Effect of Na2SiO3 on heavy metal uptake by field grown Basella alba L. in Matara, Sri Lanka

Abstract

In this study, we investigated heavy metal uptake and the effects of Na2SiO3 on heavy metal absorption by field grown Basella alba L (Basellaceae). The concentrations of Fe, Cr, Pb and Cd in the field soils were 29755.30 ± 292.02, 32.99 ± 0.97, 26.01 ± 1.02, 0.13 ± 0.004 µg/g, respectively. These concentrations are significantly below the maximum permissible limits reported by FAO/WHO. Although Fe, Cr, Pb and Cd were present in the soil, only Fe was absorbed by B. alba; the tissue concentrations of other heavy metals were below the detection limit. The distribution of Fe from soil to different plant parts was investigated by calculating transfer factors. Low transfer factors indicated low absorption and translocation of Fe from soil to plant tissue. We also investigated the effects of Na2SiO3 on metal absorption by applying two different concentrations of Na2SiO3 (Si-100 mg/L and Si-50 mg/L) alongside a control. There was a significant reduction of Fe absorption in B. alba treated with Si-100mg/L of Na2SiO3 compared to that of plants treated with Si-50 mg/L of Na2SiO3 and the control.

Keywords

• Heavy metal uptake
• maximum permissible limits
• silicon