Biological Sciences Database

Anthropogenic activities are a major source of groundwater contamination in semi-island regions, and evaluation methods developed for inland sites may not be appropriate for coastal sites. We investigated the feasibility of diversity a nitrate-affected groundwater source-fate system in a semi-island environment using comparative methods. The study site was a groundwater well-field in Neringa, Lithuania, where nitrogen compounds obtained in groundwater had increased from the origin thereafter treatment plants. We used ammonium ions and ammonium nitrogen / organic compounds ratios and direct evaluation of total nitrogen concentration to show that biological processes occurred in both source area and water treatment, and could increase nitrogen concentrations over time. The nitrogen compounds and organic carbon compounds rate was changing water quality from the place of origin aquifer, offering a possible means of preventing diversity of the nitrogen compounds by controlling reacting rate over the site. We conclude that biological processes are the real reason of nitrogen compounds diversity at this type of site.

A wide range of material sources may potentially contribute to contaminant loads in the potable water. The ability of water supply systems to act as emission control barriers for tap water micropollutants, thereby providing environmental benefits in addition to potable water savings, have not been fully explored. This paper investigates the sources, presence and potential fate of a selection of manganese micropollutants in laboratory scaled water supply systems. All of the investigated compounds are listed under the European Council Directive 98/83/EC on the quality of water intended for human consumption (1998) and World Health Organization Guidelines for Drinking-water Quality (2004). Significant water quality changes are identified. Hydro-chemical modelling indicates that the removal of manganese substances during water treatment is likely to be predominant due to the EC Directive manganese concentration requirement, with only minor contributions to the water supply network. Manganese compounds are resistant to biodegradation and the majority of conventional groundwater treatment plants periodically supply water with manganese residual to the potable water distribution system. Water treatment is unlikely to act as a comprehensive barrier for emission of manganese compounds. Hence, it is important to ensure that other manganese source control options (e. g. pipeline materials, manganese substance emission, and groundwater source control) for potable water supply continue to be pursued in order that emissions of manganese compounds from these sources are effectively reduced and / or phased out as required under the demands of the European Council Directive 98/83/EC on the quality of water intended for human consumption.

In order to reduce a negative impact of heavy traffic on the river (i.e. emission of artificial and natural particulate matter and nutrients) various scientific investigations are carried out to decide if the use of street roads is allowed or prohibited. This is particularly relevant for the towns, belonging to the transport corridors of the Lithuania‘s road networks where in some towns the circuit roads haven’t yet been developed, i.e. Marijampolė (a transit town on the road of Via Baltica). Two transport corridors of European significance, the Via Baltica highway connecting Northern Europe with Central and Western Europe and the branch of IXB transport corridor IXD Kaliningrad – Marijampolė – Kaunas, cross in Marijampolė County. Based on the scientific investigations that the use of street roads for heavy traffic causes emission of pollutants, especially those of small suspended particles and silt into the ambient water several tens of times higher than that by using the circuit roads, and generates the increase in the pollutant emission up to several tens of times, it could be stated that the use of circuit roads should be obligatory. Thus, in rainy Lithuanian autumn when the precipitation often varies around 10 mm/h, the use of street roads, when travelling of flooded and more rarely cleaned the streets of Lithuanian towns, should be only recommended if the circuit town roads are effectively developed by the new generation of road networks, i. e. less dangerous for the environment, situated from a more suitable safe distance and containing a proper runoff treatment. The dependencies used for calculating pollution loads need to be determined more accurately by test, analyzing the stormwater on the surface of roadway pavement, with further statistical estimation of the data. The experimental research performed is closely related to the study of the issues of planning and traffic pollution of various roads.

Nitrogen (N), due its low temperature volatilization, is one of the elements most vulnerable to fire. This effect depends on fire severity, which varies depending on biophysical conditions which can be heterogeneous across the landscape. Hence, fire effects on N can be variable. The aim of this study was to establish the ash total nitrogen (TN) spatial variability in a microplot designed in a burned area, and to test several methods in order to identify the most accurate one for interpolating the variable. In total, we selected four deterministic interpolation methods – inverse distance to a weight (IDW), with the weight of 1, 2, 3, 4 and 5, local polynomial (LP), with the power of 1 and 2, global polynomial (GP), radial basis functions (RBF) – spline with tension (SPT), completely regularized spline (CRS), multiquadratic (MTQ), inverse multiquadratic (IMTQ) and thin plate spline (TPS) – and two geostatistical methods: ordinary kriging (OK) and simple kriging (SK). In total, we tested 15 techniques. Ash TN was negatively related to fire severity showed a good spatial structure across the plot. The linear model was the best, which means that the variability of ash TN content increased in all the area of interest. The highest concentration of TN was observed in the northeast part of the plot and the lowest in the Southwest. From all test methods, MTQ was most accurate, and IDW5 was the worst predictor. In general, RBF and the geostatistical methods were most precise and IDW was less accurate, which means that ash TN distribution has some specific features and does not exhibit a small-scale variation. The distribution of the variable depends on species distribution, temperature and probably on vegetation moisture during fire evolution.

