Naslov
Analytical Investigation of Metal and Non-metal Elements Presence in Artificial Snow Samples

Autori
Rončević, Sanda ; Pitarević, Lovorka

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Proceedings of the IV Conference on Inorganic Elemental Analysis / - Pardubice, 2005, 139-141

Skup
IV Conference on Inorganic Elemental Analysis

Mjesto i datum
Pardubice, Češka Republika, 18.09.2005. - 23.09.2005

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
artificial snow; chemical modification of snow cover; chloride determination; metal determination; nitrogen; water analysis

Sažetak
Abstract Determination of several metal and non- metal elements in artificial snow samples from ski race tracks were performed. Atomic spectrometry methods were applied in analysis of metal content, UV/VIS spectrophotometry in analysis of nitrogen species, and classic volumetric methods in chloride content analysis. Chemical modifications of snow piste conditions were established from greater concentrations of alkaline and alkaline earth metals measured. The results obtained for essential and toxic metals and non-metals content show different elemental composition of artificial snow compared to natural snow and water. Possible impact of added salts on natural water reservoir is discussed. Key words: artificial snow, chemical modification of snow cover, chloride determination, metal determination, nitrogen, water analysis Snow cover amount depend upon meteorological conditions and the location in the landscape. Because of the demand for skiing even in periods and areas with little snow, the production of artificial snow has become widespread in ski areas. Artificial snow production requires the transport of surface water from the walleyes to higher regions and additional technology for the actual snow production. To make snow, water cooled to just above its freezing point is pumped under high pressure through the nozzles of a "snow gun." Compressed air or electric fans are usually used to help atomise the water into fine droplets and to disperse them over a wide area where they will freeze before they hit the ground. Various impact on the environment induced by artificial snow production are addressed, in particular negative effects created by installation of devices for producing artificial snow, the use of resources for producing artificial snow, the effects on the water balance of a slope and slope stability. Those impacts include also direct consequences for vegetation, the impact on the soil properties, the disturbance of biotopes, and the impact on landscape aesthetics1. Compared with undisturbed natural snow, artificial snow can have negative impact on vegetation due to its dense structure, and therefore its longer duration on the surface. A longer duration of the snow cover is associated with later start of the regeneration of vegetation and shorter vegetation period. The use of artificial snow also affects the available nutrients, the pH value and average moisture of the soil. The first is because surface water has a different chemical composition to natural rain the second, less soil forms by biological activity of soil organism, and third, because of the increased amount of snow-melt water. There are also some positive aspects of artificial snow production. For example, the maintenance of a continuous snow cover reduces the mechanical impact on vegetation and soil caused by the wheels of piste caterpillars. It also leads to approximately stable temperature at the soil surface, and it is not necessary to collect the snow from different areas to provide a continuous snow cover. The increase in soil moisture can have a positive effect on the biomass production in naturally dry areas. However, it is difficult to draw general conclusions about artificial snow influences because of its dependence on site characteristics. To prevent snow freezing at the surface of ski race tracks covered with artificial snow, some chemical substances are usually spread along. There are two categories of chemical substances for chemical maintaining of piste conditions, i.e. endothermic and exothermic. The first is represented by sodium chloride, potassium chloride and urea, and the second is represented by magnesium chloride and calcium chloride. All of those substances are corrosive and could easily be absorbed by soil. The effects of urea on alpine vegetation were already studied, and it was noted that the extreme growth of some plant species was due to high concentrations of added ammonia salts. Recently, the use of urea or some urea-based fertilizers in alpine ski race tracks preparation is restricted due to negative environmental impacts. The World Cup women's slalom race named ''Golden Bear'' was for the first time held in Croatia in January 2005. Ski race tracks were prepared in Nature Park Medvednica, which is huge forest and recreational area located near the Croatian capital. The highest peak Sljeme has an elevation of 1035m, and its snow cover in winter season is highly depended of meteorological condition. For the alpine race event, ski piste was covered with artificial snow by pumping the water from downhill reservoirs. The samples from ski race track were collected in February after the sport event was held, and in April at the beginning of snowmelt season. The collected samples were analysed in laboratory after melting into water. Standard spectrophotometric methods were used for determination of nitrate, ammonia and phosphate content. Chloride content was determined by standard Mohr method. Atomic emission and atomic absorption techniques were used for metal content determination. Sample preparation procedures, in most cases, were based on preconcentrations from large volume of melted snow. For metal content determination by inductively coupled plasma spectrometry or atomic absorption spectrometry, the samples were dried and the acid digestion of residue was performed afterward. Results from samples collected in February shows slightly variations in metal and chloride contents depending on sampling site. Samples collected in April have less chloride content. The alkaline and alkaline earth metal content shows variations depending on sampling site, and on sampling period. Lower Na and K contents were found in snowmelt period, but rise for Ca and Mg was noted. Determination of elements by atomic spectrometry methods gave results for some essential and toxic metals such as Fe, Mn, Ni, Cr, Co, Cu, Zn, Cd, Ba, and Pb. It was found that the measured values are lower then values of metal content from natural water reservoir, but higher then values from natural snow samples. Additional cover of natural snow that was fallen down before sampling might explain the first fact. The greater concentrations were measured for several metals in samples from April than in those from February, which might imply precipitation from upper layer during melting occurred. The measured content of nitrogen species was extremely low and the basic question of urea use in snow track preparation could be withdrawn based on analyses performed. There was no evidence of ammonia salts presence even highly sensitive analytical methods were applied. Water samples from downhill water catchments were collected after snow melting and the same analytical procedures were carried out to found possible rise in chloride concentrations. The measured chloride content was in low concentration range, and it did not show pollution effects due to the chemical maintaining of snow piste. Generally, low concentrations of metals and non-metals in artificial snow samples which are mixed and diluted with natural snow, were found. To establish the impacts of some highly corrosive species on water ecosystem, analytical data obtained from first attempt of monitoring were not sufficient. Beside repetitive sampling and analysis of artificial and nature snow cover, in further study planning must be include the soil analysis of samples from ski piste. It is already known that the negative effects on environmental system by artificial snow production and chemical maintenance of snow tracks with salt addition are usually generated by repeated use. Therefore, continuous monitoring of environmental samples that are modified by human action can be important mean of identifying and controlling possible corrosion and pollution in sensitive ecosystem such as Nature Park Medvednica. 1. S. Wipf et al, Journal of Applied Ecology, 42 (2005) 306-316.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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