United States EPA/625/12-91/002 Environmental Protection November 1991 Agency Technology Transfer Description and Sampling of Contaminated Soils A Field Pocket Guide ------- Technology Transfer EPA/625/12-91 /002 &EPA Description and Sampling of Contaminated Soils: A Field Pocket Guide Center for Environmental Research Information U.S. Environmental Protection Agency 26 West Martin Luther King Drive Cincinnati, OH 45268 rJ5y Printed on Recycled Paper ------- Notice This guide has been reviewed by the U.S. Environmental Protection Agency and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. ------- Contents Page How to Use This Guide ix Chapter 1. Field Methods, Equipment, and Documents 1 1.1 Nature of Soil Pollutants* and Surface Pollution Situation* 1 1.2 Soil Parameters for Field Sampling and Characterization 2 1.3 Field Description of Soils 3 1.4 Field Sampling and Testing 5 1.5 Field Equipment and Documents 5 1.6 Use of EPA's Environmental Systems Monitoring Laboratory 6 Chapter 2. Site Characteristics... 19 2.1 Climate and Weather* 19 2.1.1 Air Temperature 20 2.1.2 Wind Speed and Direction* 20 2.1.3 Humidity 20 2.2 Slope* 21 2.3 Surface Erosion and Erodibility* 22 2.4 Surface Runoff* 23 2.5 Vegetation* 24 2.6 Macro- and Mesofauna* 26 Chapter 3. Field Description and Analysis of Soils 27 3.1 Soil Physical Parameters 28 3.1.1 Soil Horizons* 31 3.1.2 Soil Texture Classes* 38 ------- iv Page 3.1.3 Soil Color* 41 3.1.4 Soil Porosity* 46 3.1.5 Zones of Increased Porosity/Permeability 48 3.1.5a Soil Structure Grades* 49 3.1.5b Extrastructural Cracks 49 3.1.5c Roots* 53 3.1.5d Surface Features* 53 3.1.5e Sedimentary Features 54 3.1.6 Zones of Reduced Porosity/Permeability 55 3.1.6a Genetic Horizons 55 3.1.6b Rupture Resistance (Consistency*) 56 3.1.6c Bulk Density* 58 3.1.6d Root Restricting Layers 60 3.1.6e Penetration Resistance (Compaction*) 60 3.1.7 Soil Engineering Parameters and Properties 62 3.1.7a Unified (ASTM) Texture 62 3.1.7b Atterberg Limits 69 3.1.7c Shear Strength 69 3.1.7d Shrink-Swell 70 3.1.7e Corrosivity* 70 3.1.8 Soil TemperatureVTemperature Regime* 71 3.2 Soil Hydrologic Parameters 73 3.2.1 Moisture Conditions* (Soil Water State) 73 3.2.2 Water Table (Internal Free Water Occurrence) 75 3.2.3 Available Water Capacity 76 3.2.4 Saturated Hydraulic Conductivity* and Soil Drainage Class 76 3.2.5 Infiltration* 77 3.3 Soil Chemistry and Biology 81 3.3.1 Organic Matter* 81 3.3.2 Odor* 83 3.3.3 Cation Exchange Capacity* 84 3.3.4 Reaction (pH)* 84 ------- Page 3.3.5 Redox Potential* (Eh) 85 3.3.6 Electrical Conductivity* (Salinity) 85 3.3.7 Clay Minerals* 86 3.3.8 Other Minerals 87 3.3.9 Fertility Potential* 90 3.3.10 Soil Microbiota* 91 3.4 Soil Contaminants 92 Chapter 4. Soil Sampling and Quality Assurance 93 4.1 Changes in Soil Sampling Procedures 93 4.2 Quality Assurance/Quality Control 94 References References 102 Appendices A.1 General Protocol for Description of Soil Cores 106 A.2 General Protocol for Soil Sample Handling and Preparation 110 A.2.1 Soil Sample Collection Procedures for Volatiles 110 A.2.2 Soil Sample Collection and Mixing Procedures for Semivolatiles and Metals 111 A.2.3 Equipment Decontamination/Disposal 112 A.2.4 Air Drying 113 A.3 General Protocol for Soil Sampling with a Spade and Scoop 116 A.4 General Protocol for Soil Sampling with Augers and Thin-Walled Tube Samplers 118 B. Manufacturers and Distributors of Soil Sampling Equipment 120 'Indicates that guidance for interpretation of observations and measurements can be found in Cameron (1991). ------- w 'X'X'X*:*:^^ Forms Page 1 -1 Checklist of Soil Physical and Chemical Property Sampling and Field Test Procedures 7 1 -2 Soil Description/Sampling Equipment and Documents Checklist 8 1 -3 Soil Sampling Quality Assurance/Quality Control Checklist 13 1 -4 Coding Sheet for ESES Site Knowledge Frames 15 1-5 Coding Sheet for ESES Soil Knowledge Frames 16 3-1 Soil Profile and Related Information 29 3-2 Unified (ASTM) Field Texture Determination Form 63 4-1 Sample Alteration Form 99 4-2 Field Audit Checklist 100 4-3 Sample Corrective Action Form 101 Tables 1 -1 Suggested Soil Parameters for Field Description 4 2-1 Index Surface Runoff Classes 25 2-2 Criteria for Placement of Hydrologic Soil Groups 25 3-1 Definitions and Designation Nomenclature for USDA Soil Horizons and Layers 32 3-2 Comparison of the 1962 and 1981 USDA Soil Horizon Designation Systems 35 3-3 Subdivisions of the C Horizon Used in Illinois 37 3-4 Abbreviations and Designations for USDA Soil Texture Classes (including coarse fraction) 40 3-5 Rupture Resistance Classes 57 3-6 Field Estimation of Soil Shear Strength 69 3-7 Guide for Estimating Risk of Soil Corrosion Potential of Uncoated Steel 72 3-8 Water State Classes 74 3-9 Guide for Estimating the Class of Saturated Vertical Hydraulic Conductivity from Soil Properties 78 ------- Page 3-10 Criteria for SCS Soil Drainage Classes 79 4-1 Summary of Hand-Held Soil Sampling Devices 95 4-2 Summary of Major Types of Power-Driven Tube Samplers 97 A-1 EPA Recommended Sampling Containers, Preservation Requirements, and Holding Times for Soil Samples 114 B-1 Manufacturers and Distributors of Soil Sampling Equipment 120 Figures 3-1 USDA soil texture triangle 39 3-2 Percentage of sand sizes in subclasses of sand, loamy sand, and sandy loam basic textural classes 42 3-3 Charts for estimating proportions of coarse fragments and mottles 43 3-4 Guide for designation of mottle contrast 45 3-5 Charts for estimating pore and root size 47 3-6 Drawings illustrating some of the types of soil structure 50 3-7 Charts for estimating size class of different structural units 51 3-8 Summary of field tests for Unified (ASTM) soil textural classification 64 vii ------- via Acknowledgments This document was prepared for EPA's Center for Environmen- tal Research Information, Cincinnati, Ohio, and the Exposure Assessment Research Division of EPA's Environmental Monitor- ing Systems Laboratory, Las Vegas, Nevada. Author: J. Russell Boulding, Eastern Research Group, Inc. (ERG), Arlington, Massachusetts Project Management: Carol Grove, EPA CERI, Cincinnati, Ohio J. Jeffrey van Ee, EPA ORD, Environmental Monitoring Systems Laboratory, Las Vegas, Nevada Heidi Schultz, ERG, Arlington, Massachusetts Editing and Production: Susan Richmond, ERG, Arlington, Massachusetts David Cheda, ERG, Arlington, Massachusetts Reviewers: Noel Anderson, Geraghty and Miller, Madison, Wisconsin Robert Breckenridge, Idaho National Engineering Laboratory, Idaho Falls, Idaho Roy Cameron, Lockheed Engineering & Sciences Com- pany, Las Vegas, Nevada H. Raymond Sinclair, Jr., Soil Survey Interpretations and Geography Staff, USDA SCS National Soil Survey Center, Lincoln, Nebraska Bobby Ward, State Soil Scientist, USDA Soil Conserva- tion Service, Indianapolis, Indiana ------- How to Use This Guide This guide describes many field methods and procedures that can be used for (1) preliminary site reconnaissance, (2) detailed site and contaminant characterization/sampling for transport/fate modeling and risk assessment, and (3) remediation selection and design. All methods and procedures described in this guide are simple and inexpensive. When used early in site reconnaissance, site characterization, or remediation projects, the methods in the guide may reduce project costs by providing a basis for more efficient application of more complex and expensive field methods, when they are needed. This guide has also been designed to serve as a companion to EPA's Guide to Site and Soil Description for Hazardous Waste Site Characterization (Cameron, 1991), which also serves as the basis for the site and soil components for metals of the Environmental Sampling Expert System (ESES) under development by EPA's Environmental Monitoring Systems Laboratory, Las Vegas. Use for Preliminary Site Reconnaissance. If a soil survey prepared by the Soil Conservation Service (SCS) of the U.S. Department of Agriculture is available for the site, this guide in combination with Cameron (1991) can be used to develop preliminary interpretations concerning the potential for site and soil conditions to facilitate or inhibit contaminant transport. Use for Detailed Site and Contaminant Characterization: 1. To assist field personnel in preparing for a visit to a contaminated site by providing checklists to ensure that no documents or equipment are accidentally left behind (see Forms 1-2 and 1-3 in Chapter 1). Ix ------- 2. To provide a concise, but comprehensive, reference source for methods of describing and analyzing site and soil characteristics in the field that require only visual/tactile observation or very simple equipment. Chapter 2 provides this information for site characteristics. Chapter 3 provides this information for soil characteristics, placing special emphasis on soil description procedures of the U.S. Soil Conservation Service. Abbreviations and codes that can be used for specific soil features are suggested to facilitate notetaking. Where soil conditions favor use of a soil probe (no coarse fragments), description procedures outlined in Appendix A.1 may be useful for characterizing soils at a site prior to sampling for detailed chemical characterization. 3. To assist in selecting and obtaining alternative soil sampling equipment if unforeseen problems at the site prevent use of sampling procedures specified in the Soil Sampling and Quality Assurance Plans. Chapter 4 provides information on sampling equipment characteristics. A series of Appendices describe some standard soil sampling and handling protocols that may help address quality control concerns related to alternative procedures that may be required by unforeseen site conditions. 4. To facilitate use of EPA's Environmental Sampling Expert System (see Section 1.6). Use for Modeling and Remediation Selection/Design. When site soil parameters that are required for modeling or remediation selection/design are known, the appropriate sections of this guide can be used for data collection. Characterizing Soils for Hazardous Waste Site Assessments (Breckenridge et al., 1991) and Cameron (1991) may assist in identifying soil parameters of interest. ------- Chapter 1 Field Methods, Equipment, and Documents This chapter provides tables and checklists that can be used to help select specific field methods, and to iden- tify equipment and documents that should be assembled prior to going into the field. 1.1 Nature of Soil Pollutants and Surface Pollution Situation Before beginning field sampling and charac- terization, it is necessary to have some knowledge of the nature of soil pollutants at a site, whether they are heavy metals, toxic organics, or both, and of the areal extent of pollution. EPA's Environmental Sampling Expert System (ESES) defines two major types of surface pollution situa- tions related to the areal distribution of the contaminants: (1) large (covers a wide area, primarily on the surface), and (2) localized (areas usually polluted near the source). Once all available site information has been evaluated, an exploratory soil sampling program may be undertaken to further define the nature and extent of soil pollutants, before developing a detailed soil sampling plan. Soil descriptions of near-surface soil cores (1.5 to 2 m) taken on a grid at the site using procedures described in Appendix A.1 may provide valuable additional information at relatively low cost prior to developing either an ex- ploratory or detailed soil sampling plan. Existing data, or soil sampling results, will indicate the nature of pollutants. Specific contaminants of concern are broadly defined in EPA's ESES as relatively mobile and toxic (residence time in the solid phase is relatively short, enhancing toxicity) or relatively nonmobile and nontoxic (residence time in the solid phase is relatively long, decreasing potential toxicity). Field Methods, Equipment, and Documents 1 ------- Field Methods, Equipment, and Documents 2 1.2 Soil Parameters for Field Sampling and Characterization This field guide assumes that: 1. Physical, hydrologic, and chemical/biological parameters of soils and contaminants have been selected for description and sampling prior to the field collection phase for characterization of a con- taminated site. 2. These parameters and methods or protocols are contained in statistically sound and detailed Soil Sampling and Quality Assurance Plans for the site. Guidance for the preparation of such plans can be found in Mason (1983), Barth et al. (1989), van Ee et al. (1990), and U.S. EPA (1986, Vol. 2, Chap. 9). Appendix D in a companion document to this field guide, Guide to Site and Soil Description for Hazard- ous Waste Site Characterization (Cameron, 1991), may provide assistance in selecting site and soil charac- terization parameters and in identifying available field, laboratory, and calculation or lookup methods for in- dividual parameters. This field guide is intended to assist in carrying out three major types of activities in the field: • Description of site and soil features based on visual and tactile observation • Field tests or measurements that involve rela- tively simple procedures and equipment • Methods for collecting undisturbed or minimally disturbed samples for physical and microbiologi- cal characterization in the laboratory Collection of samples for chemical characterization in the laboratory is not covered in detail in this guide, be- cause it is assumed that this is defined in detail in the Sampling and Quality Assurance Plans for the site. However, general protocols for sample handling and preparation and for sampling with a spade and scoop, augers, or thin-walled tube samplers are contained in Ap- pendices A.2 through A.4. Specialized field procedures involving more com- plicated equipment, such as for measuring unsaturated hydraulic conductivity, are not covered in this field guide. ------- Procedures involving such methods should be described in the Sampling Plan. 1.3 Field Description of Soils Multiple soil profile descriptions at a site can provide a great deal of information that may be useful in evaluating the variability of soil properties, and the direc- tions and potential for transport of contaminants in the subsurface. Detailed soil profile descriptions have not been commonly used at contaminated sites. One purpose of this field guide is to encourage greater use of this rela- tively easy field method. Table 1-1 summarizes the key features that should be noted in detailed soil profile descriptions and identifies the sections in this field guide that cover individual fea- tures. Preparation of a complete, detailed soil profile description requires the digging of a pit so that feature can be observed laterally as well as vertically. Although this method is time consuming, the ability to observe small- scale lateral variations in soil features associated with in- creased or reduced soil permeability, justifies, in most instances, a limited number of such soil profile descrip- tions at a site. Where soils are not rocky, a thin-wall soil probe can be used to prepare a moderately detailed soil profile description in a sufficiently short time so that larger scale variations in soil characteristics can be identified. Appen- dix A.1 describes a general protocol for description of soil cores. Table 1-1 recommends that all the features used in preparing a pit soil profile description be observed. It should be recognized, however, that the soil core may be too small a sample of the subsurface to accurately describe a number of features, such as transitions between horizon boundaries, certain types of soil structure (columnar, for example), pore and root distribution, and genetic horizons (fragipans, for example). These features are indicated with an asterisk in Table 1-1. Preparation of an accurate, detailed soil profile description requires training and experience, and such descriptions are best done under the supervision of some- one familiar with procedures developed by the Soil Con- servation Service in the U.S. Department of Agriculture. Field Methods, Equipment, and Documents ------- Field Methods, Equipment, and Documents 4 KWXXttWX-KWW'KWM'W^ Table 1-1. Suggested Soil Parameters for Field Description Parameter Section in Guide Horizons 3.1.1 USDA Texture 3.1.2 Color 3.1.3 Porosity 3.1.4 Zones of Increased Porosity/Permeability Soil structure 3.1. 5a Extrastructural cracks 3.1.5b Roots 3.1.5c Surface features 3.1. 5d Sedimentary features 3.1.5e Zones of Reduced Porosity/Permeability Genetic horizons 3.1.6a Consistency 3.1.6b Root restricting layers 3.1 .6d Compaction 3.1.6e Moisture Condition 3.2.1 Water Table 3.2.2 Saturated Hydraulic Conductivity 3.2.4 Clay Minerals 3.3.7 Other Minerals 3.3.8 Odor 3.3.2 Soil Profiles R* R R R* R* r R* R R* R* R R* r R R R" r r r Soil Samples R R R r r r r R R r R = Recommended for all situations. r = Recommended where climatic, geologic, and soil conditions make parameter significant. * Soil pit may be required for accurate description of this soil feature. ** Estimation of Ksat class based on other observable features. ------- Soil samples for chemical characterization in the laboratory should generally not double as samples for detailed soil description, because exposure to the air before placement in sample containers should be mini- mized. However, abbreviated descriptions should be made to identify the samples and possibly help in relating sample results to other soil profile descriptions. Table 1 -1 recommends that, at a minimum, soil horizon (or depth in- crements), color, texture, moisture condition, and relation- ship to the water table be observed. The table also identifies several other features (porosity, structure, and roots) for which observations would be useful, if the nature of the sample allows (soil core) and exposure to air is less of a concern (heavy metals in aerated soil). 1.4 Field Sampling and Testing A number of tests involving relatively simple proce- dures and equipment can be used to measure or charac- terize soil physical and chemical properties. Such tests are generally not as accurate as laboratory tests but have the advantage of being inexpensive and may be used for preliminary screening or selection of samples for more ac- curate laboratory testing. Form 1-1 provides a checklist of soil engineering, physical, and chemical parameters for which field tests are described in this field guide. Special sampling procedures for microbiological characterization are covered in Section 3.3.10. Before going into the field, this checklist should be used to identify the specific tests that appear to be of value for the site of interest. This procedure will assist in locating the appropriate section of the field guide where specific procedures are described, and in identifying equipment needs (see next section). 1.5 Field Equipment and Documents Form 1-2 is a checklist of over 90 items that may be required for field description, analysis, and sampling of soils. Major categories covered in this checklist include (1) documents, (2) protective equipment, (3) miscellaneous equipment, (4) site surface characterization, (5) soil description equipment/materials, (7) texture analysis and sample preparation equipment, (8) sample, equipment, Field Methods, Equipment, and Documents ------- Field Methods, Equipment, and Documents and waste containers and forms, and (9) field testing and analysis. Form 1 -3 contains a checklist of around 20 items related to quality assurance and quality control of the sam- pling process, such as (1) QA/QC forms and samples, (2) material required for sample preservation and transport, and (3) decontamination equipment. These checklists have two columns: the first is to identify those items that are needed for the site in ques- tion; the second column can be checked when the item has been obtained and packed. Required items can be identified by reviewing the site Soil Sampling Plan and Quality Assurance Plan and the checklist of field tests contained in this guide (Form 1 -1 ). 1 .6 Use of EPA's Environmental Systems Monitoring Laboratory EPA's Environmental Systems Monitoring Laboratory is developing an Environmental Sampling Ex- pert System (ESES) which ultimately will integrate a Geographic Information System and Site Description Sys- tem (including data quality objectives, quality assurance and quality control, and site description) with a Knowledge Frame Manager (for analysis, interpretation of data, and report preparation) for contaminated sites. The Guide to Site and Soil Description for Haz- ardous Waste Site Characterization (Cameron, 1991) provides the basis for the site and soil components for me- tals in the ESES. Site and soil parameters (called Ob- ject/Attributes in the ESES), are assigned "values" which have significance for contaminant transport and fate. Form 3-1 (Soil Profile and Related Information) contains space to record observations related to all the site and soil knowledge frames in EPA's ESES. Data on this form can be coded on Forms 1-4 and 1-5 (Coding Sheet for Use of ESES Site and Soil Knowledge Frames) to aid in data interpretation using the ESES or Cameron (1991). These forms also indicate the section in this guide that covers description procedures and nomenclature. Where standard SCS descriptive procedures do not readi- ly allow assignment of a "value" for the ESES, definitions used in the ESES are provided for use during field obser- vations. Cameron (1991) provides additional definitions of terms. ------- Form 1-1. Checklist of Soil Physical and Chemical Property Sampling and Field Test Procedures Soil Physical Properties Color ignition test (Section 3.1.3) Extras!ructural crack tests (Section 3.1.5b) Fragipan identification (Section 3.1.6a) Cementation test (Section 3.1.66) Bulk density (Section 3.1.6c) Pocket penetrometer test (Section 3.1.6e) Soil temperature regime characterization (Section 3.1.8) Soil moisture (Section 3.2.1) Water table estimation (Section 3.2.2) Available water capacity (Section 3.2.3) Saturated hydraulic conductivity class estimation (Section 3.2.4) Soil drainage class placement (Section 3.2.4) Soil Engineering Properties Unified (ASTM) texture (Section 3.1.7a) Atterberg limits (Section 3.1.7b) Shear strength (Section 3.1.7c) Shrink-swell tests (Section 3.1.7d) Corrosivity characterization (Section 3.1.7e) Soil Chemical Properties Organic matter ignition test (Section 3.3.1) Cation exchange capacity/exchangeable acidity (Section 3.3.3) pH (Section 3.3.4) Redox potential (Section 3.3.5) Electrical conductivity (Section 3.3.6) Clay minerals—nitrobenzene test (Section 3.3.7) Calcium carbonate—HCI test (Section 3.3.8) Soluble salts—chloride and sulfate (Section 3.3.8) Gypsum acetone test (Section 3.3.8) Iron oxides—ignition and streak tests (Section 3.3.8) Manganese—streak and hydrogen peroxide tests (Section 3.3.8) Sampling for soil microbiota (Section 3.3.10) Field Methods, Equipment, and Documents ------- Field Methods, Equipment, and Documents mmy&m&>&mzx»s»mim&xi»>&mi^M^fm&ms». Form 1-2. Soil Description/Sampling Equipment and Documents Checklist Check first column to identify needed items. Check second column when item has been obtained and packed prior to leav- ing for the field. Documents Sampling plan Quality assurance plan Health and safety plan Log books Protective Equipment Protective suits Boots Gloves (inner/outer) Duct tape Respirators, respirator cartridges, and/or dust masks Raingear and/or warm clothing Insect repellent (should not contain chemicals that will be target analytes or in matrix spikes) Miscellaneous Keys for access to site, graphite lubricant for locks Folding table Camera and film Flashlight and extra batteries Toolbox, including hacksaw Calculator Site