Neha Haresh Ruchandani and D.Meena.S.Rao*
Dept. Of Botany, R. K. T. College, Ulhasnagar
*Dept. Of Botany, R. K. T. College, Ulhasnagar
A major environmental concern due to dispersal of industrial and urban wastes generated by human activities is the contamination of soil. Controlled and uncontrolled disposal of waste, accidental and process spillage, mining and smelting of metalliferous ores, sewage sludge application to agricultural soils are responsible for the migration of contaminants into non-contaminated sites as dust or leachate and contribute towards contamination of our ecosystem. The present study was undertaken to study the effect of heavy metals on the growth of Brasicca juncea and thereby its utilization for phytoremediation. The minimum amount of lead (0 mg/gm) was found in plant treated in 0 % concentration of lead acetate and maximum amount of lead (0.0011 mg/gm) was found in plant treated in (0.6%) concentration of lead acetate. The percentage germination for control, 0.2, 0.4, 0.6 percent lead acetate treated seedling was 89%, 88%, 86.66% and 83% respectively. The length of shoot was found much less in plant treated in 0.6% concentration of lead acetate (10 cm), as compared to the length of shoot in plant treated with 0% concentration of lead acetate (8 cm). Length of roots was found maximum in 0.6% concentration of lead acetate (2 cm), as compared to the length of shoot in plant treated with 0% concentration of lead acetate (0.5 cm).
It was found that Brasica juncea tolerated highest concentration of heavy metals and can accumulate lead. Key Words: leachate, heavy metals, lead, phytoremediation, Brasicca juncea.
Heavy metal contamination of soil, water and air has caused serious environmental hazard in the biosphere due to rapid industrialization and urbanization. Lead is probably one of the most frequently encountered heavy metals in polluted environment. The primary sources of this metal include mining and smelting of metalliferous ores, burning of leaded gasoline, disposal of municipal sewage and industrial wastes enriched in lead as well as using of lead-based paint (Kabata-Pendias and Pendias 1984; Seaward and Richard-son 1990). Relatively high levels of lead concentrations were recorded as high as 7,000 µg/ gm in roadside soil (Kabata-Pendias and Pendias 1984) and 13,380 µg/gm in mining district soil (Wick land 1990). In recent years it has been reported that some plant species known as hyper accumulator derived from heavy metal-contaminated areas have the ability to accumulate unusually high content of heavy metals without dramatically being impacted in their growth and development. (Reeves, Brooks and Malaises 1985; Baker and Brooks 1989). This raises the suggestion that these hyper accumulators may provide the basis for phytoremediation of heavy metal-contaminated sites (Baker et al. 1991). Phytoremediation potential of a few such species for heavy metal-contaminated soil and water has recently been detected (Brown et al. 1994; Kumar et al. 1995; Dushenkov et al. 1995; Huang et al. 1997; Blaylock et al. 1997). Lead as a Heavy metal:
Lead (Pb) exists naturally in many forms throughout the world & has a soil retention time of 150-5000 yrs. Lead is among those heavy metals which have no known biological function. Never the less, numerous investigations show that plants can accumulate lead via root and shoot, and that the lead concentrations in plant tissues are significantly related to the lead levels in environment (Kabata-Pendias and Pendias 1984; Nwosu et al. 1995; Sawidis et al 1995; Xiong 1998). Excessive lead accumulated in plant tissue can be toxic to most plants, leading to decrease in seed germination, root elongation and biomass, inhibition of chlorophyll biosynthesis, as well as cell disturbance and chromosome lesion (Balsberg Pahlsson 1989; Kumar et al. 1991; Fargasova 1994;...