Phytoremediation of Heavy Metals from Soil and their Effects on Plant Physiology - A Review
Abstract
Now a day Heavy metal (HMs) is environmental problem and it pollute water, air and soil etc. HMs and metalloids are environmental pollutant, particularly cadmium, lead, arsenic. It liberated both from the natural and anthropogenic processes. HMs group accumulates in the ecosystem through anthropogenic activities, mostly by agriculture and industries process. When they accumulate to toxic levels in soil, it adversely affects pant and crop productivity. To remediate the soil from HMs different plant species assessment were carried out. According to the review the highest Bioaccumulation concentration factor (BCF) for Torilis leptophylla (L.) Rchb.f. species was 51.52 for Pb, Translocation factor (TF) was 17.18 for the Catharanthus roseus (L.) G. Don species for Chromium and Bioaccumulation concentration (BAC) was Catharanthus roseus (L.) G. Don species was recorded 83.66 for Chromium. The highest level of BCF and TF for Polygonum labrum species were 1.090 and 1.78 for Arsenic. Arsenic is the most poisonous element generated from agro chemicals, fossil fuel burning, smelting of metals, pharmaceutical industries. The common effects of arsenic on plants are oxidative stress, decreasing the bioavailability of the essential element and morphological change. Cadmium belong to toxic Cadmium cause various diseases to plant like chlorosis, necrosis and shunted growth, moreover it effect the physiological process, reduces carbon fixation, osmotic pressure, transpiration and decreasing chlorophyll. Lead is important HM extensively found in nature in deposition of solid waste, slag from mining, firing in shooting ranges, smelting and automobiles naturally produce from weathering, erosion of rock layer and ore deposits phenomenon. It reduces the conduction power of the plant stomata that ultimately affect the transpiration process and reduce the yield of the crop. Further studies should focus on cost-effective strategies to enhance phytoremediation of contaminants and the unknown effects of HMs on plant.