Surface Characterization Max/min thermometer Humidity gage or sling psychrometer Hand-held anemometer 4-ft staffs with flags or flagging (for wind direction indicators) Clinometer for slope measurement 6-ft rod and colored tape to mark eye level for clinometer readings (Continued) ------- Form 1-2. (Continued) Soil Description Equipment/Materials Field notebook, pencils, ballpoints, and markers Clipboard with cover Microcassette recorder, spare microcassettes and batteries (optional for notetaking) Map of soil sampling locations Soil profile and related information forms (Form 3-1) Unified (ASTM) texture determination form (Form 3-2) Other soil data collection forms: Carpenters rule (for measuring horizon depth) and/or steel tape 30-cm by 2-m plastic sheet for placing soil cores for description Munsell Soil Color book Knife (for cleaning exposed soil surfaces) Nails (for marking horizon boundaries) 10 power hand lens (surface features, mineral identification, carbonate test) Sand size and coarse fragment determination scales 1/2 in. mesh (for estimating areal distribution of features on excavated profile) Tile probe (soil depth determination in rocky soil) Stiff, 2-mm wire for crack depth measurement Graded sand of uniform color for crack characterization (excavation method) Stereoscopic microscope (5 to 6 in. working distance, 20 to 80 power) Small high intensity 6v flexible lamp (for illuminating microscope) (Continued) :::::::::::::::::*::W*:*y*ra^ Field Methods, Equipment, and Documents 9 ------- Field Methods, Equipment, and Documents 10 :*:•:•:%*:*:•:•:*:•:•:•:•:•:•:•:• ww Form 1-2. (Continued) Soil Sampling Equipment (specified in Sampling Plan) Hand-held sampling devices (Check all items that may be required at the site.) Shovel/spade Spoons Scoops Screw-type auger Barrel/bucket auger (regular, sand, mud, stone, planer, in situ soil recovery) Thin-walled tube Chisel rock breakers Crescent wrenches, vice grips, pipe wrenches (for changing drill rod length and sampling tips) Weighted plastic mallet Tube sampler cleaning tool Power-driven sampling devices (Check types planned for use at the site.) Auger Split spoon Thin-walled tube samplers Texture Analysis and Sample Preparation Equipment Sieves (3 in., 1/2 in., No. 10, for characterizing coarse fraction) Hanging spring scale with canvas sling or pail (for weighing coarse fragments) No. 10 mesh stainless steel screens (for TOC and semivolatile samples) No. 10 mesh Teflon® screens (for metals samples) Compositing bucket/mixing containers (stainless steel, glass, Teflon®-lined suitable for all contaminants; aluminum pans for any contaminant except Al; plastic for metals analysis only) 1 -m square piece of suitable plastic, canvas, or rubber sheeting (for sample preparation) (Continued) ------- Form 1-2. (Continued) Sample, Equipment, and Waste Containers and Forms Brown plastic trash bags for dirty equipment White plastic trash bags for clean equipment Ziplock type plastic bags for protecting equipment that cannot be decontaminated (cameras, notebooks, etc.) Sample containers (sealed clean and labeled plus 20 percent) Plastic bags for sample containers Sample description/identification forms Sample labels/tags Soil moisture tins Field Testing and Analysis Photoionization detector (PID) or flame ionization detector (FID) Calibration gases for meters Hydrogen gas for FID Specialty gas meters (HCN, etc.) Explosimeter Scale/balance (0.1 gram accuracy) for weighing of samples (moisture, bulk density, organic matter) Infrared lamp, or small oven, and thermometer scaled to at least 120°C (for drying samples for moisture, bulk density, and organic matter tests) Portable gas soldering torch and porcelain crucible or small tin (not Al) with wire bracket or tongs (for ignition tests) Saran-ketone mixture (bulk density clod method) or sand-measuring or rubber balloon apparatus (bulk density excavation method) pH measurement kit and standard solutions (spare batteries, if necessary), and/or color dyes, pH test strips Glass or plastic stirring rod (pH test) Small containers for mixing water and soil (pH, specific conductance tests) (Continued) Field Methods, Equipment, and Documents 11 ------- Field Methods, Equipment, and Documents 12 X*x*x*x*:':'K*x*K*:*:'XW Form 1-2. (Continued) Field Testing and Analysis (Continued) Conductivity meter and specific conductance standards Quart container of distilled deionized water in squeeze bottle (for pH, texture, and carbonate tests) Common laboratory spatulas (for texture tests) Porcelain spot plate (carbonate test, iron oxide, manganese oxide scratch tests) Clean glass rod (carbonate test) 10-percent HCI in plastic squeeze bottle (carbonate test) Solution of malachite green in nitrobenzene (for clay minerals test) Hydrogen peroxide (manganese test, organic matter tests) Test tubes or plastic vials and 5-percent silver nitrate, and 5-percent barium chloride solutions (chloride and sulfate tests) Small stoppable bottle, filter paper, and acetone (gypsum test) Field sampling glove box and core paring tool (for aseptic core samples for microbiological analysis—see Section 3.3.10) ------- Form 1-3. Soi! Sampling Quality Assurance/Quality Control Checklist Check first column to identify needed items. Check second column when item has been obtained and packed prior to leav- ing for the field. Forms _ _ List of sample locations where duplicates and other QA samples are to be taken _ _ Sample alteration form (Form 3-1 ), multiple copies _ _ Field audit checklist (Form 3-2) _ _ Soil sample corrective action form (Form 3-3) QA Samples (check types specified in QA Plan)* Double-Blind Samples _ _ Field evaluation samples (FES) _ _ Low level field evaluation samples (LLFES) _ _ External laboratory evaluation samples (ELES) _ _ Low level external laboratory evaluation samples (LLELES) _ _ Field matrix spike (FMS) _ _ Field duplicate (FD) _ _ Preparation split (PS) Single-Blind Samples _ _ Field rinsate blanks (FRB) — also called field blanks, decontamination blanks, equipment blanks, and dynamic blanks _ _ Preparation rinsate blank (PRB) — also called sample bank blanks _ _ Trip blank (TB) — also called field blank Sample Preservation and Transport _ _ Chest or 6-pack cooler _ _ Ice _ _ Max/Min thermometer _ _ Chain-of-custody forms and seals _ _ Shipping forms _ _ Analytical analysis request forms, if different from chain-of-custody forms (Continued) Field Methods, Equipment, and Documents 13 ------- Field Methods, Equipment, and Documents 14 :*w*:*:o:-x-»:*:*:*:*:*:*:*xw^ Form 1-3. (Continued) Decontamination _ _ Decontamination vessel _ _ Wash solution(s) — should be specified in Sampling Plan. _ _ Garden spray cans for wash fluids _ _ Rinse solutions (acetone, deionized water) _ Labels for containerized wastes (solid or liquid) * See van Ee et al. (1 990) for more detailed discussion of these types of samples. ------- Form 1-4. Coding Sheet for ESES Site Knowledge Frames Object/Attribute Source* Nature of Heavy Test Metal Pollutants results (enter elements concentrations — see Table 3-1 in Cameron [1991]) Climate/Weather Lookup Macrofauna and 2.6 Mesofauna Slope 2.2 Surface 2.3 Erosion/Erodibility Surface Pollution 1.1 Situations Surface Runoff 2.4 Vegetation 2.5 Wind Speed/Direction 2.1 .2 Value Mobile/ Nonmobile/ Toxic Nontoxic Humid Temperate Dry Many Common Few Steep (>1 2%) Moderate (3-1 2%) Flat (<3%) Severe Moderate Slight to none Large areas Localized areas Rapid (H, VH) Medium (M) Slow (L, VL) Ponded (N) Dense Scattered/Sparse Absent Gale Breezy Calm to light *Use observations recorded on Form 3-1 or refer to indicated section number in this guide. For lookup methods, refer to Appendix D in Cameron (1991). Field Methods, Equipment, and Documents 15 ------- Field Methods, Equipment, and Documents 16 Form 1-5, Coding -Sheet for ESES Soil Knowledge Frames Object/Attribute Bulk Density (g/cc) Cation Exchange Capacity (meq/100g soil) Clay Minerals Color Compaction Consistency Corrosivity Electrical Conductivity (Salinity, mmhos/cm) Fertility Potential Source* 3.1. 6c Lab 3.3.3 Lab 3.1.2 3.3.7 Lab 3.1.3 3.1.6e 3.1. 6b 3.1.7e Lookup 3.3.6 Lab 3.3.9 Lab Value Low(<1.3) . Medium (1.3-1. 6) High(>1.6) Low(<12) Medium (12-20) High (>20) Abundant (>27%) Mod/Slight(1-27%) None/Neg. (<1%) Dark Red and Yellow Brown Gray/Whitish Mottled High Moderate Low/Slight High Moderate Low/Weak Cemented High Moderate Low Nonsaline (<2) Slight (2-4) Moderate (4-8) Very (8-1 6) Extremely (> 16) High Moderate Low (Continued) ------- Form 1-5. (Continued) Object/Attribute Source* Horizons 3.1.1 Hydraulic 3.2.4 Conductivity (micrometers/s) Infiltration/ 3.2.5 Percolation (cm/hr) Microbiota 3.3.10 Lab Moisture 3.2.1 Conditions Lab Odor 3.3.2 Organic Matter 3.3.1 Lab Porosity 3.1.4 Reaction (p.H) 3.3.4 Value Master Horizons Transitional Disturbed Buried High(>10) Moderate (0.1 -10) Low (0.01 -0.1) Inhibited (<0.01) High (>5) Medium (1.5-5.0) Low (0.1 5-1 .5) Inhibited (<0.1 5) Abundant Common Few None Wet Moist Dry High Mod/Slight None Abundant (>4%) Moderate (2-4%) Sparse (<2%) Coarse (>5mm) Medium (2-5mm) Fine(0.5-2mm) Very fine (<0.5rnm) Acid (<6.6) Neutral (6.6-7.3) Alkaline (>7.3) (Continued) Field Methods, Equipment, and Documents 17 ------- Field Methods, Equipment, and Documents 18 w^^ Form 1-5. (Continued) Object/Attribute Source* Value Redox Potential Roots Structure Grades Surface Features Temperature Temperature Regimes Texture Classes 3.3.5 3.1.5c 3.1.5a 3.1.5d 3.1.8 3.1.8 Lookup 3.1.2 High Oxidized Intermediate Highly Reduced Many Common Few Structureless Weak Moderate Strong Prominent Distinct Faint High Medium Low Pergelic Cryic Frigid-lsofrigid Mesic-lsomesic Thermic-lsothermic Hyperthermic- Isohyperthermic Fragmental Sandy Silty Loamy Clayey Organic soils *Use observations recorded on Form 3-1 or refer to indicated section number in this guide. For laboratory and lookup methods, refer to Appendix D in Cameron (1991). ------- Chapter 2 !06SSiSeiS®®iiSS8SittSttitStiiliit Site Characteristics This chapter covers a number of weather-related factors that affect the ease or difficulty of soil description and sampling in the field (Section 2.1) and other site surface features at locations where soils are described or sampled. These features include slope (Section 2.2), sur- face erosion (Section 2.3), surface runoff (Section 2.4), vegetation (Section 2.5), and macro- and mesofauna as- sociated with the surface and subsurface (Section 2.6). 2.1 Climate and Weather Climate exerts a profound influence on soil directly through soil forming and weathering processes such as precipitation, evapotranspiration, and temperature, and in- directly by its influence on vegetation. Climate is a known factor at a site that is usually evaluated by analysis of meteorologic records from nearby weather stations, al- though in some instances detailed monitoring of meteorologic parameters such as precipitation, tempera- ture, and wind may be required as a part of site charac- terization and remediation. This guide does not cover methods for systematic monitoring of climatic factors. Weather refers to the state of the atmosphere at a site during field investigation activities. Unusual weather conditions are usually noted during the sampling and description of soils. Weather usually doesn't become a concern during field work unless conditions, such as rain or snow, adversely affect the carrying out of field proce- dures or create health and safety concerns for field per- sonnel. The major weather parameters to be monitored during field work include air temperature, wind speed and direction, and humidity. The site health and safety officer is primarily responsible for evaluating adverse weather conditions and pacing field activities accordingly, but field personnel should communicate their own feelings about working under adverse weather conditions. ::::Wi^::::::::::::y:y::::::::ftW*::W:y:;:W:^ Site Characteristics 19 ------- Site Characteristics 20 2.1.1 Air Temperature Air temperature is primarily a concern when it is at one extreme or the other. Heat becomes a special con- cern when protective clothing must be worn on site, be- cause the impervious material used increases sweating and the possibility of heat stress from dehydration. Ex- treme cold makes sampling and notetaking difficult. Max- min thermometers are relatively inexpensive and daily extremes should be recorded along with periodic observa- tions through the day, if appropriate. Wind speed (see Section 2.1.2) should be monitored when working in the winter to determine wind chill temperatures. Humidity (see Section 2.1.3) should be monitored when the climate is humid and temperatures are high. 2.1.2 Wind Speed and Direction In winter, wind speed should be monitored to es- timate wind chill temperature. Hand-held anemometers can be used for this purpose. High winds create un- favorable conditions for soil sampling, especially when soil is dry, because of the possibility of contamination from blowing surface soil and the mobilization of contaminated subsoil that is brought to the surface. When it is breezy, personnel should position themselves upwind during soil sampling, and avoid sampling in locations where con- taminated soil might blow into the exclusion area. Four- foot staffs with flags or flagging placed around the site can serve as wind direction indicators. Wind speed and direc- tion should be recorded at each location where soils are sampled. EPA's ESES defines wind speed classes as follows: Gale: >32 mph (>37 knots) Breezy: 4 to 32 mph (3 to 37 knots) Calm to light: <4 mph ( <3 knots) 2.1.3 Humidity Relative humidity, the ratio of measured atmos- pheric water vapor pressure to that which would prevail under saturated conditions, is the most commonly used measure of atmospheric moisture. For general field use, relative humidity can be measured using a humidity gage, but if very accurate measurements are desired, a sling psychrometer should be used. ------- Humidity is primarily a concern for field operations when it is very high or very low. Very high humidity as- sociated with high temperatures increases the danger of heat stress in field personnel, especially when protective clothing must be used on site. When sampling for soil moisture when the humidity is low, special care should be taken to minimize exposure of soil to the air to avoid drying before the sample is sealed. 2.2 Slope Slope is an important site feature that influences the distribution of precipitation between the soil and sur- face runoff, and the movement of soil water. Slope gradient is usually measured as a percentage, but may be measured in degrees. Both gradient and the length of the slope (to the point where surface runoff loses its energy and deposits suspended soil particles) are required for es- timating erosion using the Universal Soil Loss Equation (see Section 2.3 below). Slope shape and topographic position influence the movement of water on the surface and in the subsurface. Slope aspect affects the moisture status of soil, with southern exposures usually drier than northern exposures due to increased evapotranspiration. Soil surveys prepared by the U.S. Soil Conserva- tion Service (SCS) differentiate soil map units in upland areas by the dominant soil series and a slope range (such as 0 to 2 percent, 2 to 6 percent, 6 to 12 percent, etc.) that is based on soil management considerations. Slope classes are based on slope gradient limits as follows (Soil Survey Staff, 1991): Classes Simple Slopes Nearly level Gently sloping Strongly sloping Moderately steep Steep Very steep Complex Slopes Nearly level Undulating Rolling Hilly Steep Very steep Slope Gradient Limits (%) Lower 0 1 4 10 20 >45 Upper 3 8 16 30 60 Site Characteristics 21 ------- Site Characteristics 22 Different SCS county soil surveys may specify dif- ferent slope ranges for a slope class within the lower and upper limits identified above. The following slope features should be observed when preparing a soil description: Gradient (percent or degrees)—Measured using a clinometer and a rod with a marking at the ob- server's eye level. Siting through the clinometer up or downslope to the marker on the rod allows a direct reading in percent or degrees. Accurate readings require that (1) the line of siting is perpen- dicular to the contour of the slope, and (2) there is no change in slope gradient over the distance the siting is taken. Length (if erosion potential is evaluated). Shape—Convex, concave, or flat. Topographic position—Summit, shoulder, back- slope, footslope, toeslope, orfloodplain. 2.3 Surface Erosion and Erodibility Field evaluation of surface erosion has two com- ponents: (1) assessment of soil loss or deposition that has occurred in the past, and (2) evaluation of the future erosion potential. In upland soils, the amount of erosion can be in- ferred by comparing observed texture and color in the A and B horizons (see Section 3.1.1 for definitions of horizons) with a nearby undisturbed soil in a similar topographic setting (if available), or with a soil profile description prepared by the SCS for the soil series to which the soil belongs. The thickness of the A horizon is reduced in moderately eroded soils, and may show mixing with the B horizon if the soil has been cultivated. Rill erosion, the removal of soil through the cutting of many small, but conspicuous channels, may be evident on unvegetated soil. In severely eroded soils, most of the topsoil is missing and gully erosion (channels that cannot be obliterated by ordinary tillage) may be evident. Soils with slight to no erosion have fully developed A horizons and surface material showing little evidence of erosion. ------- In depressional areas, the thickness of soil that has accumulated as a result of accelerated erosion can be measured by finding the top of the natural A horizon, provided the eroded material can be differentiated by color, texture, and other soil features. Surface con- taminated soil preferentially concentrates in such areas, and special sampling may be desirable. Use of the Universal Soil Loss Equation (USLE) or its revised version (RUSLE) to estimate erosion potential from a site requires the following field observations: (1) slope gradient and length (see Section 2.2 above) and (2) vegetation (Section 2.5). The soil credibility factor (K) can usually be obtained from SCS soil series interpretation sheets. If classification of a soil is uncertain, the K factor can be estimated using soil erodibility nomographs (SCS, 1983). The following soil properties must be described or estimated to use these soil nomographs: (1) percent silt plus very fine sand, (2) percent sand (0.10 to 2.0 mm), (3) percent organic matter (see Section 3.3.1), (4) soil struc- ture (see Section 3.1.5a), and (5) permeability class (see Section 3.2.4). EPA's ESES defines soil erodibility classes based on estimated annual soil loss, using the USLE or RUSLE, as follows: Severe: >10 metric tons/hectare. Moderate: 2.5 to 10 metric tons/hectare. Slight: <2.5 metric tons/hectare. 2.4 Surface Runoff Surface runoff potential is important for evaluating the potential for transport of contaminants at the soil sur- face to surface streams or water bodies. SCS defines six runoff classes that can be used for qualitative comparison of runoff from different locations at a site (See Table 2-1). Placement requires measurement of the slope gradient (see Section 2.2) and measurement or estimation of the saturated hydraulic conductivity (see Section 3.2.4). Computation of runoff by SCS's Curve Number Method requires placement of soils in hydrologic groups Site Characteristics 23 ------- Site Characteristics 24 based on saturated hydraulic conductivity (Ksat—see Sec- tion 3.2.4) and water table characteristics (Section 3.2.2). If the hydrologic class of the soil of interest is not known, it can be determined using Table 2-2. 2.5 Vegetation Vegetation at a site serves as an indicator of site history and site productivity and is a major determinant in erosion potential at a site (see Section 2.3). Features observed and noted should include the nature, kind, extent, and distribution of plants and plant cover. The charts in Figure 3-3 (Section 3.1.2) for estimat- ing areal percentages of coarse fragments and mottles also can be used to estimate amount of vegetative cover. Vogel (1987) describes more precise methods for measur- ing vegetation cover such as the point-quadrant method, rated microplots, and line intercepts. Stunted vegetation or discolored leaves may be an indication of toxic effects from contaminants in the soil. In heavy metal contaminated sites, sampling of vegetation along with soil may be desirable to assess exposure through bioaccumulation. EPA's ESES defines qualitative vegetation classes as follows: Dense: Site completely covered with vegetation of predominant forms or varying composition and species, usually with slow temporal variability. Scattered to sparse: Plant cover, aerial, or soil surface vegetation, is intermittent or infrequent at site. Absent: No visible macrovegetation can be ob- served, but some scattered soil vegetation cover (e.g., algal-lichen crusts or mosses) may be evident. ------- Table 2-1. Index Surface Runoff Classes Slope Gradient (%) Concave*** <1 1-5 5-10 10-20 >20 Runoff Classes* Ksat Class" VH N N N VL VL L H N N VL L L M MH N N L M M H ML N L M H H VH L N M H VH VH VH VL N H VH VH VH VH * Abbreviations: Negligible-N; very low-VL; low-L; medium-M; high-H; and very high-VH. These classes are relative and not quantitative. ** See Section 3.2.4 for definitions. Assumes that the lowest value for the soil occurs at <0.5 m. If the lowest value occurs at 0.5 to 1 m, reduce runoff by one class. If it occurs at >1 m, then use the lowest saturated hydraulic conductivity <1 m. VL Ksat is assumed for soils with seasonal shallow or very shal- low free water. *** Areas from which no or very little water escapes by flow over the ground surface. Table 2-2. Criteria for Placement of Hydrologic Soil Groups Criteria* Soil Group* A B C D Ksat >55 5.5 to 55 .55 to 5.5 <.55 Free Water Depth/Duration DV**(>1.5m) DorDV(>1 m) >S (>0.5 cm) S or SV (0 to 0.5 m); T through P * The criteria are guidelines only. They are based on the as- sumption that the minimum saturated hydraulic conductivity occurs within the uppermost 0.5 m. If the minimum occurs between 0.5 and 1 m, then Ksat for the purpose of placement is increased one class. If the minimum occurs below 1 m, then the value for the soil is based on values above 1 m using the rules previously given. ** See Section 3.2.2 for meaning of abbreviations. Site Characteristics 25 ------- Site Characteristics 26 2,6 Macro- and Mesofauna Soil macrofauna, such as burrowing animals, earthworms, and larger insects that can be measured in centimeters, and mesofauna, such as smaller mollusks and arthropods, affect soil profiles by mixing, changing, and moving soil material. The activities of soil macro- and mesofauna tend to increase the secondary permeability of soil horizons and thus provide preferential paths for sub- surface migrations of contaminants. Surface features that animals produce include ter- mite mounds, ant hills, heaps of excavated earth beside burrows, the openings of burrows, paths, feeding grounds, and earthworm or other castings. These features can be described in terms of (1) number of structures per unit area, (2) proportionate area occupied, and (3) volume of aboveground structures. Krotovinas, irregular tubular streaks of soil material with contrasting color or texture, resulting from filling of tunnels made by burrowing animals, may be observed in soil pits. Where soils are contaminated with heavy metals, collection of soil macro- or mesofauna