Impact of heavy metals-enriched dust particles on the growth, metal accumulation and gas exchange attributes of various plant species in urban areas of Faisalabad, Pakistan

The current experiment was conducted to assess the impact of different heavy metals (HMs) present in the air associate with fine dust particles on four plant species (Sorghum bicolor, Zea mays, Conocarpus lancifolius and Ficus carica) distributed at multiple locations of Faisalabad in Punjab, Pakistan in pots. The plant species were exposed to air pollution on four sites to explore their impact on morphological attributes and uptake of HMs (i.e., Cadmium, Chromium, Nickle, and lead) in selected plant species tissues. Results indicated that the plants at Sargodha Road showed the minimum roots, shoots and leaves fresh weight (-32%, -35% and -41%, respectively,) compared control site. The chlorophyll concentrations were reduced significantly in all the four plant species by 34%, 29%, 31% and 27% for S. bicolor, Zea mays, Conocarpus. lancifolius and Ficus carica, respectively, compared to control at Sargodha Road. The maximum HMs concentration i.e., Cd (0.09), Cr (0.36), Ni (0.69) and Pb (11.4) mg kg-1 dry weight, respectively was found in the soil of S. bicolor growing pots at Sargodha Road. The bioaccumulation factor was also maximum in plants grown along Sargodha Road. This study shows that the urban dust led to the accumulation of metals in studied plant species, thereby posing potential threat of food chain contamination. (author)