Soil quality of simulated landfill exposure to plastics in context of heavy metal analysis

Abstract

It is imperative to have soil guidelines that consider commodities on the market especially biodegradable plastics that are increasing in popularity nowadays. In this short communication, heavy metal in soil was investigated after degrading plastics commonly used on the market. The plastic materials included virgin linear low-density polyethylene, plastic waste of polyolefin origin, and biodegradables of oxo- and hydro-based types. Soil/water matrix that simulates arid land conditions was used. Metals including cobalt, chromium, cadmium, and nickel, among others, were studied after exposure of three continuous months. It was noted that background concentrations reduced with water indicating that leachate might contain the majority of the transferred metals from plastics. In particular, the concentration of nickel in soil was detected to be 84 ppm after exposure to type I of the oxo-biodegradable commercial plastics. Furthermore, the material of similar source started to retain nickel by day 74 of exposure. This surpasses both Canadian and Australian guidelines discussed herein. Furthermore, nickel concentrations exceeded international guidelines and point towards the need for remediation. Mean values of chromium exceeded soil control results and the USA remediation values in the case of single screw compounded plastics. It should also be noted that the work conducted points towards metal trace detection limits that are tied to waste and sludge disposal in an improper manner with time.

Keywords: Cobalt; Landfill; Metal; Nickel; Plastics; Waste.