for chemical analysis may provide evidence of bioaccumulation for ex- posure assessment, provided that similar species on near- by uncontaminated soils with similar characteristics can be obtained for comparison. Macro- and mesofauna are described for EPA's ESES by species and abundance per unit area as follows: Class Number/m2 Macrofauna Many >10 Common 5-10 Few 1-5 None 0 Mesofauna Many >100,000 Common 100-100,000 Few 10-100 None <10 ------- Chapter 3 Field Description and Analysis of Soils This chapter presents field test and soil description pro- cedures that can be done visually or with simple field equipment. Appendix D of Cameron (1991) identifies ref- erences where more detailed information can be found about more complex field procedures for measuring specific soil parameters. For nonengineering applications, the soil taxonomy of the U.S. Soil Conservation Service is the most widely used system for describing and classifying soils. The basic reference on this system is Soil Taxonomy, Agricultural Handbook 436 (Soil Survey Staff, 1975). Revisions and amendments are periodically published in looseleaf form as Soil Taxonomy Notes. The most recent edition of the pocket-sized Keys to Soil Taxonomy (Soil Survey Staff, 1990) is the best concise reference source on classifica- tion of soils, and is recommended for use in the field (price and ordering information are given in the reference sec- tion). Unfortunately, the most up-to-date reference for current SCS soil description procedures, a major revision of Agricultural Handbook 18, Soil Survey Manual (Soil Survey Staff, 1991), is not yet readily available. Most of the soil description procedures in this guide are taken from the latest version of the new manual. Other important ref- erences for field investigation procedures for noncon- taminant parameters are published by SCS (1971 and 1984). Procedures from the geologic literature for descrip- tion of unconsolidated material below the weathering zone are also included in this chapter. Field Description and Analysis of Soils 27 ------- Field Description and Analysis of Soils 28 3.1 Soil Physical Parameters A number of soil physical parameters such as coarse fragments, pores, mottled colors, roots, lateral fea- tures, and mineral concentrations require area measure- ments on the ground surface or the wall of a pit for conversion to volume or weight percentages. Section 3.1.2 includes charts for estimating proportions of a fea- ture at the surface, but if more accurate measurements are desired, traverses on an arbitrary grid can be used. Coarse screening such as hardware cloth or rat wire with a 1/2-inch mesh makes a convenient and durable grid for small and medium objects as large as 2 to 4 inches (5 to 10 cm). A screen 1 foot square is suitable for most situations. Marking every fifth, tenth, or twentieth wire in each direction, or at intersections, with paint makes counting easier. When the screen is tacked over the area to be measured, a small wire pointer pushed into the soil at the intersection of each wire allows the most accurate counting of features in the grid. SCS (1971, Section I2.7) provides additional guidance on making linear and volume measurements. Form 3-1 provides a sample form for description of a soil profile. This form follows the sequence of features for description of soil horizons in this chapter. Standard forms used by SCS and coding sheets for computer programs, which" automatically prepare narrative soil profile descriptions, can also be used. A dug pit that provides a lateral view of soil horizons is best for accurate and detailed soil profile description. Thin-walled tube samplers are the next best alternative. Appendix A.1 outlines procedures for soil descriptions using tube samplers and augers. Com- prehensive descriptions using one or two pits, along with less detailed tube/auger sampler descriptions at each sampling site, would probably provide the maximum amount of useful data. ------- Form 3-1. Soil Profile and Related Information Soil Type or Designation Date ID No. Described by Location Elevation Wind Speed/Direction (2.1.1) _ Other Weather Conditions (2.1) Parent Material Topographic Position (2.2) Slope Gradient Slope Length Slope Shape Slope Aspect Erosion (2.3) Surface Runoff Class (2.4) Vegetation (2.5) Macro- and Mesofauna (2.6)_ Engineering Properties (3.1.7) USCS Texture Shear Strength Corrosivity_ Soil Temperature/Regime (3.1.8) Water Table (3.3.3) Depth (Max/Min) Thickness, if Perched Duration Drainage Class (3.2.4) Infiltration (3.2.5) Redox Potential (3.3.5) Electrical Conductivity (3.3.6) Fertility Potential (3.3.9) Soil Classification Additional Notes (Continued) ^ Field Description and Analysis of Soils 29 ------- Field Description and Analysis of Soils 30 x>HwXw:vX*:vM-:*:w-X':w Form 3-1. (Continued) Horizon (3.1.1)* Depth Boundary Texture (3.1.2) Fines (<2 mm) >2 mm % >2 mm description Color (3.1.3) Moist Dry Mottles (3.1.3) Color Description Pores (3.1.4) Structure (3.1.5a) Roots(3.1.5c) Surface Features (3.1.5d) Sedimentary Features (3.1.5e) Consistency (3.1.6b) Moist/Dry Cementation Bulk Density (3.1.6c) Compaction (3.1.6e) Water State (3.2.1) AWC (3.2.3) Ksat (3.2.4) OM (3.3.1) Odor (3.3.2) CEC (3.3.3) pH (3.3.4) Clay Minerals (3.3.7) Carbonates (3.3.8) Other Minerals (3.3.8) Microbiota(3.3.10) ------- 3. 1. 1 Soil Horizons Table 3-1 provides a key to SCS's 1981 system for designating master horizons, layers, and transitional horizons, along with the lower case letters that are used for subordinate distinctions within horizons. If an SCS soil survey of the site is available, the soil series descriptions should be reviewed for a general idea of the types of horizons likely to be encountered. SCS soil surveys pub- lished prior to around 1984 contain soil profile descriptions using the 1962 system. Table 3-2 compares the 1962 and 1981 systems and provides approximate equivalencies where nomenclature has changed. In glaciated areas, it may be useful to make more precise designations for the C horizon. Table 3-3 shows subdivisions and diagnostic characteristics of four types of C horizons recognized by the Illinois State Geological Sur- vey. If this notation is used in the description, it should be clearly noted on the field sheet. Key features to record are the depth and charac- teristics of the boundary between horizons. The following nota- tion can be used to describe horizon boundaries or contacts: Distinctness a — abrupt (<2 cm) c — clear (2-5 cm) g — gradual (5-1 5 cm) d — diffuse (>5 cm) Topography s — smooth (nearly a plain) c — clear (pockets with width > depth) i — irregular (pockets with depth > width) b — broken (discontinuous) A disturbed soil has been truncated or manipulated to the extent that its principle pedogenic characteristics have been severely altered or can no longer be recognized. A buried soil, or paleosol, is covered by an alluvial, loessial, or other depositional surface mantle of more recent material, and usually lies below the weathering profile of the soil at the land surface. As noted in Section 3.1 .5, buried soils may have high secondary porosity com- pared to materials above and below it, forming a potential zone for preferential movement of contaminants. :::::::^^^ .. .. .. Field Description and Analysis of Soils 31 ------- Field Description and Analysis of Soils 32 s*:*:*:*:*:*:*^*:*^ Table 3-1. Definitions and Designation Nomenclature for USDA Soil Horizons and Layers (Adapted from SSSA, 1987) Master Horizons and Layers O Horizons—Layers dominated by organic material, except lim- nic layers that are organic. A Horizons—Mineral horizons that formed at the surface or below an O horizon and (1) are characterized by an ac- cumulation of humified organic matter intimately mixed with the mineral fraction and not dominated by properties charac- teristic of E or B horizons; or (2) have properties resulting from cultivation, pasturing, or similar kinds of disturbance. E Horizons—Mineral horizons in which the main feature is loss of silicate clay, iron, aluminum, or some combination of these, leaving a concentration of sand and silt particles of quartz or other resistant materials. B Horizons—Horizons that formed below an A, E, or O horizon and are dominated by (1) carbonates, gypsum, or silica, alone or in combination; (2) evidence of removal of car- bonates; (3) concentrations of sesquioxides; (4) alterations that form silicate clay; (5) formation of granular, blocky, or prismatic structure; or (6) a combination of these. C Horizons—Horizons or layers, excluding hard bedrock, that are little affected by pedogenic processes and lack properties of O, A, E, or B horizons. Most are mineral layers, but limnic layers, whether organic or inorganic are included. R Layers—Hard bedrock including granite, basalt, quartzite, and indurated limestone or sandstone that is sufficiently coherent to make hand digging impractical. Transitional Horizons Two kinds of transitional horizons occur. In one, the properties of an overlying or underlying horizon are superimposed on properties of the other horizon throughout the transition zone (i.e., AB, BC, etc.). In the other, distinct parts that are charac- teristic of one master horizon are recognizable and enclose parts characteristic of a second recognizable master horizon (i.e., E/B, B/E, and B/C). Alphabetical Designation of Horizons Capital letters designate master horizons (see definitions above). Lowercase letters are used as suffixes to indicate specific char- acteristics of the master horizon (see definitions below). The lowercase letter immediately follows the capital letter designation. (Continued) ------- Table 3-1. (Continued) Numeric Designation of Horizons Arabic numerals are used as (1) suffixes to indicate vertical sub- divisions within a horizon and (2) prefixes to indicate discon- tinuities. Prime Symbol The prime symbol (') is used to identify the lower of two horizons having identical letter designations that are separated by a horizon of a different kind. If three horizons have identical designations, a double prime (") is used to indicate the lowest. Subordinate Distinctions within Horizons and Layers a — Highly decomposed organic material where rubbed fiber content averages <1 /6 of the volume. b — Identifiable buried genetic horizons in a mineral soil. c — Concretions or hard nonconcretionary nodules of iron, aluminum, manganese, or titanium cement. e — Organic material of intermediate decomposition in which rubbed fiber content is 1/6 to 2/5 of the volume. f — Frozen soil in which the horizon or layer contains permanent ice. g — Strong gleying in which iron has been reduced and removed during soil formation or in which iron has been preserved in a reduced state because of saturation with stagnant water. h — Illuvial accumulation of organic matter in the form of amorphous, dispersible organic matter-sesquioxide complexes, where sesquioxides are in very small quantities and the value and chroma of the horizons are <3. i — Slightly decomposed organic material in which rubbed fiber content is more than about 2/5 of the volume. k — Accumulation of pedogenic carbonates, commonly calcium carbonate. m — Continuous or nearly continuous cementation or induration of the soil matrix by carbonates (km), silica (qm), iron (sm), gypsum (ym), carbonates and silica (kqm), or salts more soluble than gypsum (zm). n — Accumulation of sodium on the exchange complex sufficient to yield a morphological appearance of a natric horizon. (Continued) Field Description and Analysis of Soils 33 ------- Field Description and Analysis of Soils 34 ti$#H8^^ Table 3-1. (Continued) o — Residual accumulation of sesquioxides. p — Plowing or other disturbance of the surface layers by cultivation, pasturing, or similar uses. q — Accumulation of secondary silica. r — Weathered or soft bedrock including saprolite; partly consolidated soft sandstone, siltstone, or shale; or dense till that roots penetrate only along joint planes and which is sufficiently incoherent to permit hand digging with a spade. s — Illuvial accumulation of sesquioxides and organic matter in the form of illuvial, amorphous dispersible organic matter- sesquioxide complexes, if both organic matter and sesquioxide components are significant and the value and chroma of the horizon are >3. t — Accumulation of silicate clay that either has formed in the horizon and is subsequently translocated or has been moved into it by illuviation. v — Plinthite which is composed of iron-rich, humus-poor, reddish material that is firm or very firm when moist and that hardens irreversibly when exposed to the atmosphere under repeated wetting and drying. w — Development of color or structure in a horizon but with little or no apparent illuvial accumulation of materials. x — Fragic or f ragipan characteristics that result in genetically developed firmness, brittleness, or high bulk density. y — Accumulation of gypsum. z — Accumulation of salts more soluble than gypsum. ------- Table 3-2. Comparison of the 1962 and 1981 USDA Soil Horizon Designation Systems Alphabetical Designation of Horizons Capital letters designate master horizons in both systems, but there are some changes in specific letter designations (see below). Lowercase letters are used as suffixes to indicate specific char- acteristics of the master horizon in both systems, but there are some changes in specific letter designations (see below). In the 1981 system, the lowercase letter always immediately follows the capital letter designation. Numeric Designation of Horizons 1962 System: Arabic numerals used as suffixes to (1) indicate kind of O, A, or B horizon, and (2) indicate vertical sub- divisions of a horizon; Roman numerals used as prefixes to indicate lithologic discontinuities. 1981 System: Arabic numerals used as suffixes to indicate verti- cal subdivisions within a horizon and as prefixes to indicate discontinuities. Their use to indicate kind of O, A, or B horizon has been eliminated. Prime Symbol 1962 System: The prime used to identify the lower sequum of a soil having two sequa (horizon sequences), although not for a buried soil. 1981 System: The prime used to identify the lower of two horizons having identical letter designations that are separated by a horizon of a different kind. If three horizons have identical designations, a double prime is used on the lowest. (Continued) Field Description and Analysis of Soils 35 ------- Field Description and Analysis of Soils ......... ................ K.«SK.^ Table 3-2. (Continued) Comparisons of Horizon Designations (see Table 3-1 for definitions) Master Horizons Distinctions 1962 0 O1 O2 A A1 A2 A3 AB A&B AC B B1 B&A B2 B3 C R IIB23t 1981 O Oi.Oe Oa.Oe A A E ABorEB — E/B AC B BAorBE B/E BorBw BC or CB C R 2B13 Subordinate Horizon 1962 — b en — f g h — ca m sa — P si r ir t — — X cs sa 1981 a b c e f g h i k m n 0 P q r s t V w X y z Source: Adapted from Guthrie and Witty (1982). ------- Table 3-3. Subdivisions of the C Horizon Used in Illinois Horizon Mineralogy Carbonates Color Structure C1 Strongly altered Leached Uniform, mottled or stained C2 Altered Unleached Uniform, mottled, or stained C3 C4 Partly Unleached Uniform; altered rare stained Unaltered Unleached Uniform Some soil structure, peds with clay films; structure of parent material— blocky; layered, or massive- dominant; often porous Less soil, structure, clay films along joints; structure of parent material—blocky; layered, or massive— dominant; often porous Massive, layered, or very large blocky; conchoidal fractures; dense Massive or layered, conchoidal fractures; dense Source: Follmer et al. (1979). Field Description and Analysis of Soils 37 ------- Field Description and Analysis of Soils 38 •.-• v1.- v-. v*-1 •" -,f f. •:•• •: •" ' 3.1.2 Soil Texture Classes Soil texture, the relative proportions of silt-, sand-, and clay-sized particles (also called particle-size distribu- tion), is an important property from which many other soil parameters can be estimated or inferred. This section focuses on the USDA soil texture classification system. Many other classification systems have been developed, but of these, only the ASTM (Unified) system, which is oriented toward soil engineering applications, is covered in this field guide (see Section 3.1 .la). Figure 3-1 shows the USDA soil texture triangle. Classification is based on the fine fraction (less than 2 mm), with modifiers applied where coarse fragments are more then 15 percent by volume. For example, a sample that plots on the texture triangle as a sand, contains 40 percent rock fragments, which are mostly around 30 mm in diameter. Using Table 3-4, the adjective modifier for 35 to 60 percent coarse fragments is the dominant rock plus the word "very." The SCS adjective for coarse fragments around 30 mm is gravelly or coarse gravelly. Thus, the full texture description would be "very coarse gravelly sand." The noun used to describe the coarse fragments is peb- bles or coarse pebbles. Table 3-4 also shows simplified descriptors for the >2 mm fraction based on the Wentworth scale, which is more commonly used by geologists. Sandy soil classes are often divided into subclass- es according to the coarseness of the sand grains. Figure 3-2 shows the criteria for subclasses of sandy soils. Table 3-4 summarizes abbreviations and designations for record- ing USDA soil texture in the field. Figure 3-3 provides charts for estimating percentages of coarse fragments in a soil horizon. Field determinations based on estimated per- centages of clay and sand should be verified by laboratory analysis of samples. The following general groupings of texture classes are sometimes used (see Table 3-4 for abbreviations): Sandy (light or coarse)—s, Is Silty (medium)—si, sil, sicl Loamy (medium)—si, I, cl, scl (sil, si, sicl may be included in this category) Clayey (heavy or fine)—sc, sic, c ------- 100 40 50 60 PERCENT SAND 80 90 100 Using Materials Less Than 2.0 mm in Size. If approximately 20% or more of the soil material is larger than 2.0 mm, the texture term includes a modifier. Example: gravelly sandy loam. Example of Use: A soil material with 35% clay, 30% silt, and 35% sand is a clay loam. Figure 3-1. USDA soil texture triangle. ffiiSSBiKiMHSB^^ Field Description and Analysis of Soils 39 ------- Field Description and Analysis of Soils 40 Table 3-4, Abbreviations and Designations for USDA Soi! Texture Classes (including coarse fraction) <2 mm Fraction >2 mm Fraction (SCS) (See texture triangla, Adjective modifier Figure 3-1 ) (see text explanation) s — sand Is — loamy sand si — sandy loam I — loam si — silt sil — silt loam cl — clay loam sicl — silly clay loam sc — sandy clay sic — silty clay c — clay <15% none <15-35% dominant rock 35-60% dominant rock + very >60% (>5% fines) dominant rock + extremely >60% (<5% fines) dominant rock adjective Other Descriptive Features of >2 mm fraction Percent Roundness Mineralogy/rock type Sorting Rock Descriptors for >2 mm Fraction (SCS) Shape/Size rounded, subrounded, angular, or irregular Adjective/Noun (diameter, mm) g — gravelly/pebbles 2-76 fg — fine gravelly/fine pebbles 2-5 mg — medium gravelly/medium pebbles 5-20 eg — coarse gravelly/coarse pebbles 20-76 k — cobbly/cobbles 76-250 st — stony/stones 250-600 b — bouldery/boulders >600 Flat (long, mm) st — stony/stones 280-600 b — bouldery/boulders >600 ch — channery/channers 2-150 fig — flaggy/flagstones 150-380 (Continued) ------- Table 3-4. (Continued) Simplified Descriptors for >2 mm Fraction (IDEM) gn — pb - fpb — cpb — cb — b — granules pebbles fine pebbles coarse pebbles cobbles boulders 2-4 4-64 4-16 16-64 64-256 >256 Source: Soil Survey Staff (1991) and IDEM (1988). The USDA soil taxonomy defines particle-size classes for differentiation of the soils at the family level (Soil Survey Staff 1975,1990) as described below: Fragmental—Stones, cobbles, gravel, and very coarse sand particles with too little fine earth to fill some of the interstices larger than 1 mm in diameter. Skeletal—Rock fragments make up 35 percent or more by volume. The dominant fine earth fraction (sandy, loamy, or clayey) is used as a modifier. Sandy—Texture of fine earth is sand or loamy sand with <50 percent very fine sand; <35 percent clay; <35 percent rocks. Loamy—Texture of fine earth is very fine sand or finer; <35 percent clay; <35 percent rocks. Sub- divisions include coarse-loamy, fine-loamy, coarse- silty, and fine-silty. Clayey—Texture of fine earth is >35 percent clay; <35 percent rocks. Subdivisions include fine and very fine. 3.1.3 Soil Color Soil color is described using Munsell Soil Color charts (available from Munsell Color Company, 2441 N. Calvert St., Baltimore, MD 21218). Color is usually a good indicator of the redox status (see Section 3.3.5) of a horizon (uniform high chroma colors indicate oxidizing con- ditions; uniform low chroma colors usually indicate reduc- ing conditions; mixed chromas indicate variable Field Description and Analysis of Soils 41 ------- Field Description and Analysis of Soils 42 Basic soil class « ? <3 Loamy Sands Sandy Loams Subclass Coarse sand Sand Fine sand Very fine sand Loamy coarse sand Loamy sand Loamy fine sand Loamy very fine sand Coarse sandy loam Sandy loam Fine sandy oam Very tine sandy oam Soil separates Very coarse sand, 2.0- 1.0 mm. Coarse sand, 1.0- 0.5 mm. 25% or more Medium sand, 0.5- 0.25 mm. Less than 50% 25% or more L ass than 25 25% or more -or- % Less than 50% 25% or more L( )ssthan25 25% or more 3 Less than 25% Betw Le 0% or mon -or- een 15 and ss than 15 -or- % Less than 50% » -ar 30% -or- /„ Fine sand, 0.25- 0.1 mm. Less than 50% Less than 50% 50% or more Less than 50% Less than 50% 50% or more Less than 50% d- Less than 30% 30% or more More th Very fine sand, 0.1- 0.05 mm. Less than 50% Less than 50% Less than 50% 50% or more Less than 50% Less than 50% Less than 50% 50% or more Less than 50% Less than 30% Less than 30% 30% or more an 40% "Half of fine sand and very fine sand must be very fine sand. Figure 3-2. Percentage of sand sizes in subclasses of sand, loamy sand, and sandy loam basic texture classes (Source: Portland Cement Association, 1973). ------- 1% 5% 15% 20% 25% ?.