Pollution and treatment efficiency of surface (rain) wastewater, forming in the production territory of meat processing company LTD ‘Krekenavos mėsa’ (centre of Lithuania in Kėdainiai district), were investigated in the period 2004-2009. On the surface of the company territory the precipitation water turns to surface wastewater, which is collected and sent down to treatment equipment. Wastewater samples were taken before and after biological treatment. The samples were investigated in the Chemical Analysis Laboratory of the Water Research institute of Lithuania University of Agriculture certified by the Environment Ministry of the Republic of Lithuania The following indices have been determined: biochemical oxygen demand (BOD7) – by titrometric method, suspended solids (SS) – by gravimetric method, having filtered the substance through a mid-thickness filter. Concentrations of oil pollutants were determined with the help of a spectrophotometric device of infrared rays IKAN-1 in the Analytical Department of Agrochemical Study Center of Lithuanian Agricultural Institute. During six years of investigation average wastewater pollution with suspended materials was 35.0 mg LE-1, which by 14% exceeded the BAC. Suspended solids determined BOD7 concentrations in surface wastewater by 46%. The best treatment effect was received in the purification of oil products - 96%, suspended solids - 60%, organic pollutants - 59%. The wastewater discharged from the company production territory to natural environment was clean as concentrations of the investigated oil hydrocarbons, biochemical oxygen demand and suspended solids in the surface wastewater were 26, 4 and 2 times respectively lower than biggest available concentration.

Advances in milk production and the expansion of dairy herds have increased the need for improved manure management and whole farm nutrient balance. It is well known in dairy management that the balanced feeding and holding technology is an important level by which milk production and milk composition can be modified. The objective of this study was to evaluate urea content and urea yield in different farms with different holding technologies. Four farms represent three cow breeds (Holstein Black and White, Latvian Brown, and cross breed XP). Individual cow milk samples (n=2740) were collected monthly from September 2009 to November 2010. Milk samples were analyzed for total protein, casein, fat, lactose, and urea content with instrumental infrared spectroscopy method. The average milk yield per cows in farms was significantly different (from 27.9 to 17.0 kg per control day). The urea content in cow milk was between 20.3 to 46.6 mg dLE-1. The average urea content in farms A, B and D was up to standard (from 15.0 to 30.0 mg dLE-1). In the farm C, average urea content ranged between 17.4 and 79.9 mg dLE-1, which indicated problems in feeding or management in the farm. It was established that milk urea content and yield significantly (p is less than 0.05) varied in farms with different dairy cow holding and feeding technologies. Urea content can be used to evaluate feed protein utilization in farms and predict environmental pollution.

Food and drinking water are the main sources of trace and major elements. Besides the elements that are vitally essential for living organisms and human health, food may contain the traces of potentially toxic elements. Environmental site specific impact is one of the influencing factors of elemental content in plants that is important issue also for quality of food crops. Quantitative content of several trace elements (e.g., Al, As, Cd, Co, Cr, Cu, Ni, Pb, Zn) detected in food crops reveal environmental background levels as well as it can be associated with unexpected food contamination. Current study involves quantitative analysis of more than 200 root vegetable samples (onions, carrots and potatoes) grown and collected in Latvia in the harvesting season of 2010. Within this study the quantitative analysis of vegetables for 9 elements (As, Cd, Co, Cr, Cu, Ni, Pb, Se, Zn) was performed. After the wet digestion of samples, the quantitative analysis was done by using inductively coupled plasma mass spectrometry (ICP-MS). Obtained results revealed wide ranges of trace elements in root vegetables, including potentially toxic elements. Comparison of element content in edible parts of vegetables and potato peel showed that a great part of elements (e.g., As, Co, Cr, Pb) is concentrated in peel; however, some elements (e.g., Cd, Se, Zn) are taken up by plants, and therefore may contaminate food more easily. Element transfer routes and their biochemistry is a complicated issue that is affected by natural environmental factors as well as by anthropogenic activities.

