Time is Money

Innovative application of standard geographic information systems (GIS) software to a complex environmental site investigation resulted in significant savings in time, labor, and therefore money.

The single biggest factor in these savings was the ability to gather all necessary field data in one trip, versus the usual three to five field trips. Savings were accomplished by licensing a single use of GIS\Key™ software from GIS\Solutions, Concord, Calif., and applying it in an imaginative way.

Located in a former borrow pit, the investigated site had a history of sand and gravel excavation and waste oil recycling, which came to an end in the 1980s. Client constraints required the team to assess the volume of contaminated material at this site in less than eight weeks, which made the customary multiple field events impossible.

Before beginning the fieldwork, the site investigation team established electronic deliverable formats with the selected laboratory.

A site investigation of this nature encompasses the collection and documentation of analytical and physical information, sample tracking, production and maintenance of a comprehensive electronic database and manipulation of this database to characterize site conditions. The process begins with the selection or design of a suitable, electronic basemap, development of templates and sorting parameters for populating the database and compilation of available, historic data. Once fieldwork has begun, the project scientists start tracking samples and documenting conditions at the site.

Physical information (e.g., soil descriptions, depth to groundwater, contacts between geologic units) is typically uploaded to the database as it is received from the field; sample tracking data (e.g., sample ID, collection date, sampling interval and required tests) are electronically compiled (preprocessed) with analytical data for construction of import templates and database uploading. Once the data have been validated and/or reviewed, real-time analysis of analytical and hydrogeologic data can begin.

Much Data, Little Time

The mission in this case was to evaluate the nature and distribution of site-related contaminants in lagoons and overburden soils at the subject site. Although the data generated during this study were expected to supplement historic information for development of remedial alternatives, the primary goal was to estimate the volume of contaminated materials so that the potentially responsible parties (PRP) could make strategic decisions regarding how the remedial process would be undertaken. This meant that the volume of contaminated materials at the site needed to be ascertained, and a report and presentation had to be prepared all within eight weeks.

Because data processing and interpretation determine the speed of confirmatory fieldwork, and multiple field studies were not possible, the investigation had to be conducted in real-time to meet the deadline. So, the team decided to map site data using GIS software that included automated import and data verification routines.

This former borrow pit was excavated for sand and gravel in the mid-1940s. Between the early 1950s and 1980s, the property was used for recycling waste oil. The oil was processed in Aboveground Storage Tank (AST) Area 1 and releases during handling appear to have flowed from here into a series of interconnected ponds at Lagoons 1 through 4. Tank bottom sludges were deposited in the Sludge Spreading Area south of AST Area 1.

Use of electronic files in the field assured the crew that mandatory fields would be completed and provided data management personnel in the office with legible information.

In 1978, additional soils were excavated from the lower gravel pit east of the ponds. About the same time, a section of the Sludge Spreading Area was partially filled, effectively dividing the original, interconnected ponds into four discrete lagoons (contaminated materials in the Sludge Spreading Area typically underlie approximately 2.5 feet of relatively clean soil). Since the lagoons were bermed, there have been at least two breaches at Lagoon 4 resulting in a release of oily sludge to the lower gravel pit.

In August 1997, the regulatory agency responsible for site oversight completed a preliminary remedial investigation of the property. The study identified approximately 0.3 feet of sludge at the bottom of Lagoons 1 and 2, and up to three feet of sludge underlain by five to 15 feet of contaminated soils at Lagoons 3 and 4, but did not delineate overall extent. These materials were found to contain volatile and semi-volatile organic compounds (VOCs and SVOCs), polychlorinated biphenyls (PCBs) and lead above acceptable levels.

A field effort, which generally includes documentation of hydrogeologic data and collection of environmental samples for laboratory analysis, is usually phased to permit data processing and interpretation. This often requires several stages to fully characterize environmental conditions and estimate the extent of contamination. For the reason discussed above, the usual routine was not possible in this case.

Data Transfer

Before beginning the fieldwork, the site investigation team established electronic deliverable formats with the selected laboratory. This enabled the team to automatically download requisite analytical data directly from its laboratory information management system to GIS\Key™'s import templates (preformatted Microsoft® Excel spreadsheets). This up-front coordination resulted in a data transfer system that eliminated manual data entry and associated transcription errors, reduced preprocessing time and produced electronic files ready for importing.

At the same time, the team began manually filling the sample tracking spreadsheet with proposed sampling information, including sample IDs, collection intervals and required test methods. This ensured that all requisite samples were collected and allowed the printing of sample container labels. Doing so eliminated double entry of data, unnecessary time in the field handwriting labels and the potential for the laboratory to run the wrong analysis or mis-identify samples because of illegible container labels.