« 30% 40% 50% Figure 3-3. Charts for estimating proportions of coarse fragments and mottles (each fourth of any one square has the same amount of black). :*s*:*:*:*K*:itt^ Field Description and Analysis of Soils 43 ------- Field Description and Analysis of Soils 44 saturation). In addition, low chroma, low value colors are often indicative of high organic matter content. Dark colors have low value (generally <3) and low chroma (generally <2). Red colors generally have hues of 10YR or 2.SYR, and values and chromas >3. Yellow colors generally have values and chromas >6 and hues of 7.5YR, 10YR, or 2.5Y. Brown colors typically have values from 3 to 6, chroma from 3 to 5, and hues of 7.5YR or 10YR. Gray or whitish colors may be of any hue with chromas <2 and values generally >3. The Munsell Soil Color charts provide precise descriptors for any soil color reading. The following data should be recorded in field description of color: Color name. Color notation (chroma, hue, value). Water state (moistor dry). Physical state (broken through ped is the stand- ard state. Others are rubbed between fingers (moist), or crushed/crushed and smoothed (dry)). Soil mottling is usually an indication of variable saturation, and is described according to abun- dance, size, and color contrast. Figure 3-3 provides charts that may help in estimating mottle abundance, and Figure 3-4 provides guidance in identifying contrast. Abbreviations, descriptors, and criteria for descrip- tion of mottles are: Abundance f — few(<2%) c — common (2-20%) m — many(>20%) Size 1 — fine (<5 mm) 2 — medium (5-15 mm) 3 — coarse (> 15 mm) Contrast (see Figure 3-4) f — faint (1 or 2 units H,C,V) d — distinct (2-4 units H,C,V) p — prominent (4-5 units H,C,V) ------- CONTRAST OF MOTTLES For Use with Munseil Color Chart 1 23456 Change in Chroma FAINT-Record as Faint Where Similar, but Low Value or Chroma. CHART DIRECTIONS: A. Select Change in HUE (None Ref. to Same Page). B. Record Greatest of VALUE or CHROMA at HUE Line Intercept (Faint, Distinct, or Prominent). Figure 3-4. Guide for designation of mottle contrast. Field Description and Analysis of Soils 45 ------- Field Description and Analysis of Soils 46 *x^^ Shape (spots, streaks, bands, tongues, tubes) Location (inped, exped) Boundaries (sharp — like a knife edge; clear- colors grade over <2 mm; diffuse — colors grade over >2 mm) Color Ignition Test An ignition test using 2 or 3 grams of soil can provide useful information for interpretation of natural soil colors. The equipment and procedures described in Sec- tion 3.3.1 for organic matter should be used, except that weighing of the samples is not required. The following provides some guidance for interpreting colors: Organic matter contributes black, brown, reddish (spodic horizons), and grayish colors. It burns away, leav- ing a whitish residue if it is the only colored material. Minerals such as quartz, which make up the bulk of sand and silt-sized particles, are mostly colorless or pale colored to gray. These particles will not change color with ignition. Mineral grains may be cemented with lime or silica or stained with iron oxide, especially in dry regions. SCS (1971, Section 17.1) describes procedures for clean- ing mineral surfaces of cement and stains. Iron oxides are red, brown, or yellow. If browns and yellows become redder and brighter with ignition, highly hydrated iron oxide (goethite) is present. Ferrous (reduced) iron is indicated by gray, blue, or green colors, and turns red when ignited to form hematite. Manganese oxides form black and purple bodies and effervesce vigorously in a 5 percent solution of hydrogen peroxide (See Section 3.3.8). Dark reddish brown and dark brown surface soils in the southeastern United States usually contain enough manganese oxides to give a positive reaction to peroxide. 3.1.4 Soil Porosity Laboratory analysis is required for accurate deter- mination of soil porosity, but field description of soil pores can provide useful qualitative data for estimating per- meability and characterization of soil variability at a site. Johnson et al. (1960) provides more detailed guidance on classification and description of soil pores. ------- Platy, Granular, or Crumb Structure Roots Pores Very Fine (less than 1 mm diameter vf vf Fine (1-2 mm diameter) Medium 2-5 mm diameter) • : • • m ^k m • Coarse (5-10 mm diameter) Very Coarse (more than 10 mm diameter) Figure 3-5. Charts for estimating pore and root size. Field Description and Analysis of Soils 47 ------- Field Description and Analysis of Soils 48 SCS describes pores according to (1) abundance, (2) size, (3) distribution within the horizon, and (4) type. Figure 3-5 can be used to estimate pore size in the field. Below are abbreviations, descriptors, and criteria for describing pores in the field: Abundance No./Unit Classes Area 1 — few <1 2 — common 1-5 3 — many >5 Size Classes Diameter Unit Area vf — very fine <0.5 mm 1 cm2 f — fine 0.5-2 mm 1 cm2 m — medium 2-5 mm 10 cm2 cos — coarse 5-1 Omm 10 cm2 vcos— very coarse >10mm 1 m2 Distribution within Horizons in — inped (most roots and pores are within peds) ex — exped (most roots and pores follow interfaces between peds) Types of Pores v — vesicular (approximately spherical or elliptical) t — tubular (approximately cylindrical and elongated) i — irregular 3.1.5 Zones of Increased Porosity/Permeability Weathering and other soil-forming processes often increase the secondary porosity and permeability of un- consolidated materials. In addition, the mode of deposition of unweathered materials may create vertical and lateral variations in permeability that should be described. In- creased secondary porosity is usually confined to the zone of soil weathering near the surface. Buried soils (paleosols) in glaciated areas represent zones of potential lateral movement of contaminants due to increased secon- dary porosity, if underlain by less permeable material. i ------- 3.1.5a Soil Structure Grades Soil structure is an important feature that affects the movement of contaminants in soil. Contaminants often move preferentially along the interfaces between soil structure units. SCS describes soil structure according to shape (see Figure 3-6 for illustrations), grade, and size (see Figure 3-7 for charts). Below are abbreviations, descriptors, and criteria for describing soil structure in the field: Grade 0 — 1 — 2 — 3 — structureless (massive or single grain) weak (poorly defined individual peds) moderate (well formed peds, but not distinct) strong (durable peds, quite evident in place; will stand displacement) Size vf — f — m — c — vc — very fine fine medium coarse very coarse pl-platy gr- granular cr- crumb <1 mm 1-2 mm 2-5 mm 5-10 mm >10 mm Shape abk- angular blocky sbk- subangular blocky <5 mm 5-10 mm 1 0-20 mm cl- columnar pr- prismatic <10 mm 10-20 mm 20-50 mm 20-50 mm 50-1 00 mm >50 mm >100 mm Accurate identification of columnar or prismatic structure generally requires a soil pit. Blocky structure can usually be identified in cores taken from thin-walled samplers, but size class cannot always be accurately identified. Augers disturb the soil too much to allow ac- curate description of soil structure. 3.1.5b Extrastructural Cracks Cracks are macroscopic vertical planar voids with a width much smaller than length and depth, which result from soil drying. Extrastructural cracks extend beyond the planar surfaces between soil structural units and represent Field Description and Analysis of Soils 49 ------- Field Description and Analysis of Soils 50 *.* * Figure 3-6. Drawings illustrating some of the types of soil structure: A, prismatic; B, columnar; C, angular blocky; D, subangular blocky; E, platy; and F, granular. ------- Shape 10 20 Platy Granular Columnar Blockv mm Crumb ' Prismatic 2 3 4 5 7 10 12 20 50 fine medium coarse coarse very fine fine medium coarse very fine fine medium Figure 3-7. Charts for estimating size class of different structural units (see also Figure 3-5 for platy, granular, and crumb structures). Field Description and Analysis of Soils 51 ------- Field Description and Analysis of Soils 52 major potential channels for increasing infiltration of water during precipitation and preferential contaminant move- ment into the soil. The presence of irreversible cracks in the soil increases ponded infiltration (see Section 3.2.5). SCS define four major types of extra-structural cracks: Surface-initiated reversible cracks form as a result of drying from the surface downward. They close after relatively slight surficial wetting and have little influence on ponded infiltration rates. Surface-initiated irreversible cracks form from freeze-thaw action and other processes, and do not close completely when rewet. They extend to the depth that frost action has occurred, and act to increase the ponded infiltration rates. Subsurface-initiated reversible cracks form in subsoils with a high shrink-swell potential as the soil dries from field capacity. They close in a matter of days if the horizon becomes moderately moist or wet. They extend to the surface (unless the surface horizon does not permit the propagation of cracks), and increase ponded infiltration and rates of soil evaporation. Subsurface-initiated irreversible cracks are per- manently present in the subsurface. Tests for Crack Characterization A crack index value may be obtained by using a blunt wire, approximately 2 mm in diameter. More detailed characterization of cracks can be accomplished by pour- ing loose sand into the crack and excavating after wetting and after the crack has closed. Penetrant cracks are 15 cm or more in depth as measured by an inserted wire. Surface-connected cracks occur at the ground surface or are covered by up to 10 to 15 cm of soil material that has very high or high saturated hydraulic conductivity with soft, very friable, or loose con- sistency. Surface connected cracks increase ponded infiltration. Crack development is primarily associated with clayey soils and is most pronounced in high shrink-swell soils (see Section 3.1.7d). ------- 3.1.5c Roots The penetration of plant roots into the soil in- creases the secondary porosity of soil, and, after the plant dies and the root decomposes, leaves channels for more rapid flow of water through the soil. The absence of roots in the near surface is also an indication of reduced porosity/permeability. A soil pit is required to accurately describe soil roots. SCS conventions for describing roots in soil are similar to those for soil pore description, although the criteria for abundance and size classes are different from those for pores. These classes are described below: Abundance No./Unit Classes Area 1 — few <1 v1 — very few <0.2 ml — moderately few 0.2-1 2 — common 1-5 3 — many >5 Unit Size Classes Diameter Area vf — very fine <0.5 mm 1 cm2 f — fine 0.5-2 mm 1 cm2 m — medium 2-5 mm 10 cm2 cos — coarse 5-1 Omm 10 cm2 vcos— very coarse >10mm 1 m2 Distribution within Horizons in — inped (most roots are within peds) ex — exped (most roots follow interfaces between peds) Figure 3-5 provides charts for estimating root size. 3.1.5d Surface Features Surface or lateral features such as clay films and silt coatings are often indicators of areas of increased per- meability in the soil. Stress formations, on the other hand, are good indicators of active shrinking and swelling of clays in the soil. SCS describes lateral features according to (1) kind, (2) amount, (3) distinctness, and (4) location. Section 13.1 in SCS (1971) provides more detailed guidance on the observation of features on ped faces. A Field Description and Analysis of Soils 53 ------- Field Description and Analysis of Soils 54 stereoscopic microscope illuminated by a high-intensity lamp is useful for more detailed observation of lateral features. Criteria for descriptors of lateral features are as follows: Kind Amount Coatings vf — very few (<5%) Clay films f — few (5-25%) Clay bridges c — common (25-50%) Sand m — many (>50%) Silt Other Stress formations Pressure faces Slickensides Distinctness Faint—Requires 10 power magnification; little con- trast in properties with material. Distinct—Detectable without magnification al- though magnifier or other tests may be required for positive identification. Contrast in properties with adjacent material evident. Prominent—Conspicuous without magnifier; properties contrast sharply with adjacent material. Location Surfaces of peds, channels, pores, primary par- ticles or grains, soil fragments, rock fragments, nodules, or concretions. 3.1.5e Sedimentary Features Sedimentary features in unweathered uncon- solidated materials often allow inferences to be made about the depositional history of the material and, when combined with particle-size distribution data, assist in the location of zones of more rapid lateral movement of con- taminants. The main features described are type and orientation. The following types and orientations are taken from the Indiana Department of Environmental Manage- ment guidelines for description of unconsoiidated material at hazardous waste sites (IDEM, 1988): ------- Type (describe thickness) Orientation 1 — bedding/lamination ver — vertical 2 — cross-stratification hor — horizontal 3 — deformation obi — oblique in bedding 4 — bedding/surface structures 5 — fossils/bioturbation 6 — massive (no structure) 3.1.6 Zones of Reduced Porosity/Permeability Low-permeability soil or other horizons in uncon- solidated material inhibit the downward movement of con- taminants. Ground water tends to perch above such zones and transport contaminants laterally. Soil features indicat- ing such zones include (1) slowly permeable genetic horizons, (2) very firm and very hard consistency classes, (3) high bulk density, (4) root restricting layers, and (5) high penetration resistance. 3.1.6a Genetic Horizons Fragipans and cemented or indurated horizons formed by the precipitation of carbonates, silica, iron oxides, or other minerals are distinctive features of certain soil series. Determination of degree of cementation re- quires wetting the sample for at least an hour (see 3.1.6b). There are substantial problems in the field iden- tification of fragipans. Witty and Knox (1989) suggest the following essential characteristics of a fragipan: 1. One or more of the subhorizons are brittle at or near field capacity throughout the subhorizon or at least in any large prismatic structural units that have horizontal dimensions of 10 cm or more and constitute 60 percent or more of the volume. 2. Air-dried fragments of 5 to 10 cm in size from any part of the horizon slake or fracture when placed in water. ^ Field Description and Analysis of Soils 55 ------- Field Description and Analysis of Soils 56 tt'ttx-x-W'X'K'X'K^M'X'f^^ 3. Roots are virtually absent, except in vertical streaks, between any large prismatic structural units that have horizontal dimensions of 10 cm or more and that constitute 60 percent or more of the volume. 4. There is evidence of pedogenesis in the form of mottles, clay films, or vertical streaks that define large prisms. Many or all fragipans also exhibit one or more of the following characteristics: 1. Relatively low vertical saturated hydraulic conduc- tivity (slow or very slow permeability), as measured or as revealed by evidence of perched water in the form of mottles, an E horizon, or seasonal seepage immediately above the pan. 2. High bulk density (commonly <35 percent porosity of the fine-earth fraction) relative to overlying horizons. 3. Large prisms defined by vertical streaks that are arranged in a polygonal pattern on a horizontal exposure. Both vertical and horizontal exposure of the horizon is required for complete description of a fragipan. 3.1.6b Rupture Resistance (Consistency) Rupture resistance, also called consistence or con- sistency, is a readily observed feature in the field. Terms used to describe rupture resistance vary depending on the moisture content of the sample tested (see Table 3-5). The very firm (moist) and very hard (dry) classes, and those that are firmer or harder, are indicative of reduced porosity/permeability. The footnotes to Table 3-5 describe the procedure for estimating rupture resistance classes. SCS recommends practice with scales to gain a more precise tactile sense of the transition between the different classes. Cementation Test. Degree of cementation can be estimated by applying the rupture resistance tests in Table 3-5 to an air-dried specimen that has then been placed in water for at least an hour. Terms used to describe ------- Table 3-5. Rupture Resistance (Consistency) Classes Moist (>DS*) Dry (DM, DV*) Conditions of Failure** Stress Applied*** Loose Very friable Friable Firm Very firm Extremely Very firm hard Rigid Very rigid Loose Specimen not obtainable — Soft Fails under very slight <8N force applied slowly between thumb and forefinger Slightly Fails under slight force 8-20N hard applied slowly between thumb and forefinger Hard Fails under moderate 20-40N force applied slowly between thumb and forefinger Fails under strong force 40-80N applied slowly between thumb and forefinger Cannot be failed between 80-1 SON thumb and forefinger but can be by applying pressure slowly with hands; fails if placed on a hard surface and gentle force applied underfoot Extremely Cannot be failed in hand, 160-800N hard but can be crushed or broken underfoot by the full body weight applied slowly Rigid Cannot be failed underfoot 800N-3J by full body weight but can be by <3J blow Very Cannot be failed by blow >3J rigid of 3J Source: Adapted from Soil Survey Staff (1991). *See Table 3-8 for definitions of abbreviations. "Standard specimens should be block-like and 25 to 30 mm on edge. If specimens smaller than the standard size must be used, corrections should be made for class estimates (i.e., a 10- cm block will require about one-third the force to rupture as will a 30-cm block). Stress is applied along the vertical in-place axis of (Continued) Field Description and Analysis of Soils 57 ------- Field Description and Analysis of Soils 58 :*x*:*:*:*x*:*x*:*:-x-x*:*xw^^ Table 3-5. (Continued) the specimen by compressing it between extended thumb and forefinger, between both hands, or between the foot and a non- resilient flat surface. If the specimen resists compression, a 1 -kg weight is dropped from progressively greater heights up to 30 cm, until rupture. ***Both force (newtons; N) and energy (joules; J) are employed. One newton is equivalent to the force necessary to accelerate a 1 -kg mass 1 meter per second per second. One joule is the ener- gy delivered by dropping a 1 -kg weight 10 cm. A tactile sense of class limits may be learned by applying pressure through the tips of the fingers or ball of the foot to postal or bathroom scales. cementation are as follows (use Table 3-5 to estimate stress applied): Class Stress Applied Uncemented <8N Weakly cemented 8-80N Moderately cemented 80-800N Strongly cemented 800N-3J Indurated >3J Other consistence classes used in the field are plasticity and stickiness. These are a function of clay con- tent and are covered in Section 3.1.7a. EPA's ESES defines the following consistency classes: High: A soil when wet that shows high cohesion of soil particles, or adhesion of soil particles to other substances. Moderate: A soil when moist that shows moderate cohesion or adhesion. Low to Weak: A soil, usually dry, that shows reduced or poor cohesion or adhesion. Cemented: A type of soil that remains hard or brit- tle after an air-dried specimen has been placed in water for at least 1 hour. 3.1.6c Bulk Density Accurate measurement of bulk density, expressed as g/cc, requires weighing a known volume of soil or determining both the weight and volume of an undisturbed ------- soil sample. Some commonly used methods are described below. Core Method. This method involves collecting a core of a known volume using a thin-walled sampler (to minimize disturbance of the soil sample), and transporting the core to the laboratory for weighing. Inserting a sam- pling cylinder inside the sampling tube allows other meas- urements to be made in the laboratory such as pore-size distribution, hydraulic conductivity, and water retention. Core samples should be placed in moisture-proof con- tainers to maintain field moisture content. Hole or Excavation Method. Bulk density can be determined directly in the field by excavating a quantity of soil, drying and weighing it (in the field or laboratory), and determining the volume of the excavation. This volume can be determined by measuring the volume of sand re- quired to fill the excavation, or placing a rubber balloon in the excavation and measuring the amount of water or some other liquid required to fill the space. SCS (1971) and Blake and Hartge (1986) describe equipment and field procedures for these methods. Coated-Clod Method. Bulk density of cohesive soils can be measured by coating a clod with a saran- ketone mixture and comparing the weights of the clod in air and water. Blake and Hartge (1986) describe this pro- cedure in detail. This procedure can be done in a field laboratory with a scale that weighs accurately to 1 gram in a range of 500 to 1,000 grams. SCS (1971) describes pro- cedures for determining the field-moist density and dry density of a clod. With these measurements, one can determine the minimum and maximum density, field mois- ture capacity, percentage of volume change, and ratio of moist and dry volumes for calculation of the coefficient of linear extensibility (COLE—see Section 3.1.7d). The bulk density at which resistance to root penetra- tion is high varies with texture as follows (SCS, 1983): Family Texture Bulk Density Sandy >1.85 Coarse-Loamy >1.80 Fine-Loamy >1.70 Coarse-Silty >1.60 Fine-Silty >1.50 Fine >1.35 Field Description and Analysis of Soils 59 ------- Field Description and Analysis of Soils 60 3,1,6d Root Restricting Layers Root restricting layers are an indicator that con- taminants will tend to move laterally along the top of the restrictive layer rather than vertically in the soil profile. SCS classifies root restricting soil layers, whether they are genetic horizons or not, based on a combination of other soil properties as follows (the sections that describe specific features are indicated in parentheses). Root depth observations are the most reliable in- dicator, with horizons incapable of supporting more than a few fine or very fine roots (see Section 3.1.5c) considered root restricting. Continuously cemented zones (see Section 3.1.6b) of any thickness are considered root restricting. Zones >10 cm below the rooting zone are con- sidered root restricting if they exhibit the following charac- teristics when water state is very moist or wet (Section 3.2.1): (1) structure is massive, platy, or is weak of any type for a vertical repeat distance of <10 cm (Section 3.1.5a); and (2) rupture resistance is very firm (firm, if sandy) or extremely firm (Section 3.1.6b), or has a large penetration resistance (Section 3.1.6e). When a root restricting layer is present, soils are classified according to the following depth classes: Very shallow <25 cm Shallow 25 to 50 cm Moderately deep 50 to 100 cm Deep 100 to 150 cm Very deep >150cm 3.1.6e Penetration Resistance (Compaction) Penetration resistance is the capacity of the soil in its confined state to resist penetration by a rigid object. It is usually reported as megapascals (1 MPa = 10 bars or 9.9 atmospheres of pressure). Large penetration resistance is an indicator of compaction or other soil fea- tures that impede vertical flow of contaminants (see Sec- tion 3.1.6a and d). Truck or tractor-mounted cone penetrometers are commonly used in engineering investigations and are increasingly being used to charac- terize the subsurface at contaminated sites. ------- For soil descriptions, the pocket penetrometer, a hand-operated, calibrated-spring penetrometer, is a useful tool for helping identify root restricting layers. It is simple to operate, and can be pushed into the soil surface, core samples, or soil exposed in an open pit investigation. Penetration resistance depends strongly on water state (Section 3.2.1), which should be specified. Orienta- tion of the axis of insertion should also be specified. SCS defines penetration resistance classes based on the pres- sure required to push a pocket penetrometer with a diameter of 6.4 mm a distance of 6.4 mm into the soil in about 1 second, as follows: Classes Penetration Resistance (MPa) Small <0.1 Extremely low <0.01 Very low 0.01-0.1 Intermediate 0.1-2 Low 0.1-1 Moderate 1-2 Large >2 High 2-4 Very high 4-8 Extremely high >8 Compacted near-surface zones resulting from equipment traffic or tillage will have large penetration resistance, and higher rupture resistance (Section 3.1.6b) and bulk densities (Section 3.1.6c) than undisturbed near- surface horizons. Soil Survey Staff (1991) and Bradford (1986) provide further guidance on use and interpretation of pocket penetrometer readings. EPA's ESES uses the following soil compaction classes: High: Surface soils have been subject to high com- paction and consequent effects on soil structure, such as by vehicular and foot traffic, or livestock. Moderate: Surface soils have been less subjected to compaction, either through reduced applications and frequency of pressure on surface soils or be- cause the soil structure is more resistant to compaction. Field Description and Analysis of Soils 61 ------- Field Description and Analysis of Soils 62 Low to Slight: Surface soils are only slightly af- fected by compaction, either because of resistance to compaction or because they are less subject to application of compacting stressor. 