Ricardo Melamed

Fundação Planetário da Cidade do Rio de janeiro, Rio de Janeiro, Rio de Janeiro, Brazil

Are you Ricardo Melamed?

Claim your profile

Publications (3)4.1 Total impact

  • R. Melamed · L. Q. Ma
    [Show abstract] [Hide abstract]
    ABSTRACT: Introduction Phosposphorus-induced lead immobilization in soils and water Assessing the effectiveness of phosphorus-induced lead immobilization in soils Field application of phosphorus amendments: case study Conclusions
    No preview · Chapter · Feb 2007
  • Source
    Ming Chen · Lena Q Ma · Satya P Singh · Rocky X Cao · Ricardo Melamed
    [Show abstract] [Hide abstract]
    ABSTRACT: A long-term field-scale demonstration project on the feasibility of using P to immobilize Pb in a Pb-contaminated urban soil was conducted. Phosphate was applied at an average rate of 3040 mg P/kg soil based on a P/Pb molar ration of 4.0, with four treatments: T0, no P application; T1, H3PO4 only; T2, 1/2 H3PO4+1/2 CaH2PO4; and T3, 1/2 H3PO4+1/2 phosphate rock. Soil samples were collected and analyzed 220 days after the P applications. For all P treatments, toxicity characteristic leaching procedure (TCLP) extractable Pb levels in surface soils (0–10 cm) were reduced to below 5.0 mg Pb/l, with T2 also effective in reducing the TCLP Pb level in subsurface soils (10–30 cm, <4.63 mg/l). Sequential extraction analysis indicates that P was effective in transforming soil Pb from non-residual fractions to a residual fraction. Such a transformation was mainly through dissolution of Pb associated with carbonate fraction and precipitation of pyromorphite-like minerals, which were confirmed using X-ray diffraction (XRD). Among these three treatments, T3 was the most effective in reducing Pb mobility and minimizing P and Pb leaching in the soil. Our research clearly demonstrates that P amendments were effective in immobilizing Pb in contaminated soil.
    Full-text · Article · Oct 2003 · Advances in Environmental Research
  • Source
    Ricardo Melamed · Xinde Cao · Ming Chen · Lena Q Ma
    [Show abstract] [Hide abstract]
    ABSTRACT: A pilot-scale field demonstration was conducted at a Pb-contaminated site to assess the effectiveness of Pb immobilization using P amendments. The test site was contaminated by past battery recycling activities, with average soil Pb concentration of 1.16%. Phosphate amendments were applied at a 4.0 molar ratio of P/Pb with three treatments: T1, 100% P from H(3)PO(4); T2, 50% from H(3)PO(4)+50% from Ca(H(2)PO(4))(2); and T3, 50% from H(3)PO(4)+5% phosphate rock. Soil samples were collected and characterized 220 days after P application. Surface soil pH was reduced from 6.45 to 5.05 in T1, to 5.22 in T2, and to 5.71 in T3. Phosphate treatments effectively transformed up to 60% of total soil Pb from the non-residual fraction (sum of water soluble and exchangeable, carbonate, Fe-Mn oxide, and organic fractions) to the residual fraction relative to the control. In addition, P treatments reduced Toxicity Characteristic Leaching Procedure (TCLP) Pb from 82 mg l(-1) to below EPA's regulatory level of 5 mg l(-1) in the surface soil. Scanning electron microscopy-energy dispersive X-ray elemental analysis and X-ray diffraction analysis indicated formation of insoluble chloropyromorphite [Pb(5)(PO(4))(3)Cl] mineral in the P-treated soils. Although H(3)PO(4) is necessary to dissolve meta-stable Pb in soil for further lead immobilization, it should be used with caution due to its potential secondary contamination. A mixture of H(3)PO(4) and Ca(H(2)PO(4))(2) or phosphate rock was effective in immobilizing Pb with minimum adverse impacts associated with pH reduction.
    Full-text · Article · May 2003 · Science of The Total Environment

Publication Stats

214 Citations
4.10 Total Impact Points


  • 2003-2007
    • Fundação Planetário da Cidade do Rio de janeiro
      Rio de Janeiro, Rio de Janeiro, Brazil
    • University of Florida
      • Department of Soil and Water Science
      Gainesville, Florida, United States