Groundwater Monitoring

Applied Science & Technology, Inc. (ASTI) offers a full range of groundwater environmental monitoring, modeling and compliance assistance services to businesses throughout the United States. These services include initial groundwater quality assessments, development of work plans, complete monitoring programs and closures. A few examples of groundwater assistance programs successfully completed by ASTI are provided below.

INITIAL GROUNDWATER QUALITY ASSESSMENT

Prior to beginning a monitoring program, the initial water quality conditions should be assessed and documented. At one site, ASTI conducted the initial baseline monitoring by providing triplicate sampling at each monitoring well and determining the coefficient of variation for each parameter. Based on the non-normal distribution of the data, ASTI conducted additional statistical evaluations. This unusual program was required by a Consent Agreement and was conducted because of the number of parameters that naturally exceeded the permit conditions. The evaluation indicated that background monitoring wells were not monitoring a single aquifer, and that special monitoring and statistical methods would be required in the operating permit.

WORK PLAN PREPARATION AND NEGOTIATIONS

Often the most important aspect of establishing a groundwater monitoring program is preparing the work plan that outlines the program specifications and obtaining agency approval for implementing the program. ASTI has prepared and obtained approval for numerous work plans for groundwater monitoring and understands the technical and quality assurance requirements of a successful program. At a minimum, a program must include representative sampling, and must provide a method for identifying only significant changes in groundwater quality.

INDUSTRIAL MONITORING

ASTI has conducted compliance groundwater monitoring programs at numerous industrial facilities. These programs included the development of a monitoring work plan, implementation of sampling and analytical tasks, data evaluation, and annual reports. The quarterly monitoring at a battery manufacturing facility in Michigan illustrates a typical program. For a period of four years, ASTI sampled the twenty well network at this facility to evaluate the groundwater concentration of heavy metals and common ions. Following each quarterly sampling event, ASTI prepared a report summarizing the analytical results, sampling and analytical procedures, and historic trends compared to permit limitations. As appropriate, wells were repaired or replaced, to maintain the network as required by the facility permit. The result of this program confirmed that the facility had not adversely impacted the local aquifer.

STATISTICAL EVALUATIONS

In addition to routine monitoring and analysis, RCRA permits often require a statistical evaluation of the monitoring data. ASTI has conducted statistical analysis and annual reporting for various RCRA facilities. These evaluations were provided annually, and included a comparison of current data to background values and historic trends, in order to identify statistically significant increases in any parameter. In all cases, the evaluations were completed per the requirements of Michigan Act 64 and RCRA, or procedures specific in a Consent Agreement.

GROUNDWATER REMEDIAL INVESTIGATION

Groundwater monitoring networks are not limited to compliance monitoring, but are often used to delineate contamination. For example, after a landfill had been identified as a potential source of local groundwater contamination, ASTI was retained to complete a Remedial Investigation. This investigation began with a preliminary boundary study to initially delineate the extent of impact and to assist in locating appropriate well locations. Based on that initial study, thirty-four off-site monitoring wells were eventually installed to determine plume characteristics and boundary conditions. The final stage included confirmation sampling of all on-site and off-site wells, characterization of the suspected plume, and negotiations with the MDNR to define final clean-up standards.

GROUNDWATER ASSESSMENT

In 1979 a 20,000 gallon waste spill occurred at a hazardous waste treatment, storage, and disposal facility. Much of the waste was recovered, but a large fraction entered the aquifer on the site. Due to the sandy soils and groundwater flow at the facility, dispersion of the materials was rapid.

ASTI's hazardous waste specialist directed the investigation to install monitoring wells, determine aquifer characteristics, identify the nature and extent of the impacts, and investigate discontinuities in the underlying clay aquiclude. ASTI determined that the plume had left the subject property, and that there was still contribution of organic pollutants from the unsaturated soils during recharge events. The investigation report provided the information required for delineation of the plume and an evaluation of remediation alternatives.

Aquifer pumping tests were also conducted to provide information for the design and operation of the remediation system. A pump and treat system was designed, and a Remedial Action Plan was prepared. The results of the investigation were submitted to the state agency for review prior to implementation.

SOILS AND GROUNDWATER INVESTIGATION

In the mid to late 1960's barrels of waste materials were disposed of in four locations on an active farm. The drums remained in place until the summer of 1984 when they were removed to a licensed disposal facility. After removal of the drums, an initial investigation was conducted to determine if any environmental impact had occurred. The initial investigation conducted in 1985 consisted of drilling 9 soil borings around the four waste sites to examine subsurface soil types and the installation of 8 monitor wells. In addition, sediment samples and surface water samples were also collected from an adjacent marsh. The initial investigation concluded that volatile compounds and metals had impacted soils and infiltrated to the water table and that lateral migration was occurring.

In 1992 ASTI was retained to review the initial investigation results, propose additional sampling and analysis as necessary, and conduct a feasibility study for site remediation. Following the initial investigation the site was included on the federal and state 'Superfund' lists. Consequently, numerous Potential Responsible Parties (PRPs) participated in the subsequent investigation and negotiations stages. ASTI coordinated sampling and design programs with the PRPs. The additional investigation included confirmation sampling for all monitoring wells to compare site conditions to those occurring in 1985. In addition, new monitoring well installation and soil sampling was conducted to determine contaminant migration, and evaluate the extent of impacts for completion of the feasibility study.

Based on the results of the investigation, a perimeter drain system and groundwater treatment system was recommended for this site. As of this writing a third stage of investigation was required by the MDNR to further delineate impacts to specific site features such as the wetlands.

SOILS AND GROUNDWATER INVESTIGATION

During the 1970's and early 1980's drums of listed hazardous waste (F006 designation) were stored outside this facility on a concrete pad. As a result of housekeeping problems, run-off from the drums and pad impacted adjacent surface and saturated soils. These impacts were identified during a routine Phase I investigation.

To determine the nature and extent of the impacts ASTI conducted a soils and groundwater investigation based on a combination of a review of existing site and area data, and the collection of soils samples. Access to adjacent properties was not obtainable, so the investigation was limited to the subject site. Since groundwater does not occur at the site, the evaluation of contaminant migration was limited to investigation of saturated soils.

The investigation indicated that the impacts extended to the north and west off of the subject property. ASTI designed a drain and sump system to contain migration on the subject property, reverse migration off-site and remediate saturated soils. Because of the nature of the released material, a major portion of the Remedial Action Plan concerned disposal and handling of excavated soils. The final plan approved by the MDNR included on-site staging and treatment of excavated soils.

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