Anthropic influences on the sedimentation rates of lakes situated in different geographic areas.

The aim of this study is to determine the effects of natural and anthropic events occurring in the last 30 years in the catchment areas of four Romanian lakes (St. Anna Lake, Red Lake, Vârşolţ Lake and Matiţa Lake) originating from four different geomorphologic areas. A total of eleven sediment cores have been processed for age and sedimentation rate determination using the (210)Pb dating method. Total (210)Pb was measured via alpha spectrometry by (210)Po using PIPS detectors, while supported (210)Pb was measured by (226)Ra using HPGe detectors. Ages and sedimentation rates were calculated using the CRS model. The values of the sedimentation rates have grown multiply in the last three decades: 2.66 times in case of the St. Anna Lake (from 0.06 ± 0.01 g/cm(2)y to 0.16 ± 0.02 g/cm(2)y), up to 6.72 times in case of Red Lake (0.36 ± 0.04 g/cm(2)y to 2.42 ± 0.36 g/cm(2)y), 4.02 times in case of Vârşolţ Lake (04 g/cm(2)y to 1.53 ± 0.18 g/cm(2)y) and up to 16.18 times in case of Matiţa Lake (0.27 ± 0.03 g/cm(2)y to 4.37 ± 0.32).