The mean content of minerals in grains varies significantly among different parts of the world as it depends on the type of grain growing conditions and fertilizer application. In this study, the content of minerals in the wheat, oat and barley grains of the crop of the year 2006 from different regions of Latvia were investigated. The grain samples were analysed for K, Mg, Ca, Na, Cu, Mn, Fe, and Zn using Atomic Absorbtion Spectrometer, and for P using spectrophotometer. Phosphorus content in different types of grains varied from 3.10 to 5.65 g kgE-1, potassium - from 4.37 to 6.10 g kgE-1, calcium - from 0.40 to 1.40 g kgE-1, magnesium - from 1.20 to 1.68 g kgE-1, manganese – from 14.50 to 55.54 g kgE-1, copper - from 3.35 to 6.01 g kgE-1, zinc - from 18.72 to 31.84 g kgE-1, iron - from 42.39 to 120.40 g kgE-1, and sodium - from 32.34 to 55.52 g kgE-1. The greatest difference was found between the content of manganese and iron in barley, wheat and oat grains, but small difference was between the mean content of P, K, Zn, Cu, Mg, and Na.

In presented study we have investigated an occurrence of 15 polycyclic aromatic hydrocarbons (PAH) in different smoked meat and fish samples. After clean up and extraction procedures, the samples were analyzed by gas chromatography-mass spectrometry (GC-MS). Large variability in PAH levels for samples of the same type was found, thus the contamination level is not strongly correlated with the type of product. In the smoked fish samples concentrations of total PAHs ranged from 0.26 to 104 mu g kgE1, and in smoked meat samples - from 1.7 to 197 mu g kgE-1. In general, the predominating PAHs in all samples were benz(a)anthracene, crysene, and cyclopenta(c,d)pyrene. Also the elimination of PAHs in smoked fish by UV irradiation was investigated. Significant decrease in carcinogenic PAH content in smoked fish was found after a 15 min exposure.

The aim of the research was to assess food safety risks in catering establishments. To analyse food safety risks during production and distribution of ready-to-eat food in catering establishments, internal database of the Food and Veterinary service of the Republic of Latvia was used. Catering establishments, food items, technological processing methods, as well as environmental objects were encoded to perform mathematical analyses of state's monitoring and surveillance data. The probability of the microbiological risk factors coliforms and S.aureus in food and environmental samples as well as the total plate count in ready-to-eat food was assessed to forecast common risks in catering establishments and to set hygiene management priorities in frame of HACCP procedures. For estimation of individual risk factors, results were statistically analysed using SPSS statistical package and a p is less than 0.05 was considered to be statistically significant. The significant differences were established between certain bacteria presence in food and such factors as food group, method of technological processing, and type of catering establishment. The results on bacterial contamination of food correlate with the results on contamination of environmental objects. The research suggests that control of food safety risks that is built on testing of pathogenic bacteria is not effective enough to evaluate actual level of implementation of hygiene measures in catering establishments. Risk assessment during routine monitoring both in state's official control level and catering establishments' self-control level should be concentrated on testing of hygiene indicator microorganisms rather than pathogenic microorganisms to establish and prevent food safety risks.

A total of 120 food samples from 6 traditional and 3 non-traditional (Oriental) public catering establishments in Latvia were taken. Preliminary all food samples were divided in three food groups (categories) depending on the components of the products and processing methods. Ready-to-eat foods (RTE) with high level of total amount of microorganisms (aerobic colony count-ACC) and total coliforms (TC), as well as appropriate infringements of hygienic requirements in public catering establishments which had an impact on microbial contamination were clarified. The reasons for microbiological contamination of RTE and the growth of the microorganisms were analyzed in dependence on food category group, the activity of hydrogen ions (pH) in food, food temperature at the sampling point, their processing mode and composition. Different indicator microorganisms including Staphylococcus, Enterobacter, Escherichia, Bacillus, yeasts, moulds and etc. were identified. The comparison between the temperature and pH and the level of microbiological contamination of the samples of food and hygienic practice in the catering establishments were clarified.

A research has been done on the possibility to increase the range of beer drinks by substituting hops with additives of other plants in the wort boiling process. The obtained data present evidence of the possibility of substituting hops by oak bark, yarrow, wormwood and oak acorn.

