Screening and comparison of remedial alternatives for the South Field and flyash piles at the Fernald site

The South Field, the Inactive Flyash Pile, and the Active Flyash Pile are in close proximity to each other and are part of Operable Unit 2 (OU2) at the Fernald Environmental Management Project (FEMP). The baseline risk assessment indicated that the exposure pathways which pose the most significant risk are external radiation from radionuclides in surface soils and use of uranium contaminated groundwater. This paper presents screening and comparison of various remedial alternatives considered to mitigate risks from the groundwater pathway. Eight remedial alternatives were developed which consisted of consolidation and capping, excavation and off-site disposal with or without treatment, excavation and on-site disposal with or without treatment and combinations of these. Risk-based source (soil) preliminary remediation levels (PRLs) and waste acceptance criteria (WACs) were developed for consolidation and capping, excavation, and on-site disposal cell. The PRLs and WACs were developed using an integrated modeling tool consisting of an infiltration model, a surface water model, a vadose zone model, and a three-dimensional contaminant migration model in saturated media. The PRLs and WACs were then used to determine need for soil treatment, determine excavation volumes, and screen remedial alternatives. The selected remedial alternative consisted of excavation and on-site disposal with off-site disposal of the fraction exceeding the WAC

Lanthanopolyoxotungstates in silica nanoparticles: multi-wavelength photoluminescent core/shell materials

We thank Dr Marc Willinger and the RNME (National Electronic Microscopy Network, Portugal) for HRTEM images. Electronic supplementary information (ESI) available: FT-IR and FT-Raman spectra, additional HRTEM images and complementary photoluminescence spectra details, see DOI: 10.1039/b919691a.Photoluminescent lanthanopolyoxotungstate core/shell nanoparticles are prepared by the encapsulation of lanthanide-containing polyoxometalates (POMs) with amorphous silica shells. The preparation of morphological well-defined core/shell nanoparticles is achieved by the hydrolysis of tetraethoxysilane in the presence of POMs using a reverse microemulsion method. The POMs used are decatungstolanthanoates of [Ln(W(5)O(18))(2)](9-) type (Ln(III) = Eu, Gd and Tb). Photoluminescence studies show that there is efficient emission from the POM located inside the SiO(2) shells, through excitation paths that involve O --> Eu/Tb and O --> W ligand-to-metal charge transfer. It is also shown that the excitation of the POM containing europium(III) may be tuned towards longer wavelengths via an antenna effect, by coordination of an organic ligand such as 3-hydroxypicolinate. The POM/SiO(2) nanoparticles form stable suspensions in aqueous solution having the advantage of POM stabilization inside the core and the possibility of further surface grafting of chemical moieties via well known derivatization procedures for silica surfaces. These features together with the possibility of tuning the excitation wavelength by modifying the coordination sphere in the lanthanopolyoxometalate, make this strategy promising to develop a new class of optical bio-tags composed of silica nanobeads with multi-wavelength photoluminescent lanthanopolyoxometalate cores.FCT- POCI/QUI/58887/2004FCT- PTDC/ QUI/67712/2006FCT- SFRH/BD/30137/2006FCT- SFRH/BPD/14954/200

Case Report - Amoebiasis cutis in HIV positive patient

Protozoan infections of the skin, particularly cutaneous amoebiasis, are rare in HIV-positive patients. We report a case of amoebiasis cutis in an HIV-positive truck driver with a history of frequent unprotected sexual exposures. He presented with multiple painful ulcers and sinuses with purulent discharge, necrotic slough and scarring in the perianal and gluteal region for the last 2 years. He was positive for HIV-1 and -2. Cutaneous biopsy revealed numerous Entamoeba histolytica in the trophozoite form, in addition to an inflammatory infiltrate and necrotic debris. He responded well to oral metronidazole and chloroquine. Amoebiasis cutis should be considered in the differential diagnosis of perianal ulcers, particularly in HIV-positive patients