Soils and sediments of Prošće Lake catchment as a possible terrigenous input in the lakes system

UDC 631.41:502.51(497.5Proščansko jezero) Anita Ptiček Siročić, Stanislav Kurajica, Dragana Dogančić & Nikolina Fišter: Soils and sediments of Prošće Lake catchment as a possible terrigenous input in the lakes system The Plitvice Lakes National Park is in the northwestern part of the Dinaric Karst in central Croatia. An important role of the soil in the karst is to purify the waters before they reach the phreatic zone. The soil is also a zone of accumulation, transformation, retardation and dilution of a potential pollutant. Knowing soil mineralogical composition is an important factor in understanding fate and transport of contaminants throughout lakes system. Samples of soil, peat and stream sediment were collected in the Prošće lake catchment and partly in the assumed zone of influence, X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR) analysis of samples was performed to determine dominant mineral species in samples. XRD analysis showed predominance of lowquartz, which was found in all samples, most often as dominant phase. Dolomite was found in half of the samples, almost always as a significant phase while calcite was dominant phase in one of the samples. In most of the samples, members of the feldspars and chlorites groups, as well as muscovite, were present as minor phases. The absorption bands in the range of 2800-3000 cm-1 due to the organic matter are visible in spectra of all samples. These minerals can enter lakes system by surface waters, primarily streams and overland flow during snow thawing and rain, and also in cases of shore erosion. Terrigenic input in lakes is small but cannot be neglected due to the longlasting preservation efforts of the Prošće Lake recharge area, and the Plitvice Lakes National Park in general, terrigenous intake still does not pose a threat to water quality and tufa production. Izvleček UDKs 631.41:502.51(497.5Proščansko jezero) Anita Ptiček Siročić, Stanislav Kurajica, Dragana Dogančić & Nikolina Fišter: Tla in sedimenti zaledja Proščanskega jezera kot možen terigen doprinos v jezerski sistem Narodni park Plitviška jezera se nahaja v severozahodnem delu Dinarskega krasa v osrednji Hrvaški. Pomembna vloga tal v krasu je, da čistijo vodo, preden doseže freatično cono. Tla so tudi območje, kjer se potencialna onesnaževala kopičijo, preoblikujejo in redčijo. Tla ta onesnaževala tudi zadržijo. Poznavanje mineraloške sestave tal je pomemben dejavnik pri razumevanju prenosa onesnaževal v jezerskem sistemu. Tla, šoto in sedimente smo vzorčili v neposrednem zaledju in na vplivnem območju Prošćankega jezera. Mineralne vrste smo določili z rentgensko difrakcijo (XRD) in infrardečo spektroskopijo s Fourierjevo transformacijo (FTIR). Analiza XRD je pokazala, da v vzorcih prevladuje kremen, ki je bil v vseh vzorcih ugotovljen kot prevladujoč mineral. Dolomit je bil najden v polovici vzorcev, skoraj vedno kot pomemben mineral, medtem ko je kalcit prevladoval samo v enem od vzorcev. V večini vzorcev so bili v manjšini še glinenci, kloritni minerali in muskovit. Absorpcijski pasovi na območju 2800-3000 cm-1 so bili zaradi organske snovi vidni v vseh spektrih. Minerale lahko v jezerski sistem prinesejo površinske vode, predvsem med taljenjem snega in ob padavinah ali obalni herozijskih procesi. Terigeni vnos je majhen, vendar ga zaradi dolgotrajnih prizadevanj za ohranitev in obnovo območja Prošćanskega jezera ni mogoče prezreti. Verjetno pa še ne ogroža kakovosti vode in nastajanja lehnjaka. Rezultati kažejo, da tla in sedimenti v zaledju Proščanskega jezera učinkovito zadržijo in čistijo vodo na poti do jezera. Vseeno lahko ob morebitnem onesnaženju v zaledju onesnaževala dosežejo jezerski sistem, če so adsorbirana na delce tal. Pozna1 Faculty of Geotechnical Engineering, University of Zagreb, Hallerova aleja 7, 42000 Varaždin, e-mail: aanitaps@gfv.unizg.hr; ddogan@gfv.unizg.hr; nfister@hotmail.com 2 Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 19, 10000 Zagreb, e-mail: stankok@fkit.hr * Corresponding Author Received/Prejeto: 25.07.2019 DOI: 10.3986/ac.v49i1.7547 ACTA CARSOLOGICA 49/1, 125-140, POSTOJNA 2020 COBISS: 1.01 ANITA PTIČEK SIROČIĆ, STANISLAV KURAJICA, DRAGANA DOGANČIĆ & NIKOLINA FIŠTER