Bába K., D. Sári, and T. Tóth. 2003. Clam coenosises on different substrates. 
The heavy metal pollution in 2000. Soosiana. 23:37-48.

10x25x25 cm quadrate samples were taken from the Middle-Tisza area, where the 
Takta and Sajó rivers charge into the Tisza river for the purpose of 
quantifications and comparisons of species and specimen numbers as well as the 
analysis of zoogeographical disributions of species. Further samples were taken 
from the Lower Tisza area in the surroundings of Algyo and Tápé. Following the 
concepts of the 1964 works of Lozek the distribution of biotopes and substrate 
types has been analysed. Furthermore the heavy metal content of the bivalve 
shells collected in 1992 and 08.09.2000 were examined at details. Heavy metal 
analyses were extended to the soft parts of the animals as well. According to 
our findings the West-Siberian (1.2) and Ponto-Caspian (3) faunas display 
complementary realtions independent from substrate composition, the faunal 
composition of soft and hard muds are quite different. The heavy metal content 
was analysed with Varian Spectrograf AA Graphite furnace spectrophotometer with 
a measurement error of 2%. Highest concentrations of heavy metals have been 
found in the shells. The contamination of the species Anodonata cygnea displayed 
lower leveles as of those of the species Unio tumidus and Unio pictorum. These 
latter species can be considered good indicators of the heavy metal 
contamination in the river.