This master thesis was performed in order to investigate arsenic stabilization in step-wise amended soil. Object of the work - soil which taken from the former wood impregnation industrial site in Forsmo, Sweden. It is contaminated with chromate-zinc-arsenate (CZA). Method of the work - three different amendments were used: zerovalent iron (Fe), fly-ash (FA) and peat (P). The test was performed in three weeks. During the first week, four mixtures (with each single additive and with all together) and blank soil was observed. During the second and third weeks test was performed step-wise adding amendments to soil+Fe mixture. Moisture was kept constant all the time. After each week extractions were made and later investigated by doing electrical conductivity, redox potential and pH tests. For elemental composition ICP-OES analysis was performed. The results of the work - the best result to stabilize arsenic were achieved by adding single iron. Stabilisation using iron, fly-ashes and peat elevated As leaching compared to non-amended soil. Step-wise amendment did not have a significant difference from single amelioration neither to arsenic, nor to other heavy metals investigated. / Darbo tikslas - įvertinti pakopinės stabilizacijos poveikį arseno bei kitų sunkiųjų metalų (SM) judrumui užterštame dirvožemyje. Darbo objektas - chromuotu cinko arsenatu užterštas dirvožemis, paimtas iš buvusios medienos apdirbimo aikštelės Forsmo vietovėje, Švedijoje. Darbo metodika - tyrimui buvo naudoti trejopi priedai: geležis (0), lakieji pelenai ir durpės. Tyrimas atliktas per tris savaites. Pirmosios savaitės metu buvo stebimi keturi dirvožemio ir jo priedų mišiniai bei kontrolinis dirvožemio mėginys. Vėliau dirvožemio ir geležies mišinys buvo pakopiniu būdu papildomas lakiaisiais pelenaisi ir durpėmis. Iš visų mišinių padarytos ištraukos ir jose matuojamas elektrinis laidumas, oksidacijos-redukcijos potencialas, pH; atlikta elementinė analizė. Darbo rezultatai - efektyviausiai arseną stabilizuoja geležis. Stabilizacija, naudojant lakiuosius pelenus ir durpes, padidino arseno išsiplovimą iš dirvožemio, lyginant su kontroliniu dirvožemio mėginiu. Pakopinė stabilizacija nebuvo efektyvesnė už vienkartinę stabilizaciją nei arseno, nei kitų tirtų sunkiųjų metalų atžvilgiu.

<p>Predmet izučavanja ove disertacije, osim poređenja različitih metoda procene rizika na&nbsp;osnovu karakterizacije kvaliteta sedimenta vodotokova Vojvodine, bilo je i ispitivanje&nbsp;mogućnosti imobilizacije te&scaron;kih metalau sedimentu primenom različitih remedijacionih&nbsp;tehnika kao i određivanje njihove efikasnosti (npr. solidifikacija/stabilizacija silikatnim&nbsp;materijalima, portland cementom, kalcijum-oksidom itd.) u zavisnosti od brojnih faktora.&nbsp;Osim pseudo-ukupnog sadržaja metala određene su i specifičnije frakcije metala sa posebnim<br />osvrtom na određivanje potencijalno biodostupnih frakcija.</p><p>Rezultati su ukazali da je naosnovu holandskih preporuka sediment pojedinih vodotokova&nbsp;Vojvodine (Begej, DTD-kanal,Nadela, Sava-&Scaron;abac) zagađen metalima (klasa 4) i da je&nbsp;neohodno izmuljivanje i remedijacija. Prema USEPA i kanadskim preporukama, neki uzorci&nbsp;su potencijalno toksični, ali nije zabeležena akutna toksičnost za test vrste u pornoj vodi. Za&nbsp;neke uzorke, i pored visoke pseudo-ukupne koncentracije (klasa 4), nije potvrđena&nbsp;potencijalna toksičnost na osnovu odnosa kiselog volatilnog sulfida i simultano ekstrahovanih&nbsp;metala. Dok se ne primene skuplje metode remedijacije i tretmana sedimenta, najbolje re&scaron;enje&nbsp;je izolovano skladi&scaron;tenje na specijalnim&nbsp; deponijama. Naredni koraci bi trebali da budu&nbsp;usresređeni na kontrolu i sprečavanje zagađenja kako bi se obezbedilo da revitalizacija ovih&nbsp;vodotoka ima trajni pozitivan uticaj na životnu sredinu i nesmetanu i bezbednu plovidbu, kao&nbsp;i na primenu određenih remedijacionih metoda. Poređenje rezultata koji su dobijeni različitim&nbsp;procenama kvaliteta sedimenta pokazalo je da ponekad nije dovoljan jedan pristup i da je&nbsp;potrebno je uključiti metode procene biodostupnosti, biotestove i aspekt radioaktivnosti. U&nbsp;uzorku sedimenta koji je kori&scaron;ćen za ispitivanje efikasnosti remedijacionih tretmana,&nbsp;pokazano je da cink, nikal i olovo imaju visok rizik po okolinu, jer seprocenat metala u&nbsp;izmenljivoj i karbonatnoj fazi kretao od 40.1 do 45.2%. Cr i Cd imaju umeren rizik, dok je&nbsp;bakar prisutan u ovim frakcijama u koncentraciji koja predviđa nizak rizik (5.3%). Ovo je u&nbsp;skladu i sa rezultatima analize porne vode i simultano ekstrahovanih metala i kiselog&nbsp;volatilnog sulfida.