Historic groundwater investigations at a 300-acre manufacturing facility in Connecticut indicated that solvent and metal contaminated groundwater was migrating off site. To preliminarily investigate off-site groundwater contamination, the collection of discrete-interval groundwater samples using a HydroPunch was attempted in twenty soil borings. The borings were located along three transects perpendicular to the general direction of groundwater flow: 1) three soil borings were located near groundwater monitoring well clusters along the downgradient facility boundary, 2) ten soil borings were located along a road at the approximate midpoint between the facility boundary and a nearby river, and 3) seven soil borings were located along the banks of the river. At each soil boring, collection of the first HydroPunch sample was attempted at ten feet below the water table; sample attempts continued at 3-meter (10-ft) intervals until refusal. Samples were analyzed for volatile organic compounds and selected metals.
Geologic materials significantly influenced the sampling program success. In the fine-grained, floodplain deposits, samples could not be collected from five of the seven soil borings, with limited sampling success in the other two borings. At the two other transects, the collected sample volumes varied significantly, dependent upon the physical characteristics of the sampled materials. Analytical results from the HydroPunch samples collected along the middle transect clearly defined the horizontal extent of solvent contamination. The vertical extent of groundwater contamination was not as well characterized, because of the anisotropic nature of the aquifer materials.