Žveplo v tleh v okolici termoelektrarne Plomin (Hrvaška)

Malenšek, Neža (author), Zupančič, Nina (mentor), Lojen, Sonja (comentor)

Termoelektrarna Plomin (TEP), Hrvaška, se nahaja na sredini vzhodne obale Istre in predstavlja glavnega onesnaževalca zraka v Istri. V letih med 1970 in 2000 je uporabljala predvsem lokalni premog (Raša), ki vsebuje med 10 in 14 ut. % žvepla in ga tako uvrščamo med premoge z visoko vsebnostjo organskega žvepla. V magistrski nalogi smo ugotavljali stopnjo onesnaženja tal z žveplom v okolici TEP. Analizirali smo 11 vzorcev tal, 3 vzorce pepela in 6 vzorcev premoga. Vzorci tal so bili odvzeti na različnih oddaljenostih od TEP v smeri vetra JZ, odvzet je bil tudi kontrolni vzorec na oddaljenosti 10 km od TEP. V premogu smo določili celokupno žveplo, v pepelu sulfat in v tleh sulfat in organsko vezano žveplo (fulvinske in huminske kisline). Vsebnost žvepla v vzorcih in izotopsko sestavo smo določili z masno spektrometrijo stabilnih izotopov. Vsebnost žvepla v smeri JZ od TEP je 100 krat večja (4 ut. %) kot v kontrolnem vzorcu (0,04 ut. %) ter pada z oddaljenostjo od TEP. V tleh prevladuje organsko vezano žveplo (>95 %), ki je večinoma vezano v huminske kisline. Vrednosti δ34SVCDT v premogu so med −5,0 in −10,0 ‰. V večini vzorcev tal je vrednost δ34S pozitivna (+7,0 do +20 ‰). Vrednosti δ34S sulfata v tleh so med +1,0 in +5,5 ‰, vrednosti δ34S za organsko žveplo pa so med -3,5 in +6,0 ‰. Takšna izotopska sestava žvepla nakazuje, da je glavni vir žvepla atmosfersko usedanje žvepla po sežigu premoga v TEP, del žvepla je naravnega (morskega) izvora. Razmerje C:N:S je 180:9:1. Glede na vrednosti faktorja obogatitve in rezultate geoakumulacijskega indeksa so tla v okolici TEP močno onesnažena z žveplom.

• Language: Slovenian
• Keywords: žveplo, izotopi, premog, tla, termoelektrarna, Raša, onesnaženje
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2017
• PID: 20.500.12556/RUL-94422
• COBISS.SI-ID: 1351774
• Publication date in RUL: 23.08.2017

Secondary language

• Language: English
• Title: Sulphur in soils around the thermoelectric power plant Plomin (Croatia)

Abstract

The Thermoelectirc power plant Plomin (TPPP), Croatia is located in the middle of the eastern coast of Istrian peninsula (Northern Adriatic), and is considered to be the prime polluter of air in Istria. Between 1970 and 2000, mainly the coal from the local coal mine (Raša) was used. Coal contains between 10 and 14 wt. % of sulphur, and is considered as high organic sulphur coal. In the master thesis we established the level of soil contamination with sulphur in the vicinity of TPPP. 11 soil samples were taken and were analysed together with 3 samples of ash and 6 samples of high-S coal. Soil samples were taken at different distances from the power plant in the prevailing wind direction (SW), the control sample was also taken at a distance more than 10 km away. The coal samples were analysed for total S, ash samples for sulphate and soil samples for sulphate and the organic (humic and fulvic) sulphur. Sulphur concentration in bulk samples, as well as isotopic composition of sulphur was determined by EA-IRMS (IsoPrime 100 with PyroCube). The concentration of sulphur in samples taken in wind direction was more than 100-times higher (4 wt. %) than at the control side (0.04 wt. %) and decreased rapidly with distance from the TPPP. The speciation analysis showed that majority of S (>95 %) is present in organic form, mostly bound to humic acids. The δ34SVCDT values of bulk coal are between −5.0 to −10.0 ‰. In most soil samples, bulk δ34S were positive (+7,0 do +20 ‰). The values of sulphate in soil range between 1.0 and 5.5 ‰, while in organic S are between -3,5 in +6,0 ‰. That indicates that the atmospheric deposition of 34S-depleted fly ash and sulphate deriving from coal are the main S sources. Some part of sulphur in soil is marine origin too. The ratio C:N:S was calculated and it is 180:9:1. Enrichment factor and geoaccumulation index results indicate that the soil nearby TPPP are strongly contaminated with sulphur.

• Keywords: sulphur, isotopes, coal, soil, power plant, Raša, contamination