Study of airborne metal deposition on some plant species at various distances from national highway 24 and parks of urban Moradabad, India

The present investigation is carried out at two urban parks to assess the soil metal and atmospheric heavy metals in plant species which are commonly growing at varying distances from heavily trafficked National Highway 24 in Moradabad city. Emission of heavy metals from the automobile exhaust and brassware industries nearby the highway contaminates the soil and surrounding plants. Unwashed leaves samples were used to assess the of total metal concentration (Cr, Cu, Cd, Fe, Ni, Zn, Pb) and for the purpose six common plant species i.e. Ficus rumphii, Polyalthia longifolia, Bauhinia variegata, Delonix regia, Alstonia scholaris and Anthocephalus kadamba were collected from both sites and were analyzed by Inductively Coupled Plasma- Optical Emission Spectroscopy (ICP-OES). The results indicate that the plants species such as Bauhinia variegata is sensitive among all the species having highest concentration of heavy metals at both of the sites and Ficus rumphii with lowest concentration, is tolerant among all the species. It possibly may be due to differences in plant morphology and leaf surface and apparently particulate size decides the extent of solubility providing the bioavailability of metals to primary consumers. Univariate (correlation study) and Multivariate statistical analysis were adopted including; factor analysis, cluster analysis and enrichment factor analysis to identify the sources and their contribution to urban soil. The major source of airborne trace metals identified were brassware industries, illegal e-waste burning automobile emissions and combustion processes.