A pot experiment was conducted to investigate the heavy metal accumulation in maize (Zea mays L.) plant grown in chromated copper arsenate (CCA) soil amended with treated composted sewage biosolid. The initial concent...A pot experiment was conducted to investigate the heavy metal accumulation in maize (Zea mays L.) plant grown in chromated copper arsenate (CCA) soil amended with treated composted sewage biosolid. The initial concentrations of chromium, copper, arsenate in the CCA soil and sewage biosolid were determined by atomic absorption spectrophotometer. These were found to be, in CCA soil: 365.8 ± 6.18, 109.22 ± 14.04, 28.22 ± 3.8 and in sewage biosolid: 35 ± 1.06, 1.0 ± 0.02, 0 mg·kg-1 respectively. The concentration of Cr, Cu and As determined in both the roots and shoots generally decreased with increase in percentage amendment concentration and number of days (20 and 40 days after planting). At 20 days, the total metal concentration ranges in roots were As (5.54 ± 0.03 - 6.69 ± 1.14), Cr (9.59 ± 0.02 - 13.22 ± 0.03), Cu (2.28 ± 0.06 - 4.53 ± 0.37) mg·kg-1 while at 40 days the values were As (5.60 ± 0.19 - 6.08 ± 0.01), Cr (9.47 ± 0.04 - 10.95 ± 0.09), Cu (3.94 ± 0.19 - 4.64 ± 0.07) mg·kg-1. For the shoot system, the concentrations of the metals at 20 days were As (5.28 ± 0.03 - 5.90 ± 0.13), Cr (9.30 ± 0.05 - 10.07 ± 0.06), Cu (3.64 ± 0.12 - 4.72 ± 0.15) mg/kg while at 40 days the values obtained were As (5.28 ± 0.03 - 5.9 ± 0.13), Cr (9.69 ± 0.14 - 10.07 ± 0.03), Cu (2.94 ± 0.72 - 4.53 ± 0.03) mg·kg-1. The roots accumulated the three heavy metals more than the shoot system at all treatments used. Concentration of arsenic, chromium and copper in the plants decreased with increasing percentage amendments. The results suggest relatively low bioavailability of the three metals in CCA soil treated with high percentages of sewage biosolid as an amendment.展开更多
In the area of recycling of spent chromated copper arsenate (CCA)-treated wood, most studies to date have focused on methods of removing/extracting the residual preservative from the wood matrix. It is well recognized...In the area of recycling of spent chromated copper arsenate (CCA)-treated wood, most studies to date have focused on methods of removing/extracting the residual preservative from the wood matrix. It is well recognized that exposure of CCA-treated wood to an acid solution can reverse the CCA fixation process thereby converting the CCA elements into their water-soluble form. The economic viability of the process is enhanced because it can be integrated with other technologies and products (e.g., “green” spray foam insulation, etc.). The market for the “green” CCA is the same as for traditional CCA-the wood treating industry, principally utility poles and pilings. A market research study was conducted to determine the suitability of spent CCA-treated wood as a source for recycled, “green” CCA for manufacturing “green” spray-foam insulation. Specifically, we wanted to discern the attitudes and overall perspectives of buyers/sellers (i.e., utilities and wood treating companies) of CCA preservatives and treated wood products, disposal methods and costs for decommissioned CCA-treated wood, and understand perceptions of and willingness-to-pay for “green” CCA preservatives extracted from the technologies used in this research. Results show that 60% of wood preservative treating respondents and 60% of electric utility company respondents are somewhat or greatly interested in using out-of-service utility poles as feedstock for “green insulation” as part of a new potential business venture.展开更多
Chemical extraction, bioremediation, and electrodialytic processes have been extensively studied for removal of copper, chromium, and arsenic from wood treated with chromated copper arsenate （CCA）. However, one prob...Chemical extraction, bioremediation, and electrodialytic processes have been extensively studied for removal of copper, chromium, and arsenic from wood treated with chromated copper arsenate （CCA）. However, one problem has not been addressed： the effects of wood species and retention levels on remediation efficiency. The objectives of this study were to investigate the effects of wood species and retention levels on removal of copper, chromium, and arsenic from CCA-treated wood samples using sodium hypochlorite. Our results showed that sodium hypochlorite （NaOC1） was very effective for removal of copper, chromium, and arsenic from CCA-C treated milled wood samples for all three species used in this study. The Cu, Cr, and As extraction efficiencies for red pine were 95 % Cu, 97 % Cr and 94 % As, for maple were 95 % Cu, 97 % Cr, and 98 % As at 4.0 kg m-3 retention levels, and for aspen were 95 % Cu, 92% Cr, and 91% As at 9.6 kg m-3 retention level, respectively. However, the results showed that wood species and initial retention levels of CCA-treated wood products played very impor- tant roles in terms of removal of Cu, Cr, and As.展开更多
