Soil Water and Ground Water Sampling

Neal Wilson

• Publisher: CRC Press
• Year: 2020
• eBook ISBN: 9781000157499
• Topic: Technology & Engineering
• Subtopic: Industrial Design
• Index: Technology & Engineering

The most recent "comprehensive" book on the subject of ground water sampling was written by Dr. Barcelona in 1986 and is still being sold today. It does not, however, include soil water sampling and analytic techniques. A considerable amount of research has since been undertaken dealing with ground water sampling equipment and techniques, making an up-to-date text a valuable commodity. The scope and detail of this book is much broader and more inclusive than previous efforts on the subject, and it provides the latest results of research in the field. The book presents a comprehensive introduction to ground water monitoring, placing monitoring in context with respective regulatory programs. It offers a unique, detailed description of the installation and operation of soil water samplers (pressure-vacuum and zero tension). It provides the most comprehensive, step-by-step guidance on monitoring well installation. The discussion of field instrumentation includes theory and operation of equipment used for obtaining static water levels, temperature, redox, pH, dissolved oxygen, specific conductance, turbidity, and alkalinity. Equipment and techniques used to obtain ground water samples are described, and several valuable checklists are included. Quality assurance and control (QA/QC) are addressed in terms that can be easily comprehended and utilized. The book also provides an excellent introduction on how ground water samples are prepared and analyzed in a laboratory. It is difficult to overestimate the quality and utility of this book. More than 46 photographs, an abundance of tables and diagrams, and a well-written style make even the most complex topic understandable. This extremely practical book should serve as the standard for ensuring ground water data reliability and comparability.

chapter one

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Ground water monitoring and site remediation

Remember when discoursing about water
to adduce first experience and then reason.
Leonardo da Vinci, 1452-1519

Introduction to ground water monitoring

Ground water monitoring may be initiated when a specific land-use activity has been identified that has or could potentially negatively alter (contaminate) the natural state of the soil and/or the ground water. If contamination has occurred, the site must be adequately characterized so that decisions can be made on how to best manage the site. Monitoring is an effort to obtain an understanding of the chemical, physical, and biologic characteristics of water through statistical sampling.¹¹ Ground water monitoring program objectives for sites that are or could become contaminated include

• Protecting ground water users and facility owners and operators

• Assessing facility design and operation

• Guiding regulatory and enforcement actions

• Developing and implementing remedial actions for contaminated sites

• Evaluating the effectiveness of environmental programs

Some of the more common ground water contamination problems include those associated with landfills, leaking underground storage tanks, spill sites, hazardous waste sites, septic tank systems, leaking industrial and municipal wastewater lagoons, improper management of industrial and municipal wastewater and sludge, and non-point source pollution derived from agricultural practices. A contaminant may be hazardous (ignitable, corrosive, reactive, lethal, or toxic) and cause acute or chronic (including carcinogenic) impacts to human health. Environmental damage may also result from ground water contamination (Figure 1.1).

Figure 1.1 A hazardous waste site.

Investigative plans

Once a contamination problem has been identified a plan needs to be formulated and implemented to assess the immediate risks to human health and the environment, quantify the constituents of concern, determine the horizontal and vertical rates of migration of the contaminant plume, develop ways to reduce or eliminate the contamination, and further identify and protect those potentially affected. A statement of what problem is to be solved, the information required, what the project objectives are and how the objectives are to be met must be concisely stated and sufficiently detailed to permit a clear understanding by all the parties involved in the data collection effort.¹⁰

Quality assurance/quality control (QA/QC) measures must be employed at every step, from monitoring point design to sample collection and analysis. Data quality objectives⁹ must be taken into account when a monitoring system is being designed as must statistical considerations.⁶ Data quality objectives are statements that provide definitions of confidence, which are required for interpretation of the data.³ QA/QC and data quality objectives are presented in Chapter 7.

A phased approach is usually undertaken to adequately characterize a site. A preliminary (Phase I) site characterization consists of a records review, a site reconnaissance, and interviews with owners, occupants, and government officials.¹ The Phase I report is then generated from the compiled information.

