Intraspecific chemical polymorphism is characteristic of essential oil bearing Thymus pulegioides (Lamiaceae). Soil chemical composition and climatic conditions can influence not only quantitative and qualitative composition of essential oils, but also on prevalence of different chemotypes in space. The purpose of study was to determine the impact of edaphic and climatic factors on T. pulegioides essential oil composition and potential chemotypes prevalence. It were investigated 131 habitats of T. pulegioides in all ten climatic sub-districts of Lithuania. Essential oils were isolated by hydrodistillation and analysed by GC-FID and GC-MS. The content of humus was estimated by oxidation method, the content of mobile potassium (K2O) and mobile phosphorus (P2O5)—flame photometry using 0.2 M HCl solution, the soil pH—electrometrically and 15 elements of soil—by energy-dispersive X-ray fluorescence. The meteorological data (temperature, rainfall, photosynthetically active solar radiation and sunshine duration) were obtained from the meteorological bulletins. Results showed that humus in soil positively, manganese and cobalt—negatively influenced on the essential oil accumulation in T. pulegioides. Carvacrol was the most common compound in the essential oil of T. pulegioides; higher amounts of sulphur and mobile phosphorus, lower amounts of sodium in soil, higher rainfall in blooming period are favourable for this compound and for potential prevalence of carvacrol chemotype. Geraniol was frequent in the eastern and the central part of Lithuania, where the temperature in vegetation season is higher, and in soils characterised by higher and lower amounts of sodium and chlorine, respectively. Thymol, linalool and α-terpinyl acetate were rare. Edaphic and climatic conditions can differently influence on essential oil yield and chemical composition of species as well as on potential prevalence of different chemotypes of same species in space.
23 May 2017 in Environmental Geochemistry and Health
A geochemical and mineralogical approach was used to analyze 3rd millennium BCE pottery from Southeast Lithuania that is attributed to the foreign Corded Ware Culture and local hunter-gatherers. SEM-EDS, XRF, XRD, and FTIR were used to study the peculiarities of the pottery and to develop hypotheses about the raw material and technology choices present. The amounts of ten major elements in the bulk and clay matrix compositions (XRF, SEM-EDS) and eleven trace analytes in the bulk compositions (XRF) were compared with the Clarke values and tested to highlight the significance (Mann–Whitney U and Wilcoxon Matched Pairs Tests) of the differences in the elemental quantities between the clay matrix and bulk compositions, and between the lighter and darker clay matrixes. These also revealed the advantage of Ward’s clustering method using the City-block distance of bulk compositions as a tool for inter-correlating ceramics in attributing them to specific communities and locations. The XRD, FTIR, and SEM-EDS mineralogical analyses indicated a predominance of iron-rich illite clay, quartz, and alkali feldspar, in addition to very low to medium firing temperatures. All of the pottery samples consisted of hydromicaceous clay from local Quaternary glacial sediments that contain weathered granitoid fragments.
22 December 2014 in Journal of Environmental Engineering and Landscape Management
Geochemical investigations were conducted on Quaternary interglacial sediments in order to reveal if they can be a natural source of 10 potentially harmful chemical elements: As, Ba, Cr, Cu, Mn, Mo, Ni, Pb, V and Zn. Determination of the total contents of elements in 680 samples was performed by EDXRF analysis. The content of Ni, Cu, Pb, Ba in all analyzed samples was lower than maximum permissible concentrations (MPC) for soil, the content of Zn, V, Cr, Mn exceeded MPC values only in several samples (≤4%). The highest percentage of anomalous samples where MPC was exceeded was characteristic of Mo (21%) and As (12.6%). Therefore, interglacial sediments, especially enriched in organic matter and other sorbents, comprise one of the possible natural sources of Mo and As. It is probable that they contribute to As and Mo anomalies in stream sediments in Lithuania.