Toxic Pollutants Survey in Soils of Electronic Waste-Contaminated Sites in Delhi NCR

Abstract

Over the years, with the advancement in technology, a rise in the usage of electronic items has been developed and along with that there has been an increase in the generation of electronic waste. This is of great concern, especially in developing countries, as it has been gradually polluting the environment, causing bioaccumulation and ultimately affecting the ecosystem function. The present study is on the pollutant-level determination of soils in the electronic waste (e-waste) dumping sites with special reference to Delhi NCR, India, and to study the effect of electronic waste contamination on soil microbial activities. Heavy metals like lead, cadmium, chromium, nickel and arsenic were studied for their contamination levels in the soil samples collected from different sites of the electronic waste dumping area. The concentrations of heavy metals were compared with a control uncontaminated sample. In India, presently there are no permissible limits set for the contamination of heavy metal pollutants in the soil. Among the heavy metals, arsenic, nickel and chromium (measured by ICP-MS), with the values of 3.15, 89.4 and 35.5 mg/kg, respectively, were found to be at high levels and are of concern. Contamination of soil with polybrominated diphenyl ether (PBDE), which is a persistent brominated hydrocarbon and which tends to bioaccumulate in the environment, was also detected by GC-MS. This shows that e-waste dumping and recycling sites are some major sources for the contamination of the environment with toxic pollutants. The effect of these toxic pollutants on soil enzyme activities was studied, and it was found that soil dehydrogenase, β-glucosidase and arylsulphatase activities were significantly reduced in the e-waste-contaminated soil samples indicating that the microbial activities are greatly affected by the toxic pollutants generated by the e-waste in the soil. Further work on the microbial community analysis of the contaminated soil samples through molecular fingerprinting is under progress. Keywords Electronic waste Heavy metals Polybrominated diphenyl ether Microbial activities