Title: | Mobile organic compounds in biochar - a potential source of contamination - phytotoxic effects on cress seed (Lepidium sativum) germination |
Address: | "UK Biochar Research Centre, School of GeoSciences, University of Edinburgh, Crew Building, King's Buildings, Edinburgh EH9 3JN, UK. UK Biochar Research Centre, School of GeoSciences, University of Edinburgh, Crew Building, King's Buildings, Edinburgh EH9 3JN, UK. Electronic address: ondrej.masek@ed.ac.uk" |
DOI: | 10.1016/j.jenvman.2014.01.045 |
ISSN/ISBN: | 1095-8630 (Electronic) 0301-4797 (Linking) |
Abstract: | "Biochar can be contaminated during pyrolysis by re-condensation of pyrolysis vapours. In this study two biochar samples contaminated by pyrolysis liquids and gases to a high degree, resulting in high volatile organic compound (high-VOC) content, were investigated and compared to a biochar with low volatile organic compound (low-VOC) content. All biochar samples were produced from the same feedstock (softwood pellets) under the same conditions (550 degrees C, 20 min mean residence time). In experiments where only gaseous compounds could access germinating cress seeds (Lepidium sativum), application amounts ranging from 1 to 30 g of high-VOC biochar led to total inhibition of cress seed germination, while exposure to less than 1 g resulted in only partial reduction. Furthermore, leachates from biochar/sand mixtures (1, 2, 5 wt.% of biochar) induced heavy toxicity to germination and showed that percolating water could dissolve toxic compounds easily. Low-VOC biochar didn't exhibit any toxic effects in either germination test. Toxicity mitigation via blending of a high-VOC biochar with a low-VOC biochar increased germination rate significantly. These results indicate re-condensation of VOCs during pyrolysis can result in biochar containing highly mobile, phytotoxic compounds. However, it remains unclear, which specific compounds are responsible for this toxicity and how significant re-condensation in different pyrolysis units might be" |
Keywords: | Charcoal/*chemistry Germination/*drug effects Hot Temperature Lepidium sativum/*drug effects/physiology Seeds/drug effects/physiology Volatile Organic Compounds/*toxicity Biochar Contaminant Germination Pyrolysis Re-condensation Volatile organic compound; |
Notes: | "MedlineBuss, Wolfram Masek, Ondrej eng England 2014/03/13 J Environ Manage. 2014 May 1; 137:111-9. doi: 10.1016/j.jenvman.2014.01.045. Epub 2014 Mar 5" |