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This study proposed and validated a method integrating in situ hydrotalcite precipitation (Virtual Curtain™ (VC) technology) with bioprocess for treating a cyanide (CN)-augmented (ca. 5 mg-CN L -1 ) sulfate-laden neutral mine drainage, from a waste rock dump (WD2) of an Australian gold mine. Efficacies of various carbon (C) sources (ethanol, lactate, and two natural substrates; Eucalyptus wood sawdust (EW) and Typha biomass (TB)) for promoting microbial reduction in both: CN-augmented WD2 water and VC-treated CN-augmented WD2 water were assessed in a 60-days microcosms study at 30 °C. The microcosms were monitored over time for pH, redox potential, dissolved hydrogen sulfide, chloride, nitrite, nitrate, sulfate, phosphate, biogas production, dissolved organic carbon, total dissolved nitrogen, and dissolved CN. The VC treatment removed a range of metals (Mg, Ni and Zn) and metalloid Se from the CN-augmented WD2 water to below detection. Other elements substantially reduced in concentration included Ba, F, Si and U. However, the VC treatment did not remove substantial nitrate, sulfate or CN. Microcosm trials revealed that the indigenous microbial community in WD2 could effectively denitrify and reduce sulfate, with TB was the most efficient C source for promoting sulfate and CN removal; whereas, EW facilitated only marginally higher sulfate reduction compared with controls. The highest sulfate reduction rate (76 g-SO 4 2- m -3 d -1 ) was achieved with VC-treated water amended with TB, indicating that VC pre-treatment was beneficial. Further, all treatments amended with external C, facilitated 100% removal of dissolved CN after 60 days, whereas only partial (65%) CN removal was recorded in the control. Overall, the proposed integrated method appears a viable option for treating neutral gold mine drainage., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

Cyanide poisoning is uncommon, but generates interest because of the presumed utility of an antidote immediately available in those areas with a high risk of cyanide exposure. As part of its regular review of guidelines, the Australian Resuscitation Council conducted a systematic review of the human evidence for the use of various proposed cyanide antidotes, and a narrative review of the relevant pharmacological and animal studies. There have been no relevant comparative or placebo-controlled human trials. Nine case series were identified. Treatment with hydroxocobalamin was reported in a total of 361 cases. No serious adverse effects of hydroxocobalamin were reported, and many patients with otherwise presumably fatal poisoning survived. Sodium thiosulphate use was reported in two case series, similarly with no adverse effects. Treatment with a combination of sodium nitrite, amyl nitrite and sodium thiosulphate was reported in 74 patients, with results indistinguishable from those of hydroxocobalamin and sodium thiosulphate. No case series using dicobalt edetate or 4-dimethylaminophenol were identified, but successful use in single cases has been reported. Hydroxocobalamin and sodium thiosulphate differ from alternatives in having negligible adverse effects, and on the basis of current evidence are the antidotes of choice. The indications for the use of an antidote, the requirements for supportive care and a recommended approach for workplaces where there is a risk of cyanide poisoning are presented. [ABSTRACT FROM AUTHOR]