The real-time investigation of this uncontrolled hazardous waste site permitted the field crew to complete contaminant delineation in about half the time required for a typical, multi-phased investigation.

The analytical data were e-mailed to the authors' firm and electronically compiled with sample tracking information (the compiler macro also confirms that the laboratory has processed all samples). The data were then uploaded to the project database using GIS\Key™ WinBuild.

Physical data were manually entered into Microsoft® Excel spreadsheets and then appended to the project database. Use of electronic files in the field assured the crew that mandatory fields would be completed and provided data management personnel in the office with legible information.

Data Interpretation and Reporting

Standard reporting routines provided with the software were used for data interpretation. These included automated queries for posting data to project basemaps and drawing management tools for creating cross sections, graphs, boring logs and contour maps. Because these routines take only minutes to run, the team could evaluate the data from many perspectives in a short timeframe and effectively present this information. Once interpretation is completed, the figures can be inserted in the final report without additional drafting.

The GIS-based software, coupled with electronic data transfer and automated uploading, enabled the team to make decisions in real time. This was how the investigation was completed in just one mobilization.

The software used for this study consisted of an integrated collection of off-the-shelf packages and customized macros designed to reduce the costs associated with the production, maintenance and manipulation of complex, environmental databases. The core software, GIS\Key™, was developed by GIS\Solutions to manage, interpret and visualize geologic, hydrologic and chemical data.

The team used Microsoft® Excel for sample tracking, manual entry of some hydrogeologic information and preprocessing of analytical data. A customized macro written in Microsoft® Visual Basic for Applications was used to compile sample-tracking information with analytical data.

Real Time Analysis

Fieldwork was completed in two weeks. The program, the purpose of which was to delineate the lateral and vertical extent of contamination, included soil borings, excavation of test pits and collection of sediment and surface water samples from the lagoons. Of the samples collected and submitted to Katahdin Analytical Services of Westbrook, Maine, certain "primary" samples were analyzed first, for lead and PCBs, within 48 hours. These analyses were expected to provide preliminary information on the extent of contaminated materials and determine the need for additional analyses or sampling locations. Based on these initial lead and PCB findings, certain samples were selected for a more complete range of analyses VOCs, SVOCs, TCLP (toxicity characteristic leaching procedure) parameters and/or additional inorganic analytes for waste characterization purposes. Turnaround time on the subsequent analyses was two weeks.

We collected 23 soil samples from test pits over two days, at depths ranging from 1.2 to 7.8 ft below ground surface (bgs). The samples were shipped to the laboratory the day they were obtained and analyzed within two working days while the field crew completed other tasks. The results were uploaded to the project database on the dates they were received.

Based on the initial data, 12 additional test pits were located, excavated and sampled one day after receiving the last of the primary sampling results from the laboratory. The samples from these new pits were then analyzed and contoured with the initially collected sample results to better define contaminant extent west of the Sludge Spreading Area, east of Lagoon 4 at the lower gravel pit and west of Lagoons 1 and 3. These additional sampling locations enabled the team to complete the analysis of contaminant extent, and no further samples were required.

The entire field investigation took only 15 days. In addition to the lead and PCB maps, the team contoured VOC and SVOC data from the waste characterization tests to confirm that the extent of contamination was well documented. These maps, and those produced to assess contaminant concentrations relative to residential and adult worker guidelines, as well as various cross sections, sludge thickness maps and bedrock surface plans (22 figures in all), were then used to calculate the volume of soil and/or sludge that could require remediation or containment under different scenarios at the site.

Cost Savings Achieved: 30 Percent Overall

The shortened schedule produced significant cost savings. As expected, the largest savings were realized from the field investigation. The team saved money by (1) mobilizing equipment to the site only once, (2) negotiating the work plan with regulators and preparing this document during the investigation, (3) using certain analyses to screen the samples and direct the sampling program to increase the value of the locations from which these samples would be taken, (4) collecting the minimum number of samples required to establish contaminant extent (this is possible only if the sampling equipment remains on site during data interpretation) and (5) eliminating unnecessary analytical tests. The remaining cost savings resulted from the construction of report-ready graphics during data interpretation, which did not require redrafting during report preparation. Overall, we saved an estimated 30 percent on the expected costs for this investigation.

The real-time investigation of this uncontrolled hazardous waste site permitted the field crew to complete contaminant delineation in about half the time required for a typical, multi-phased investigation. Furthermore, we are convinced that the benefits of real-time data management can be applied to most environmental site investigations.

This article originally appeared in the March 2003 issue of Environmental Protection, Vol. 14, No. 2, p. 28.

This article originally appeared in the 03/01/2003 issue of Environmental Protection.

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