Phytotoxicological assessment of AMD affected river waters in “Sredna Gora”, Bulgaria to Lepidium sativum L.

Abstract

The ongoing pollution of water bodies from decommissioned mines and mining waste facilities in Bulgaria is a serious problem, leading to a contamination of river waters with heavy metals. Although the chemical analyses of acid mine drainage (AMD) affected waters provide information about their toxicity, this information is not enough to evaluate the potential impacts on the biota. For this, different biological responses are used to assess the toxicity of the polluted waters.The goal of the research was to determine the phytotoxicity (using Lepidium sativum) of five affected river waters. The lower reaches of the rivers flow though agricultural areas and are often used for irrigation by local farmers, increasing the chance of produce contamination.The effect of the working solutions on seed germination and primary root growth of L. sativum was assessed by the following indices: Relative seed germination (RSG), relative root growth (RRG) and germination index (GI, the product of RSG and RRG).The obtained results have shown the connection between germination/root growth inhibition and concentrations of heavy metals in working solutions, but there is no connection between germination/root growth inhibition and pH levels.