Aleksandra Sas-Nowosielska

The use of indigenous plant species and calcium phosphate for the stabilization of highly metal-polluted sites in southern Poland

Highly metal-polluted (Pb, Cd, Zn) soil from a non-ferrous mine and smelter site in southern Poland, further referred to as “Waryński” soil, was used to test indigenous plant species for stabilization effectiveness of heavy metals in soils. Results of pilot investigations with commercially available cultivars of plant species showed that these cultivars could not grow on this highly polluted soil even with the application of soil amendments to stabilize the heavy metals. Based on these results, mesocosm and field experiments with an indigenous, metal-tolerant ecotype of Deschampsia cespitosa from the Waryñski site were carried out. The mesocosm experiment showed that applications of calcium phosphate (3.8% w/w) as a heavy metal-stabilizing amendment decreased Cd and Zn concentrations 2 and 3-fold respectively in leachates, whereas lead content was not significantly changed. This decrease in the concentration of heavy metals in leachates was correlated with a lower accumulation of Pb, Cd and Zn in the roots and shoots of D. cespitosa, ecotype Waryñski. In the field experiment, lower accumulations of Cd in roots and shoots and Zn in shoots in the amendment added plot were observed during the second year of investigations. In the first growing season, D. cespitosa plant cover in the amendment enriched mesocosms ranged from 95 to 100%, compared to 10% in mesocosms without calcium phosphate. In the second year of the experiment, in non-amendment enriched mesocosms D. cespitosa was substituted with Cardaminopsis arenosa(95% cover). C. arenosa is an undesirable species for phytostabilization, as it accumulates high amounts of zinc and cadmium in its shoots, even thought it provided better growth cover in not amended soils. However, in amended mesocosms, soil surface cover by D. cespitosa was still very high (90%). Similar results were obtained in field experiments. Addition of calcium phosphate to the soil also resulted in excellent D. cespitosa root system development when compared to soils without amendment. In amended mesocosms, high plant cover and root system development significantly decreased the volume of leachates and improved water retention. These results indicate that the use of D. cespitosa, ecotype Waryński in combination with calcium phosphate as a heavy metals immobilizing agent is sufficient to restore a dense vegetative cover to highly heavy metal-polluted soil.

A Heavy Metal Environmental Threat Resulting from Combustion of Biofuels of Plant Origin

Several assessments of the potential biomass supply in Europe show that the best means of biomass production are growing energy crops on agricultural land. Cultivation of energy crops on agricultural areas might lead to accumulation of heavy metals in plant tissues and reemission of contaminants into the atmosphere during combustion. The goal of the present study was to assess how soil contamination influences heavy metals accumulation in energy plant tissues. The current paper presents the results of screening of selected plants (Spartina pectinata, Miscanthus sp., Helianthus tuberosus, Elymus elongatus) conducted in uncontaminated region of Poland (North-Eastern part of the country) aimed at finding natural abilities to uptake small amounts of heavy metals and accumulate is in the plant tissue. Based on this screening, Miscanthus sp. was tested on heavy metal contaminated arable soil in Southern Poland. This species accumulates high amounts of metals what may cause high emission of contaminants during biomass combustion.

Feasibility Studies for Phytoremediation of Metal-Contaminated Soil

Phytoremediation, which is the use of herbaceous plants and trees to stabilize, recover, or volatilize pollutants in contaminated soil, is considered an emerging new technology. The application of phytoremediation is said to be environmentally friendly, relatively low in cost, andhigh in public acceptance. However, there are still a number of limitations that affect its implementation on a large scale. The most considerable limitations are: narrow range of contaminant concentrations within which the method can be applied (potential of plant toxicity), dependence on weather, time-dependent growing season, and requirement for management of by-products. Until recently, themost commonly appliedphytoremediationmethodshavebeen phytoextraction and phytostabilization, particularly for soils pollutedwith heavy metals. Phytoremediation is more a biological than a technical approach, and it is difficult to create a definitive protocol that could be applied to any polluted site. The limiting factors differ from site to site, and therefore each project protocol, must be customized to site-specific conditions.

How to Grow Environmental – Sound Biofuels

EU strategy of renewable energy development assumes an increase of energy from renewable sources, up to 7.5% in 2010 and to 14% in 2020. In terms of that project production and usage of woody and herbaceous energy crops for power and heat generation on contaminated sites is said to be a pro20 position for wide spectrum of brownfields. Persistent soil pollutants, like heavy metals, are source of soil degradation and create the most complicated problems, as the phenomenon of natural attenuation, which is functioning in case of many other pollutants, is not applicable here. For environmental friendly combustion process (Nussbaumer, 2003) plants used as energy crop, should be free from harmful compounds. There is a luck of easily available information related to the physiological properties of plants concerning heavy metals uptake. Heavy metal concentration in plants is related to the plant species and cultivars. Possibilities of using the list of plants with the low level of heavy metal shoot concentration should help to grow environmentally safe energetic crop. For production of biomass with low level of heavy metals different chemo31 stabilization scenarios for various areas are expected. First contaminated soils should be remediated before energy crop production. Chemicals introduced to the soil bind metals and diminish metal uptake by plants. Appropriate soil pH also could stabilize metal migration in the soil compartment.