Posted July 7, 2019
Technology expected to offer significant cost, safety and environmental benefits pre- and post-remediation of contaminated sites.
Houston, original release June 27th 2019.Updated July 9th 2019 exclusively for DredgeWire:
PartracGeoMarine Inc., the Houston based Marine Survey and Consultancy company, are pleased to announce the award by the US Department of Defense (DoD) of a 3-year contract to demonstrate a new tool for mapping the in situ distribution of Contaminants of Concern (COCs) in aquatic sediments. The tool will be especially useful for the rapid, pre-remedial, characterization of sites of concern, and in the assessment and monitoring of post-remedial effectiveness. Many DoD sites are located in environmentally sensitive areas, therefore both the identification of COCs in aquatic sediments and the eventual remediation of contaminated sites are of particular importance to the DoD.At present, there are some 46 active, and 35 completed, ESTCP/SERDP projects investigating contaminated sediments at about thirty different DoD sites in the continental US and around the world.The award is part of the Environmental Security Technology Certification Program (ESTCP), the DoD's environmental technology demonstration and validation program.
Aquatic gamma spectrometer
Partrac, together with its Netherlands based partner Medusa Explorations, will deploy the new instrument at up to three contaminated DoD Superfund sites to map the distribution of COCs such as Polycyclic Aromatic Hydrocarbons (PAHs), Polychlorinated Biphenyls (PCBs) and heavy metals, e.g. mercury, lead, zinc.
Dr. Patrick Friend, PartracGeoMarine’s Business Development Consultant (Americas), said “We are really excited to be bringing this new instrument over from Europe to be used in the US. This technology is a potential game-changer in the way that contaminated sediments are mapped, and can offer significant cost and safety benefits over traditional contaminated sediment sampling and mapping methods”.
Dr. Ronald Koomans, Director of Medusa ExplorationsB.V. said “We have trialed this technology in Europe over the past few years, and have successfully mapped the distribution of contaminated sediments in ports, harbors, and rivers - the Port of Rotterdam and the River Elbe, for example. We can use the tool not only for new site investigations, but also for post-remediation monitoring of sites that have been capped, for example, to test capping efficiency.”
Prioritizing contaminated areas for remediation
The new instrument coming to the US is a specially adapted aquatic gammaspectrometer developed by Medusa Radiometrics. This is a passive instrument that measures the natural geochemical signature of sediments which can then be related to the sediment contaminant content. The tool works equally well for both naturally deposited and dredged sediments in all aquatic environments - marine, riverine and lacustrine. It has a number of other applications including rapid in situ mapping of silt contentand grain-size distribution, and even the quasi real-time mapping of sediment transport.
Of particular interest to the dredging industry is the capability of the tool to map the grain size of dredged sediments – whether pre-dredge or post-dredge in the placement area.
Mapping silt content of dredged sediments in placement area
Partrac sees the new technology as a game-changer that will offer significant benefits in terms of cost savings and safety over traditional state of the art screening practices for contaminated sediments, as well as in the monitoring of remediated sites. At present, contaminant distribution is ‘mapped’ by collecting discrete sediment samples to produce a spatial ‘distribution’ of contaminants by kriging or similar. Sediment sampling, usually by grab or corer, is time consuming, costly, and involves handling of a relatively large number of samples to produce a significant distribution. The problem with discrete sampling is that the spatial scale at which contaminant content varies is not known a priori, so potential hotspots can be missed. The new technology will deliver improved data (better resolution) on sediment contaminant distribution, faster screening methods, and ultimately improved site remediation at lower costs. Considerable cost reductions are expected, with the requirement for only a small number of samples to be collected for calibration purposes, resulting in favorable benefit/cost ratios, as well as benefits in terms of health and safety (exposure/handling of contaminated sediments).
It is expected that the new technology will be of interest to the environmental remediation and dredging industries.