VOLUME 42 (1-3)/December 2013

The contents and concentration trends of 53 elements in four vegetation species and their parts have been investigated. The studied samples include culture plants (wheat and sunflower) taken from the areas of Maritsa East-2 and Maritsa East-3 TEPSs as well as wild plants (Hypericum perforatum and Typha) collected from the Troyanovo-3 mine of Maritsa East lignite basin. According to the number of elements that exceed the lower limit of average values of terrestrial vegetation, the analyzed vegetation species could be arranged as follows: Hypericum perforatum > sunflower > Typha ≥ wheat. It has been found that in wheat and sunflower the elements with coefficient of concentration (CC) ≥3 exceeding the average values of terrestrial vegetation are Au and Cr, and Au and Sr, respectively. Most of the trace elements concentrate in wheat and sunflower stem+leaves while in Hypericum perforatum trace elements accumulate in blossoms. It has also been identified that the accumulated trace elements in Typha are equally distributed in all parts of the plant.

The study area is located in Southeast Bulgaria. The main factors affecting climate in Burgas lowland are the proximity to the Black Sea and to mountains. The aim of the study is to quantify the long-term value of the baseflow and other water balance elements. The methods include Turc-Radiation equation, equation relating baseflow coefficient with the aridity index, regression set for Conterminous USA based on climatic parameters, etc. All water balance elements are estimated as reasonable, as compared with available data from previous studies. Therefore, the methods applied are recognized as suitable for the study area. The results show that the baseflow varies from 20 to 70 mm per year, and the baseflow coefficient ranges from 5 to 10 percent in respect to the proximity to the Black Sea coast. Possible impact of the climate change on the groundwater recharge and baseflow is evaluated based on the climate scenario for the period between 2040 and 2070. The expected decrease of baseflow as a result of the increased aridity is up to 50% in comparison to the baseline state.