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Field Measurement of Oxidation-Reduction Potential (ORP)

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COPY COPY Revision History The top row of this table shows the most recent changes to this controlled document. For previous revision history information, archived versions of this document are maintained by the SESD Document Control Coordinator on the SESD local area network (LAN). History Effective Date SESDPROC-113-R2, Field Measurement of Oxidation-Reduction April 26, 2017 Potential (ORP), replaces SESDPROC-013-R1 General: Corrected any typographical, grammatical, and/or editorial errors. Title Page: Changed the EIB Chief from Danny France to the Field Services Branch Chief John Deatrick, and the Field Quality Manager from Bobby Lewis to Hunter Johnson. Section 2.2: Figure 6 modified for clarity. Section 3.3: Use of overtopping cell described consistent with current practice. SESDPROC-113-R1, Field Measurement of Oxidation-Reduction January 29, 2013 Potential (ORP), replaces SESDPROC-013-R0 SESDPROC-113-R0, Field Measurement of Oxidation-Reduction August 7, 2009 Potential (ORP), Original Issue SESD Operating Procedure Page 2 of 22 SESDPROC-113-R2 Field Measurement of ORP Field Measurement of ORP(113)_AF.R2 Effective Date: April 26, 2017 COPY TABLE OF CONTENTS 1 General Information ............................................................................................................ 4 1.1 Purpose........................................................................................................................... 4 1.2 Scope/Application ......................................................................................................... 4 1.3 Documentation/Verification ......................................................................................... 4 1.4 References ...................................................................................................................... 4 1.5 General Considerations ................................................................................................ 5 1.5.1 Safety .......................................................................................................................... 5 1.5.2 Records ....................................................................................................................... 6 1.5.3 Shipping ...................................................................................................................... 6 2 Background ........................................................................................................................... 7 2.1 General ........................................................................................................................... 7 2.2 Instrumentation............................................................................................................. 8 2.3 Redox Chemistry ......................................................................................................... 14 2.4 Applications ................................................................................................................. 15 2.5 Limitations ................................................................................................................... 16 3 Methodology ........................................................................................................................ 18 3.1 Standard Solutions ...................................................................................................... 18 3.2 Verification and Calibration ...................................................................................... 19 3.3 Measurement ............................................................................................................... 20 3.4 Reporting ..................................................................................................................... 21 SESD Operating Procedure Page 3 of 22 SESDPROC-113-R2 Field Measurement of ORP Field Measurement of ORP(113)_AF.R2 Effective Date: April 26, 2017 COPY 1 General Information 1.1 Purpose This document describes procedures, methods and considerations to be used and observed when conducting field Oxidation-Reduction Potential (ORP) measurements in aqueous environmental media, including groundwater, surface water and certain wastewater. The measurement of soil ORP is a non-standard measurement and procedures should be developed on a project-specific basis. 1.2 Scope/Application This document describes procedures generic to all ORP measurement methods to be used by Science and Ecosystem Support Division (SESD) field personnel when collecting and handling samples in the field. On the occasion SESD personnel determine that any of the procedures described in this section are inappropriate, inadequate or impractical and that another procedure must be used to obtain an ORP measurement, the variant procedure will be documented in the field logbook, along with a description of the circumstances requiring its use. Mention of trade names or commercial products in this operating procedure does not constitute endorsement or recommendation for use. 1.3 Documentation/Verification This procedure was prepared by persons deemed technically competent by SESD management, based on their knowledge, skills and abilities and has been tested in practice and reviewed in print by a subject matter expert. The official copy of this procedure resides on the SESD local area network (LAN). The Document Control Coordinator (DCC) is responsible for ensuring the most recent version of the procedure is placed on the SESD LAN and for maintaining records of review conducted prior to its issuance. 1.4 References Faulkner, S.P., W.H. Patrick, Jr., and R.P. Gambrell. 1989. Field techniques for measuring wetland soil parameters. Soil Sci. Soc. Am. J. 53:883-890. Megonigal, J.P., W.H. Patrick, Jr., and S.P. Faulkner. 1993. Wetland identification in seasonally flooded forest soils: soil morphology and redox dynamics. Soil Sci. Soc. Am. J. 57:140-149. D.K. Nordstrom and F.D. Wilde. 2005. National Field Manual, Chapter A6, Section 6.5: Reduction Oxidation Potential (Electrode Method). USGS. Pankow, J.E. 1991. Aquatic chemistry concepts. Lewis Publishers, Inc. Cheleas, Michigan. USA. Pruitt, B.A. 2001. Hydrologic and soil conditions across hydrogeomorphic settings. Dissertation. The University of Georgia, Athens, GA. USA. SESD Operating Procedure Page 4 of 22 SESDPROC-113-R2 Field Measurement of ORP Field Measurement of ORP(113)_AF.R2 Effective Date: April 26, 2017 COPY Soil Survey Staff. 1998. Keys to soil taxonomy, 8th Edition. United States Department of Agriculture, Natural Resources Conservation Service, Washington, DC. USA. Standard Methods. 1992. Standard Methods for the Examination of Water and Wastewater, 18th Edition. Prepared and published jointly by: American Public Health Association, American Water Works Association, Water Environment Federation. American Public Health Association, Washington, DC. USA. Stumm, W. and J.J. Morgan. 1981. Aquatic chemistry: an introduction emphasizing chemical equilibra in natural waters, 2nd Ed. John Wiley & Sons, New York. USA. USEPA. 2001. Environmental Investigations Standard Operating Procedures and Quality Assurance Manual. Region 4 Science and Ecosystem Support Division, Athens, GA. USEPA. 2007. Safety, Health and Environmental Management Program Procedures and Policy Manual. Science and Ecosystem Support Division, Region 4, Athens, GA. Wikipedia entry. Reduction Potential. http://en.wikipedia.org/wiki/Reduction_potential. Retrieved April 2, 2009. 1.5 General Considerations 1.5.1 Safety Proper safety precautions must be observed when verifying or calibrating instruments for measurement of Oxidation-Reduction Potential. Refer to the SESD Safety, Health and Environmental Management Program Procedures and Policy Manual (most recent version) and any pertinent site-specific Health and Safety Plans (HASP) for guidelines on safety precautions. These guidelines should be used to complement the judgment of an experienced professional. Reagents commonly used in the preparation of ORP calibration standards are toxic and require care when handling. When using this procedure, avoid exposure to these materials through the use of protective clothing, eye wear and gloves. Safety precautions when handling and preparing verification solutions should include gloves and eyewear to prevent dermal and eye contact, and a mask to avoid inhaling dust particles when handling dry materials. Vigorous flushing should be used if the reagents or solutions come in contact with skin or eyes. Following is specific information on commonly used solutions. The application of the solutions is described in detail in Section 3.1, Standard Solutions, of this procedure. • Quinhydrone (CAS# 106-34-3) is a skin and respiratory irritant and is poisonous if ingested. Safety precautions when handling quinhydrone should include gloves to prevent dermal contact and a mask to avoid inhaling dust particles when mixing dry SESD Operating Procedure Page 5 of 22 SESDPROC-113-R2 Field Measurement of ORP Field Measurement of ORP(113)_AF.R2 Effective Date: April 26, 2017 COPY material to prepare calibration standards. Vigorous flushing should be used if concentrated material comes in contact with skin or eyes. • Zobell’s solution is also an irritant and toxic if ingested. The same handling precautions apply when mixing and using Zobell’s solution as when using quinhydrone. Zobell’s reacts with acid to form harmful byproducts, including hydrocyanide gas. • Light’s solution contains ferro- and ferric-cyanide compounds
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