Toxicity evaluation of weathered coal fly ash-amended manure compost

Sam S S LAU, Jonathan W C WONG*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

58 Citations (Scopus)


The general use of manure compost is limited by its residual toxicity, and hence a study was performed to evaluate the use of weathered coal fly ash (lagoon ash) to alleviate the toxicity of manure compost. Mature and immature manure compost were amended with lagoon ash at 0, 5, 10 and 20% (w/w dry weight basis), and their phyto-toxicity was evaluated by germination and root length growth of lettuce seed. The immature manure compost had significantly higher contents of NH4-N, PO4-P, and acid- and water-extractable Cu and Zn contents than those of mature manure compost. Ash amendment caused a significant increase in electrical conductivity (EC), but a decrease in NH4-N, PO4-P, and DTPA-, CaCl2- and water-extractable Cd, Cu, Pb and Zn contents of both manure compost. Addition of lagoon ash at a rate of 5% for immature manure compost and 10% for mature manure compost resulted in a higher seed germination rate and root length growth. The germination index demonstrated significant negative correlations with EC, NH4-N and DTPA extractable Cd, Cu, Pb and Zn contents. The present study supports the use of lagoon ash for amending manure compost to reduce the availability of trace elements and NH4-N.

Original languageEnglish
Pages (from-to)243-254
Number of pages12
JournalWater, Air, and Soil Pollution
Issue number3-4
Publication statusPublished - 2001

Scopus Subject Areas

  • Environmental Engineering
  • Environmental Chemistry
  • Ecological Modelling
  • Water Science and Technology
  • Pollution

User-Defined Keywords

  • Coal fly ash
  • DTPA
  • Germination index
  • Heavy metals
  • Manure compost


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