Wood construction elements are widely used in buildings and they can be used in construction elements such as roofs, floorings, windows and doors. As wood is combustible material, there are lot of fire regulations that should be fulfilled at the design stage of any building project. In Latvia, as in some other countries usage of wood in building constructions is limited. Wood materials are an ecologically friendly material and a renewable resource, and its usage should be promoted. The paper presents an overview of heat distribution in wood floorings exposed to standard heat fluxes which is different compared to wood members exposed to high heat radiation. Fire spread and self-ignition investigation on wood floorings is carried out in this research. The results show different kinds of the temperature distribution in the cross section of the wood member cross section depending on heat radiation and location of the temperature measurement point. Temperature distributions in wood during fire can be completely different in dependence on heat radiation and cross section of the wood member. The wood materials in floorings do not reach the self-ignition temperature during standard heat radiation.

This article presents the description of oak woodland key habitats and their importance in the maintaining of biodiversity as well as a necessity of management and monitoring. The lichens Lichenes and its percental cover features have been described. The exposition of lichen species depending on the cardinal points has been analysed. The article presents the characteristics of ecological indicators of lichens in the objects. The lichenoindicative evaluation and comparison of oak woodland key habitats in Latvia have been carried out.

The objective of the studies was to evaluate the suitability of sand reed filter for the treatment of wastewater from milk collection post and on the basis of the studies performed to determine the minimal length of filtration path in order to reach the normative wastewater treatment level. In 2003, in Padargupiai village (Ariogala municipality, Raseiniai district) experimental treatment facilities for wastewater from milk collection post were constructed. As the pollution of such wastewater after pre-treatment (primary treatment) is 2 times higher than that of domestic wastewater, the filtration path in constructed wetlands was made 2 times longer (up to 10 m long). On the basis of the study results the dependence equations were made, with the help of which the amounts of the main pollutants contained in wastewater of milk collection posts were calculated, after the wastewater is filtered through the sand layer of different length. As calculations have shown, the treatment of wastewater from milk collection posts until the allowable rates depends on the constructed wetlands with the length of the filtration path of 7 m. The removal of organic pollutants, total nitrogen and total phosphorus from wastewater flowing through such media are 97.2%, 68.7%, and 91% respectively. The studies performed allowed to improve the calculations of the necessary area of constructed wetlands in order to reach the normative treatment level of wastewater from milk collection posts according to the index biochemical oxygen demand (BOD5).

Basing on the economic, ecological and social points of view, the polder systems in the Nemunas lowland are considered as unique, requiring a great deal of annual state subsidies. According to the land-improvement programme, during the period of 2006-2008, Lithuanian polder system are planned to be yearly granted 2.15 million euro from the State budget, whereas the local administration of Silute district, which is exploiting the polders of the Lower Nemunas - more than half of the sum (63%). The article includes the analysis of exploitation expenses and statistical estimation of the Lower Nemunas' polders during the period of 1996-2006 as well as the investigation of the funds distribution on routine repairs, reconstruction and maintenance work. The average annual expenses on the pump stations, dikes, ditches and roads during the research period were determined. The analysis of the previous decade's expenses shows that the statistical average of the expenditure on the polder systems of Silute district amounts to 0.68+-0.13 million euro a year. The yearly renovation of polders depreciation should be obviously awarded a grant of the amount not less than 0.72 million euro.

On the basis of this research and the investigations of other authors (1992 - 2002), the paper presents the comparison of the treatment efficiency of domestic wastewater treatment facilities functioning by different natural means. From all the studied three natural wastewater treatment facilities, constructed wetlands are considered as most efficient for domestic wastewater treatment: here the removal of organic pollutants and biogenic compounds is 85-98% and 67-95% respectively. Biological ponds are most suitable for the treatment of domestic wastewater, the discharge and pollution of which is fluctuating within a wide range. However, such ponds do not always ensure the treatment until the allowable rates. Their treatment efficiency according to biochemical oxygen demand (BOD5) is 49.6%. Total nitrogen amount contained in wastewater outflow from the treatment facilities with biological ponds was on the average 22.2 mg lE-1. The biggest problem of those ponds is rather low P removal efficiency (only 29.5%). Therefore wastewater flowing out of the ponds needs additional treatment. The usage of subsoil filtration fields is limited because their arrangement requires light soils. When arranging the distribution pipeline below the freezing zone, in many places the requirement that the pipes must be 1 m above the maximum ground water level is violated. The pipes should be arranged in places where there is no recipient for treated wastewater outflow. The load of subsoil filtration fields should not exceed 300 m**3 haE-1 per month. From the economical point of view, domestic wastewater treatment facilities with flowing ponds require least expenses.