Abstract
The industrial environmental “hot spots” create significant ecological hazards for terrestrial and aquatic ecosystems. Guidelines and legislation often refer to the total amount of contamination without to estimate the complex relationship between the environmental factors and the toxicant. In cases of suspicion for adverse effect on the environment bio-assessment can be used as a tool to detect the presence of hazardous chemicals. Bioassays with vascular plants are considered to be universal tools of identifying the combined effects of pollutants. The purpose of this articleis to evaluate the toxicological effect of plant-soil complex treated with wastewater from Radomir Metal Industries “. The conclusion is that the sewage from the metallurgical pant “Radomir Metal” is used properly for irrigation of arable land. The question can be which kind of plants issuitable to be cultivated there.The effluent is seems toxic for the aquatic systems and has a slight negative impact on the soil breathing and germination of treated plants. Nevertheless, in the bioassay for all examined plants stimulus effect under the treatment with soil extract on the weight of roots and stems have been registered.Keywords: risk assessment, soil pollution, soil respiration, energy of germination, root growth;
Introduction
Human activities all over the earth have increased environmental pollution by heavy metals in agricultural soil. Contamination with heavy metal is a major problem for crop quality, human health, and environmental quality. Most of the heavy metals are persistent in soil because of their immobile nature (5, 23). Chemical analysis are often insufficient to provide insight into the potential ecological risk, since they do not allow an evaluation of possible combined effects of the different contaminants mixed together, as well as to the their bioavailabilty. Guidelines and legislation often refer to total metal content in the soil, while they do not consider what proportion of that total amount may be biologically available to the organisms. Actually, environmental risks are related to the bioavailability of metals in soils. Therefore, bioassays which can mitigate these constraints are recommended for the assessment of ecological risks in soils or other matrices (8). Contaminated sites pose significant environmental hazards for terrestrial and aquatic ecosystems. They are sources of pollution and may result in ecotoxicological effects. At severely contaminated sites acute effects occur, but the core problem lies in possible long-term chronic effects. Effects of toxicants at high concentrations that induce a high rate of acute mortality are observed easily, even in complex communities. The effects of toxicants at low concentrations that do not immediately result in acute mortality are much more difficult detectable. In such cases, communities are shaped not only by the effects of the toxicant but also to a great extend by other environmental factors. As a result, the complex relationship between a multitude of environmental factors and the composition of the community obscures the effects of the toxicants (25). Ecotoxicological effects occur at all levels of the biological organization, from the molecular to the ecosystem level. Not only may certain organisms be affected, but the ecosystems as a whole in its function and structure (16). The purpose of this article is by using bioassay to produce ecotoxicological assessment of the soil complex treated with wastewater from “Radomir Metal Industries”.
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