</p><p>Istraživanje prikazano u radu je dalo odgovor na pitanje da li remedijacija može uspe&scaron;no da&nbsp;ukloni zagađenje, u smislu imobilizacije metala u stanje kada oni vi&scaron;e neće biti opasnost po&nbsp;okolinu. Svi primenjeni tretmani doveli su dosmanjenja procenta kumulativno izluženih&nbsp;metala iz S/S sme&scaron;a, ali nijedna sme&scaron;a tretiranog sedimenta i ispitivanih imobilizacionih&nbsp;agenasa ne pripada grupi inertnog otpada ukoliko se kumulativne izlužene koncentracije&nbsp;metala porede sa koncentracijama koje za otpad propisuje Evropska Unija (2003/33/EC).&nbsp;Ukoliko nam je cilj dobijanje nehazardnog otpada onda moramo primeniti u tretmanu&nbsp;sedimenta kontaminiranog metalima najmanje 30% imobilizaconih agenasa (cementa,&nbsp;kalcijum-oksida). Najveća efikasnost u imobilizaciji metala postignuta je kori&scaron;ćenjem&nbsp;cementa i kalcijum-oksida u sme&scaron;i (30% cementa i 10% kalcijum-oksida) i primenom termičkog tretmana na vi&scaron;oj temperaturi (1100⁰C) sa glinom (20% gline) &scaron;to je zaključeno na osnovu koeficijenata difuzije i indeksa izlužljivosti. Dominantan mehanizam izluživanjametala iz ovih sme&scaron;a je difuzija.</p> / <p>This work is concerned with the comparison of the different methods of metal risk assessment&nbsp;in sediments based on examination of the qualityof water courses in Vojvodina. Besides, it&nbsp;deals with the possibility of applying remediation treatments of contaminated sediment and&nbsp;with the efficiency of the different methods, that is the techniques, for immobilization of&nbsp;sediment heavy metals by applying S/S and thermal treatments. A dominant mechanism is&nbsp;proposed for the process of leaching ofthe metals from treated mixtures.</p><p>Comparison of the results obtained by the different methods of sediment quality assessment&nbsp;showed that in some cases one approach to solving this problem is not &nbsp;sufficient. Metal&nbsp;concentrations in particular sediment samples (the Begej, the DTD Canal, the Nadela, the&nbsp;Sava at &Scaron;abac) indicate the presence of contamination, the analyzed samples being of Class 4.&nbsp;According to the Dutch regulations, a sedimentof &nbsp;Class 4 is of unacceptable quality and&nbsp;requires urgent intervention in the sense of sediment dredging, disposal into special depots,&nbsp;and, if possible, remediation. For some samples, despite a high pseudo-total concentration&nbsp;(Class 4), no potential toxicity was confirmed onthe basis of the ratioof the acidic volatile&nbsp;sulfide and simultaneously extracted metals. The results showed that, apart from chemical&nbsp;analyses, biological tests are also necessary, but also sequential extraction analysis, which can&nbsp;more clearly define the way of metal binding to the particular sediment fractions, to allow a&nbsp;more reliable prediction of metal mobility, potential toxicity and bioavailability. In the&nbsp;analysis of sediment quality it is also necessary toinclude the aspect of radioactivity, as it has&nbsp;been shown that the results of this analysis can, not only confirm some of the results of the&nbsp;other analyses, but also indicate the sediment age, origin of contamination and potential&nbsp;toxicity.The subsequent steps should be directed to the control and prevention of&nbsp;contamination, in order to ensure that the water course reviatalization has a lasting positive&nbsp;effect on the environment, an unimpared and safe navigation and application of remediation&nbsp;methods.