Studies and Determination of Heavy Metals in Waste Tyres and their Impacts on the Environment

Abstract

Uncontrolled burning of waste vehicle tyres causing environmental pollution has become a popular practice in developing countries like Nepal. Such activities were banned in many countries considering the environment and public health hazards but the official ban was ignored in many countries like Nepal. An experiment was conducted in a laboratory scale in an attempt to understand the potential discharge of trace metals content in Kathmandu Valley due to scrap tyre fires. For this purpose, four tyre types viz., CYCN, CSKR, BTIN and BBJP were collected representing the first two categories from passenger car and the last two from motorbike. An Atomic Absorption Spectrophotometer (AAS) was used for determination of metal concentration. Among the five heavy metals determined, Zn was detected in significantly high levels in all the tested tyre samples whereas Cd and Cr were found significantly less in many of them. The concentrations of Cd, Cr, Fe, Pb and Zn ranged from 0.020 - 27.1 g/g, 0.14 - 1.18 g/g, 17.8 - 381 g/g, 0.96 - 458 g/g and 3.95 8.21 mg/g respectively. It was found that the metal concentration also varied with the tyre types and qualities. The potential discharge of the metals per representative scrap tyre mass was also estimated. Results indicate that the metal pollutants due to the uncontrolled burning of the scrap tyres could significantly contribute to deteriorate the environmental condition of the Valley.