3.1.7 Soil Engineering Parameters and Properties Texture, clay content (amount and types of clays), and strength behavior at different moisture contents are the key properties affecting soil engineering. A number of classification systems have been developed for the selec- tion of soil materials and design of foundations and earthen structures. The ASTM (Unified) soil classification is the most widely used at contaminated sites and is the only one covered in this guide. Only field procedures for preliminary estimation of soil engineering properties are covered here. Laboratory tests are required for accurate determination of soil en- gineering properties. Once the Unified soil class has been identified, other properties such as permeability and suitability for different types of engineering applications can be estimated using Figure 4-14 in SCS (1990). 3.1.7a Unified (ASTM) Texture Form 3-2 can be used to record the results of 11 tests for field classification of soil texture for engineering uses. These tests are drawn from Brown et al. (1991), SCS (1990), and Soil Survey Staff (1991). Figure 3-8 sum- marizes how the results of these tests are used to es- timate texture in the Unified soil classification system. Procedures for specific tests identified in Figure 3-8 are described below, along with some alternative versions described by Soil Survey Staff (1991): Test 1 - Coarse-Grained Soil Test a. Spread a sample of soil on a flat surface (clip- board) and examine the particles. b. Approximate the grain size by visual inspection. c. If more than 50 percent of the grains are easily distinguished by the unaided eye, the material is a coarse soil; if less than 50 percent of the grains are easily distinguished by the unaided eye, the material is a fine soil. ------- Form 3-2. Unified (ASTM) Field Texture Determination Form (adapted from Brown et al., 1991) Sample No. Site: Date: Sampling Location: Person(s) Performing Test:. SANDS AND GRAVELS Test 1 (coarsegrained) Test 2 (gravel) Tests (finegrained) COMMENTS: SILTS AND CLAYS Test 4 (plasticity) Test 5 (ribbon) Test 6 (liquid limit) Test 7 (clod strength) Test 8 (dilatancy) Test 9 (toughness) Test 10 (stickiness) Test 11 (organic soils)_ COMMENTS: tftWfcWSWSfc::^ Field Description and Analysis of Soils 63 ------- F/e/d Description and Analysis of Soils 64 ^ 3 i JD O c n a 1 O) 0 c o (0 .2 I i c. C3 I (0 0) E (0 Q) N i o s c I s "5 * D) i 10 o d> .H 0 \ 1 (X • CM CLEAN GRAVELS Will not leave a stain on a wet palm 5 Nonplastic fines O U Plastic fines 1* DIRTY GRAVELS Will leave a stain on a wet palm ,2 CM £*- in 1 CO "o C CO Q. 1 D) "3 •6 I 1 1 tf) •o i a e O) c o D) O 5 u. tn .E 1 *0> 'D I H I _N •s O CO o 1 c o a c i Q. 0) o ««M CLEAN SANDS Will not leave a stain on a wet palm 0) Nonplastic fines O tn Plastic fines I* DIRTY SANDS Will leave a stain on a wet palm 1* o K(/>cn£u.£ «)£ Jocco o^ ts'5-6'2'5 o g, HOOco5j: E S.E o>>£ o S 0 c o z d j i § X u Very High SS3NIXOI1S g Medium to High Medium if SS3NHODO1 •D 1C None to Very Slow 0 §0) _g cnz 1 NOUOVSd AONVi\niQ-8 isei 0 o>£ §.2> Ztn Medium to High 2£ I! coE x: D) 2x II HiON3dlS ONIHSHdO o in V S V g A S A uwn oiinon-9 »sej. 0) I 1 D) g Very Strong Noaaid-s isei D SOILS f nftho 1 Test 3 FINE-GRAINE material (by weight) is individual grains not visible to the naked eye. * c g i> * 0 | i- c i t c c : i i 1 e i " t 3 X T i r 3 i f K 3) i- 5 3 > i > •* 1 I i 1 Test 11-HIGHLY ORGANIC SOILS Readily identi Figure 3-8. Summary of field tests for Unified (ASTM) soil textural classification (Source: SCS, 1990). ------- d. If some of the particles could be aggregates of fine particles, saturate a small sample of the soil with water. e. Rub a large marble-sized (2 cm) sample between the thumb and forefinger. Sand grains (coarse material) will feel rough and gritty, whereas aggregates of fine materials will break down and feel silky. Alternative Jar Method (Soil Survey Staff, 1991) f. Thoroughly shake a mixture of soil and water in a straight-sided jar or test tube, and allow the mixture to settle. g. Sand sizes will fall out first, in 20 to 30 seconds; successively finer particles will follow. Estimate the proportions of sand and fines from their relative volumes. Test 2 - Sand/Gravel Tests 2.a Gravel/Sand a. Spread a representative sample of soil on a flat surface. b. If more than one-half of the visible grains are greater than 2 mm, the material is gravel; if they are not, it is a sand. 2.b Clean/Dirty Test c. Remove any coarse material greater than 2 mm in diameter. d. Saturate the remaining materials with water and work it with your hands. e. Hands will not be stained when fines are less than 5 percent (GW or GP; SW or SP); hands will be stained when there is more than 12 percent fines, and weak casts can be formed (GM or GC; SM or SC). 2.c Sorting Test f. Take a second sample of soil and place it on a flat surface. Spread it out and observe the grain size distribution. g. If coarse materials consist of evenly distributed particle sizes, the material is well graded (GW or SW); if they are chiefly of one size particle or large ::::::::::::::¥:::S^ Field Description and Analysis of Soils 65 ------- Field Description and Analysis of Soils 66 and small particles without intermediate sizes, the material is poorly graded (GP or SP). Test 3 - Fine-Grained Test a. When Test 1 indicates fine-grained soils, complete Tests 4 through 7 to determine if the material is clayey or silty. b. If Test 2b indicates dirty sands or gravels (>12 per- cent fines), complete Test 4 to determine whether fines are plastic or nonplastic. Test 4 - Plasticity Test a. Wet and mold a small 2 x 2 x 2 cm (3 teaspoons) soil sample so that it can be rolled into a thread without crumbing. The material will not stick to the hands if the correct amount of water is added. b. Roll the moist soil with the palm of the hand on any clean, smooth surface, such as a piece of paper or clipboard, to form a coarse thread and pull it apart. c. Observe difficulty of pulling thread apart: GC, SC, CH, or CL = tough (hard to pull apart); GM, SM, or MH = medium tough; GM, SM, or ML = weak (easily pulled apart). Alternative Plasticity Test (from Soil Survey Staff, 1991) d. Find the minimum thickness a 4-cm long roll must have to support its own weight: nonplastic = >6 mm; slightly plastic = 4-6 mm; moderately plastic = 2-4 mm; very plastic = <2 mm. Test 5 - Ribbon Test a. Take a quantity of soil measuring at least 2x2x2 cm (3 teaspoons). Square and wet it with water until it reaches a plastic state. This condition prevails when the soil contains just enough mois- ture so that it can be rolled into 3-mm diameter threads. These threads or ribbons are formed by squeezing and working the sample between the thumb and forefinger. Plastic limit is governed by clay content. b. Observe properties of ribbon: ML = weak, (breaks easily); MH = hard (does not break easily); CL = flexible with medium strength; CH = strong and flexible. ------- Test 6 - Liquid Limit Test (from SCS, 1990) a. Take a pat of moist soil with a volume of about 8 cc (1.2 in.3) and add enough water to make the soil soft but not sticky. b. Rapidly add enough water to cover the outer sur- face, and break the pat open immediately. c. A positive reaction has occurred when the water has penetrated through the surface layer: LL = low, if water has penetrated (ML, CL); LL = high, if the water has not penetrated (MH, CH). [Note: direct sunlight facilitates observation of this phenomena]. Test 7 - Dry Crushing/Clod Strength Test a. Obtain a dry block of soil at least 2 cm (3/4 in.) in its smallest dimension. b. Crush the clod between fingers and observe the ef- fort required: ML = easily crushed; CL or MH = medium-hard to break; CH = almost impossible to break. Test 8 - Dilatancy Test (from SCS, 1990) a. Mold material into a ball about 15 mm (1/2 in.) in diameter. Add water, if needed, until it has a soft but not sticky consistency. b. Smooth the soil in the palm of one hand with the blade of a knife or spatula. c. Shake horizontally, striking the side of the hand against the other several times. Note the ap- pearance of water on the surface. Squeeze the sample and note the disappearance of water. d. Describe the reaction: none = no visible change (CH); slow = water appears slowly on the surface during the shaking and does not disappear or dis- appears slowly when squeezed (CL, MH); rapid = water appears quickly on the surface during shak- ing and disappears quickly when squeezed (ML). Test 9 - Toughness Test (from SCS, 1990) a. Take the specimen for the dilatancy test and shape it into an elongated pat and roll it on a hard surface or between hands into a thread about 3 mm (1/8 in.) in diameter. (If it is too wet to roll, spread it out and let it dry.) Field Description and Analysis of Soils 67 ------- Field Description and Analysis of Soils 68 :*x*:*:*:*:*:-:-:*:*:*:«^^^^^^ b. Fold the thread and reroll repeatedly until the thread crumbles at a diameter of 3 mm (1/8 in.). The soil has reached its plastic limit. c. Note the pressure required to roll the thread and the strength of the thread: circumferential breaks = CH or CL material; longitudinal cracks and diagonal breaks = MH. d. After the thread crumbles, lump the pieces together and knead until the lump crumbles. e. Note the toughness of the material during knead- ing. Describe toughness: low = only slight pressure required to roll the thread near the plastic limit, the thread and lump are weak and soft (ML); medium = medium pressure is required to roll the thread near the plastic limit, the thread and lump have medium stiffness (CL, MH); high = considerable pressure required to roll the thread near the plastic limit, the thread and lump are very stiff (CL, CH); nonplastic = thread cannot be rolled (CL, CH). Test 10 - Stickiness Test a. Saturate a sample of the soil and let it dry on the hands. b. Observe ease with which soil is rubbed off: ML is brushed off with little effort; CL or MH require moderate effort to brush off; CH requires rewetting to completely remove. Alternative Stickiness Test (from Soil Survey Staff, 1991) c. Saturate a sample of the soil and press between thumb and forefinger. d. Observe the adhesion to thumb and forefinger when they are pulled apart: nonsticky = practically no adhesion (ML); slightly sticky = sticks to thumb or forefinger (MH); sticky = adheres to both, stretches slightly before breaking (CL); very sticky = adheres to both, stretches decidedly (CH). Test 11 - Organic Soils Test a. Smell soils suspected of having a high organic matter content. b. A distinctive, pungent musty odor is indicative of organic soils. ------- c. Feel texture of soil: PT = spongy or fibrous texture; OL or OH = nonfibrous. d. If nonfibrous, do plasticity test (Test 6): OL = low plasticity; OH = high plasticity. 3.1.7b Atterberg Limits Atterberg limits define various states of fine- grained soil material ranging from dry to liquid. The shrinkage limit (SL) is the water content at which a fur- ther reduction in water does not cause a decrease in the volume of the soil mass. The plastic limit (PL) is the water content at which soil changes from a semi-solid to a plastic state. At the plastic limit, a fine-grained soil will just begin to crumble when rolled into a thread approximately 3 mm (1/8 in.) in diameter. The liquid limit is the water content at which soil consistency changes from a plastic to a liquid state. This is the water content at which a pat of soil, cut by a groove 2 mm wide will flow together for a dis- tance of 13 mm (1/2 in.) under the impact of 25 blows in a standard liquid limit apparatus. Accurate determination of Atterberg limits requires collection of samples for laboratory analysis. 3.1.7c Shear Strength Shear strength can be estimated approximately in the field by the ease with which a sample can be penetrated by the thumb, as described in Table 3-6. Table 3-6. Field Estimation of Soil Shear Strength Consistency Identification Shear Strength Procedure (tons/ft2 or kg/cm2) Soft Easily penetrated several <0.25 inches by thumb Firm Penetrated several inches by 0.25 to 0.50 thumb with moderate effort Stiff Readily indented by thumb, but 0.50 to 1.00 penetrated only with great effort Very Readily indented with thumbnail 1.00 to 2.00 Stiff Hard Indented with difficulty by >2.00 thumbnail Source: SCS (1990). Field Description and Analysis of Soils 69 ------- Field Description and Analysis of Soils 70 siy*:*:!:*?:^ 3.1.7d Shrink-Swel! Certain clays shrink when pore water is lost during drying and subsequently swell during wetting. High shrink- swell clays are of concern at contaminated sites because deeply penetrating cracks create pathways for con- taminant movement during the early stages of the wetting phase. Where sodium rich clays with high dispersivity exist in the subsurface, a form of erosion called piping is also a concern. SCS defines shrink-swell potential classes based on linear extensibility (LE (%) = 100 x moist length - dry length/dry length) or the coefficient of linear extensibility (COLE = LE/100), as follows: Class LE(%) COLE Dbd/Mdb Low <3 <0.03 <1.1 Medium 3-6 0.03-0.06 1.1-1.2 High 6-9 0.06-0.09 1.2-1.3 Very high >9 >0.09 >1.3 LE can be measured by collecting a core from a wet or moist soil, carefully measuring its wet length, and setting it upright in a dry place. If the sample shrinks in a symmetrical shape without excessive cracking or crum- bling, its length should be measured and LE calculated. If the core crumbles or cracks, the coated clod method for bulk density measurement (see Section 3.1.6c) and the ratio of dry bulk density (Dbd) to moist bulk density (Mbd) should be used to place samples in shrink-swell classes (see table above). SCS (1971, Section I4.3) and SCS (1983) provide additional information on these procedures. SCS (1971) also describes a simple test for rough deter- mination of maximum potential shrinkage and density of disturbed soils. 3.1.7e Corrosivity SCS soil series interpretation sheets give separate corrosion potential ratings for uncoated steel and for con- crete. If classification of a soil is uncertain, corrosivity can be estimated using the following field and laboratory- measured parameters: Uncoated steel — Texture (Section 3.1.2), water table (Section 3.2.2), drainage class (Section 3.2.4), total acidity or extractable acidity as a rough equivalent to total acidity (Section 3.3.3), resistivity ------- at field capacity, and conductivity of saturated extract (Section 3.3.6). Concrete — Texture (Section 3.1.2), reaction (Section 3.3.4), and laboratory analysis of sodium and/or magnesium sulfate (ppm) and sodium chloride (ppm). Table 3-7 shows criteria for soils with high, moderate, and low corrosion potential for uncoated steel. Table 603-8 in SCS (1983) provides criteria to estimate corrosion potential for concrete. 3.1.8 Soil Temperature/Temperature Regime Soil temperature affects evaporation rates of water and volatile contaminants and influences the amount of microbiological activity in the soil. In soil classification, mean annual or summer soil temperature and the relation- ship between mean summer and mean winter soil temperature are used for placement in soil temperature regimes. Ground-water temperature gives a close estimate of mean annual soil temperature if monitoring wells are available with water at a depth of 1 0 to 20 meters. Alterna- tively, the average of four temperature measurements taken at a depth of about 50 cm equally spaced throughout the year gives a good estimate of mean annual soil temperature. For mean summer temperature, readings may be taken on June 15, July 15, and August 15, and for mean winter temperature, on December 15, January 15, and February 15. SCS (1971, Section I4.4) and Smith et al. (1960) describe more detailed procedures for soil temperature regime measurement, including special procedures where ground water or bedrock is shallow. Taylor and Jackson (1986) discuss types of thermometers and methods for measuring soil temperature for other applications. EPA's ESES defines the following soil temperature classes based on point thermal measurements taken on the surface or with depth of soil at a point in time, or over a period of time: High:38°C(100.4°F) Medium: 8-38°C (46.4 to 100.4°F) Low: <8°C (46.4°F) Field Description and Analysis of Soils 71 ------- Field Description and Analysis of Soils 72 Table 3-7. Guide for Estimating Risk of Soil Corrosion Potential of Uncoated Steel Class Low Drainage Class and Texture Excessively drainec Total Acidity* (meq/ 100g) i <8 Resis- tivity* (Ohm/ cm) >5,000 Conduc- tivity* (mmhos/ cm) <0.3 coarse-textured or well-drained coarse- to medium-textured soils; or, moderately well drained, coarse-textured soils; or, somewhat poorly drained coarse-textured soils Moderate Well-drained, 8-12 moderately fine-textured soils; or moderately well drained, coarse- and medium-textured soils; or somewhat poorly drained, moderately coarse-textured soils; or, very poorly drained soils with stable high water table High Well drained, fine- textured, or stratified soils; or, moderately well drained fine- and moderately fine-textured or stratified soils; or, somewhat poorly drained, medium- to fine-textured or stratified soils; or poorly drained soil with fluctuating water table 2,000 to 5,000 0.3 to 0.8 <2,000 >0.8 * See Table 603-7 in SCS (1983) for further guidance on how measurements should be made and interpreted. ------- 3.2 Soil Hydrologic Parameters 3.2.1 Moisture Conditions (Soil Water State) The terms used to describe soil properties may vary depending on the soil moisture content of the sample being observed. Soil water state is a more precise term for moisture conditions (Soil Science Society of America, 1987). Soil water state should be noted for any observa- tions of properties that may vary with moisture content, such as color and consistency. Table 3-8 describes three main soil water state classes (dry, moist, and wet) and eight subclasses within these categories, as defined by SCS. The water state classification of a particular soil sample will depend on (1) texture (whether it is coarse or not), (2) how strongly water is held by the soil (suction), and (3) the amount of gravimetric water held by the soil in relation to the amount held at specified reference suction pressures (i.e., 1,500 kPa for dry soils). Referring to Table 3-8, the following can be used as guidelines for field estimation of soil water state: Dry (VD) — Very little visual or tactile change be- tween field observation and after air-dried samples. Moist (MD) — Visual or tactile change between field observation and after air drying. Wet — Water films evident, but no free water (WN); free water present (WA). Between moist/wet and moderately dry/very dry separations, Soil Survey Staff (1991) describes four field water state tests: (1) color value test, (2) ball test, (3) rod test, and (4) ribbon test. These tests require calibration with the results of tests on similar soils that have been conducted at different known points on the moisture reten- tion curve. The following rules of thumb can be used to es- timate actual percentages of water at different points on the moisture characteristic curve: Water (%) at 1,500 Kpa = 0.4 x estimated clay content Water (%) of air dry soil = 0.1 x estimated clay content Field Description and Analysis of Soils 73 ------- Field Description and Analysis of Soils :*x*x-xott*:*:-:*:-:\x*:'W Table 3-8. Water State Classes 74 'm^ Class Criteria Suction Retention (kPa)* (% gravimetric moisture) Dry (D) Very dry (DV) Moderately dry (DM) Slightly dry (DS) Moist (M) Slightly moist (MS) Moderately moist (MM) Very moist (MV) Wet (W) Nonsatiated (WN) Satiated (WA) >1500 >1-1500 <.35 x % water at 1500kPa .35 - 0.8 x% water at 1500kPa 0.8 to 1.0 % water at kPa %waterat1500kPato MWR MWR** to UWR" UWR** to 1 or 0.5 kPa No free water Free water present Source: Soil Survey Staff (1991). 'Coarse soil material is considered wet at 0.5 kPa suction and moist from 0.5 to 1500 kPa if it meets the following criteria: (1) sand or sandy-skeletal family particle-size criteria, (2) coarser than loamy fine sand, (3) <2 percent organic carbon, (4) <5 per- cent water at 1500 kPa, and (5) computed total porosity of the <2 mm fabric exceeding 35 percent. "UWR = upper water retention = % water at 5 Kpa (coarse soil) = % water at 10 KPa (other soil). MWR = midpoint water reten- tion = halfway between UWR and % water at 1500 Kpa. ------- Methods for accurately measuring moisture con- tent in the field require relatively sophisticated equipment and are not discussed further here (see Appendix D in Cameron (1991), for information on field methods). The same is true for accurate measurement of water retention at different matric potentials (moisture characteristic curves). Moisture content and moisture characteristic curves are most commonly measured in the laboratory from samples collected in the field. Soil moisture tins with a capacity for about 250 grams of soil, filled to the brim and sealed with tape or plastic bags with any extra air removed before sealing, are best for determining field moisture content at the time of sampling. Undisturbed core samples are best for laboratory measurement of moisture characteristic curves. SCS (1971, Section 14.1) describes procedures for determining water content that can be done in a field laboratory with the following equipment: balance accurate to 0.1 g; oven with thermometer or thermostat, or stove, hot plate, or infrared lamp; and thermometer with scale up to150°C. 3.2.2 Water Table (Internal Free Water Occurrence) SCS does not define a class for saturation (i.e., zero air-filled porosity) because the term implies that all of the pore space is filled with water, a situation which can- not be readily evaluated in the field. Free water develops positive pressure when its depth is below the top of a wet satiated zone (the top of water in an unlined borehole after equilibrium has been reached). SCS classifies free water occurrence (perched or regional water table) into classes depending on (1) thick- ness (if perched), (2) depth, and (3) duration as follows: Classes Criteria Thickness if perched Extremely thin (TE) <10 cm Very thin (TV) 10 to 30 cm Thin (T) 30 cm to 1 m Thick (TK) >1 m Field Description and Analysis of Soils 75 ------- Field Description and Analysis of Soils 76 Depth Very deep (DV) >1.5m Deep(D) 1.5 to 1 m Moderately deep (DM) 1 to 0.5 m Shallow (S) 0.5 m to 25 cm Very shallow (SV) <25 cm Cumulative Annual Duration Absent (A) Not observed Very transitory (TV) Present <1 month Transitory (T) Present 1 to 3 months Common (C) Present 3 to 6 months Persistent (PS) Present 6 to 12 months Permanent (P) Present continuously 3.2.3 Available Water Capacity Available water capacity (AWC) is the amount of plant-available soil moisture, usually expressed as inches of water per inch of soil depth. It is commonly defined as the amount of water held between field capacity and the wilting point. AWC is important in developing water budgets and designing drainage systems. Determination of AWC requires sampling of soil for moisture content when it is at field capacity. This requires sampling just after the soil has drained after a period of rain and humid weather, after a spring thaw, or after heavy irrigation. SCS (1971, Section 14.1) describes several other procedures for bringing a plot to field capacity by wetting, and several methods for wetting clods or cores to approximate field capacity. SCS (1983) provides further guidance on calculation and estimation of AWC. 3.2.4 Saturated Hydraulic Conductivity and Soil Drainage Class The terms permeability and saturated hydraulic conductivity are often used interchangeably to refer to the ease with which water moves through the soil under saturated conditions. Permeability rates are typically reported in units of in./hr based on percolation tests; saturated hydraulic conductivity may be reported in units of u.m/s, m/s, cm/day, in./hr, or cm/hr. Accurate field meas- urement of both saturated (KSat) and unsaturated hydraulic ------- conductivity requires relatively complex instruments and procedures that are not covered here (see Appendix D in Cameron (1991) for information on these methods). SCS currently defines six classes for describing soils based on saturated hydraulic conductivity: Saturated Hydraulic Conductivity Class (u.m/s) ' (in./hr) Very low (VL) <0.01 <0.001 Low(L) 0.01-0.1 0.001-0.01 Moderately low (ML) 0.1-1 0.01-0.14 Moderately high (MH) 1-10 0.14-1.4 High(H) 10-100 1.4-14.2 Very high (VH) >100 >14.2 Class placement is based on geometric mean of multiple measurements. Various methods have been developed for obtain- ing rough estimates of KSat based on various soil proper- ties. Table 3-9 provides a basis for estimating KSat based on field observations of structure, texture, and pores. See Section 3.1.2 for identification of textural classes, Section 3.1.4 for pore definitions, and Section 3.1.5a for definitions of structural units. O'Neal (1952) describes a procedure for somewhat more precise estimation of soil permeability classes (which are defined slightly differently from those listed above) based on (1) structure, (2) shape and overlap of aggregates, (3) visible pores, and (4) texture. Soil Survey Staff (1991, Chapter 3) provides figures for KSat class placement based on soil bulk density and texture. Soil drainage class refers to the frequency and duration of wet periods for the water regime associated with undisturbed soil conditions. Table 3-10 summarizes SCS criteria for seven soil drainage classes. 