Toxicological analysis of the content of military canteens buried for 70 years in the karst cave in Kočevsko, South-Eastern Slovenia

Za odkrivanje ostankov materialnih sledi se na dobro ohranjenih predmetih lahko opravijo forenzične preiskave. V Breznu v Debliških livadah je bilo odkritih večje število predmetov, ki so bili odvrženi v jamo v maju in juniju 1945. Med odkritim materialom so bile tudi vojaške čutare. Nekatere izmed čutar so še vsebovale tekočino, nekatere pa tudi poltrdo, gelasto oborino. Tekočina in oborina iz čutar sta vsebovali kovine, ki so se najverjetneje s časom izlužile iz kovinske posode. Korozija čutar nakazuje prisotnost minerala hematita. Vsebina čutar je nadalje vsebovala nekaj raztopljene organske snovi (celotni organski ogljik – TOC v tekočini 9,22 mg/l, v tekočini ekstrahirane oborine 34,1 mg/l), nekaj mikrobne biomase ter relativno visoke koncentracije nitrata (240 mg/l v tekočini, 55 mg/l v ekstrahirani oborini) in sulfata (18mg/l v tekočini, 836 mg/l v ekstrahirani oborini). Bakterijskih indikatorjev, Escherichia coli in enterokokov, ki bi kazali na fekalno kontaminacijo vsebine, v vzorcih nismo zaznali. Raztopina in oborina sta izkazovali podobno stopnjo toksičnosti, okrog 20%inhibicijo bioluminiscence bakterije Vibrio fischeri. Glede na Pravilnik o pitni vodi tekočina s sedanjimi kemijskimi lastnostmi ni primerna za uživanje. Rezultati ne kažejo nujno na toksičnost izvornih tekočin iz časa, ko so bile čutare odvržene v jamo, ampak bi se toksičnost lahko razvila postopoma zaradi izluževanja kovin iz posode, zlasti aluminija, in (bio)kemijskih reakcij. Navkljub stabilnim jamskim razmeram, ki so jim bile izpostavljene čutare, ugotovljeni parametri ne podpirajo dolgoročne ohranitve stabilne DNA za morebitne nadaljnje forenzične analize.Forensic examinations can be performed on well-preserved objects to detect material traces. A large number of objects were discovered in the cave Breznov Debliških livadah, which were dumped in the cave in May and June 1945. Among the discovered material there were also military canteens (drinking bottles). Some canteens still contained liquids, and some even a semi-hard, gel precipitate. The liquid and precipitate from the analyzed canteens contained metals that were most likely leached from the metal containers. The corrosion of the canteens is indicated by the presence of a hematite mineral. The content of canteens contained some dissolved organic matter (Total Organic Carbon, TOC, in the liquid = 9.22 mg/l, in the liquid from extracted precipitate = 34.1 mg/l), some microbial biomass and relatively highnitrate concentrations (240 mg/l in liquid, 55 mg/l in extracted precipitates) and sulfate (18 mg/l in liquid, 836 mg/l in extracted precipitate). Bacterial indicators, Escherichiacoli and enterococci, indicating faecal contamination of the canteens‘ contents, were not detected. The liquid and precipitate exhibited a similar degree of toxicity, about20% inhibition of the bioluminescence of Vibrio fischeri. According to the Slovenian Rules on drinking water, the liquid with the present chemical properties is not suitable for human consumption. The results do not necessarily indicate that liquids were already toxic when the canteens were thrown into the cave, but the toxicity could have developed progressively due to (bio)chemical reactions and leaching of metals, in particular aluminum, from the canteens. In spite of the stable cave conditions to which canteens have been exposed, the observed parameters do not support long-term preservation of stable DNA for potential future forensic analyses