</p><p>In the sediment sample (Class 4) that was usedfor the examination of the efficiency of it&nbsp;appeared that zinc, nickel and lead exhibit a high risk, as the percentages of these metals in&nbsp;the exchangeable and carbonate phases were in the range from 40.1 &nbsp;to 45.2%. On the other&nbsp;hand, chromium and cadmium exhibited a moderaterisk, whereas copperin these fractions&nbsp;was present at the levels corresponding to a low risk (5.3%). This is alsoin agreement with&nbsp;the results of pore water analysis and simultaneously extracted metals and acid volatile&nbsp;sulphide examinations.</p><p>The investigations presented in this work provided an answer to the question whetehr the&nbsp;remediation can successfully remove the contamination in the sense of the immobilization of&nbsp;metals in a state that will not be harmful tothe environment. All the treatments applied&nbsp;yielded a decrease of the percentage of cumulatively leached metals from the S/S mixtures,&nbsp;but none of the mixtures of treated sediments with the tested immobilization agents belongs to&nbsp;the group of inert materials if the cumulative leached concentrations are compared with the&nbsp;concntrations for the wastes given by the EU legislation (2003/33/EC). Ifthe goal is to obtain a non-hazardous material it is necessary to treat the contaminatedsediment with at least 30% of the immobilizing agent (cement or calcium oxide). Based on the diffusion coefficients and leachability index, the highest immobilization efficiency was achieved using a mixture of cement and calcium oxide (30% of cement and 10% of CaO) and by applying thermal treatment at a higher temperature (1100⁰C) with clay (20%). A dominant mechanism of leaching metals from these mixtures is diffusion.</p>

<p>U radu je ispitan i razvijen novi pristup tretmanu kože goveda prirodnom smolom &scaron;elak, koja je dozvoljena za kori&scaron;ćenje u hrani, u cilju redukcije unakrsne mikrobiolo&scaron;ke kontaminacije sa kože na goveđe meso. Mehanizam ovog tretmana je baziran na imobilizaciji mikroorganizama na dlaci tretirane kože i prevenciji njihovog fizičkog prenosa sa dlake na meso trupova tokom procesa obrade zaklanih goveda.<br />U in vitro uslovima, tretman uzoraka vizuelno čiste i suve kože 23% rastvorom &scaron;elaka u etanolu je redukovao prenos sa kože na sunđere kojima je koža uzorkovana brisevima: ukupne mikroflore (TVC) za 6,6 log (&gt;1000 puta vi&scaron;e u odnosu na 2,9 log redukcije kod tretmana samo etanolom), generičke Escherichia coli za najmanje 2,9 i Enterobacteriaceae za najmanje 4,8 log. Ove redukcije sve tri grupe mikroorganizama su bile značajno vi&scaron;e u odnosu na redukcije postignute tretmanom kože kombinacijom ispiranja sanitajzerom i vakumiranja. Značajno vi&scaron;e redukcije prenosa TVC sa kože na sunđerske briseve su postignute kori&scaron;ćenjem vi&scaron;ih koncentracija &scaron;elaka (23% i 30%) u odnosu na niže (4,8-16,7%) i u slučajevima kada je temperatura rastvora &scaron;elaka bila 20, 30 ili 40oC u odnosu na 50oC i 60oC. Takođe, tretman kože &scaron;elakom je značajno (3,7 puta) redukovao prevalencu E. coli O157 na prirodno kontaminiranoj, neinokulisanoj koži, kao i broj E. coli O157 na ve&scaron;tački inokulisanim kožama (redukcija od 2,1 log), u odnosu na odgovarajuće netretirane kontrole.<br />U uslovima laboratorijskog modela direktnog kontakta kože i mesa, tretman kože (različitih kategorija čistoće) 23% rastvorom &scaron;elaka je značajno smanjio prenos mikroorganizama sa tretirane kože na sterilno goveđe meso: do 3,6 log cfu/cm2 redukcije ukupnog broja bakterija (TVC), do 2,5 log cfu/cm2 Enterobacteriaceae (EC) i do 1,7 log cfu/cm2 generičke E. coli (GEC). Redukcija prenosa TVC je bila značajno vi&scaron;a, a redukcije EC i GEC slične, u odnosu na redukcije nakon tretiranja kože kombinacijom ispiranja-vakumiranja sanitajzerom.