3.2.5 Infiltration The amount of precipitation reaching the ground surface that enters the soil is determined by the infiltra- tion capacity. In a dry soil, infiltration is usually rapid, un- less there is an impervious crust at the surface. As time passes, infiltration slows until the ponded infiltration rate is attained, which is determined by the saturated hydraulic Field Description and Analysis of Soils 77 ------- Field Description and Analysis of Soils 78 :*:*:*:*^ Table 3-9, Guide for Estimating the Class of Saturated Vertical Hydraulic Conductivity from Soil Properties Class Name Rate* Soil Properties" Very High <100 High 100-10 Moderate 10-1 Mod. Low 1-0.1 -Fragmental -Sandy with coarse sand or sand texture, and loose consistence -More than 0.5 percent medium or coarser vertical pores with high continuity -Other sandy, sandy-skeletal, or coarse-loamy soil materials that are very friable, friable, soft, or loose -When very moist or wet has moderate or strong granular structure; or strong blocky structure of any size or prismatic structure finer than very coarse, and many surface features except stress surfaces or slickensides on vertical surfaces of structural units -0.5 to 0.2 percent medium or coarser vertical pores with high continuity -Sandy in other consistence classes except extremely firm or cemented -10 to 35 percent clay with moderate structure, except platy, or strong very coarse prismatic structure; and with common surface features except stress surfaces or slickensides on vertical surfaces of structural units -0.1 to 0.2 percent medium or coarser vertical pores with high continuity -Other sandy classes that are extremely firm or cemented -18 to 35 percent clay with other structures and surface conditions except pressure or stress surfaces -Greater than 35 percent clay and moderate structure except if platy or very coarse prismatic; and with common vertical surface features except stress surfaces or slickensides -Medium or coarser vertical pores with high continuity, but <0.01 percent (Continued) ------- Table 3-9. (Continued) Class Name Rate* Soil Properties* Low 0.1-0.01 Very Low <0.01 —Continuous moderate or weak cementation -Greater than 35 percent clay and meets one of the following: weak structure; weak structure with few or no vertical surface features; platy structure; common or many stress surfaces or slickensides -Continuously indurated or strongly cemented and with less than common roots -Greater than 35 percent clay and massive or exhibits horizontal depositional strata and less than common roots Source: SCS (1983). 'Micrometers/second. **A given soil profile would have most, but not necessarily all, of the soil properties associated with a particular class. Table 3-10. Criteria for SCS Soil Drainage Classes Excessively drained. Water is removed very rapidly. Internal free water occurrence commonly is very deep; annual dura- tion is not specified. The soils are commonly very coarse tex- tured, rocky, or shallow. Some are steep. All are free of mottling related to wetness. Somewhat excessively drained. Water is removed from the soil rapidly. Internal free water occurrence commonly is very deep; annual duration is not specified. The soils are usually sandy and rapidly pervious. Some are shallow. A portion of the soils are so steep that a considerable part of the precipita- tion received is lost as runoff. All are free of the mottling re- lated to wetness. (Continued) Field Description and Analysis of Soils 79 ------- Field Description and Analysis of Soils 80 x*;*:':tt«w:':*x<*H*x*:^ Table 3-10. (Continued) Well drained. Water is removed from the soil readily but not rapidly. Internal free water occurrence commonly is deep or very deep; annual duration is not specified. Water is available to plants throughout most of the growing season in humid regions. Wetness does not inhibit growth of roots for sig- nificant periods during most growing seasons. Well drained soils are commonly medium textured. They are mainly free of the mottling related to wetness. Moderately well drained. Water is removed from the soil some- what slowly during some periods of the year. Internal free water occurrence commonly is moderately deep and tran- sitory through permanent (Section 3.2.2). The soils are wet for only a short time during the growing season, but long enough that most mesophytic crops are affected. They com- monly have a slowly pervious layer within the upper 1 m, periodically receive high rainfall, or both. Somewhat poorly drained. Water is removed slowly enough that the soil is wet at shallow depth for significant periods during the growing season. Internal free water occurrence commonly is shallow and transitory or common. Wetness markedly restricts the growth of mesophytic crops unless ar- tificial drainage is provided. The soils commonly have one or more of the following characteristics: contain a slowly per- vious layer, have a high water table, receive additional water from seepage, or occur under nearly continuous rainfall. Poorly drained. Water is removed so slowly that the soil is wet at shallow depths periodically during the growing season, or remains wet for long periods. Internal free water occurrence is shallow or very shallow and common or persistent. Free water is commonly at or near the surface for long enough during the growing season that most mesophytic crops can- not be grown unless the soil is artificially drained. The soil, however, is not continuously wet directly below plow-depth. Free water at shallow depth is usually present. This water table is commonly the result of a shallow, slowly pervious layer within the soil, of seepage, of nearly continuous rainfall, or of a combination of these. Very poorly drained. Water is removed from the soil so slowly that free water remains at or very near the ground surface during much of the growing season. Internal free water occur- rence is very shallow and persistent or permanent (Section 3.2.2). Unless the soil is artificially drained, most mesophytic crops cannot be grown. The soils are commonly level or depressed and frequently ponded. If rainfall is high or nearly continuous, slope gradients can be moderate or high. Source: Soil Survey Staff (1991). ------- conductivity of the soil. Infiltration rate is usually measured in rates of in./hr or cm/hr. Extrastructural cracks (Section 3.1.5D) may greatly increase infiltration rates compared to soils with similar texture that do not have cracks. SCS's permeability classification system (SCS, 1983) can be used to describe infiltration classes: Permeability Class (in./hr) (cm/hr) Very slow Slow Moderately slow Moderate Moderately rapid Rapid Very rapid <0.06 0.06-0.2 0.2-0.6 0.6-2.0 2.0-6.0 6.0-20 >20 <0.15 0.15-0.5 0.5-1.5 1 .5-5.0 5.0-15.2 15.2-50.8 >50.8 3.3 Soil Chemistry and Biology Most procedures for characterization of soil chemistry require collection of samples for laboratory analysis. This section focuses on pH and mineralogical parameters that can be tested in the field using relatively simple equipment and procedures. Most of these tests are drawn from SCS (1971). 3.3.1 Organic Matter Organic matter (more precisely measured in the laboratory as organic carbon) affects contaminant mobility primarily by its high sorptive capacity. Accurate determina- tion of total organic carbon (TOC) requires collection of samples for laboratory analysis. In the field, black or dark colors generally indicate high organic matter content in near-surface horizons. In most mineral soils, organic matter is moderately low to high in the A horizon, and low in the subsoil. Severely eroded soils, where the topsoil has been completely removed; alluvial soils, where flooding deposits topsoil; and buried soils may not follow this pattern. SCS defines the following classes for organic matter: Field Description and Analysis of Soils 81 ------- Field Description and Analysis of Soils 82 Class % Organic Matter Very low (VL) <0.5 Low(LL) 0.5-1.0 Moderately low (ML) 1.0-2.0 Medium (MM) 2.0-4.0 High (HH) >4.0 Note that organic matter content is generally 1.7 to 2.0 times the TOC. An ignition test can be used in the field to approximate organic matter content and check its con- tribution to soil color. Equipment for this test includes (1) thermometer and heat lamp, (2) portable gas soldering torch, (3) a porcelain crucible or small tin can (not aluminum), (4) wire brackets or tongs to hold the con- tainer, and (5) a balance accurate to 0.1 grams. Ignition Test Procedure (adapted from SCS, 1971) 1. Dry about 30 grams of soil to 110°C under a heat lamp. 2. Weigh as accurately as possible about 10 grams of dried soil and place in a crucible or tin, supporting it with tongs or wire bracket. 3. Apply the flame of the torch to the bottom and lower walls of the outside of the container. Por- celain and metal glow red at 500°C. At this temperature, organic matter is completely burned and the water of hydration is removed from the common oxide and clay minerals. 4. Observe changes in color in the specimen. Apply heat more than once until there is no more change apparent in the specimen. Do not apply the flame directly to the sample if burning or oxidation are the purpose of the test, because unpredictable reduc- ing conditions exist in parts of the torch flame. If or- ganic matter is the only material giving color to the soil, it burns away leaving a whitish residue. See Section 3.1.3 for interpretation of other color changes. 5. When no more change is apparent, cool and weigh sample again. The loss in weight divided by the original weight times 100 equals the organic matter in sandy soils and materials high in organic matter. ------- If much clay is present, the loss also includes water of hydration in the minerals. Organic matter also reacts with hydrogen peroxide. In contrast to manganese oxides (see Section 3.3.8), the reaction starts slowly, builds up, and continues. Organic matter reactions decrease with depth, whereas man- ganese oxide reactions remain constant. Test No. 11 in Section 3.1.7a describes proce- dures for classifying organic soils in the Unified soil clas- sification system. SCS uses a number of tests for classification of organic soils (histosols) including sodium pyrophosphate color, fiber percentages, and pH in 0.01 M calcium chloride. Since organic soils do not commonly occur at hazardous waste sites, these tests are not described here. If organic soils are present at a site and more detailed characterization is required, refer to Lynn et al. (1974) and Appendix III in Soil Survey Staff (1975). 3.3.2 Odor High organic matter content in soil is associated with a distinctive, pungent musty odor (see Test 11 in Sec- tion 3.1.7a). Organic rich topsoil in mineral soils can also be distinguished from subsoil that is low in organic matter by this odor. Volatile organic contaminants can impart distinctive odors to soil. Gasoline has an odor familiar to most people; aging gives petroleum a musty odor. Some other contaminants that may give soil a noticeable odor include halogens, ammonia, turpentine, phenols and cresol, picrates, various hydrocarbons, and unsaturated organic pesticides. Caution should be exercised in observing soil odors. They should not be vigorously inhaled from any soil, since even natural soils may contain potentially harm- ful microorganisms. Soils where noticeable artificial odors are present should be checked for volatile concentrations using a detection instrument (HNu, organic vapor analyzer, etc.). The health and safety officer should be consulted to determine whether special protective equip- Field Description and Analysis of Soils 83 ------- Field Description and Analysis of Soils 84 merit, such as a respirator, should be used by individuals who are working close to the soil surface taking samples. EPA's ESES uses the following odor classes: High: A distinct odor, from naturally occurring soil organic materials with a distinctive pungent, musty odor, or sharp distinct odor from chemical con- taminants. Moderate to slight: A less distinct to faint odor, from naturally occurring soil organic materials, or from various odor-producing chemical contaminants. None: No detectable odor by olfactory means. 3.3.3 Cation Exchange Capacity (CEC) Cation exchange capacity, measured in milli- equivalents per 100 grams (meq/100 g) orcentimoles per kilogram (cmol/kg), is a measure of the soil's ability to ab- sorb (and release) cations. It is an especially important parameter at sites contaminated by heavy metals, be- cause heavy metals will often replace exchangeable ions such as sodium, potassium, calcium, and magnesium that exist in natural soil. Measurement of CEC requires collec- tion of samples for laboratory analysis. SCS (1971, Sec- tion I9.7 and I9.8) describes relatively simple chemical tests that can be carried out in the field to estimate ex- changeable calcium and exchangeable sodium. The measurement of extractable acidity, also called exchangeable acidity or extractable hydrogen be- cause it measures exchangeable ions that contribute to soil acidity, is required for evaluation of soil corrosivity (see Section 3.1.7e). Section 6H in SCS (1984) describes specific procedures for determining extractable acidity in the laboratory. EPA's ESES uses the following CEC classes (ex- pressed as meq/100 g soil): high (>20), medium (12-20), 3.3.4 Reaction (pH) A variety of methods are available for field meas- urement of pH (colorimetric, paper test strips, pH meter). Specific procedures and instructions accompanying equip- ment for the method used should be followed. For RCRA sites, EPA Method 9045A Revision 1, November 1990, should be used (U.S. EPA, 1986). ------- Soil Survey Staff (1991) defines 13 pH classes for soil as follows: Class pH Ultra acid (UA) <3.5 Extremely acid (EA) 3.5 - 4.5 Very strongly acid (VS) 4.5 - 5.0 Strongly acid (SA) 5.1 - 5.5 Medium acid (MA) 5.6 - 6.0 Slightly acid (SA) 6.1 - 6.5 Neutral (NA) 6.6 - 7.3 Mildly alkaline (MA) 7.4 - 7.8 Moderately alkaline (MO) 7.9 - 8.4 Strongly alkaline (SA) 8.5 - 9.0 Very strongly alkaline (VA) >9.0 3.3.5 Redox Potential (Eh) Redox, or oxidation-reduction potential (Eh), is measured in volts or millivolts (mV) as the potential dif- ference in a solution between a working electrode and the standard hydrogen electrode. Whether soil conditions are oxidizing (aerobic) or reducing (anaerobic) will strongly af- fect the types of microbiological activity and contaminant transformation and degradation processes that may occur. The mobility of many heavy metals varies with oxidation state. In unsaturated soil, aerobic conditions prevail, and measurement of Eh requires collection of soil water samples using a suction lysimeter. The Eh of saturated soil should be measured using ground-water samples from properly purged monitoring wells. EPA's ESES uses the following redox potential classes: highly oxidized (>+400 mV), intermediate (+400 to -100 mV), and highly reduced (<-100 mV). 3.3.6 Electrical Conductivity (Salinity) In arid and semi-arid areas, soluble salts may ac- cumulate in the soil and are called saline. The electrical conductivity of a saturation extract is the standard measure of salinity. Electrical conductivity is commonly reported in units of decisiemens/meter or millimhos/cen- timeter (1 dS/m = 1 mmho/cm). Electrical conductivity SrBKSKSBiSK::*:^ Field Description and Analysis of Soils 85 ------- Field Description and Analysis of Soils 86 WSSSSSrSSSS^^ measurement or estimation is required for evaluation of soil corrosivity (see Section 3.1.7e). Salinity classes, based on electrical conductivity of a saturation extract, are defined in EPA's ESES as follows: Electrical Conductivity Class (dS/m or mmho/cm) Nonsaline 0-2 Slightly saline 2-4 Moderately saline 4-8 Very saline 8-16 Extremely saline >16 Note that Soil Survey Staff (1991) uses slightly different terms for these classes. SCS (1971, Section I9.6) describes a relatively simple procedure for water extraction that can be used in the field or a field laboratory for measuring approximate soluble salt percentage. Accurate determination requires laboratory preparation of soil samples. SCS (1984, Sec- tion 8A) describes procedures for preparing a saturated paste and obtaining a saturation extract for electrical con- ductivity measurement. Measurement of the resistivity of the saturated paste (SCS, 1984, Section 8E) is required for evaluating soil corrosion potential for uncoated steel. Richards (1954) and Richards et al. (1956) describe procedures for testing saline soils in more detail and provide charts and graphs for estimating total salt from electrical conductivity measurements. Rhoades and Oster (1986) describe more complex instrumentation for collecting soil water using in situ samplers and measuring soluble salts with in situ or remote monitors. The electrical conductivity, also termed specific conductance, of ground-water samples can be readily measured in the field using a conductivity meter. Electrical conductivity is a measure of the total dissolved solids in the ground water and should not be confused with the soil salinity test described above. 3.3.7 Clay Minerals The following procedures can be used to identify the dominant mineralogy of the clay size-fraction: ------- Clay Mineral Test 1. Prepare a saturated solution of malachite green in nitrobenzene to use as an indicator solution (follow prescribed safety procedures when handling nitrobenzene). 2. Add several drops of the indicator to a small sample (1 g) of soil and observe color of wetted soil as follows: blue or green-blue = kaolinite; yel- low-red = montmorillonite; purple-red = illite. Mica Shine Test Rub a small clod of air-dried soil with a knife blade. A shiny surface indicates a micaceous soil with high plasticity. EPA's ESES defines the following clay mineral abundance classes (see Section 3.1.2 for estimation of texture): abundant (>27 percent), moderate to slight (1 to 27 percent), none to negligible ( <1 percent). 3.3.5 Other Minerals Concentrations of minerals may form in soil horizons as a result of dissolution and precipitation processes. These concentrations are described by SCS according to (1) type, (2) amount or quantity, (3) size, (4) shape, and (5) composition. The following are abbrevia- tions of descriptors and criteria for describing concentra- tions in soil: Types m — masses (soft, no clearly defined boundaries) n — nodules and concretions (hard, clearly defined boundaries) c — crystals (single or complex clusters) srf — soft rock fragments (weakly cemented or noncemented) Amount/Quantity f — few(<2%) c — common (2-20%) m — many :y:::::::::y^^^ Field Description and Analysis of Soils 87 ------- Field Description and Analysis of Soils 88 Size fine ( <2 mm) medium (2-5 mm) coarse (5-20 mm) very coarse (20-76 mm) extremely coarse (>76 mm) Shape rnd — rounded cyl — cylindrical pi — platelike ir — irregular fe — ferruginous mn — manganiferous sal — saline Composition calc — calcareous arg — argillaceous yp — gypsiferous sil — siliceous The following features and tests can be used to identify major non-clay minerals in the field. Carbonates (calcareous) The presence of free calcium carbonate in soil can be readily determined based on effervescence in dilute hydrochloric acid. The test procedure is as follows: 1. Place 1 g of soil material (about the size of a marble) in the well of a porcelain spot plate. Thoroughly moisten the soil with a few drops of deionized water; stir with a clean glass rod to remove entrapped air. 2. Add three drops of dilute 10 percent (4 N) cold HCI from a plastic squeeze bottle and immediately ob- serve for effervescence of the treated sample under a hand lens if possible. 3. If effervescence is observed, record intensity as follows: vse — very slightly effervescent (few bubbles seen) sle— slightly effervescent (bubbles readily seen) ------- ste—strongly effervescent (bubbles form low foam) ve—violently effervescent (thick foam forms quickly) 4. Repeat procedure on a second 1 -g sample. Dolomite (calcium-magnesium carbonate) effer- vesces slowly in cold acid unless the mineral is very finely divided. If dolomite is suspected, place the sample in a container and warm it for 15 minutes after covering it with the acid solution. Soluble Salts (saline, gypsiferous) White incrustations that do not effervesce can be separated and checked for water solubility and taste. Chlorides, nitrates, and sulfates of sodium and potassium are very water soluble. Chloride salts can be tested by shaking a sample of soil in distilled water, placing about 10 mL of the supernatent solution (after the solids have settled) in a test tube, and adding a few drops of 5 percent sodium nitrate solution. Chlorides are indicated by the for- mation of a thick, milky precipitate of silver chloride. The formation of a heavy white precipitate after adding a 5 per- cent barium chloride solution to a separate supernatent sample indicates sulfate ions. SCS (1971, Section I9.6) provides further details for these tests. Crystals of gypsum, which may occur as a white in- crustation in voids, are rhombic plates, laths, or some- times fibers. Gypsum crystals can be scratched with the fingernail, do not effervesce in acid, and are very slowly soluble in water. Gypsum Acetone Test. Place 1 part soil and 10 parts water (by weight) in a small bottle. Seal the bottle and shake by hand at 15-minute intervals. Filter the ex- tract through filter paper. Mix a 50-50 solution of the filtrate and acetone. The formation of a milky precipitate indicates the presence of gypsum. SCS (1971, Section I9.6) describes a somewhat more complex semi-quantitative test for gypsum using acetone which can be used in the field. Iron Oxides (ferruginous) Goethite and hematite commonly occur as segregated bodies in soils. Hematite is red; solid bodies, such as nodules or sheets may be dark brown or almost Field Description and Analysis of Soils 89 ------- Field Description and Analysis of Soils 90 black but have a red streak if rubbed on a rough porcelain surface or a tough paper. Goethite bodies commonly are red but may be yellow or brown and are generally softer than hematite bodies. In an ignition test (see Section 3.1.3), hematite will show little color change; the duller colors of goethite will brighten when it changes to hematite. If gray, blue, or green materials turn red when ignited, ferrous iron is present. Manganese Oxide (manganiferous) Black and very dark brown concretions and coat- ings on cleavage planes are likely to be the manganese oxide pyrolusite or a closely related mineral. It has a dark brown streak and is very soft, producing the streak even on paper. A procedure similar to the carbonate test using a dilute (5 percent) solution of hydrogen peroxide instead of HCI will result in the rapid evolution of small bubbles with a usually rapid consumption of the hydrogen peroxide if manganese oxides are present. See Section 3.3.1 for further guidance in differentiating possible reactions with organic matter. SCS (1971, Section I7.2) discusses in more detail the identification of minerals and mineral groups in the field. 