D10: Impact of Contaminants - Hydromod

Integrated Water Resource Management for Important Deep European Lakes and their Catchment Areas
EUROLAKES
D10: Impact of Contaminants
FP5_Contract No.: EVK1-CT1999-00004
Version: 4.0
Date: 25/07/01
File: D10-vers.4.0.doc
Page 50 of 136
acute moderate toxic but negative long-time effects like reproductive interference and
malformation have been observed at low atrazine dosages ( aquatic makrophytes > benthic organisms > zooplankton > fishes
LD50-values (96 h) of fishes lie in the range of 3.5 - 20 mg/l but chronic values lie at 0.5
- 1.0 mg/l. The author continues that atrazine is very persistent and represses the primary
production in stagnant water at a concentration of ≥ 20 µg/l. First effects occur in
the phytoplankton and periphyton. In plant communities no effects are determined at
low values but concentrations of 1 - 5 µg/l impair single algae. An impairment of the
photosynthesis and a change in the range of species take place at concentrations of
100 µg/l. The displacements of species are different in the experiments but it tends to
result in an expansion of resistant species in those niches where sensible species are
eliminated. Also at 100 - 500µg/l indirect effects like changes of the water quality and
the reduction of herbivore populations are recognised. This causes a change in the diet
of fish. Although chronic effects to aquatic animals have an important relevance only a
few are known. 4 - 5 µg/l causes histological changes at the kidneys and 80 µg/l causes
cell damages [FENT 1998].
Model System Measuring Parameter Effect
specific single algae
marine phytoplankton
microcosm (pond)
photosynthesis
primary production
phytoplankton productivity
mesocosm (pond) phytoplankton productivity
micro- res. mesocosm phytoplankton productivity
(pond)
makrophytes abundance
Inhibition
Reduction
reduction
green algae reduced
chlorophyll-values increased
reduction
substitute of sensitive breeds
Table 7-2: Atrazine-Effects at Concentrations till 50 µg/l [FENT 1998]
Lowest Effect-
Concentration
(µg/l)
1
6
15
20
50