No abstract

No abstract

-Skadar Lake is the largest shallow lake in southeastern Europe. It is located within a national park, and is included in the Ramsar List of international important wetlands, so its preservation and protection from pollution is very important. The aim of this study was to investigate bioaccumulation of the ecotoxic metals Cd, Pb and Cr from sediments of Skadar Lake in the aquatic macrophyte Trapa natans L. Samples of sediment and plants were collected at nine locations covering all major water inputs to the lake as well as locations where contamination could be expected. The obtained results indicate that sediments from the Skadar Lake are only locally contaminated with Cd (0.03-1.18 mg kg ). The highest bioaccumulation of all metals from sediment to Trapa natans L. was observed in the root, with accumulation effi ciency decreasing in the order Cd > Cr > Pb. Translocation from root to stem was also higher for Cd than for Cr and Pb, while the translocation from stem to leaf was comparable for all three metals. From the three investigated metals Cd showed the highest mobility. The results indicate that Trapa natans L. may be a very promising bioindicator of trace metal contamination in Skadar Lake.

This paper provides a comprehensive study of the persistence of butyltins and phenyltins in contaminated marine sediments and presents the first data on their degradation potentials in porewaters. The study's aim was to explain the different degradation efficiencies of organotin compounds (OTC) in contaminated sediments. The transformation processes of OTC in sediments and porewaters were investigated in a field experiment using species-specific, isotopically enriched organotin tracers. Sediment characteristics (organic carbon content and grain size) were determined to elucidate their influence on the degradation processes. The results of this study strongly suggest that a limiting step in OTC degradation in marine sediments is their desorption into porewaters because their degradation in porewaters occurs notably fast with half-lives of 9.2 days for tributyltin (TBT) in oxic porewaters and 2.9±0.1 and 9.1±0.9 days for dibutyltin (DBT) in oxic and anoxic porewaters, respectively. By controlling the desorption process, organic matter influences the TBT degradation efficiency and consequently defines its persistence in contaminated sediments, which thus increases in sediments rich in organic matter.

No abstract