<br />U uslovima male komercijalne klanice sa nezadovoljavajućom procesnom praksom (klanje prljavih goveda i neadekvatna higijena procesa klanja i obrade), tretman koža zaklanih goveda 23% rastvorom &scaron;elaka je rezultirao značajnom mikrobnom redukcijom na mesu trupova goveda nakon skidanja kože: 1,7 log cfu/cm2 TVC, 1,4 log cfu/cm2 EC i 1,3 log cfu/cm2 GEC. Redukcija TVC na mesu trupova je bila značajno vi&scaron;a, a redukcije EC i GEC slične, u odnosu na redukcije nakon tretiranja kože ispiranjem-vakumiranjem sanitajzerom.<br />Ova istraživanja su po prvi put pružila naučne dokaze da se tretman kože goveda u cilju imobilizacije mikroflore na dlaci može uspe&scaron;no koristiti u cilju smanjenja kontaminacije mesa trupova tokom procesa skidanja kože, unapređenja finalnog mikrobiolo&scaron;kog statusa mesa i bezbednosti goveđeg mesa uop&scaron;te. Da bi se ostvario puni potencijal ovog novog tretmana u praksi, neophodna su dalja istraživanja u cilju njegove tehničke optimizacije u uslovima industrije mesa.</p> / <p> In this research, a new approach to cattle hide treatments, based on using a natural, food-grade resin, Shellac, to reduce microbial cross-contamination from the hides onto carcass meat, was developed and evaluated. The basis of this treatment is immobilisation of microorganisms on cattle hide&rsquo;s hair and subsequent reduction of their transmissibility from the hair onto carcass meat during dressing of slaughtered cattle.<br /> Under in vitro conditions, treatment of samples of visually clean and dry hides with 23% Shellac-in-ethanol solution reduced sponge-swabbing recoveries of general microflora (TVC) by a factor of 6.6 logs (&gt;1000-fold greater than the 2.9 log reduction observed by ethanol alone), and of generic E. coli (GEC) and Enterobacteriaceae (EC) by factors of at least 2.9 and 4.8 logs, respectively. The reductions of these three groups of microorganisms were superior to those achieved by a sanitizer rinse-vacuum hide treatment. Significantly greater reductions of TVC recoveries from hides were achieved when using higher Shellac concentrations (23.0% and 30.0% rather than 4.8-16.7%) and when Shellac solution temperatures were 20-40&deg;C rather than 50-60&deg;C. Furthermore, the Shellac-based treatment also markedly reduced the E. coli O157 prevalence (3.7-fold reduction) on natural, uninoculated hides, as well as the counts of E. coli O157 on artificially inoculated hides (2.1 log reduction) when compared to corresponding untreated controls.<br /> Under the conditions of a hide-to-meat direct contact laboratory-based model, treatment of hides (of varying visual cleanliness) with the 23% Shellac solution produced significant reductions of microbial transfer from treated hide onto sterile beef: up to 3.6 log10 CFU/cm2 of TVC, up to 2.5 log10 CFU/cm2 of EC and up to 1.7 log10 CFU/cm2 of GEC. TVC reductions of microbial transfer from treated hide onto beef achieved by the Shellac hide treatment were superior to those achieved by the comparative sanitizer rinse-vacuum hide treatment, but reductions of EC and GEC did not differ between the two hide treatments.<br /> In a small commercial abattoir with unsatisfactory process practices (slaughtering dirty cattle, inadequate process hygiene), treatment of hides with Shellac produced significant microbial reductions on skinned beef carcasses: 1.7 log10 CFU/cm2, 1.4 log10 CFU/cm2 and 1.3 log10 CFU/cm2 of TVC, EC and GEC, respectively. TVC reductions on skinned beef carcasses achieved by the Shellac hide treatment were superior to those achieved by the comparative sanitizer rinse-vacuum hide treatment, but reductions of EC and GEC did not differ significantly between the two hide treatments.<br /> These investigations produced the first scientific evidence that treatment of cattle hides with aim of immobilising microflora on the hair can be very successfully used to reduce carcass meat contamination during the skinning operation, thus improving the microbiological status of the final beef carcasses as well as the beef safety in general. To achieve the full potential of this new treatment in practice, further research aimed at its further technical optimization under real-life meat industry conditions is necessary.</p>