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To date, approximately 6000 tons of uranium has been disposed of onto tailings dams per year by gold mining activities in South Africa. These uranium bearing tailings dumps contain significant amounts of radium and are therefore possible sources of substantial amounts of radon gas. Due to the large sizes of these dams, measurements of the radon exhalation for the whole dam using established and conventional methods become time consuming and labour intensive. In this study, radon exhalation rates from a gold mine tailings dam around mining area of Odendalsrus were measured using passive “sealed tube” method and CR-39 gas etched track monitors known as Radon Gas Monitors (RGMs). Twenty samples were collected at the depths ranging from 90 cm to 1 m from the tailings for exhalation rate measurements. Radon exhalation rates from these samples were found to vary from 0.0410 ± 0.0042 Bq/m2· s to 0.440 ± 0.045 Bq/m2· s with a mean value of 0.102 ± 0.021 Bq/m2· s and a standard deviation of 0.087 Bq/m2· s. The results of these measurements show very high radon exhalation rate and radium content from one particular sample which requires further investigations.

Recent studies have shown that Leptographium lundbergiiand L. truncatumare morphologically similar. This has led to suggestions that the species, which both occur in Europe and are associated with European scolytid bark beetles, might represent a single taxon. Synonymising these two species based on their similar morphology has been resisted in the past. This is primarily due to the fact that L. lundbergiiis the type species of the genus and it was felt that such a decision should be based on more intensive study. PCR amplified DNA fragments of isolates of L. lundbergiiand L. truncatumfrom numerous geographic origins were compared on the basis of the DNA sequence from the ITS2 region and part of the 5.8S gene of the rRNA operon. Phylogenetic analyses show that L. lundbergiiand L. truncatumisolates group together and separate from the outgroups, L. wingfieldii, Ceratocystis fimbriataand C. albofundus. Based on these data and the morphological similarity of the two species, we conclude that L. truncatumis a synonym of L. lundbergii.