Assessment of phytotoxicity of leachates from landfilled waste and dust from foundry

The study assesses the contamination, classification and phytotoxicity of foundry waste. The presented results are a part of the research on the agrotechnical use of foundry waste. Landfilled foundry waste (LFW) and dust samples were taken from one of the Polish foundries. An analysis of the waste and its leachate composition was conducted. Phytotoxicity tests were carried out using Lepidium sativum. The aim of the phytotoxicity study was to evaluate germination and root growth after 72 h and the accumulation of heavy metals after 7 days. LFW was least contaminated with heavy metals and metalloids compared to dust. The composition of the foundry dusts depended on the unit of the foundry, from which it was collected. It was found that electric arc furnace dust (EAFD) was the most polluted by heavy metals among the dust samples. According to the requirements of Polish regulations most of tested waste were classified as non–hazardous, and EAFD as hazardous waste due to high Pb concentration in leachate. Phytotoxicity tests have shown a low phytotoxicity of the leachate from most of the tested waste. The results of the accumulation test showed that an excess of metal and metalloids in leachate was not directly related to its accumulation in plants. A negative correlation between EC, Cu, Co, Fe, Pb, Cr, K, Na, sulfate, fluoride, ammonia, phenol and formaldehyde concentration in leachate and GI was found. It was stated that the Fe, Mn, As and Se in plants was significantly correlated with concentrations in leachate.