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In this paper, we demonstrate that reduction of Hg(II) to Hg0 under anaerobic conditions, followed by volatilization of Hg0 to the atmosphere, might be responsible for the removal of Hg from tropical hydromorphic soils. We conducted a series of kinetic batch experiments in which we added Hg(II) to anoxic suspensions of a soil clay fraction and haematite nanoparticles. The clay fraction came from three depths in a hydromorphic soil by the Leblond River in French Guiana, South America: close to the upper and lower boundaries (30–40 cm and 90–100 cm) and within the central part (60–70 cm) of the frequently water-saturated clay horizon. We prepared a second set of soil clay fraction suspensions with Fe(III) citrate, whose reduction acted as a source of dissolved Fe(II) to investigate the influence of Fe(II) on the production of Hg0. Reduction of Hg(II) to Hg0 occurred with all samples amended with Fe(III) citrate. Laboratory experiments with haematite suspensions demonstrated that adsorption of Fe(II) to the haematite surface created very reactive sites for the reduction of Hg(II), while in the absence of haematite particles, no production of Hg0 occurred. The greatest production of Hg0 was found for the depth intervals 30–40 cm and 90–100 cm, where the total mercury concentration exhibits a local minimum. The observed pseudo-first order rate constants for the 90–100 cm depth sample were close to rate constants reported for abiotic reduction of Hg(II) by Fe(II) adsorbed on mineral surfaces. Significant production of Hg0 was found for the 90–100 cm depth interval sample, both with and without Fe(III) citrate. A biotic pathway as well as abiotic reduction by Fe(II) might be involved in the reduction of Hg(II) to Hg0. [ABSTRACT FROM AUTHOR]

Background: Balloon catheters facilitate pulmonary vein (PV) isolation, but current technology is limited by either a single ablative element, potentially leading to over-ablation of thin and under-ablation of thick tissue, or prolonged procedure times. Visualized by electroanatomical mapping, a novel compliant radiofrequency balloon catheter with 10 irrigated, flexible electrodes can simultaneously and independently deliver energy. Herein, we evaluated the feasibility, safety, and short-term efficacy of this radiofrequency balloon in a multicenter, single-arm, first-in-human study., Methods: Paroxysmal atrial fibrillation patients underwent PV isolation with the radiofrequency balloon delivered over-the-wire with a deflectable 13.5F sheath. Radiofrequency energy is delivered simultaneously from all electrodes-up to 30 s posteriorly and 60 s anteriorly. Esophageal temperature was monitored in all patients; the esophagus was also mechanically deviated in 10 patients., Results: At 4 sites, 39 patients were treated by 9 operators. The radiofrequency balloon isolated all targeted PVs (152/152), 79.6% with a single application. Electrical reconnection occurred in only 7/150 PVs (4.7%) on adenosine/isoproterenol challenge. Mean procedure, balloon dwell, and fluoroscopy times were 101.6, 40.5, and 17.4 min, respectively. Esophagogastroduodenoscopy revealed asymptomatic esophageal erythema in 5 patients. Phrenic nerve palsy occurred in a patient in whom phrenic pacing was inadvertently omitted. At 3 months, imaging revealed no PV stenosis, and early atrial arrhythmia recurrence occurred in only 10/39 (25.6%) patients., Conclusions: The compliant radiofrequency balloon can directionally tailor energy delivery for efficient, effective, and reasonably safe acute PV isolation., Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: ISRCTN 11764506.