Characterization and Extractability of Copper, Manganese, and Zinc in Swine Manure Composts
- Jenn-Hung Hsu * and
- Shang-Lien Lo
Swine (Sus domesticus) manure was comprehensively characterized with respect to Cu, Mn, and Zn in feed additives. This research was conducted to study the leachability and identify factors influencing the leachability of these elements from separated swine manure (SSM) composts to assess its environmental hazard. Several chemical properties were determined to assess the degree of maturity of eight SSM composts. A series of extraction schemes were used to determine base-extractable metals and their distribution on humic substance fractions (humic acid, HA; fulvic acid, FA; and nonhumic fraction, NHF), chemical fractionation, synthetic acid rainwater (SAR) solubility, and extractability at various pH levels of metals in composts. We evaluated the influence of dissolved organic carbon from compost on the extractability of these metals. The SSM composts were enriched with Cu (154–1380 mg kg−1), Mn (239–976 mg kg−1), and Zn (372–2840 mg kg−1). The SAR and neutral-pH extractable fractions of Cu, Mn, Zn, and organic C were generally low (<10% of their total content). Copper leachability in Sample F2 compost, however, was high (20%), resulting from immaturity and associated substantial dissolution of organic C (18%). High extractability (86%) of Cu from humic substances (HS) extraction and at high pH levels (>8) resulted from dissolution of organic matter. Conversely, the extractability of Mn and Zn at alkaline pH levels was low. The major portions of Cu, Mn, and Zn were found in the organic, oxide, and carbonate fractions, respectively, regardless of their content in these composts. The results of this study show that Cu in SSM compost is primarily bound to organics.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .