【国外标准】 Standard Guide for Recovery of Aqueous Cyanides by Extraction from Mine Rock and Soil

5.1 This guide is intended as a means for obtaining an extract from mine rock and soil samples to measure cyanide content in the aqueous portion of the sample on a dry weight basis. Cyanide is analyzed in mine rock and soil extracts for measurement of cyanide concentration; however, improper sample collection and extraction can result in significant positive or negative bias.5.2 This guide is designed to mobilize aqueous cyanides present in the solids, so that the resulting extract can be used to assess leachate that could potentially be produced from mine rock or soil.5.3 This guide is not intended to simulate actual site leaching conditions.5.4 This guide produces extracts that are amenable to the determination of trace cyanides. When trace cyanides are being determined, it is especially important that precautions be taken in sample preservation, storage, and handling to avoid possible contamination of the extracts.5.5 This guide uses a comparative test method and is intended for use as a routine method for monitoring mine rock and soils. It is assumed that all who use this guide will be trained analysts capable of performing it skillfully and safely. It is expected that work will be performed in a properly equipped laboratory applying appropriate quality control practices such as those described in Guide D3856.5.6 This guide identifies proper methods for obtaining mine rock and soil samples for the specific purpose of measuring cyanide concentrations.1.1 This guide is applicable for the collection, extraction, and preservation of extracts from mine rock and soil samples for the analysis of cyanide in the extracts. Responsibilities of field sampling personnel and the laboratory are indicated.1.2 The sampling, preservation, and extraction procedures described in this guide are recommended for the analysis of total cyanide, available cyanide, weak acid dissociable cyanide, and free cyanide by Test Methods D2036, D4282, D4374, D6888, D6994, D7237, and D7284. The information supplied in this guide can also be applied to other analytical methods for cyanide, for example, US EPA Method 335.4.1.3 The procedure options methods appear in the following order:  Procedure Option Sections  Option A Laboratory Processing of Field Preserved Samples 11 and 12  Option B Laboratory Processing of Moist Field Samples 13 and 141.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.