S.Rddan et al -ERAS-2000 Danube Programme:
Danuba Delta Ecosystems
(1995)
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EROS.2OOO
DANUBE PROGRAMME
:
STATE OF ECOSYSTEMS
WITHIN THE DANUBE DELTA IN 1995
n.)
)2,
Silviu Raonru1,
Claudia
StnrcHtel,
Andrei GRNctul,
Gydngyi Ruzsn2,
Sorin Corneliu RAnRru',
Maria RAoRtt'
' National
Institute of Marine Geology and Geo-ecology
- GEoEcoMAR, 23-25, D. Onciul Str., 70318 Bucharest
2 institute of Environmental
Research and Engineering,294,
Spl. Independentei,
77703 Bucharest.
3 Geological
Institute of Ronnania,
1, Caransebes Str., 79678 Bucharest.
Abstract, The Danube Delta may be considered a natural
filter, which acts as a buffer interface between
the Danube River supplies, rich
in contaminants
collected
from a large catchment area, and the western Black Sea. During the 1995 research cruise, sediment, water and
biota sampling was carried out in 62 stations,
located within the main lakes and channels of the deltaic water system and also, within
Razim-Sineie
lacustrine complex. The data obtained poini out patterns and trends of the input, dispersal and deposition of the sediments
and the pollutants within the main ecosystems. The metallic pollutants
in sediments are not exceeding, usually,
the normal values, but
show increasing
trends in areas controlled by Danube River direct supplies (Megteru-Foftuna,
Gorgova-Uzlina
depressions and Razim-
Sinoie complex). The same areas show high values of the magnetic susceptibility
and radioactivity
of the sediments. The distribution of
the physical-chemical
parameters of the Danube Delta waters is influenced mainly by natural
factors and subordinately
by more or less
direct anthropogenic causes. Suspended solid contents are induced both by particulate matter inputs of riverine origin, and by
phytoplanldon
"blooms". The nutrient ooncentrations
in walershow generally moderate values for nitrites and nitrates, not exceeding
the
alfowabie
contamination
levels. As concerns trace metals in water, the rnain increasing concentration
t