by means of the Models
MONERIS, MODEST and NIIRS. For nitrogen total emissions of 124 ktN/a were esti-
mated for the Odra basin. 64% of these emissions were caused by diffuse sources (mainly
groundwater and tile drainage). For Phosphorus the emission was 12.8 ktP/a, with a contri-
bution of diffuse sources to this sum of 38%. The comparison of calculated and observed
loads shows that the mean deviation for the investigated sub catchments of Odra is 22% for
nitrogen and 32% for phosphorus. The spatial resolution of the emission calculations allows
the identification of regional hot spots and the derivation of specific regional measures to
reduce the emissions into the Odra. For the heavy metals emissions of 10,8 t/a (Cd), 175 t/a
(Cu), 113 t/a (Pb) and 1190 t/a (Zn) were estimated. A comparison of different models for
the nitrogen inputs by groundwater shows that with the present knowledge of processes and
data base a conceptual model achieve the same results than a detailed mechanistic ap-
proach.
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