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1

Potential risk of remaining PCBs and management strategies in Europe

Kikuchi R., Santos S. M., Gerardo R.

Environmental Biotechnology

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2006

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Vol. 2, No. 2

69-77

EN

Polychlorinated biphenyls (PCBs) are persistent hazardous chemicals and are now out of production worldwide. Although over 20 years have passed since the Helsinki Convention promoted the elimination of PCB use, it is difficult to put an end to PCB emissions in a short time because PCBs have a long lifetime in the environment and a major portion of PCBs are emitted from electrical equipment manufactured before the Helsinki Convention but still used today. PCBs have an impact on human sperm integrity in the European male population; furthermore, Arctic ecosystems such as those supporting polar bears and seals are exposed to risks due to the long-distance transport of PCBs. Most European countries have no proper facilities for PCB treatment. After analyzing extensive information about PCB treatments, it is concluded that the thermal process is technically sound and cost-effective. This study contributes to the promotion of treatments in most European countries storing PCBs with the aim of pursuing a sustainable future.

2

Plant-to-soil pathways in the subarctic - qualitative and quantitative changes of different vegetative fluxes

Gorbacheva T. T., Kikuchi R.

Environmental Biotechnology

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2006

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Vol. 2, No. 1

26-30

EN

Considering plant-to-soil pathways, decomposition of vegetative fluxes such as litter and litterfall is one of the important processes that adjust the carbon cycle and nutritional elements in the formation of a forest's organogenic horizon. However, there is little information available on this subject, and the fractional structure (amount, type and interrelation) of organic matter also seems to receive little attention. Using 7 different vegetative samples, a field study was performed over 3 years to find the relation between phenolics content and mass losses in the subarctic region (N66° and E31°). In addition, climate effects on this relation were investigated. The data obtained from this field study testify that (i) an intensive loss of organic matter occurred in active parts of various litterfalls and (ii) leached phenols were related with mass losses (decomposition rates) of vegetative fluxes (litterfalls and litters) to the soil. The statistic analysis suggests that (iii) total mass losses of samples (except litter) were connected with both the temperature sum and the precipitation sum, and (iv) phenolics losses also had a similar trend in different kinds of litterfall.

3

A pilot-scale example of phytoremediation in the arctic area: comparison of zones placed at different distances from a metal emission source

Kikuchi R., Gorbacheva T. T., Gerardo R.

Environmental Biotechnology

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2006

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Vol. 2, No. 1

37-45

EN

Biological methods for soil rehabilitation are comparatively cheap, but it is only a few years since the strategies of biological remediation were adopted. This paper therefore discusses the possibility of using the approach of phytoremediation (a biological method) for tackling heavy metal-contaminated land with harsh climatic conditions in the arctic region. A preliminary research on a pilot scale of 4 ha was carried out on territories subjected to continuing pollution load from the Monchegorsk smelter complex (67°51'N and 32°48'E in Russia) in order to investigate the feasibility of phytoremediation under a harsh climate (annual mean temperature of -1°C) and current pollution load (~450 to ~2,400 g ha-1 y-1 Ni, ~750 to ~2,700 g ha-1 y-1 Cu and other depositions): after a compost substratum was added to the contaminated land, metal-tolerant plants (willow and birch collected in the tolerance zone) were used for this research. The results obtained over 3 years showed the applied plants had good phytostabilization (i.e. the fixation of metals in chemically inert form); the Ni concentration (457.2 mg kg-1) and the Cu concentration (338.3 mg kg-1) in the willow leaves in the test field were 117 times and 147 times greater, respectively, than those in the background field. It is therefore indicated that Ni, Cu and other metals can be removed from metal-contaminated land by harvesting the plants (i.e. removal of annual litterfall of deciduous trees from the contaminated territory).