Extractability and phytotoxicity of heavy metals and essential elements from plastics in soil solutions and root exudates

Plastic waste is increasing and is a serious environmental problem. Among the threats associated with plastics is the release of contaminants into the environment. This study aimed to evaluate the efficiency of metals release from plastics (low-density polyethylene (LDPE), polyethylene terephthalate (PET), and polypropylene (PP)) as affected by different soil solution types, artificial root exudates, and distilled water. The extent of metal release varied depending on the type of solution and plastic used. Metals were leached most effectively from plastics in soil solutions, followed by root exudates, and least effectively by distilled water. LDPE released the highest concentrations of Cu and Na into solution, PP released the greatest amount of Fe, and PET released the most Cr. The efficiencies of Mg and Zn release from the plastics (PP and PET) varied by solution type. Among the plastics studied, LDPE exhibited the strongest ability to adsorb metals, such as Fe, Cr, Mg, and Zn from soil solutions. The amount of metal released from the plastics was also dependent on pH, dissolved organic carbon (DOC) concentrations, and the electrical conductivity (EC) of the solutions. Moreover, plastic extracts were found to have negative effects on germination and growth in Lepidium sativum.

Automated summary

Plastic waste is a serious environmental problem and can release contaminants into the environment. This study evaluated the release of metals from plastics under different soil solution types, artificial root exudates, and distilled water. The results showed that metal release was most efficient in soil solutions, followed by root exudates and least efficient in distilled water. Different types of plastics differed in their metal release concentrations, with LDPE releasing the highest concentrations of Cu and Na, PP releasing the most Fe, and PET releasing the most Cr. The release of metals from plastics was also influenced by pH, dissolved organic carbon concentrations, and electrical conductivity of the solutions. Plastic extracts were found to have negative effects on germination and growth in Lepidium sativum.