The possible role of the surface active substances (SAS) in the airborne transmission of SARS-CoV-2

Surface active substances (SAS) have the potential to form films at different interfaces, consequently influencing the interfacial properties of atmospheric particulate matter (PM). They can be derived from both human activities and natural processes and can be found in an indoor and outdoor environment. This paper’s fundamental question is the possible role of the SAS in stabilizing respiratory aerosols in the closed space. In that context, we discuss results of preliminary measurements of the SAS and dissolved organic carbon (DOC) concentrations in the water-soluble fractions of PM2.5 and PM10 that were sampled simultaneously in primary school inside and outside of the building. The concentrations of SAS were determined using highly sensitive electrochemical measurements. It was observed that SAS and DOC concentrations have been enhanced indoor in both PM fractions. Consistent with these results, a discussion arises on the possibility that SAS could play a crucial role in respiratory droplet dispersion as stabilizers, especially in a closed space. At the same time, we assume that they could prolong the lifetime of respiratory aerosols and as well viability of some (possible SARS-CoV-2) virus inside of the droplets

Water Quality in Hydroameliorated Agricultural Areas

Three-year investigations (2007-2009) of water quality in hydroameliorated agricultural areas were carried out at the experimental amelioration field “Jelenščak” Kutina, on hydroameliorated Gleyic Podzoluvisol. Soil was drained in four different drainpipe spacing variants (15 m, 20 m, 25 m and 30 m), set up in four replications. The areas of spacing variants were: 1425 m2, 1900 m2, 2375 m2 and 2850 m2. The same crop was grown in each research year in all variants and the same agricultural management practices were applied. Winter wheat was grown in 2007 and in 2009 and soybean in 2008. Samples of drainage water were taken at drainpipe outlets into the canal. The following parameters were determined in the samples: nitrate concentration and concentration of chlortoluron. Based on the drainage water analysis, it was established that nitrate concentration as well as chlortoluron concentration exceeded the prescribed MAC values (10 mg.dm-3 NO3-N) in each year and in all variants. Nitrogen concentration in drainage water exceeded the MAC in five months (2006/07), in two months (2008) and in seven months (2008/09). Concentration of chlortoluron in drainage water exceeded the MAC (100 ŋg.dm-3) in five months (2006/07) and in seven months (2008/09). Maximum nitrate concentration was up to 28.42 mg.dm-3, and that of chlortoluron up to 365 ŋg.dm-3

Solubility of Benzo[a]pyrene and Organic Matter of Soil in Subcritical Water

A dynamic subcritical water extraction method of benzo[a]pyrene from soils is under consideration. The optimum conditions for benzo[a]pyrene extraction from soil are described including the soil treatment by subcritical water at 250 °C and 100 atm for 30 min. The effectiveness of developed method was determined using the matrix spiking recovery technique. A comparative analysis was made to evaluate the results of benzo[a]pyrene extraction from soils using the subcritical water and organic solvents. The advantages of the subcritical water extraction involve the use of ecologically friendly solvent, a shorter time for the analysis and a higher amount of benzo[a]pyrene extracted from soil (96 %). The influence of subcritical water extraction on soil properties was measured the investigation of the processes occurring within soil under the influence the high temperature and pressure. Under appropriate conditions of the experiment there is the destruction of the soil organic matter while the composition of the soil mineral fraction remains practically unchanged

A short review of environmental and health impacts of the gold mining

Gold mining is attracting increasing attention in many countries of the world. On the other hand, this sector causes numerous environmental and human health issues. The main problems are associated with: (i) Acid Mine Drainage (AMD) with low pH values and high concentrations of heavy metals, (ii) using large quantities of hazardous chemicals such as mercury and cyanide and (iii) mining dust. Degree of the impact depends of the scale mining (small or large scale), type of mine (surface and underground) as well as of the chemical reagents that use in the production process. Modern technology has made it possible to reduce environmental impacts of mining activities. This brief review looks at the gold mining sector (industrial and artisanal) and its key impact on environmental as well as on health of workers and communities (residents who live in proximity to the mine).

Agriculturae Conspectus Scientificus

Summary Th ree-year investigations (2007)(2008)(2009)) of water quality in hydroameliorated agricultural areas were carried out at the experimental amelioration fi eld "Jelenščak" Kutina, on hydroameliorated Gleyic Podzoluvisol

Climate and aridity change

Significant global warming occurred in the twentieth century and especially in the most recent decades. Climate change is a complex phenomenon, accompanied by a wide variety of effects. Rapid alternation, between severe heat wave/drought and abundant rainfall/ flooding, is more and more obvious. The article presents the annual and vegetation season meteorological conditions changes at Kaunas (Lithuania), Horki (Belarus), Sisak (Croatia) and Sarajevo (Bosnia and Herzegovina) between 1996-2016. According to the aridity index, based on temperature and rainfall as weather parameters, this study analyzed the climate dryness risk. This study demonstrates how climate change affects traditional temperature and aridity zones. The movement of temperature and aridity zones could trigger ecosystem migration and land use change. However, the evidence and velocity of ecosystem migration and adaptation in response to the shifting of temperature and aridity zones require more researchVytauto Didžiojo universitetasŽemės ūkio akademij