We evaluated the differences in total polyphenol content (TPC) of beverages prepared by three methods (Hario V60, espresso and pour-over coffee) using single-origin beans roasted at four temperatures. The beans were roasted based on the degree of roasting: the lightest roasting had a final temperature of 204 °C (first roasting), a slightly darker roasting had a final temperature of 205 °C (second roasting), a dark roasting had a final temperature of 215 °C (third roasting) and the darkest roasting had a final temperature of 220 °C (fourth roasting). TPC in the beverage was highest for the Hario V60 for all temperatures, ranging from 32.0 to 46.8 mg GAE g–1 (gallic acid equivalent per 1 g of ground beans). The third roasting had the highest TPC, ranging from 34.6 to 46.8 mg GAE g–1 for all methods of preparation, whereas the content for the fourth roasting ranged from 28.6 to 32.3 mg GAE g–1. Our results indicated that the differences in TPC in the beverage depended on the preparation method (P < 0.001) and the degree of roasting (P < 0.001). The most nutritional coffee was prepared using the Hario V60 with the third roasting.

As the area of the Slovak Republic is 49,036 km², there are many potential contaminants that can affect its population. In the socialist era the town of Strážske located in the Košice Municipal Region was the centre of production of polychlorinated biphenyls (PCB) inter alia and nowadays about 3,500 metric tonnes of PCB are persisting there and present the greatest PCB environmental risk in the central Europe. The heavy metal contamination in Slovakia is caused by the natural background as well as by the former mining activities. In Slovakia there are about 17 thousand old mining works, i.e. adits, stocks, and impoundments. Contamination of the ground and surface waters in the Spiš–Gemer Ore Mountain (SGOM) area is caused by mine drainage. Arsenic, antimony, copper, mercury, cadmium, and zinc are the main pollutants of natural waters. All contaminated areas are currently monitored according to the national and EU legislation and nutrient load reduction programmes. As a result of this the level of inorganic and organic micropollutants in surface water and water reservoirs will be reduced together with the negative impact of water pollution on the environment in Eastern Slovakia region.

This chapter deals with disinfection of water used for human and animal consumption. Water is the most abundant chemical component of the Earth and is very extensively used by mankind. Anthropogenic pressure on the environment leads to decrease in water quality. The quality of water is determined using the most important range of parameters (physical, chemical, and microbiological). This chapter discusses major pollutants of water, protection of water sources, microorganisms causing the main waterborne diseases and methods of treatment, and disinfection of water. Different methods are used to disinfect drinking water. One of the most frequently used methods is disinfection with active chlorine, which is the only method providing continuous protection against microbial regrowth. However, this method has also some disadvantages (e.g., formation of trihalomethane and haloacetic acid precursors) linked to increased risk of cancer. It is important to remember that none of the products used to disinfect water is capable of ensuring complete safety of treated water if the water comes from unsuitable sources.

ABSTRACT:The aim of this study was to examine drinking water on three farms in eastern Slovakia and to determine experimentally the optimum dose for adequate disinfection in terms of devitalisation of potential pathogens while observing the limit for residual active chlorine (0.3 mg/l) in drinking water. Our investigations included bacteriological examination focused on general contamination and indicator bacteria (bacteria cultivated at 22 and 37 °C, total coliforms, E. coli, enterococci), physico-chemical examination (pH, ammonium ions, nitrites, nitrates, chlorides, free chlorine, chemical oxygen demand COD Mn and Ca + Mg), and EEM (excitation emission matrix) fluorescence spectroscopy which focused on the presence of natural organic matter (NOM). After determining the optimum single dose of Chloramine T for disinfection of water used for watering of animals, the bacteriological quality of water was checked on the 5 th day after the disinfection. The results showed that water quality was better on Farm No. 3 than on Farms No. 1 and No. 2. The weather (precipitation) evidently affected the quality of water on all three farms and was associated with some risk to animals consuming this water. The experimentally determined doses of Chloramine T appeared relatively efficient on Farm No. 1 and Farm No. 3, while the Chloramine T dose estimated for adequate disinfection on Farm No. 2 had to be increased considerably but was still much lower than the dose recommended by the manufacturer of this preparation. It appeared effective to adjust the intervals between individual chlorine treatments according to weather conditions (heavy rain) instead of increasing the active chlorine dose.

The quality of water in a well that serves as an individual drinking water source, located in the Slovakian region previously burdened with mining activities, was investigated in relation to the quality of surface water in the same region. Selected microbiological and physicochemical parameters were determined in samples of ground water (well) and surface water (brook and river). Plate counts of coliform bacteria, E. coli, enterococci and bacteria cultivated at 22 °C and 37 °C were determined. Microbiological quality of samples collected from the well was generally satisfactory. Examination of the samples of surface water (river) showed a significant organic pollution indicated by fluorescence spectra. In all water samples the values of: pH, electrical conductivity, dissolved oxygen, ammonium ions, nitrites, nitrates, chlorides and chemical oxygen demand (CODMn) were below the limits set by the state legislation. In the surface water, high levels of arsenic were found. The sum of calcium and magnesium in the well water was close to or below the recommended minimum level. In this well water, the level of antimony exceeded 10-fold the maximum limit for drinking water and was of the largest concern as this well water has been used for drinking, cooking, and watering of animals and vegetables for a long period of time. This poses a risk of accumulation of this metalloid in the food chain.