Site use history includes title searches, insurance atlases, aerial photographs, site plans, site records, utility company records, and interviews with individuals who have lived near or worked at the site for an extended period of time.⁴ Existing hydrogeologic information includes soil surveys, geologic and hydrologic maps and reports, topographic maps, and well records.

Figure 1.2 Workers in level B protective suits with self-contained breathing apparatus at a hazardous waste spill site.

The initial site reconnaissance may include the use of an organic vapor monitor, an explosivity meter, video camera recorders, still cameras, and a hand-held soil sampler. Safety is of paramount importance — a site safety plan should be formulated, documented, approved, and adhered to for each phase of the investigation (see Chapter 6) (Figure 1.2).

Field notes for site reconnaissance should include dates, times, personnel, maps of the salient site features, and descriptions of what was found at the site. Field notes may become evidence in court, so the notes should be made in ink in a notebook with a sewn binding and be descriptive and accurate. If a video camera recorder is used, a verbal narrative should be included describing date, time, site, name of persons at the site, the direction the camera is facing (e.g., “now facing north”), and what the camera is recording. Photographs should be labeled with date and time, site, photographer, and a description of what the photograph represents. Sometimes several years may elapse before a photograph may become a critical piece of evidence; photographs should be labeled promptly after processing, so labeling is not neglected.

Existing site information may be expanded with direct, field-investigation methods including borings, test pits, piezometers, monitoring wells, push-type sampling devices (various sizes of driven well points, such as the Geoprobe^© or Geopunch^©), or soil gas surveys. Borings, piezometers, and temporary monitoring wells (Figure 1.3) provide information about soils, geology, and ground water chemistry, flow direction(s), and rate(s).

Figure 1.3 Installation of a monitoring well with a hollow stem auger (photograph courtesy of CME Company).

Ground water, soil gas, and lithologic samples may be collected with push-type samplers (Figure 1.4). Push-type samplers can provide rapid results and can be cost effective in horizontally and vertically delineating contaminant plumes. Push-type samplers may also assist in placing final monitoring points. Push-type samplers may be limited to shallow applications (generally less than 70 ft) in unconsolidated sand, and their use in more lithified formations or even gravel may cause probe refusal or may bend the probe. When approved by regulatory agencies, field analysis of key constituents (versus an entire scan) may be possible.¹²

Geophysical methods may be employed either to evaluate natural hydrogeologic conditions such as depth to water table, aquifer extent, or depth to bedrock surface or to locate buried wastes, drums, or tanks.² Geophysical methods include airborne, surface, or downhole geophysics. Soil gas surveys may provide information about the aerial extent of contamination at a site. Indirect methods of obtaining geologic information, such as geophysical methods and soil gas surveys, may be used to augment the evidence gathered from direct field methods but should not be used as a substitute for them.⁸ Data derived from monitoring points may provide information about the extent of contamination but generally not about the original mass of contaminants (Barcelona, M.J., personal communication).

Figure 1.4 A push-type (Geoprobe^®) sampling device mounted in a van.

Monitoring plans

When a decision is made to monitor a site a monitoring plan must then be developed and implemented. A monitoring plan is comprised of an environmental monitoring system (EMS), and a sampling and analysis plan which are all covered by a QA/QC component. A monitoring plan includes specifying the types, number, and vertical and horizontal placement of the final monitoring points, which may include soil water samplers, piezometers, and monitoring wells. Domestic and municipal wells may also provide information on the extent of ground water contamination.

The configuration of a monitoring system depends on an analysis of the information compiled during the previous phases of the investigation. If the s...

Table of contents

• Cover
• Title Page
• Copyright Page
• Preface
• The Author
• Acknowledgements
• Table of Contents
• Chapter 1 Ground water monitoring
• Chapter 2 Soil water monitoring devices
• Chapter 3 Design and installation of monitoring wells
• Chapter 4 Static water levels and geochemical field parameters
• Chapter 5 Equipment and techniques used for obtaining ground water samples
• Chapter 6 Ground water sampling plans
• Chapter 7 Quality assurance/quality control and laboratory analysis
• Index