Aquatic plant Trapa natans L. as bioindicator of trace metal contamination in a freshwater lake (Skadar Lake, Montenegro)

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–1), generally contaminated with Cr (15.8–180 mg kg–1), the concentrations of both elements frequently exceeding sediment quality guidelines, while concentrations of Pb were low (2.7–17.4 mg kg–1). The highest bioaccumulation of all metals from sediment to Trapa natans L. was observed in the root, with accumulation efficiency 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.