文摘A pot experiment was conducted to investigate the heavy metal accumulation in maize (Zea mays L.) plant grown in chromated copper arsenate (CCA) soil amended with treated composted sewage biosolid. The initial concentrations of chromium, copper, arsenate in the CCA soil and sewage biosolid were determined by atomic absorption spectrophotometer. These were found to be, in CCA soil: 365.8 ± 6.18, 109.22 ± 14.04, 28.22 ± 3.8 and in sewage biosolid: 35 ± 1.06, 1.0 ± 0.02, 0 mg·kg-1 respectively. The concentration of Cr, Cu and As determined in both the roots and shoots generally decreased with increase in percentage amendment concentration and number of days (20 and 40 days after planting). At 20 days, the total metal concentration ranges in roots were As (5.54 ± 0.03 - 6.69 ± 1.14), Cr (9.59 ± 0.02 - 13.22 ± 0.03), Cu (2.28 ± 0.06 - 4.53 ± 0.37) mg·kg-1 while at 40 days the values were As (5.60 ± 0.19 - 6.08 ± 0.01), Cr (9.47 ± 0.04 - 10.95 ± 0.09), Cu (3.94 ± 0.19 - 4.64 ± 0.07) mg·kg-1. For the shoot system, the concentrations of the metals at 20 days were As (5.28 ± 0.03 - 5.90 ± 0.13), Cr (9.30 ± 0.05 - 10.07 ± 0.06), Cu (3.64 ± 0.12 - 4.72 ± 0.15) mg/kg while at 40 days the values obtained were As (5.28 ± 0.03 - 5.9 ± 0.13), Cr (9.69 ± 0.14 - 10.07 ± 0.03), Cu (2.94 ± 0.72 - 4.53 ± 0.03) mg·kg-1. The roots accumulated the three heavy metals more than the shoot system at all treatments used. Concentration of arsenic, chromium and copper in the plants decreased with increasing percentage amendments. The results suggest relatively low bioavailability of the three metals in CCA soil treated with high percentages of sewage biosolid as an amendment.
文摘In the area of recycling of spent chromated copper arsenate (CCA)-treated wood, most studies to date have focused on methods of removing/extracting the residual preservative from the wood matrix. It is well recognized that exposure of CCA-treated wood to an acid solution can reverse the CCA fixation process thereby converting the CCA elements into their water-soluble form. The economic viability of the process is enhanced because it can be integrated with other technologies and products (e.g., “green” spray foam insulation, etc.). The market for the “green” CCA is the same as for traditional CCA-the wood treating industry, principally utility poles and pilings. A market research study was conducted to determine the suitability of spent CCA-treated wood as a source for recycled, “green” CCA for manufacturing “green” spray-foam insulation. Specifically, we wanted to discern the attitudes and overall perspectives of buyers/sellers (i.e., utilities and wood treating companies) of CCA preservatives and treated wood products, disposal methods and costs for decommissioned CCA-treated wood, and understand perceptions of and willingness-to-pay for “green” CCA preservatives extracted from the technologies used in this research. Results show that 60% of wood preservative treating respondents and 60% of electric utility company respondents are somewhat or greatly interested in using out-of-service utility poles as feedstock for “green insulation” as part of a new potential business venture.
文摘Chemical extraction, bioremediation, and electrodialytic processes have been extensively studied for removal of copper, chromium, and arsenic from wood treated with chromated copper arsenate （CCA）. However, one problem has not been addressed： the effects of wood species and retention levels on remediation efficiency. The objectives of this study were to investigate the effects of wood species and retention levels on removal of copper, chromium, and arsenic from CCA-treated wood samples using sodium hypochlorite. Our results showed that sodium hypochlorite （NaOC1） was very effective for removal of copper, chromium, and arsenic from CCA-C treated milled wood samples for all three species used in this study. The Cu, Cr, and As extraction efficiencies for red pine were 95 % Cu, 97 % Cr and 94 % As, for maple were 95 % Cu, 97 % Cr, and 98 % As at 4.0 kg m-3 retention levels, and for aspen were 95 % Cu, 92% Cr, and 91% As at 9.6 kg m-3 retention level, respectively. However, the results showed that wood species and initial retention levels of CCA-treated wood products played very impor- tant roles in terms of removal of Cu, Cr, and As.
