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This study identifies a source of heavy metal pollution in the Tarnia-Ostra area, Suceava County, Romania, using both chemical and biological techniques. Samples collected from the sterile dumps and the surrounding soil were digested and analyzed for total metals and arsenic by inductively coupled plasma-optical emission spectroscopy (ICP-OES) and atomic absorption spectrometry (AAS). High concentrations of heavy metals, such as copper (3.12 g/kg), arsenic (0.68 g/kg), lead (2.67 g/kg), zinc (0.43 g/kg) and barium (0.54 g/kg), found in that region, may pose a high risk to the environment and public health through the food chain. The large amounts of Cu, Fe, Pb, Zn and As of the collected samples diminished much the germination of wheat (Triticum aestivum L.), used in this study as a marker of toxicity. However, after the removal of the heavy metals by treating the aqueous extracts with sodium hydroxide solutions, the germination parameters returned to normal. The quantification of heavy metal levels by ICP-OES provides a better understanding of the potential ecological risks and contamination status of the tailings dumps. Instead, wheat germination tests can be reliable and inexpensive biological methods to prove the harmful effect of heavy metals and arsenic on plants.

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Heavy metals are destructive environmental stressors that greatly reduce plant growth and productivity. Here, the content of some heavy metals (Fe, Cu, Zn and Mn) and mineral nutrients (Ca, Mg and K) in silver fir (Abies alba Mill.) and European beech (Fagus sylvatica L.) wood from two sites in the Tarnipa mining area (North-Est Romania) was analyzed. The first site (no. 1) is located near a big tailings dump, whereas the other one (no. 2) is situated 6 km South, in a less polluted area. The purpose of this work was to evaluate the present-date levels of such elements in the investigated biological materials and to compare them. Measurements of heavy metal content in wood were performed with an AAS flame spectrometer, whereas an ICP-OES spectrometer was used for soil and tailings dump samples. The Mn content was higher in the site no. 1 located near the dump, for both species, but the difference was statistically significant only for the European beech trees. The Zn content of samples from the site no. 1 was lower than that corresponding to the second one (no. 2) for both species, but significant for the silver fir only. However, there was not found a significant difference in respect to both iron and copper in the samples collected from the two species and two different sites. Furthermore, the content of Ca and Mg of both species was found higher for the site no. 2, suggesting a better state of nutrition of the investigated trees than of those located near the tailings dump. The content of calcium and magnesium of silver fir was negatively correlated with the diameter of the trees collected from both sites.

Abstract

Heavy metal pollution of ecosystems is of great concern, due to the persistence of metals in ecosystem. In this regard, the mountainous pastures of Romanian Carpathians, especially those in the areas of abandoned mines, need particular attention. The aim of this work was to assess the effect of heavy metals and metalloids exposure on cuticular wax composition of tall fescue leaves (Festuca arundinacea). Therefore, we have particularly investigated the variations of long chain hydrocarbon fractions, which are acknowledged to act as a protection for plants especially in toxic environments. The exposure experiments were conducted in triplicates for arsenic and the following metal ions: Ba2+, Cu2+, Fe2+ and Pb2+. The 0.5 mM aqueous solutions of their corresponding salts were used as treatment solutions. Triplicate experiments were also performed for control samples using distilled water as exposure media. The plantlets were kept for growing in controlled environment for 15 days followed by n-hexane hydrocarbon fraction extraction from 0.5 g of sampled leaves. The obtained extracts were semi-quantitatively analyzed (identification followed by peak area measurement) through an optimized method based on gas-chromatography coupled with mass spectrometry. We focused on the measurement of several long chain n-alkanes with the following number of carbon atoms: C21-C31. Significant differences were obtained between results performed for Ba2+, Pb2+ and Fe2+, when compared to AsO43- and Cu2+, which may suggest multiple mechanisms through which the tested plants could develop and adapt when exposed to various chemicals characterized by different degrees of toxicity.

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