In 2001, the National Research Council (NRC), in a report titled A Risk-Management Strategy for PCB-Contaminated Sediments, identified the need to collect undisturbed surface sediments. Surface sediments are an important source for most exposure of fish to polychlorinated biphenyls (PCB) via direct uptake from water in contact with sediments. These sediments also are an important source of exposure for fish that feed on prey contaminated by their interactions with the sediment and interstitial and overlying water. Thus, contaminant concentrations in surface layer sediments have become a focus of monitoring and assessment. In response to this priority, a review and literature search were conducted for the U.S. Environmental Protection Agency, National Exposure Research Laboratory to identify available technologies for sampling surface sediment that can collect undisturbed sediments up to 1 meter below the interface of the water and sediment (EPA, 2004). In reviewing the literature, 40 styles of samplers corresponding to three different types of devices - core, grab, and dredge (bed) material - were evaluated against project requirements. Of the three different types of devices, the grab samplers were determined to be best designed to collect surface sediments that are distributed horizontally. However, surface sediment collected from these samplers can be perturbed during the sampling process by the bow wave induced by descent, as well as action of the sampling device. As a result of this perturbation, fine-grained particulates in the surface sediment can be washed out from the collected sample. The review concluded that a new sampling technology must be developed to achieve the requirements for undisturbed sample collection set forth in the NRC report. A new approach in sampling design is required to collect undisturbed sediments. The new design must encompass the entire process of collecting the undisturbed sediment-interface sample in a sealable container,
transferring it intact from the bottom to the surface, and subsampling, if necessary. Other desirable features include adaptability of the design to a variety of construction materials and deployment options. Furthermore, the cost for construction and use must not be prohibitive.