The Use of the Direct Test on Substrate in the Assessment of Phytotoxicity of Foundry Waste
Abstract The article presents the results of phytotoxicity tests on foundry dust and landfilled waste. Currently, all of this waste is being reused. The results supplement the previous study on the phytotoxicity of waste leachate. The research has focused on phytotoxicity tests performed directly on the waste. Watercress (Lepidium sativum L.) was used as the test plant. The germination test (GI) and the accumulation test were used to assess phytotoxicity. The results show that the dust from electric furnaces, classified as hazardous waste, was the most phytotoxic. Most of the dust samples inhibited germination and root growth. A possible cause of this phytotoxicity was the high content of heavy metals and low pH. The phytotoxicity were different from previous studies on waste leachate. A lower phytotoxicity effect was found for those waste leachates. The differences could have been caused by the higher concentration of toxic substances available to plants in the direct test. Moreover, the direct contact of sprouts and roots of L. sativum could have contributed to the higher phytotoxicity of the wastes than the leachate. Therefore, it seems appropriate to use both tests simultaneously to assess the phytotoxicity of waste.