3 Methods and materials
3.1 Location of the study area
3.1.1 Neckar River and its tributaries
The Neckar River is a tributary of the Rhine; it drains densely populated and
important industrial areas in Southwest Germany (Fig. 3.1). Before 1973, The Neckar
River was heavily polluted by industrial and municipal discharges, which is wel}
documented by water, biota, and sediment research (Frrstner and Mtiller 1973;
Remhard and Frrsmer 1976; Miiller and Prosi 1977; MiJller and Prosi 1978; M011er
1980, 1981, 1986; MOiler et al. 1993).
There are 27 locks along the navigable tmddle and lower section of the Neckar
River. Large amounts of suspended particles deposit in front of the dams due to low
water flow rate. At site Lauffen alone 700,000 m 3 of heavily polluted sedtrnents
accumulated under overlying water. These contaminated sediments pose problems for
this aquatic ecosystem.
The sampling sites represent different depositional environments of the Neckar
River and its tributaries (Fig. 3. i).
1. Neckar at Lauffen. This site was chosen because of the large amounts of
contaminated sediments and the high heavy metal concentrations in the sediments. It
is a representative site for the ecological problems in the Neckar River. The river
flows very slowly at this site, which leads to a deposition of fine particles and
biological debris. This gives good preconditions for the research of diagenetic
processes.
2. Neckar at Kochendorf. The sediments were moderately polluted. The carbonate
contents was highest at this site (about 30 %; Miiller et al. 1993).
3. Neckar at Wieblingen. The sediments were moderately polluted. The dam is
often open because of large water flow after heavy rains. As a result, the sediments
are removed and transported to a lower section of the river.
4. The Elsenz River at Neckargemiind. The Elsenz is a tributary of the Neckar
River. It drains mainly agricultural area. The sediments mainly derive from soil
runoff and have low contents of heavy metals.
5. The Enz River at Vaihingen. The Enz is one of the largest, and most heavily
polluted tributaries. This river has great influence on the Neckar River. The level of
biological productivity is high and is reflected by the surface organic carbon (7.1%).
Carbonate content was about 6 % (MOiler et al. 1993).
6. The Schwarzbach River at Neckarbischofsheim. The Schwarzbach is a tributary
of the Elsenz River. The water flow is low. The sampling site is located at
Neckarbischofsheim, where serious fish kills occurred in April 1992.
3.1 Location of the study area
3.1.1 Neckar River and its tributaries
The Neckar River is a tributary of the Rhine; it drains densely populated and
important industrial areas in Southwest Germany (Fig. 3.1). Before 1973, The Neckar
River was heavily polluted by industrial and municipal discharges, which is wel}
documented by water, biota, and sediment research (Frrstner and Mtiller 1973;
Remhard and Frrsmer 1976; Miiller and Prosi 1977; MiJller and Prosi 1978; M011er
1980, 1981, 1986; MOiler et al. 1993).
There are 27 locks along the navigable tmddle and lower section of the Neckar
River. Large amounts of suspended particles deposit in front of the dams due to low
water flow rate. At site Lauffen alone 700,000 m 3 of heavily polluted sedtrnents
accumulated under overlying water. These contaminated sediments pose problems for
this aquatic ecosystem.
The sampling sites represent different depositional environments of the Neckar
River and its tributaries (Fig. 3. i).
1. Neckar at Lauffen. This site was chosen because of the large amounts of
contaminated sediments and the high heavy metal concentrations in the sediments. It
is a representative site for the ecological problems in the Neckar River. The river
flows very slowly at this site, which leads to a deposition of fine particles and
biological debris. This gives good preconditions for the research of diagenetic
processes.
2. Neckar at Kochendorf. The sediments were moderately polluted. The carbonate
contents was highest at this site (about 30 %; Miiller et al. 1993).
3. Neckar at Wieblingen. The sediments were moderately polluted. The dam is
often open because of large water flow after heavy rains. As a result, the sediments
are removed and transported to a lower section of the river.
4. The Elsenz River at Neckargemiind. The Elsenz is a tributary of the Neckar
River. It drains mainly agricultural area. The sediments mainly derive from soil
runoff and have low contents of heavy metals.
5. The Enz River at Vaihingen. The Enz is one of the largest, and most heavily
polluted tributaries. This river has great influence on the Neckar River. The level of
biological productivity is high and is reflected by the surface organic carbon (7.1%).
Carbonate content was about 6 % (MOiler et al. 1993).
6. The Schwarzbach River at Neckarbischofsheim. The Schwarzbach is a tributary
of the Elsenz River. The water flow is low. The sampling site is located at
Neckarbischofsheim, where serious fish kills occurred in April 1992.