Contamination of urban areas is directly connected with the lack of adequate waste management planning. Problems mostly arise in former military bases, garages, warehouses and areas with other facilities. For many decades environmental problems caused by pollution in areas of military use were not managed in Latvia. The aim of this research is to assess visual environmental quality and study heavy metal contents in soil of ‘Jaunais Mežaparks’ after demolishing works in the capital of Latvia – Riga, as well as to provide comparison to the former military ‘Daugavgrīva’ site. Research was carried out from November 2011 to February 2012 by soil sampling and further analysis and comparison of the heavy metal content in soil with target and boundary levels in legislation. ‘Jaunais Mežaparks’ is a former military area which is planned to be reused in future. The former military site is planned to be used as the residential neighborhood and is situated close to important recreational object in Mežaparks area – Lake Ķīšezers. According to Riga Development Plan old military sites must be remediated in accordance with environmental legislation if the contamination exceeds critical concentration values. Thus, this case study includes assessment of visual pollution as well as soil heavy metal contamination study. Recommended actions as well as direct remediation technologies to reduce the poisonous impact of contamination to environment in this area are proposed.

The growing economy with following industrialization and urbanization has led to environmental contamination with trace elements worldwide. In urban environment, the large inputs of anthropogenic contaminants in atmosphere are arising from mobile and stationary sources. The snow sample analysis is one of methods to monitor air contamination with heavy metals in urban areas. The aim of this research is to analyse heavy metal contamination and distribution in urban environment of Jelgava city. The samples were collected twice in January and February. Snow samples were collected in 20 urban area sampling plots and one natural area sampling plot with three repetitions taken from 1.0 to 1.5 kg of snow. The concentration of trace elements was estimated in 126 melted and filtrated snow water using inductively coupled plasma spectrometer (ICP-OES). The average heavy metals and nutrients concentrations were calculated for each sample. The concentrations data of trace elements were analysed using agglomerative hierarchical clustering method. The results show differences between results in January and February. The differences are related to anthropogenic impact intensity differences during the exposition periods of snow. The clustering results of snow samples taken in January show three clusters, but snow samples taken in February show four clusters.

The research paper focuses on description of the pig (Sus scrofa domestica) farming tendencies in Latvia with the scope to give feeding characteristics in relation to emission outcome. In the recent years the concentration of pigs in farms with a herd size more than 10,000 has increased. With increase of the large farms the average feed consumption is more affected by one operator. Efficient utilization of nutrients content in feeding is crucial to meet environmental goals. It is one of the steps to achieve Nutrient Use Efficiency. There is relationship between crude protein and reduction of reactive nitrogen. Feed content not only affects excreted nitrogen, but also pH of manure and total ammonia Cal nitrogen. It is complex abatement measure to quantify reduction of the emission because of impact of various environmental factors. In Latvia, the most common are sows cross breeds (Yorkshire × Landrace) and on January 1, 2019 the biggest group accounted was fattening pigs with average dry feed consumption per day from 0.33 kg (live weight from 5 to 6 kg) up to 3.6 kg (live weight from 80 to 120 kg) with crude protein value from 163.5 g to 155.3 g per 1 kg feed dry matter. Excreted nitrogen (Nex) was calculated for these groups of pigs less than suggested values in guidelines for emission calculation. The highest calculated total NH3 emission is from fattening pigs group with live weight from 55 to 90 kg although the highest calculated Nex is for lactating sows. NOx also calculates as NO2 and the highest value was 3.23 g per one lactating sow.

