Isotopic, geophysical and biogeochemical investigation of submarine groundwater discharge : IAEA-UNESCO intercomparison exercise at Mauritius Island

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Environmental Radioactivity 104 (2012): 24-45, doi:10.1016/j.jenvrad.2011.09.009.Submarine groundwater discharge (SGD) into a shallow lagoon on the west coast of Mauritius Island (Flic-en-Flac) was investigated using radioactive (3H, 222Rn, 223Ra, 224Ra, 226Ra, 228Ra) and stable (2H, 18O) isotopes and nutrients. SGD intercomparison exercises were carried out to validate the various approaches used to measure SGD including radium and radon measurements, seepage-rate measurements using manual and automated meters, sediment bulk conductivity and salinity surveys. SGD measurements using benthic chambers placed on the floor of the Flic-en-Flac Lagoon showed discharge rates up to 500 cm/day. Large variability in SGD was observed over distances of a few meters, which were attributed to different geomorphological features. Deployments of automated seepage meters captured the spatial and temporal variability of SGD with a mean seepage rate of 10 cm/day. The stable isotopic composition of submarine waters was characterized by significant variability and heavy isotope enrichment and was used to predict the contribution of fresh terrestrially derived groundwater to SGD (range from a few % to almost 100 %). The integrated SGD flux, estimated from seepage meters placed parallel to the shoreline, was 35 m3/m day, which was in a reasonable agreement with results obtained from hydrologic water balance calculation (26 m3/m day). SGD calculated from the radon inventory method using in situ radon measurements were between 5 and 56 m3/m per day. Low concentrations of radium isotopes observed in the lagoon water reflected the low abundance of U and Th in the basalt that makes up the island. High SGD rates contribute to high nutrients loading to the lagoon, potentially leading to eutrophication. Each of the applied methods yielded unique information about the character and magnitude of SGD. The results of the intercomparison studies have resulted a better understanding of groundwater-seawater interactions in coastal regions. Such information is an important pre-requisite for the protection management of coastal freshwater resources.The financial support provided by the IOC and IHP of UNESCO for travel arrangements, and by the IAEA’s Marine Environment Laboratories for logistics is highly acknowledged. MAC and MEG were supported in part by the US National Science Foundation (OCE-0425061 and OCE-0751525). PPP acknowledges a support provided by the EU Research & Development Operational Program funded by the ERDF (project No. 26240220004), and the Slovak Scientific Agency VEGA (grant No. 1/108/08). The International Atomic Energy Agency is grateful to the Government of the Principality of Monaco for support provided to its Marine Environment Laboratories

Current intravesical therapy for non-muscle invasive bladder cancer

Item does not contain fulltextIntroduction: Transurethral resection of the bladder tumour (TURBT) is still the standard initial treatment for non-muscle invasive bladder cancer (NMIBC). However, even after a radical resection, recurrence (30 - 80%) and progression (1 - 45%) are commonly seen. Intravesical therapy provides direct contact of the agent with the bladder mucosa and clearly has improved the outcome, especially in high-risk disease. Areas covered: The role of a good initial TURBT is emphasized. Risk assessment tools are discussed. Different intravesical therapies are enumerated according to the latest literature, with the emphasis on Bacillus Calmette-Guerin (BCG), including the discussion on the optimal dose and schedule. New developments are mentioned. Expert opinion: A radical TURBT is essential for good prognosis. For optimal visualisation of tumours, fluorescence techniques should be used with low threshold, especially in case of suspicion of carcinoma in situ (CIS). Increased completeness of the resection will lead to less persisting disease and less need for adjuvant treatment. A re-TURBT should be done when in doubt of radical resection (judged by the pathologist or the surgeon). Risk assessment is essential, but the available tools are outdated. A single post-operative instillation (SPI) with chemotherapy is only indicated in low-risk disease. BCG is the treatment of choice for high-grade disease. BCG should be given as maintenance. Awareness of deterioration of the prognosis after progression is of great importance. In BCG failures, cystectomy should be strongly advised. Chemotherapy in combination with hyperthermia seems to be a new promising treatment