Determination of phytotoxicity of wastes of mechanical processing of polymer mixtures with their mechanical activation

TLDR: In this article, the level of phytotoxicity of sludge on the germination of soybeans and barley was within acceptable limits and did not exceed 3.33% in the most sensitive crops -watercress and mustard.

Abstract: Biotesting to assess the complex relationships between soil, contaminants and living organisms and to determine the impact on ecosystems of pollutants whose concentrations may be beyond the sensitivity of the methods of determination and the composition of which cannot be determined. The aim is to establish the level of phytoxicity of wastes of mechanical processing of polymer mixtures, which are extracted from solid household waste with the help of indicator plants. Methods. Evaluation of phytotoxic effects was performed by vegetation methods according to ISO: 17402-2008, 17126-2005a, 11269-1: 2012a, 11269-2: 2012b. Contamination levels of the test samples were assessed according to ISO 16198.Objects of research: watercress seeds, mustard, wheat, corn, soybeans, barley and sludge from the processing of polymer mixtures composed of polymer particles of different composition and quantity, along with the remnants of paper labels. Studies of the content of heavy metals (Pb, Cu, Cd, Zn, Ni) were performed by atomic absorption method on a spectrophotometer type CAS-120.1 in accordance with generally accepted methods. Results. The studied sludge does not negatively affect the process of germination of watercress, mustard, corn. The level of phytotoxic effect of sludge on the germination of soybeans and barley was within acceptable limits and did not exceed 3.33%. The study of migration of heavy metals present in the sludge and their accumulation during the growth and development of plants showed their insignificant content regardless of the sludge content. Only the lead content was higher than in the control 2.13 times and 1.83 times higher than in "relatively clean soil". Conclusions. Determination of phytotoxicity of this type of sludge on the process of germination and vegetation changes of plants should be carried out on the most sensitive crops - watercress and mustard. A study of the migration of heavy metals present in the sludge and their accumulation during plant growth showed the presence of bound forms of heavy metals copper, nickel, cadmium and zinc - the migration of which has not been established. However, mobile forms of lead that migrate from the sludge and accumulate in plants have been identified.