The Impact of Humic Substances as Remediation Agents to the Speciation Forms of Metals in Soil

AbstractHumic substances (HS) are the most widespread group of organic substances in natural environment and have high stability. The main terrestrial reserves are found in the form of naturally occurring ore, peat or lignite. The aim of this paper is to study possibilities to use HS as agents for remediation of contaminated with heavy metals soil and impacts of HS of metal speciation forms in it. It has been proved that HS are able to bind to metal ions and change their speciation forms in soils. The ability to form complexes with metal ions depends on the type of soil, type of metal, as well as concentrations of HS in soil. The study was carried out in experimental conditions and analytical method to determine availability of metals to living organisms was used for spiked soils. Remediation by using HS has shown good result for diminishing the content of biologically available copper and lead

Fog Regime in Latvia and Factors Affecting it: Case Study-Riga Airport

Fog is a hazardous weather phenomenon, which can impact traffic (especially air traffic) and air quality. The aim of this study is to analyse fog climatology, the trends of long-term changes of fog events and factors affecting them in general, in Latvia, but especially in Riga airport. For a 50-year period of observations, the analysis of the fog frequencies, long-term changes and atmospheric conditions favourable for the occurrence of fog events in Latvia has been studied. During the analysis two inter-annual maxima of fog frequency were found in spring and autumn, and the seasonal differences in the formation of fog were also approved by the satellite data on low cloud cover.

Power centres and marginal landscapes: Tracking pre- and post-conquest (late Iron Age and Medieval) land-use in the Cēsis Castle hinterland, Central Latvia

During the late Iron Age, the eastern Baltic was inhabited by Finno-Ugric and Baltic speaking societies whose territories were conquered in the thirteenth century as a result of the crusades. This paper examines the degree to which indigenous landscapes were transformed as a result of the crusades, and the evidence for maintenance of indigenous land-use practices. Vegetation and land-use history are reconstructed using palynological data from Cēsis castle and its terriitory. Comparison is made with selected palynological, archaeological and documentary data across Livonia (Latvia and Estonia) and contrasted with the greater impact of the crusades in nearby Prussia. Despite the emergence of key power centres in the medieval period, including towns and castles such as Cēsis, many parts of the rural landscape remained largely unchanged by the crusades, particularly in those more marginal landscapes studied in this paper. Lower intensity land-use can be linked to poor agricultural soils but also reflect the limited colonisation of rural landscapes beyond the major towns and castles. Indigenous societies and practices survived to a greater degree, with later agricultural intensification in the fourteenth century reflecting the increasing political stability, growth of urban centres, establishment of serfdom and the development of the manorial system

Le tracé de l’identité européene de l’Espagne aux Pays Baltes

This book contains selected papers from the meetings «To think the Identity» and «Identities on the move» held in the Institute for Research into Identities and Society (University of Lleida) during 2010. The aim is to understand the reasons that allow social cohesion throughout the creation of identities and its adaptation. Identity is individual and collective, momentary and secular, apparently contradictory terms that can only coexist and fructify if they entail a constant adaptation. Thus, in a changing world, the identities are always on the move and the continuity of society requires a permanent move. Values, Culture, Language and History show the societies in permanent evolution, and demand an interdisciplinary perspective for studying. Attending this scope, outstanding historians, sociologists, linguistics and scientists offer here a diachronic and interdisciplinary approach to this phenomenon: how men and women have been combining the identity and the move in order to feel save into a social life from Middle Ages to current days, and how different items, in our present society, built the framework of identities