The total heavy metal content of soils can be determined quickly and at low cost by various chemical analysis methods. Low concentrations may indicate that a contamination problem does not exist, but the degree of a potential problem, when concentrations reach higher levels, cannot be fully assessed by assay alone. Nor, as a general rule, can an assay implicate a specific source of the contamination. Particle-by-particle determination of species (i.e., phase or mineral) as well as the characterization of particle size, external and internal morphology, can be used to assess both bioavailability and source. The species is related to stability, either in the soil or the body. In addition, the size and shape distributions may be related to specific sources. Source information may be obscured through the process of dissolution of one phase and re-precipitation of another phase as a rim or cement that are recognizable morphologies. The imaging capabilities of the scanning electron microscope (SEM) coupled with the elemental analysis provided by energy dispersive spectroscopy (EDS) can be used to acquire both chemical and physical information. However, at the generally low concentrations of interest, the manual SEM analysis of samples is rather time-consuming (and expensive). Fortunately, the particles of interest stand out bright against the background in SEM images acquired in the backscattered electron mode and can be recognized, measured, and analyzed automatically using computer-controlled scanning electron microscopy (CCSEM). When the species and geometries are relatively simple, the analysis can be fully automated. In more complex situations, stored data (images and spectra) can be reviewed and particles can be relocated rapidly for additional manual analysis. The methods and case studies are presented.

Peter J. Kane and Catherine Mosher, The Woods Hole Group, Inc.

Keith W. Henn and Andrew Kendrick, Tetra Tech NUS, Inc.

Passive diffusion bag (PDB) samplers offer a viable alternative to conventional low-flow sampling techniques for collection of groundwater samples for volatile organic compound analyses. PDB samplers, however have both advantages and limitations that must be weighed prior to full-scale implementation for groundwater sampling in place of conventional methods. Based upon the use of PDB samplers at multiple sites with varying hydrogeological settings and contaminant conditions, the advantages and limitations of the PDB samplers will be presented. Alterations to the typical PDB design and modified field practices will be discussed which may assist in overcoming some of the data quality objective issues related to the use of the PDB sampler. In addition to traditional sampling purposes, it will be shown how the PDB sample results have assisted in formulating a better understanding of vertical contaminant distributions and preferential migration pathways in certain aquifer systems.

Mark W. Roberts, McRoberts & Roberts, LLP

In 1992, oil was detected during the removal of a 6,000 gallon underground storage tank. During the subsequent investigation which included investigation of the UST, historic research, governmental file reviews, age analysis of petroleum from three separate properties, ground water flow analysis in a complicated two aquifer environment, fate and transport modeling and witness interviews, it was determined that the contamination was from two off-site sources and not from the UST that was removed. This is an excellent example of how the various forensic techniques can be integrated to solve issues of liability. This site was the subject of a case that went to trial in April 2000 so excellent exhibits exist concerning the various forensic tools that were employed during the investigation.

Monica N. Danon-Schaffer, M.Eng., P. Eng., CH2MHILL

This paper is a study of Canadian environmental legislation and the way it is administered across the provinces and territories, as well as understanding the use of environmental forensic techniques illustrated in a case study from the province of British Columbia.

Environment Canada administers and enforces the two (2) most important pieces of environmental legislation in the country, the Canadian Environmental Protection Act, 1999 and the pollution prevention provision of the Fisheries Act. Environment Canada uses enforcement and compliance promotion as its guiding principle to environmental obedience. The Enforcement Program under CEPA, 1999 is responsible for enforcing the Canadian environmental legislation to ensure compliance with the laws administered by Environment Canada. Two types of agreements between the Federal regulations and provincial/territorial legislation are administered under CEPA, 1999. Protection of the environment is a jurisdiction shared with the Federal Parliament and Provincial/Territorial Legislatures. Provincial environmental legislation varies from province to territory. Provincial environmental legislation in British Columbia is enacted under the Waste Management Act, which contains the Contaminated Sites Regulation (amended 1997). The Regulation will be used throughout the following case study.

This case study, from the province of British Columbia, is described to illustrate the use of environmental forensic techniques. The study involves acid rock drainage (ARD) from the Britannia Mine, a mine located in South western British Columbia, that has been closed for approximately twenty-five (25) years and discharges between 4 - 40 million litres of ARD, depending on the time of year into nearby Howe Sound every day. The ARD occurs as an oxidation of sulphide mineralization exposed to air and water. The sources of ARD contamination from this site are copper, aluminium, iron, zinc and manganese. Current copper concentrations discharging from the 4100 Portal Level range from 40 - 100 mg/L. Environmental forensic techniques are applied to describe the origin of the contaminant release, the timing of the release, the distribution of the contamination, finding the responsible parties and allocating remediation costs for cleanup. Other forensic techniques described include the use of aerial photography, and geochemistry to determine contaminant degradation.

Willard A. Murray, Harding ESE

In the late 1980s a municipal water supply company discovered chlorinated solvent contamination in their wellfield. Special water treatment systems were required to treat the water prior to distribution to the municipal water supply system. This prompted the State Environmental Protection Agency to conduct an industrial survey at facilities upgradient of the wellfield to identify potential sources. Several areas of concern were identified due to historical subsurface disposal practices by industries in the valley, and it was concluded that groundwater contamination was a regional problem. Subsequently, chlorinated solvent contamination was discovered at a pump manufacturing facility located across the street and immediately upgradient from the wellfield. The municipality sought to recover the entire cost of their required treatment plant from the pump manufacturing facility that was across the street. The pump manufacturer said we will pay our fair share, but we are not the only ones responsible for the contamination of the groundwater in the valley. The municipality said we don’t care, you should pay it all. Hence a legal battle ensued. A calculation of the mass of contamination leaving the pump manufacturing facility property was compared with the mass of contamination being extracted from the aquifer by the municipality. This revealed that less than 10% of the mass of contamination being extracted from the aquifer by the wellfield was coming from the facility. Investigation outside of the site revealed significant contamination in the aquifer upgradient of the pump manufacturing facility. Furthermore, contaminant fingerprinting indicated that much of the contamination in the wellfield wells must have been coming from a source different from the pump manufacturing facility. After unsuccessful arbitration but before a court trial, the case was finally settled.