Decontamination of water polluted by heavy metals with Taro (Colocasia esculenta) cultured in a hydroponic NFT system

Abstract

The toxicity and bioaccumulation of two heavy metals-lead (Pb) and cadmium (Cd)-in a semi-aquatic plant, Colocasia esculenta (L. Schott), from a synthetic heavy metal solution were studied. Young plants of equal size were grown hydroponically in shallow raceways containing Hoagland medium amended with 20, 40, and 60 mg l -1 of Pb and 2, 4, and 6 mg l -1 of Cd. The medium containing heavy metals was allowed to flow through the raceways with a change in influent heavy metal solution on every 5th day. The experiment was continued for 20 days. A set of control raceways-one comprised of nutrient medium with heavy metal supplements, devoid of plants, and another with the plants and nutrient medium having no metal supplement-was also simultaneously run. Chlorosis in the leaves was the prominent toxicity symptom observed due to Pb and Cd on the test plants. A significant decrease in the relative growth, biomass productivity, and total chlorophyll content were noticed in the plants with an increase in concentration of metal supplement in the solution and exposure time. Both metals accumulated to higher concentrations in the roots than in shoots, suggesting that the metals were bound to the root cells and their translocation to the leaves was limited. The results of the 20-day-long experiments indicate that from a phytoremediation perspective, C. esculenta is a promising plant species for remediation of wastewater polluted with lower concentrations of Pb and Cd.

Phytoremedial potentials of <em>Ipomoea aquatica</em> and <em>Colocasia esculenta</em> in soils contaminated with heavy metals through automobile painting, repairing and service centres

“…Ipomoea reptans (Water spinach), Eichhornia crassipes (water hyacinth), Salvinia molesta, Ipomoea aquatica (Kankun) and Colocasia esculenta (Habarala) are some examples that have the potential of hyperaccumulation of heavy metals. Some of these species are found to be quite effective in remediating contaminated areas (Reeves and Baker, 2000;Mahamud et al, 2008;Bindu et al, 2010;Kruatrachue et al, 2015;Mazumdar and Das, 2015). Results of many studies have proven that I. aquatica and C. esculenta have the potential to remediate contaminated soil, water and sediments.…”

“…Results of many studies have proven that I. aquatica and C. esculenta have the potential to remediate contaminated soil, water and sediments. C. esculenta is also a promising plant species for remediation of waste water polluted with Pb and Cd (Bindu et al, 2010).…”

Cadmium Removal from Aqueous Solutions Using <I>Macaranga peltata</I>:A Potential Plant for Phytoremediation

“…The rapid industrialization in developing countries with an enormous and increasing demand for heavy metals has resulted into high anthropogenic emission of these pollutants into the environment (Bindu et al, 2010). Since heavy metals are non-degradable, the contamination of water bodies and soil by these metals causes a serious environmental problem, threatening human health, crop productivity and biodiversity.…”

Evaluation of heavy metals accumulation by two emergent macrophytes from the polluted soil: an experimental study

“…Over the last few decades, the discharge of heavy metals into the environment (soil, water, and air) has become a critical problem in many countries including India. Heavy metal pollution in the soil is a condition of global concern with regards to its direct/indirect implications on plants, animals, and human health (Bindu et al 2009). …”