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Abstract. Tabacarie coastal lake has been surrounded, during the past century, by the fast developing city of Constanta. Consequently, the lake has directly suffered from human interventions, such as dredging, embankments and heavy pollution. The lake surface sediments are generally fine grained: clayey silts and silts, with sands appearing only on dredged bottoms. The review of the chemical composition of upper sediments pointed out the presence of large quantities of certain heavy metals, in particular: Zn, Ba, Cu and Pb, dispersed, mainly, near the discharge points of rainwater pipes.
Key words: lacustrine sediments, bathymetry, geochemistry, heavy metals
1. Introduction
The Tabacarie lake is situated in the North-Western part of the South Dobrogea, close to the contact with the Central Dobrogea (the Capidava-Ovidiu fault). The lake, situated at the northern limit of the Constanta city and having a surface of approximately 99 ha, was formed by the damming of a river valley; genetically, the lake is a fluvial-maritime creek (Fig. 1). Geologically and sedimentologically, the lake Tabacarie area is closely related to the evolution of the Siutghiol lake, situated northwards and communicating with the Tabacarie lake through a sluiceway equipped with a sluicegate.
Previous studies have been carried out by the main author between 1991-1993, revealing and characterizing the Tabacarie Lake's main features (geography, geomorphology and geology).
2. The bathymetry of the Tabacarie lake basin
Relatively isolated from natural sources (ground water is insufficient to balance loses), Tabacarie lake has a hydrological level (about +1.20 - +1.70 m above the 1975 Black Sea level) which depends upon the influx of water from Siutghiol lake. The excess water flows out of Tabacarie lake into the sea via a sluice at Pescarie.
Stormwater runoff and rainwater and waste water that flow into Tabacarie lake led to its environmental decline. From 1978 to 1979, the lake basin was dredged and the bank remodelled with walkways.
Bathymetry measurements performed in 1993 allowed the detailed charting of the lake (Fig. 2).
The dredging works intensely affected the northern part of the lake, causing the deepest areas (maximum depth of 3.70 m), where the topography of the bottom includes relatively abrupt drop-offs (Fig. 3).
Bathymetric Maps are made in different years: in 1993, by the main author; in 2007, designed by...