Soil and groundwater as the leachate may contaminate surrounding watersheds, thus different pollutants from closed dumps and landfills pose significant risks to human health and ecology. Pollution may lead to soil and water degradation however it might be diminished through sustainable dump site closure projects and processual management. Several decades of clays and clay minerals studies lead to modified clay composites concept that is one of the potential promising solutions for building the landfill covering material and serve as capping biocover layer at the same time. As humic substances are constituents of soil organic matter, pollutants can be sorbed on the surfaces of complex molecules. These kind of humic acid-clay mineral composite materials thus might become as low cost building material component − covering material. Construction of such layer is to be performed as a combination of clay-humic composites and landfill mined fine fraction of waste with small amendment of natural soil. Several hypotheses that are already proven has to be mentioned: a) Clay minerals produce composites with humic substances; 2) Clay-humic complexes reduce through sorption both organic and inorganic pollutants; 3) Low risk of toxic by-products from landfill mined waste fine fraction can be the problem; 4) Such composites mostly would trap toxic contaminants (e.g., pharmaceuticals) found in reworked fine fraction of waste. The aim of the work is to provide alternative solution for landfill closure by giving theoretical considerations from multidisciplinary knowledge of environmental engineering, chemistry and waste management.

The paper presents the results of investigations on wastewater formation and its treatment in constructed wetlands (CW) with horizontal flow. The investigations were carried out on a dairy farm in the period of 1995-2004. On farmsteads containing cattle sheds, the pollution of wastewater is 2-3 times higher compared with domestic wastewater. The largest amount of slowly decomposing organic pollutants is retained during wastewater filtration via a septic tank (62.7% according to CODCr). During wastewater filtration through a horizontal CW, the amount of retained organic pollutants biochemical oxygen demand (BOD5) and chemical oxygen demand (CODCr) is 93.6%. During wastewater filtration through CW, nutrients (Ntotal and Ptotal) treatment efficiency on the dairy farms, where Ntotal concentration is 101.0 mg lE-1, is one the average 61.4% of nutrient load, and 41.4% of P where Ptotal concentration is 21.5 mg lE-1. The analyzed wastewater treatment facilities (septic tank + CW) are distinct for their buffering capabilities. They are affective enough, however due to limited P removal processes in sustainable natural environment, additional P-removal means are to be used in wastewater treatment facilities arranged on dairy farms.

The processing of milk in dairy companies produces a certain amount of wastewater and liquid wastes. During the treatment process of such wastes sludge is accumulated in treatment facilities. The sludge is a rather valuable soil fertilizer; however, apart from plant available nutrients, it also contains large amounts of pollutants. The paper analyzes the quality of wastewater treatment process performed in treatment facilities of dairy companies, and specifies the amounts of plant available nutrients contained in sludge accumulated during the treatment process of wastewater and liquid wastes. The amounts of heavy metals contained in sludge are compared with their maximum allowable concentrations determined in the environmental requirements for soil fertilization (Aplinkosaugos reikalavimai..., 2001). On the basis of the study results and normative documents of environment protection, the article presents optimal rates and regime for sludge fertilization as well as analyzes the agro-technical and qualitative characteristics of sludge spreaders made at the Water management Institute of Lithuanian University of Agriculture and used during the technological process of fertilization.

The paper presents the investigations performed by Water Management Institute of Lithuania University of Agriculture on the pollution and treatment efficiency of wastewater formed in an up-to-date slaughterhouse built in 2003. Wastewater is canalized from the slaughterhouse by red and green sewerage systems. Initially the wastewater is pre-treated in a fat separator, further treatment process is performed in physical-chemical treatment facilities and settling ponds. After primary treatment, the wastewater is directed into two-stage constructed wetlands of horizontal flow. The wastewater in slaughterhouse is about 4-5 times more polluted than domestic wastewater containing even 20 times higher for concentration. During the primary treatment process (fat separator + physical-chemical treatment device + settling pond), from 73.1 to 98.9% of pollutants are removed. After primary treatment, indices of wastewater are similar to those of domestic wastewater: pH - 8.5, biochemical oxygen demand (BOD5) - 98 mg lE-1 of O2, Ntotal and Ptotal - 46 and 8.9 mg lE-1 respectively. After biological treatment in two-stage constructed wetlands of horizontal flow, the wastewater satisfies the environmental protection requirements according to organic (BOD5) and biogenic (Ntotal and Ptotal) pollutants and thus may be realised into the environment. Regression dependencies of medium and strong relation (R**2=0.503-0.893) of pollutants BOd5, SS (suspended sediments), Ntotal and Ptotal in treated wastewater on the total of constructed wetlands have been determined.