3.3.9 Fertility Potential Soil fertility is the ability or status of a soil to supply water and nutrients necessary for plant growth. Inherent physical characteristics, such as soil structure and avail- able water capacity, provide the basic elements of fertility potential, and are not easily modified. The nutrient status of a soil, on the other hand, can be improved by fertilization. Nutrient status is evaluated by analyzing samples in the laboratory for nutrients essential for plant growth such as nitrogen, potassium, and phosphorus. Soil reac- tion (pH) is an important chemical parameter, because it strongly influences the availability of nutrients. The key physical parameters affecting fertility potential are aeration and water availability, because plant roots require both air and a ready supply of moisture for optimum growth. These factors can be evaluated by ob- serving soil properties such as soil texture (Section 3.1.2), ------- depth to water table (Section 3.2.2), available water capacity (Section 3.2.3), and soil drainage class (Section 3.2.4). Deep, well-drained soils with a high available water capacity have the greatest fertility potential, provided nutrient status is favorable. Shallow soils with low avail- able water capacity have low fertility potential even if nutrient status is favorable. EPA's ESES defines the following soil fertility potential or status classes: High: Nutrients necessary for plant growth readily supplied. Moderate: Nutrients necessary for plant growth in moderate supply. Low: Nutrients necessary for plant growth in low supply. 3.3.10 Soil Microbiota Microorganisms in soil and ground water are now recognized as being of major importance in affecting the transformation and fate of many organic contaminants and heavy metals. The study of soil microbiota from soil samples requires carefully controlled laboratory condi- tions. The major concern in the field is that procedures used to collect soil samples do not allow contamination by microorganisms from other sources. Soil samples must be collected using sterilized tools and placed in sterilized con- tainers. Samples of near-surface soils for microbiological study should be taken from a soil pit. Scoops or trowels used to collect samples from each soil horizon should go through usual decontamination procedures. As a final step, they should be heated with a blow torch and cooled by being stuck into the horizon to be sampled before soil material is dug out and placed into containers. Samples for microbiological study taken from greater depths where oxygen is low require special asep- tic handling procedures to prevent oxygen from harming anaerobic microorganisms. Leach et al. (1988) describes in detail procedures for collecting such samples, which in- volve preparing nitrogen-filled sampling containers in the laboratory, and using a field sampling glove box that has been purged with nitrogen gas to reduce the oxygen level below detectable limits. Field Description and Analysis of Soils 91 ------- Field Description and Analysis of Soils 92 EPA's ESES defines the following abundance classes for soil microorganisms (as number per gram of soil): abundant (>1,000,000), common (10,000- 1,000,000), few (100-10,000), none (<100). 3.4 Soil Contaminants Visual identification of zones of soil contamination is sometimes possible when the contaminants are in an immiscible liquid phase or a solid phase. Iridescence of an oily phase in water may indicate contamination from syn- thetic organics. Solid phases should be described by color and consistency (granular, tarry, etc.). Possible con- tamination by heavy metals from artificial pigments is evi- dent from bright colors. Toxic effects of contaminants on surface vegetation also may be evident. In any event, the presence of contaminants must be confirmed by laboratory analysis of samples. Organic vapor detectors are relatively simple in- struments that are used to identify the presence of volatile organics. The way in which readings are taken (distance from sample being checked, location in borehole, length of reading) should be recorded along with the readings them- selves. Procedures should be performed consistently, and any departures from usual procedures noted. Increasingly sophisticated field equipment in mobile laboratories is being used for onsite contaminant analysis. Use of such equipment is not covered in this guide. Ford et al. (1984) describe methods for monitoring toxic gases and vapors with portable field instruments. ------- Chapter 4 Soil Sampling and Quality Assurance Sample design, sample location, equipment and sam- pling methods, and quality assurance/quality control (QA/QC) procedures should all be determined before sampling begins and be recorded in the Soil Sampling and Quality Assurance Plans for the site. Mason (1983) and Barth et al. (1989) provide detailed guidance on statistical aspects of sampling design and quality assurance. These documents will outline the specific procedures that will be required during field sampling. This chapter has two purposes: (1) to provide information that may be useful if unforeseen conditions require modification of the procedures specified in the sampling plan, and (2) to provide forms that may be useful in carrying out QA/QC procedures. 4.1 Changes in Soil Sampling Procedures Soil description, use of field analytical equipment, and soil sampling should be conducted in a uniform and consistent manner, following procedures specified in the Soil Sampling and Quality Assurance Plans. If unforeseen conditions arise at the site during the field investigation and sampling that prevent carrying out the specified pro- cedures, it may be necessary to develop alternative ap- proaches at the site. Any such changes must be documented and approved (see Section 4.2). One situation requiring departure from specified procedures is when soil conditions are unfavorable for the equipment being used to collect samples. If this situation occurs, the following tables may help identify alternative sampling tools: Soil Sampling and Quality Assurance 93 ------- So/7 Sampling and Quality Assurance 94 Table 4-1 summarizes information on applications and limitations for use of 15 types of hand- operated soil sampling devices. Table 4-2 summarizes information on applications and limitations for use of 10 common types of power-driven tube samplers. Appendix B provides the names and addresses of 24 manufacturers and distributors of manually operated and power-driven soil sampling equipment. If the use of different sampling equipment requires altering the standard sampling protocol, the new protocol should be clearly specified. Appendices A.2 to A.4 provide some general soil handling and sampling protocols that can be used for guidance if revised protocols must be developed at the site. 4.2 Quality Assurance/Quality Control Any change in standard procedures for field collec- tion of soil samples must be justified, described, and ap- proved by the appropriate project personnel. Form 4-1 (Sample Alteration) can be used for this purpose. Multiple copies of this form should be available for use. Soil sampling personnel should be aware that their work may be subject to a field audit to ensure that soil sampling and other QA/QC procedures are being fol- lowed. Form 4-2 contains a checklist of major items that should be covered in a field audit. Field personnel would do well to review this checklist periodically as a reminder of areas in which they would be held accountable in the event of a field audit. The results of a field audit, or review of analytical results, may identify problems areas requiring corrective action. If the need for corrective action is identified during a field audit, it should be implemented immediately. Resampling may be required if analytical results fall out- side the acceptable limits specified in the Quality As- surance Plan. Form 4-3 (Soil Sample Corrective Action Form) can be used to identify problem areas and specify measures required to correct the problems. When resam- pling is required, this form should be taken into the field and the specified procedures carefully followed. ------- Table 4-1. Summary of Hand-Held Soil Sampling Devices Sampling Device Applications Limitations Spoons and Scoops Shovels and Picks Augers* Screw Auger Standard Bucket Auger Sand Bucket Auger Mud Bucket Auger Dutch Auger In Situ Soil Recovery Auger Eijkelcamp Stoney Soil Auger Planer Auger Surface soil samples or the sides of pits or trenches A wide variety of soil conditions Cohesive, soft, or hard soils or residue General soil or residue Bit designed to retain dry, loose, or granular material (silt, sand, and gravel) Bit and bucket designed for wet silt and clay soil or residue Designed specifically for wet, fibrous, or rooted soils (marshes) Collection of soil samples in reusable liners; closed top reduces contamination from caving sidewalls Stoney soils and asphalt Clean out and flatten the bottom of predrilled holes Limited to relatively shallow depths; distributed samples Limited to relatively shallow depths Will not retain dry, loose, or granular, material May not retain dry, loose, or granular material Difficult to advance boring in cohesive soils Will not retain dry, loose, or granular material Similar to standard bucket auger (Continued) Soil Sampling and Quality Assurance 95 ------- Soil Sampling and Quality Assurance 96 Table 4-1. (Continued) Sampling Device Applications Limitations Tube Samplers** Soil Probe Thin-Walled Tubes Soil Recovery Probe Veihmeyer Tube Peat Sampler Cohesive, soft soils or residue; representative samples in soft to medium cohesive soils and silts Cohesive, soft soils or residue; special tips for wet or dry soils available Similar to thin-walled tube; cores are collected in reusable liners, minimizing contact with the air Cohesive soils or residue to depth of 3 meters Wet, fibrous, organic soils Sampling depth generally limited to less than 1 meter Similar to Veihmeyer tube Similar to Veihmeyer tube Difficult to drive into dense or hard material; will not retain dry, loose, or granular material; may be difficult to pull from ground 'Suitable for soils with limited coarse fragments; only the stoney soil auger will work well in very gravelly soil. "Not suitable for soils with coarse fragments. Source: Adapted from Brown et al. (1991) and Rehm et al. (1985). ------- Table 4-2. Samplers Summary of Major Types of Power-Driven Tube Sampling Device Applications Limitations Split Spoon Sampler Disturbed samples from cohesive soils Thin-Walled Samplers Fixed-Piston Undisturbed Sampler samples in cohesive soils, silt, and sand above or below water table Hydraulic Piston Sampler (Osterberg) Stationary Piston Sampler Wireline Piston Sampler Free Piston Sampler Open Drive Sampler Similar to fixed-piston sampler Undisturbed samples in stiff, cohesive soils; representative samples in soft to medium cohesive soils, silts, and some sands Undisturbed samples in cohesive soils and noncohesive sands; used with clamshell device on hollow-stem auger Similar to stationary piston sampler Similar to stationary piston sampler Ineffective in cohesionless sands; not suitable for collection of samples for laboratory tests requiring undisturbed soil Ineffective in cohesionless sands Not possible to limit the length of push or to determine amount of partial sampler penetration during push In heaving sands only one sample per borehole can be collected because clamshell remains open after sampling Not suitable for cohesionless soils Not suitable for cohesionless soils (Continued) :*B*:*:*s*B*s*^ Soil Sampling and Quality Assurance 97 ------- So/7 Sampling and Quality Assurance 98 X'XtoKW^ Table 4-2. (Continued) Sampling Device Applications Limitations Pitcher Undisturbed samples Sampler in hard, brittle, cohesive soils and cemented sands; representative samples in soft to medium cohesive soils, silts, and some sands; variable success with cohesionless soils Denison Undisturbed samples Sampler in stiff to hard cohesive soils, cemented sands, and soft rocks; variable success with cohesionless materials Vicksburg Similar to Denison Sampler sampler except takes wider diameter samples Frequently ineffective in cohesionless soils Not suitable for undisturbed sampling of loose, cohesionless soils or soft cohesive soils Source: Adapted from Rehm et al. (1985) and Aller et al. (1989). ------- Form 4-1. Sample Alteration Form Project Name and Number:_ Material to Be Sampled: Measurement Parameter: Standard Procedure for Field Collection and Laboratory Analysis (cite references): Reason for Change in Field Procedure: Variation for Field Procedure: Special Equipment, Materials, or Personnel Required: Initiator's Name: Date: Project Approval Date: Laboratory Approval: Date: QA Officer/Reviewer: Date: Sample Control Center: Date: :*y*:*:*:::*:*&::S::^^ Soil Sampling and Quality Assurance 99 ------- So/7 Sampling and Quality Assurance 100 KoX'XvX'i'XW'WX':*:-:*:^^ Form 4-2. Field Audit Checklist Records to Inspect Chain-of-custody forms Analytical analysis request forms (if different from chain-of-custody forms) Sample tags Site description forms Log books Sampling Procedures to Inspect Equipment Techniques Decontamination Collection of duplicate and field blank samples Security Sample storage and transportation Containers Contaminated waste storage and disposal Site description form entries ------- Form 4-3. Sample Corrective Action Form Project Name and Number: Sample Data Involved: Measurement Parameter(s): Acceptable Data Range: Problem Areas Requiring Corrective Action: Measures Required to Correct Problems: Means of Delecting Problems and Verifying Correction: Initiator's Name: Date: Project Approval: Date: Laboratory Approval: Date: QA Officer/Reviewer: Date: Sample Control Center: Date: Soil Sampling and Quality Assurance 101 ------- References 102 References Aller, L, et al. 1991. Handbook of Suggested Practices for the Design and Installation of Ground-Water Monitoring Wells. EPA/600/4-89/034. Available from ORD Publica- tions, U.S. EPA/CERI, 26 W. Martin Luther King Dr., Cin- cinnati, OH, 45268, 221 pp. Also published in 1989 by National Water Well Association, Dublin, OH, in its NWWA/EPA series, 398 pp. Barrett, J. et al. 1980. Procedures Recommended for Overburden and Hydrologic Studies of Surface Mines. GTR-INT-71. U.S. Forest Service, Intermountain Forest and Experiment Station, Ogden, UT, 106 pp. Barth, D.S., B.J. Mason, T.H. Starks, and K.W. Brown. 1989. Soil Sampling Quality Assurance User's Guide, 2nd ed. EPA 600/8-89/046 (NTIS PB89-189864). Environmen- tal Monitoring Systems Laboratory, Las Vegas, NV, 89193-3478, 225+pp. Blake, G.R. and K.H. Hartge. 1986. Bulk Density. In: Methods of Soil Analysis, Part 1, 2nd ed., A. Klute (ed.), Agronomy Monograph No. 9. American Society of Agronomy, Madison, Wl, pp. 363-275. Bradford, J.M. 1986. Penetrability. In: Methods of Soil Analysis, Part 1, 2nd ed., A. Klute (ed.), Agronomy Monograph No. 9. American Society of Agronomy, Madison, Wl, pp. 463-478. Breckenridge, R.P., J.R. Williams, and J.F. Keck. 1991. Characterizing Soils for Hazardous Waste Site Assess- ments. Superfund Ground-Water Issue Paper. EPA/600/8- 91/008. Environmental Monitoring Systems Laboratory, Las Vegas, NV, 89193-3478. ------- Brown, K.W., R.P. Breckenridge, and R.C. Rope. 1991. Soil Sampling Reference Field Methods. U.S. Fish and Wildlife Service Lands Contaminant Monitoring Operations Manual, Appendix J. Prepared by Center for Environmen- tal Monitoring and Assessment, Idaho National Engineer- ing Laboratory, Idaho Falls, ID, 83415. [Final publication pending revisions resulting from field testing of manual.] Cameron, R.E. 1991. Guide to Site and Soil Description for Hazardous Waste Site Characterization, Vol. 1, Metals. EPA 600/4-91/029. Environmental Monitoring Systems Laboratory, Las Vegas, NV, 89193-3478. Cameron, R.E., G.B. Blank, and D.R. Gensel. 1966. Sam- pling and Handling of Desert Soils. NASA Technical Report No. 32-908. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA, 91109. Follmer, L.R., E.D. McKay, J.A. Lineback, and D.L. Gross. 1979. Wisconsinan, Sangamonian, and Illinoian Stratig- raphy in Central Illinois. ISGS Guidebook 13, Appendix 3. Illinois State Geological Survey, Champaign, IL. Ford, P.J., P.J. Turina, and D.E. Seely. 1984. Charac- terization of Hazardous Waste Sites—A Methods Manual: Vol. II. Available Sampling Methods, 2nd ed. EPA 600/4- 84-076 (NTIS PB85-521596). Environmental Monitoring Systems Laboratory, Las Vegas, NV, 89193-3478. Guthrie, R.L. and J.E. Witty. 1982. New Designations for Soil Horizons and Layers and the New Soil Survey Manual. Soil Sci. Soc. Am. J. 46:443-444. Indiana Department of Environmental Management (IDEM). 1988. Requirements for Describing Uncon- solidated Deposits (draft revised 11/18/88). IDEM, In- dianapolis, IN. Johnson, W.M., J.E. McClelland, S.B. McCaleb, R. Ulrich, W.G. Hoper, and T.B. Hutchings. 1960. Classification and Description of Soil Pores. Soil Science 89:319-321. Leach, L.E., F.P. Beck, J.T. Wilson, and D.H. Kampbell. 1988. Aseptic Subsurface Sampling Techniques for Hol- low-Stem Auger Drilling. In: Proc. Third Nat. Outdoor Ac- tion Conf. on Aquifer Restoration, Ground Water Monitoring and Geophysical Methods. National Water Well Association, Dublin, OH, pp. 31-51. ycKyftK£^i^&wy&&y^y&sfc^ References 103 ------- References 104 Lynn, W.C., W.E. McKinzie, and R.B. Grossman. 1974. Field Laboratory Tests for Characterization of Histosols. In: Histosols: Their Characterization, Use and Classifica- tion. Soil Science Society of America, Madison, Wl, pp. 11-20. Mason, B.J. 1983. Preparation of Soil Sampling Protocol: Techniques and Strategies. EPA-600/4-03-020 (NTIS PB83-206979). Environmental Monitoring Systems Laboratory, Las Vegas, NV, 89193-3478,102 pp. O'Neal, A.M. 1952. A Key for Evaluating Soil Permeability by Means of Certain Field Clues. Soil Sci. Soc. Am. Proc. 16:312-315. Portland Cement Association. 1973. PCA Soil Primer. En- gineering Bulletin EB007.045. Portland Cement Associa- tion, Skokie, IL, 39 pp. Rehm, B.W., T.R. Stolzenburg, and D.G. Nichols. 1985. Field Measurement Methods for Hydrogeologic Investiga- tions: A Critical Review of the Literature. EPRI EA-4301. Electric Power Research Institute, Palo Alto, CA. Rhoades, J.D. and J.D. Oster. 1986. Solute Content. In: Methods of Soil Analysis, Part 1, 2nd ed., A. Klute (ed.), Agronomy Monograph No. 9. American Society of Agronomy, Madison, Wl, pp. 985-1006. Richards, L.A. (ed.). 1954. Diagnosis and Improvement of Saline and Alkali Soils. U.S. Department of Agriculture Handbook No. 60,160 pp. Richards, L.A., C.A. Bower, and M. Fireman. 1956. Tests for Salinity and Sodium Status of Soil and Irrigation Water. U.S. Department of Agriculture Circular 982. Smith, G.D., F. Newhall, and L.H. Robinson. 1960. Soil- Temperature Regimes—Their Characterization and Pre- dictability. SCS-TP-144. USDA Soil Conservation Service, 14pp. Soil Conservation Service (SCS). 1971. Handbook of Soil Survey Investigations Procedures. SCS, Washington, DC, 98pp. Soil Conservation Service (SCS). 1983. National Soils Handbook. [Available for inspection in SCS County, Area, or State Offices. A revised handbook was in preparation at the time this pocket guide was completed.] ------- Soil Conservation Service (SCS). 1984. Procedures for Col- lecting Soil Samples and Methods of Analysis for Soil Survey. Soil Survey Investigations Report No. 1. U.S. Government Printing Office. Soil Conservation Service (SCS). 1990. Elementary Soil Engineering, Chapter 4. In: Engineering Field Manual for Conservation Practices. SCS, Washington, DC. Soil Science Society of America. 1987. Glossary of Soil Science Terms. SSSA, Madison, Wisconsin. Soil Survey Staff. 1975. Soil Taxonomy: A Basic System of Soil Classification for Making and Interpreting Soil Surveys. U.S. Department of Agriculture Agricultural Handbook No. 436. Soil Survey Staff. 1990. Keys to Soil Taxonomy, 4th ed. SMSS Technical Monograph No. 6. Dept. Crop and Soil Environmental Sciences, Virginia Tech, Blacksburg, VA, 24061-0404, 422 pp ($12.00). Soil Survey Staff. 1991. Examination and Description of Soils, Chapter 3. In: Soil Survey Manual (new edition). Agricultural Handbook No. 18. Soil Conservation Service, Washington, DC. [Note that this supercedes the 1951 handbook by the same title, and the 1962 supplement. This manual was at the publisher at the time this pocket guide was completed.] Taylor, S.A. and R.D. Jackson. 1986. Temperature. In: Methods of Soil Analysis, Part 1, 2nd ed., A. Klute (ed.), Agronomy Monograph No. 9. American Society of Agronomy, Madison, Wl, pp. 927-940. U.S. Environmental Protection Agency (EPA). 1986. Test Methods for Evaluating Solid Waste. SW-846 (NTIS PB88-239223 and PB89-148076). van Ee, J.J., L.J. Blume, and T.H. Starks. 