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Weathered soils contaminated with commercial-grade Aroclor 1260 from three sites in Canada were used to investigate the polychlorinated biphenyl (PCB) phytoextraction potential of nine plant species (Festuca arundinacea, Glycine max, Medicago sativa, Phalaris arundinacea, Lolium multiflorum, Carex normalis, and three varieties of Cucurbita pepo ssp. pepo) under controlled greenhouse conditions. The soils used varied in PCB concentration (90-4200 microg/g) and total organic content (0.06-2.02%). Greenhouse experiments controlled for PCB volatilization through the use of a vented enclosure and by isolating the contaminated soils with parafilm. After 8 wks, PCB concentrations of 47-6700 microg/g were observed in root tissues. Although PCB concentrations in shoot tissues were lower (< 1-470 microg/g), the absolute amounts of PCBs observed in shoot tissue were significant (1.7-290 microg) once shoot biomass was accounted for. Congener signatures indicated that tetra- to hexa-chlorobiphenyls contributed the largest proportions to shoot tissues, but hepta-to nona-chorobiphenyls were also present in measurable amounts. Overall, the results indicate that varieties of C. pepo were more effective at extracting PCBs from soil than other plants screened The evidence suggests that this was mainly due to root uptake of PCBs and tranlocation to the shoots, rather than volatilization of PCBs from soil. All plants screened showed signs of stress in the most highly contaminated soil (4200 microg/g), but not in the two lower PCB contaminated soils (250 and 90 microg/g, respectively). No detectable decreases in soil PCB concentrations were observed in these short-term greenhouse experiments, but the results suggest that this may be achievable through multiple plantings.

Since the discovery of its insecticidal properties and its subsequent widespread use, DDT [2,2-bis(chlorophenyl)-1,1,1-trichloroethane] has accumulated in the environment, having a wide range of adverse effects on nontarget species. Due to their hydrophobicity, DDT and other persistent organic pollutants are difficult to remove from contaminated soils, and increasingly so through time as weathering occurs. Phytoremediation is an emerging plant-based technology that may be used to cost-effectively remove or neutralize contaminants in the environment. For some phytoremediation strategies, it must first be possible to translocate hydrophobic chemicals across the root and through the shoot via an aqueous transpiration stream. The objective of this study was to compare the ability of five plant varieties (zucchini, tall fescue, alfalfa, rye grass, and pumpkin) to mobilize and translocate DDT. Plants were grown in the greenhouse in soil contaminated with DDT and its metabolites, DDD and DDE (sigmaDDT refers to all of DDT, DDD, and DDE) at two concentrations (high approximately 3700 ng/g, and low approximately 150 ng/g). All trays were covered with laboratory Parafilm to limit volatilization. Cucurbita pepo species (pumpkin and zucchini) achieved the highest translocation and bioaccumulation factors, and also extracted the highest absolute amounts of sigmaDDT from both the high and low sigmaDDT soils. In the high sigmaDDT soil treatment, pumpkin accumulated 1519 ng of sigmaDDT in the roots and 57,536 ng of sigmaDDT in the shoots, and zucchini accumulated 2043 ng of sigmaDDT in the roots and 35,277 ng of sigmaDDT in the shoots. With the exception of alfalfa and pumpkin, principal component analysis detected no preferential translocation or transformation of sigmaDDT compounds within the plant. The success of the Cucurbita pepo species in this study to extract and translocate such hydrophobic molecules may be related to their high transpiration volume, large above-ground biomass, and composition of root exudates. This suggests potential for their application in phytoremediation.

Contaminants, in freezing ground or elsewhere in the world, are of concern not simply because of their presence but because of their potential for detrimental effects on human health, the biota, or other valued aspects of the environment. Understanding these effects is central to any attempt to manage or remediate contaminated land. The polar regions are different from other parts of the world, and it would be naïve to assume that the mass of information developed in temperate regions can be applied without modification to the polar regions. Despite their obvious environmental similarities, there are important differences between the Arctic and Antarctic. The landmass of the Arctic is much warmer than that of the Antarctic and as a result has a much greater diversity and abundance of flora. Because of its proximity to industrial areas in the Northern Hemisphere, the Arctic also experiences a higher input of contaminants via long-range aerial transport. In addition, the Arctic, with its indigenous population and generally undisputed territorial claims, has long been the subject of resource utilisation, including harvesting of living resources, mineral extraction, and the construction of military infrastructure. The history of human activity in Antarctica is relatively brief, but in this time there has been a series of quite distinct phases, culminating in the Antarctic now holding a unique position in the world. Activities in the Antarctic are governed by the Antarctic Treaty, which contains provisions dealing with environmental matters. The differences between the polar regions and the rest of the world, and between the Arctic and the Antarctic, significantly affect scientific and engineering approaches to the remediation of contamination in polar regions. This paper compares and contrasts the Arctic and Antarctic with respect to geography, configuration, habitation, logistics, environmental guidelines, regulations, and remediation protocols. Chemical contamination is also discussed in terms of its origin and major concerns and interests, particularly with reference to current remediation activities and site-restoration methodology.

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