Lead immobilization in soil using new hydroxyapatite-like compounds derived from oyster shell and its uptake by plant

Md Faysal Hossain; Md Shoffikul Islam; Md Abul Kashem; Khan Towhid Osman; Yanbo Zhou

doi:10.1016/j.chemosphere.2021.130570

Lead immobilization in soil using new hydroxyapatite-like compounds derived from oyster shell and its uptake by plant

Chemosphere. 2021 Sep:279:130570. doi: 10.1016/j.chemosphere.2021.130570. Epub 2021 Apr 14.

Authors

Md Faysal Hossain¹, Md Shoffikul Islam², Md Abul Kashem³, Khan Towhid Osman³, Yanbo Zhou⁴

Affiliations

¹ Department of Soil Science, University of Chittagong, Chittagong, 4331, Bangladesh; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, No. 130, Meilong Road, Shanghai, 200237, China.
² Department of Soil Science, University of Chittagong, Chittagong, 4331, Bangladesh. Electronic address: msislam@cu.ac.bd.
³ Department of Soil Science, University of Chittagong, Chittagong, 4331, Bangladesh.
⁴ State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, No. 130, Meilong Road, Shanghai, 200237, China; National Engineering Laboratory for Industrial Wastewater Treatment, East China University of Science and Technology, No. 130 Meilong Road, Shanghai, 200237, China. Electronic address: zhouyanbo@ecust.edu.cn.

PMID: 33895674
DOI: 10.1016/j.chemosphere.2021.130570

Abstract

Protecting the natural environment and ecological systems from the inorganic pollutants such as lead (Pb) has highlighted the urgent need to develop new and effective approaches for this substance's immobilization in soil. In this study, new, low-cost, and eco-friendly hydroxyapatite (HAp)-like compounds were prepared by reacting oyster shell (Oys) with diammonium phosphate ((NH₄)₂HPO₄) (DAP) and calcium hydroxide (Ca(OH)₂) at 25-28 °C (OyOHr) and 100 °C (OyOHh). Furthermore, OyOHr and OyOHh were assessed for their effectiveness to immobilize Pb in soil and suppress Pb uptake by Indian spinach (Basella Alba L.). Application of 0.5% OyOHr and OyOHh to soil (by weight) reduced Pb concentration in the shoots by 76.9-78.0% compared to control (CK), to a level that was slightly higher (by 15.5-21.5%) than the recommended food safety level (2 mg kg^-1) suggested by WHO. The changes in Pb fractions revealed that the total contents of oxidizable and residual forms in OyOHr or OyOHh after harvest was >415.0 mg kg^-1, which indicated that >92% of Pb when added to the soil, was immobilized and not able to be taken up by plants. The proposed Pb immobilization mechanism might be the dissolution of OyOHr or OyOHh followed by hydroxypyromorphite (Pb₁₀(PO₄)₆(OH)₂) (HP) formation. Due to their facile preparation and eco-friendly and excellent Pb immobilizing characteristics, OyOHr or OyOHh could be readily integrated into current farming systems to mitigate the risk of Pb transferring to plants. However, OyOHr seemed a better immobilizing agent correspond to OyOHh in terms of cost and efficiency.

Keywords: Hydroxyapatite-like compounds; Indian spinach; Lead uptake; Oyster shell; Remediation.

MeSH terms

Animals
Durapatite
Lead
Ostreidae*
Soil
Soil Pollutants* / analysis

Substances

Soil
Soil Pollutants
Lead
Durapatite