1990. A Ration- ale for the Assessment of Errors in the Sampling of Soils. EPA/600/4-90/013. Environmental Monitoring Systems Laboratory, Las Vegas, NV, 57 pp. Vogel, W.G. 1987. A Manual for Training Reclamation In- spectors in the Fundamentals of Soils and Revegetation. Soil and Water Conservation Society, Ankeny, IA, 178 pp. Witty, J.E. and E.G. Knox. 1989. Identification, Role in Soil Taxonomy, and Worldwide Distribution of Fragipans. In: Fragipans: Their Occurrence, Classification, and Genesis, N.E. Smeck and E.J. Ciolkosz (eds.), SSSA Sp. Pub. No. 24. Soil Science Society of America, Madison, Wl, pp. 1-9. References 105 ------- Description of Soil Cores 106 Appendix A.1 General Protocol for Description of Soil Cores Careful description of soil conditions at sampling loca- tions can provide valuable information for interpreting soil analyses. Soil cores, which provide relatively undis- turbed cross sections of the soil, are best for soil descrip- tion. A few major features like texture, color (but not accurate description of mottling or variations in color), and potential zones of contamination can be described from auger samples, but not much more. At the outset, it should be decided whether soil descriptions will be made from the actual samples to be analyzed or from separate cores taken at the site. Describing actual samples has the advantage of allowing direct correlation of analyses with observed features, but will result in longer exposure of the sample to the air before it is placed in the sample container. This may not be desirable, even for samples taken for analysis of semi- volatiles and metals. Table 1-1 contains an abbreviated list of suggested features to be described from soil samples. Taking separate cores allows more leisurely and detailed observation of soil features. The soil can also be handled as necessary without concern about affecting its integrity for analyses. When equipment is being used just to describe soil features, decontamination procedures between locations also may be less rigorous, provided that there is no danger that contaminants with very low detection limits could be spread to uncontaminated areas. The upper 1.5 to 2 meters, which have been af- fected by soil weathering processes, should receive the most careful attention for description because this is where the most complex features are likely to be en- ------- countered. Weathering may extend below 2 m in older landscapes formed in temperate to humid climates. Below the zone of weathering, the more simplified descriptions typical of geologic drill logs are appropriate. General pro- cedures for describing both types of cores are outlined below. Soil Cores (weathered zone, usually 1.5 to 2 m) 1. Near the location where the core is to be taken, spread a plastic sheet about 30 cm wide and 2 meters long on the ground, and place on it a fully extended carpenters rule or range pole marked with gradations that match the depth increments on the tube sampler to be used (i.e., in./ft or cm/meter). 2. Clear any litter away from the ground surface and take the first core. An open tube sampler that ex- poses most of the core when it is pulled out is easiest to use for this purpose. Remove the core and place it on the sheet at the zero end of the rule. If the presence of volatile contaminants is suspected, take the reading of the core as soon as it is brought to the surface with field instrumenta- tion (photoionization or flame ionization detector). Also take a reading near the top of the core hole and record the measurements. 3. Repeat coring process trying to take equal incre- ments (12-in. increments are usually possible in the upper 2 or 3 ft; 6-in. increments when the soil is very dry and in deeper, denser horizons), placing each core on the sheet at the appropriate depth in- terval until the desired maximum depth has been reached. If the presence of volatile contaminants is suspected, readings with field instruments should be made of each core as soon as it is brought to the surface, and near the top of the hole before taking the next increment. 4. If penetration is difficult in very dense or very dry soils, a weighted plastic mallet can be used to drive a sampler with a T-handle into the ground. If such conditions are typical, consider using samplers with specially designed weighted drivers. Description of Soil Cores 107 ------- Description of Soil Cores 108 5. !f rock fragments prevent further penetration of the tube sampler before the desired depth has been obtained, an auger (screw or bucket) can be used. If the diameter of the auger is larger than that of the tube sampler (usually the case), discard the soil material brought up by the auger for the depth increments already sampled. 6. When the depth of interest is reached, pull up the auger at regular intervals and place soil by the rule on the sheet at the appropriate depth location. To prevent mixing of loose soil material from different depth increments, place material at chosen incre- ments (e.g., 12 in.) on opposite sides of the rule. 7. Once the complete soil is laid out on the sheet, visually examine the cores and place nails or some other kind of marker at the places where color changes indicate transitions between horizons. 8. Carefully split the cores. A knife may be used to create a shallow groove, but the core should not be sliced all the way through because this will disturb structural features. Place one-half with the interior side facing up, and the other half with the interior side facing down (exposing the surface that was used for the initial visual inspection). 9. Visually examine the interior face of the cores for transitions in structural units, texture, or other fea- tures. Adjust the locations of initially placed horizon markers on the sheet, if appropriate, and add addi- tional markers for subhorizons, if required. 10. Describe each soil horizon using Form 3-1. Refer to the appropriate sections of Chapter 3 for proce- dures and abbreviated codes for descriptors of soil parameters. Cores below Weathered Zone (usually 1.5 to 2 m) Cores from greater depths can be described using essentially the same procedures as described above, ex- cept that the greater length requires placement of cores in holders where depth increments are side-by-side rather than end-on-end, and that generally fewer features are described. Most drillers and consultants have their own drill log forms. At a minimum, the following information ------- should be recorded when describing cores below the weathering horizon: 1. Type of sample (split spoon, shelby tube, etc.) 2. Thickness driven/thickness recovered 3. Blow count (per 6 in.), if driven 4. Depth interval Descriptions of depth intervals tend to be more ab- breviated than near-surface soil profile descriptions and apply to regular depth intervals rather than transitions between horizons (although such transitions should be noted and described). Features should be described in a consistent sequence. The following features, when present, should be described: 1. Texture (USDA and Unified estimated textures, coarse fragments) 2. Sorting and roundness 3. Moisture condition (moist, wet, dry, presence of water table) 4. Color and mottling 5. Consistency (rupture resistance, cementation) 6. Secondary porosity features 7. Sedimentary structures 8. Presence of organic matter 9. Effervescence in dilute, 10 percent cold HCI (cal- careous parent material) 10. Visible presence of synthetic chemicals (oil, gasoline, solvents) 11. Reading from field instrumentation (photoionization or flame ionization detector) Description of Soil Cores 109 ------- So/7 Sample Handling and Preparation 110 Appendix A.2 General Protocol for Soil Sample Handling and Preparation If questions arise in the field concerning sample handling and preparation procedures as specified in the Soil Sam- pling Plan for the site, this general protocol can be used. Any departures from procedures contained in the site Soil Sampling Plan should be documented and justified (see Form 4-1). The procedures described here generally apply to any type of soil sampling. They have been compiled primarily from procedures described in Brown et al. (1991). Specific procedures for different types of sampling tools are described in Appendices A.3 and A.4. A.2.1 Soil Sample Collection Procedures for Volatiles 1. Tube samplers are preferred when collecting for volatiles. Augers should be used only if soil condi- tions make collection of undisturbed cores impos- sible. Soil recovery probes and augers, with dedicated or reusable liners (see Table 4-1), will minimize contact of the sample with the atmosphere. 2. Place the first adequate grab sample, maintaining and handling the sample in as undisturbed a state as possible, in 40-mL septum vials or in a 1 -L glass wide mouth bottle with a Teflon®-lined cap. Do not mix or sieve soil samples. 3. Ensure the 40-mL containers are filled to the top to minimize volatile loss. Secure the cap tightly. 4. Examine the hole from which the sample was taken with an organic vapor instrument after each ------- sample increment. Record any instrument readings. 5. Label and tag sample containers, and record ap- propriate data on soil sample data sheets (depth, location, etc.). 6. Place glass sample containers in scalable plastic bags, if required, and place containers in iced ship- ping container. Samples should be cooled to 4°C as soon as possible. 7. Complete chain-of-custody forms and ship as soon as possible to minimize sample holding time (see Table A.1 for maximum holding times for various constituents). 8. Follow required decontamination and disposal pro- cedures (see A.2.3). A.2.2 Soil Sample Collection and Mixing „ Procedures for Semivolatiles and Metals 1. Collect samples. 2. If required, composite the grab samples, or use discrete grab samples. 3. If possible, screen the soils in the field through a precleaned O-mesh (No. 10, 2 mm) stainless steel screen for semivolatiles, or Teflon®-lined screen for metals (some metals in stainless steel could contaminate the sample). 4. Mix the sample in a stainless steel, aluminum (not suitable when testing for Al), or glass mixing con- tainer using the appropriate tool (stainless steel spoon, trowel, or pestle). 5. After thorough mixing, place the sample in the mid- dle of a relatively inexpensive 1-m square piece of suitable plastic, canvas, or rubber sheeting. 6. Roll the sample backward and forward on the sheet while alternately lifting and releasing op- posite sides or corners of the sheet. 7. After thorough mixing, spread the soil out evenly on the sheet with a stainless steel spoon, trowel, spatula, or large knife. Soil Sample Handling and Preparation 111 ------- So/7 Sample Handling and Preparation 112 8. Take sample container and check that a Teflon® liner is present in the cap, if required (see Table A-1 for recommended sample containers for dif- ferent contaminants). 9. Divide the sample into quarters, and take samples from each quarter in a consecutive manner until appropriate sampling volume is collected for each required container. Separate sample containers would be required for semivolatiles, metals, dupli- cate samples, triplicate samples (split), and spiked samples. 10. Secure the cap tightly. The chemical preservation of solids is generally not recommended. 11. Label and tag sample containers, and record ap- propriate data on soil sample data sheets (depth, location, other observations). 12. Place glass sample containers in scalable plastic bags, if required, and place containers in an iced shipping container. Samples should be cooled to 4°C as soon as possible. 13. Complete chain-of-custody forms and ship as soon as possible to minimize sample holding time (see Table A-1 for maximum holding times for various constituents). Scheduled arrival time at the analyti- cal laboratory srfould give as much holding time as possible for scheduling of sample analyses. 14. Follow required decontamination and disposal pro- cedures (see A.2.3). A.2.3 Equipment Decontamination/Disposal Decontamination procedures may vary from state to state and site to site. Detailed procedures should be specified in the Soil Sampling Plan. A very general proce- dure is outlined here: 1. Any disposable solid contaminated equipment (plastic sheets, screens, etc.) should be placed in plastic bags for temporary storage and sealed in metal barrels for final transport/disposal. 2. Reusable equipment should be washed and rinsed using decontamination procedures specified in the Soil Sampling Plan. ------- 3. Collect swipes and decontamination blanks, if required, to evaluate the possibility of cross-contamination. A.2.4 Air Drying Samples collected for chemical analysis in the laboratory do not normally need to be air dried. However, air drying may be desired in the field for evaluation of soil physical and hydrologic properties. In some instances, air drying of contaminated samples involving semivolatiles and metals may be desired before sending samples to the analytical laboratory. 1. Weigh sample and record weight if percent mois- ture is required. 2. Spread out the soil sample on a stainless steel sheet and allow to air dry. This may take 3 days or more. If samples are to be analyzed for possible contaminants, samples should be placed so as to prevent possible cross-contamination. If they are to be analyzed for microbiological activity, samples should be placed in containers through which fil- tered air can be passed. 3. When dry, weigh and record weight if percent moisture is required. 4. Break up soil aggregates and pull apart vegetation and root mat, if present. Weigh nonsoil vegetation fraction, and archive or discard, as required. 5. Remove large rocks and weigh. Archive for pos- sible analysis. 6. Crush the entire soil sample with a rolling pin, stainless steel spoon, or some similar tool. Blend with stainless steel spoon for 30 minutes. 7. Sieve through an O-mesh (No. 10, 2 mm) screen. Any type of screen is acceptable, if soils are not contaminated. Use disposable stainless steel (semivolatile contamination) or Teflon® (metal con- tamination) if soil samples are contaminated and the chemical integrity of the sample must be maintained. 8. Spread out the sample, mark off quarters, and take sample from each quarter in a consecutive manner until appropriate sample volume is collected. Soil Sample Handling and Preparation 113 ------- Soil Sample Handling and Preparation 114 x*K*:*K'>:*:*X'K'X*K*:'Xw Archive remaining sample for future analysis, if needed. 9. When ready for shipment to the analytical laboratory, shake the sample to mix thoroughly. 10. Follow required decontamination and disposal procedures (see A.2.3). Table A-1. EPA Recommended Sampling Containers, Preservation Requirements, and Holding Times for Soil Samples Contaminant Acidity Alkalinity Ammonia Sulfate Sulfide Sulfite Nitrate Nitrate-Nitrite Nitrite Oil and Grease Organic Carbon Metals Chromium VI Mercury Other Metals Cyanide Organic Compounds Extractables Including Phthalates, Nitrosamines, Organo- chlorine Pesticides, PCBs, Nitroaromatics, Isophorone, Polynuclear Aromatic Hydrocarbons, Haloethers, Chlorinated Hydrocarbons, and TCDD Container* Preservation** P,G P,G P,G P,G P,G P,G P,G P,G P.G G P.G P,G P.G P,G P,G G, Teflon®- lined cap Holding Time*** 1 4 days 1 4 days 28 days 28 days 28 days 48 hours 48 hours 28 days 48 hours 28 days 28 days 48 hours 28 days 6 months 28 days 7 days until extraction 30 days after extraction (Continued) ------- Table A-1. (Continued) Contaminant Container* Preservation* Holding Time*** Extractables (Phenols) Purgables Halocarbons and Aromatics Acrolein and Acrylonitrate Orthophosphate Pesticides Phenols Phosphorus Phosphorus, Total Chlorinated Organic Compounds G, Teflon®- lined cap G, Teflon®- lined septum G, Teflon®- lined septum P,G G, Teflon®- lined cap G G P,G G, Teflon®- lined cap 7 days until extraction 30 days after extraction 14 days 3 days 48 hours 7 days until extraction 30 days after extraction 28 days 48 hours 28 days 7 days *P = polyethylene, G = glass. "All samples cooled to 4°C. Sample preservation should be per- formed immediately upon sample collection. For composite samples, each aliquot should be preserved at the time of collec- tion. When impossible to preserve each aliquot, then samples may be preserved by maintaining 4°C until compositing and sample splitting is completed. '"Samples should be analyzed as soon as possible after collec- tion. The times listed are the maximum times that samples may be held before analysis and still be considered valid. Samples may be held for longer periods only if the analytical laboratory has data on file to show that the specific types of samples under study are stable for the longer time. Source: Barth et al., (1989); for additional information, see Mason (1983). So/7 Sample Handling and Preparation 115 ------- So/7 Sampling with a Spade and Scoop 116 :*K*:!:!:::::':*H*:*:W^^^ Appendix A.3 General Protocol for Soil Sampling with a Spade and Scoop The simplest and most direct method of collecting soil samples for subsequent analysis is with a spade and scoop. A normal lawn or garden spade can be used to remove the top cover of soil to the required depth, and then a smaller stainless steel scoop can be used to collect the sample. This method can be used in most soil types, but is limited to sampling the near surface. Samples from depths greater than 50 cm become extremely labor intensive in most soil types. Very accurate, representative samples can be collected with this procedure depending on the care and precision demonstrated by the sampler. A flat, pointed mason trowel can be used to cut a block of soil when relatively undisturbed samples are desired. A stain- less steel scoop or lab spoon will suffice in most other ap- plications. Chrome-plating on instruments, common with garden implements such as potting trowels, should be avoided. Procedure (drawn from Ford et al., 1984) 1. Clear the area to be sampled of any surface debris (twigs, rocks, litter). It may be advisable to remove the first 8 to 15 cm of surface soil for an area ap- proximately 15 cm in radius around the drilling location to prevent near-surface soil particles from falling down the hole. 2. Carefully remove the top layer of soil to the desired sample depth with a precleaned spade. ------- 3. Using a precleaned stainless steel scoop or trowel, remove and discard a thin layer of soil from the area which came in contact with the shovel. 4. Collect and handle sample using procedures described in A.2.1 (Soil Sample Collection Proce- dures for Volatiles) and A.2.2 (Soil Sample Collec- tion and Mixing Procedures for Semivolatiles and Metals). So/7 Sampling with a Spade and Scoop 117 ------- So/7 Sampling with Augers and Thin-Walled Tube Samplers 118 KW Appendix A.4 General Protocol for Soil Sampling with Augers and Thin-Walled Tube Samplers Hand-held augers and thin-walled tube samplers can be used separately or in combination. Where rocky soils do not limit the use of tube samplers, a combination of augers to remove soil material to the depth of interest and tube samplers for actual sample collection allows the most precise control of sample collection. Depths to 2 meters can be readily sampled and up to 6 meters where condi- tions are favorable. Tables 4-1 and 4-2 provide informa- tion on the advantages and disadvantages of different types of augers and tube samplers for sampling under dif- ferent soil conditions. The recently developed in situ soil recovery auger and probe allow collection of samples in dedicated or reusable liners that reduce cross-contamination of samples and minimize contact with the atmosphere (see Table 4-1 and Appendix B). Specific sampling tools may require slightly dif- ferent handling methods. For example, if sampling devices and drill rod extensions do not have quick connect fittings, crescent or pipe wrenches may be required to change equipment configurations. The procedure described below is for hand-held equipment. Procedures for power-driven augers or tube samplers are essentially the same (drawn from Ford et al., 1984, and Brown et al., 1991). 1. Attach the auger bit to a drill rod extension and fur- ther attach the "T" handle to the drill rod. 2. Clear the area to be sampled of any surface debris (twigs, rocks, litter). It may be advisable to remove ------- the first 8 to 15 cm of surface soil for an area ap- proximately 15 cm in radius around the drilling location to prevent near-surface soil particles from falling down the hole. 3. Begin drilling, periodically removing accumulated soils. This prevents accidentally brushing loose material back down the borehole when removing the auger or adding drill rods. 4. After reaching the desired depth, slowly and care- fully remove auger from boring. When sampling directly from auger, collect sample after auger is removed from boring. Discard the upper portion of the sample, which may contain soil that has fallen to the bottom of the hole from the sidewalls. Proceed to sample handling and mixing proce- dures (see A.2.1 and A.2.2). 5. If taking a core sample, remove auger tip from drill rods and replace with a precleaned thin-walled tube sampler. Install proper cutting tip. (An optional step is to first replace the auger tip with a planer auger to clean out and flatten the bottom of the hole before using the thin-walled tube sampler.) 6. Carefully lower corer down borehole. Gradually force corer into soil. Care should be taken to avoid scraping the borehole sides. Hammering of the drill rods to facilitate coring should be avoided, as the vibrations may cause the bore walls to collapse. 7. Remove corer and unscrew drill rods. 8. Remove core from device (this may require remov- ing cutting tip) and discard top of core (ap- proximately 2.5 cm), to eliminate soil that may have fallen down from higher horizons. 9. Handle sample using procedures described in A.2.1 andA.2.2. So/7 Sampling with Augers and Thin-Walled Tube Samplers 119 ------- Manufacturers and Distributors of Soil Sampling Equipment 12° W&S8$!$^^ Appendix B xmv&»Z'»&;&s*x»Kmi&»x>z!: Manufacturers and Distributors of Soil Sampling Equipment Table B-1. Manufacturers and Distributors of Soil Sampling Equipment (Compiled from Barrett et al., 1980; Ford et al., 1984; Rehm et al., 1985; SCS, 1983) Supplier Types of Samplers Acker Drill Company P.O. Box 830 Scranton, PA 18501 Art's Manufacturing and Supply (AMS) 105 Harrison American Falls, ID 83211 1/800/635-7330 Boyle Brothers P.O. Box 25068 1624 Pioneer Road Salt Lake City, UT 84125 Carl's Machine Shop and Supply Co. 1202 ^ainSt. Woodward, OK 73801 Mining Products Division Christensen Diamond Products Company 1937 S. 300 West Salt Lake City, UT 84115 Power-driven samplers Manual samplers In situ soil recovery auger and probe Planer auger Power-driven samplers Power-driven samplers Power-driven samplers (Continued) ------- Table B-1. (Continued) Supplier Types of Samplers Clements Associates, Inc. RR1 Box 186 Newton, IA 50208 515/792-8285 Forestry Suppliers P.O. Box 8397 Jackson, MS 39284-8397 Gidding Machine Company 401 Pine Street P.O. Box 406 Fort Collins, CO 80521 Hansen Machine Works 1628 North C Street Sacramento, CA 95814 Joy Manufacturing Company Montgomery Industrial Center Montgomeryville, PA 19936 Longyear Company 925 Delaware Street, SE Minneapolis, MN 55414 Mobile Drilling Company 3807 Madison Ave. Indianapolis, IN 46227 Oakfield Apparatus Company P.O. Box 65 Oakfield, Wl 53065 Odgers Drilling, Inc. Ice Lake Road Iron River, Ml 49935 Penndrill Manufacturing Div. Pennsylvania Drilling Co. P.O. Box 8562 Pittsburgh, PA 15220 Manual samplers Manual samplers Clinometer Power-driven samplers Veihmeyer probe Power-driven samplers Power-driven samplers Power-driven samplers Manual samplers Power-driven samplers Power-driven samplers (Continued) Manufacturers and Distributors of Soil Sampling Equipment 121 ------- Manufacturers and Distributors of Soil Sampling Equipment 122 SSSSgS/imSSSSilXSSISSISagmmsmxmKK Table B-1. (Continued) Supplier Types of Samplers Pitcher Drilling Company 75 Allemany Street Daly City, CA 94014 Reed Tool Company 105 Allen Street P.O. Box 3641 San Angelo, TX 76901 Reese Sale Company P.O. Box 645 2301 Gibson St. Bakersfield, CA 93302 Sauze Technical Products Corp. 345 Cornelia St. Plattsburgh, NY 12901 518/561-6440 Service Truck Body Shop 1259 Murray Alexandria, LA 71301 Soilmoisture Equipment Corp. P.O. Box 30025 Santa Barbara, CA 93105 805/964-3525 Soiltest, Inc. P.O. Box 931 2205 Lee Street Evanston, IL 60202 312/869-5500 Sprague and Henwood, Inc. 221 West Olive Street Scranton, PA 18501 Wildco 301 Cass Street Sag in aw, Ml 48602 517/799-8100 Power-driven samplers Power-driven samplers Power-driven samplers Eijkelcamp stoney soil auger Manual samplers Manual samplers Power-driven samplers Penetrometer Selves Power-driven samplers Manual samplers ------- |