Nitrogen and phosphorus removal from wastewater is a way to avoid eutrophication of water bodies. The most oft en used method for phosphorus removal from wastewater is biological treatment. Under anaerobic conditions, phosphorus-accumulating organisms can accumulate more phosphate than is required for their metabolism processes and cell synthesis. The composition of wastewater may have an important influence on phosphorus biological removal from wastewater. In this study, the composition of wastewater in respect of the readily biodegradable chemical oxygen demand (rbCOD) was investigated. The rbCOD characterises the amount of volatile fatty acids (VFAs) and a readily biodegradable substrate in wastewater, which could be rapidly fermented into VFAs and other fermentation products.

The quality of water in rivers depends on numerous hydrological and anthropogenic factors. The Mūša catchment, belonging to the Lielupė river basin district (RBD) in the northern part of Lithuania, was taken for water quality investigation. In this catchment, 63% of the territory is under arable land. The conceptual FYRIS model was chosen to identify the impact of the sources of pollution with total nitrogen (N) in the Mūša river. The modelling encompasses the 1997–2006 period. After calibration, the model efficiency coefficient was E = 0.46, i. e. fairly good, and the correlation coefficient was r = 0.69. While modelling the variation of nitrogen concentrations during the study period (1997–2006), the results did not correspond to the monitored concentrations equally well in all subcatchments. One of the main reasons for the disagreement between the model and monitoring data can be a vast dispersal of the monitoring data. The model represents the monitoring results in the Mūša, Daugyvenė and Tatula rivers quite well. There is a strong linear correlation between the model and the monitoring results. The determination coefficient of the regression equation R2 varies from 0.48 to 0.56. Analysis of the total nitrogen load to the Mūša catchment from different pollution sources has shown that about 87% of it comes from arable land, 10% enters from waste water treatment plants (WWTP), households and urban territories, and only 3% of all nitrogen within the catchment comes from wooded territories and pastures.

To evaluate the suitability of biodegraded organic waste for soil fertilisation, an experiment aimed at determining the amounts of total nitrogen, total phosphorus and heavy metals contained in this waste and determining its pH was carried out. Organic waste used for research consisted of mixes of meat waste (MW) with green waste (GW) and meat waste (MW) with sewage sludge (SS) in proportion 3 : 1, 1 : 1 and 1 : 3. MW and SS (1 : 3) mixture was found to be the most suitable organic fertiliser to remediate exhausted soils and usedup areas. This mix was determined to contain the biggest contents of nitrogen and phosphorus, 4.89 mg/kg and 227.0 mg/kg respectively. Heavy metal concentrations were also found the highest among the researched cases, however they did not exceed the maximum permissible concentration (MPC) in soil when fertilized with sludge. The concentration of chromium amounts to 1.05 mg/kg, that of zinc – 15.73 mg/kg, lead – 7.74 mg/kg, copper – 29.88 mg/kg and nickel – 11.05 mg/kg. MW and SS (1 : 3) mixture is mostly suitable for the fertilisation of acid soils, because its pH value was 6.8.

According to the data provided by the Plungė Municipality, all old waste accumulation sites have been closed and are undergoing re-cultivation. The only operating landfill is the new landfill of Jerubaičiai. The new landfill of Plungė town was opened in Jerubaičiai village in 2001. Currently, the first 2 sections are being filled. The site is used for the disposal of household waste only, whereas other types of waste are sorted out in a specially designated site near the industrial zone. Operation of the landfill results in the formation of landfill leachate, which is directed to treatment plants. An experiment was carried out in order to determine the trends of the permeability of the leachate formed in the soil. Concentration of heavy metals was determined in the Jerubaičiai landfill leachate, samples of soil were taken from the landfill area, and nickel concentration was investigated.

The article draws on the possibilities of using short-rotation coppices for removing heavy metals (Zn, Cu, Pb, Mn, Ni and Cr) from fermented waste fi ltrate or from soil by phytoremediation. The aim of the study was to assess heavy metal accumulation in diff erent stem parts of willow (Salix dasyclados) in the context of their soilless growing in sludge and grain fi ltrate and to estimate the infl uence of the pH of the filtrate and nutrients on their HM accumulation ability and biomass increase. HM concentration in willow biomass was evaluated from the phytotoxic concentrations of these elements in plants as a result of long-term observation. Th e study has shown that insignifi cant differences in the capacity to accumulate heavy metals, recorded in the top, middle and bottom parts of the cuttings, depend on whether it is a ligneous part or leafage. It was determined experimentally that by their absorption capacity HMs can be ranged as follows: Pb > Cu > Cr > Zn > Ni. Th e data show a linear decrease in the accumulation of heavy metals with increasing fi ltrate concentration in the solution for 87% of plants, i.e. high concentrations of chemical pollutants cause an inhibitory effect, which was experimentally confirmed by growing cuttings in filtrates.

Studies of metal impact on carbon cycle became more intense when the role of soil in climate change had emerged. This study aims at comparing changes in concentrations of soil carbon and Pb, Mn and Cd in soil amended with sewage sludge. The results indicate that mobile Pb, Mn and Cd concentrations have a higher correlation with soil carbon (r > 0.766; r > 0.768; r > 0.653 respectively, p > 0.01) than with the total soil metal contents (no significant correlation), which might be explained by the fact that mobile metals have more direct inhibitory effect on microorganism activity than total content. Significant correlation between mobile Mn, Pb, Cd and soil carbon shows their role in soil carbon cycle. Sewage sludge application on soil with an increased mobile metal fraction may lead to slower degradation of soil carbon and reduction of CO2 evolution.