Plenary Lecture
Flows of Dissolved Organic Substances and Factors Controlling It
Professor Maris Klavins
Department of Environmental Science
University of Latvia
Riga, Latvia
E-mail: maris.klavins@lu.lv
Abstract: The impact on sea and coastal areas is influenced by chemical composition of waters and loads of dissolved substances to the sea. Of importance in this respect are flows of natural organic substances – humic substances (major part of dissolved organic carbon DOC). Transfer from adjacent areas, but also industrial effluents and non-point pollution sources can be sources of increased fluxes of DOC. The number of studies of dissolved organic carbon (DOC) during the last few years is very much growing and the interest is more and more moving from sum parameters (colour, COD, TOC, DOC, BOD) towards parameters describing composition of dissolved organic matter (DOM). As far as dissolved organic matter is composed from a large number of individual molecules, their isolation and characterisation seems to be too complex task. Instead of that, the sum of parameters describing properties of majority of organic substances can be used.
The aim of this study is to describe long term changes of DOC concentrations in surface waters, factors controlling DOC runoff, spatial variability of water chemical composition, possible impacts of pollution sources, and to analyze the character of compositional changes.
Impact of other major water ingredients on DOC budgets has been studied. The dynamics of DOC flows depending on landuse pattern and soil properties are described, including emissions by industrial and agricultural production. The water chemistry of a large number of lakes and rivers has been determined and the possible impact of water chemical composition on water quality has been evaluated.
As a tool spectral analysis of DOC has been used, for example applying fluorescence index. The changes of DOC concentrations follow a pattern common for Rivers in Northern Europe and much depends on the river discharge regime. Higher concentrations of organic carbon are observed in autumn and other maximum. In the pool of TOC, a major role is played by dissolved organic substances and only during spring and autumn seasons particulate organic carbon reaches up to 5 % of the TOC.
Brief Biography of the Speaker: Maris Klavins graduated from the University of Latvia in 1979, doctoral dissertation defended in Moscow University (Russia) in 1985, but habilitation thesis in University of Latvia in 1993. Maris Klavins (professor, dr.habil.chem.) is head of Environmental science department of Faculty of Geography and Earth sciences, University of Latvia. M.Klavins is member of editorial boards of 6 scientific journals, member of 3 societies related to environmental chemistry issues and full member of Academy of Sciences of Latvia. M.Klavins has been leader of several projects related to the environmental issues mostly doing with environmental pollution and management, and quality of water, but including also political and social sciences and sustainable development science.