Environmental Science and Pollution Research

, Volume 23, Issue 19, pp 19580–19589 | Cite as

High-VOC biochar—effectiveness of post-treatment measures and potential health risks related to handling and storage

  • Wolfram Buss
  • Ondřej MašekEmail author
Research Article


Biochar can contain volatile organic compounds (VOCs), formed and introduced during the pyrolysis process. In some pyrolysis units or under specific conditions during production, pyrolysis vapours can deposit on biochar in significant amounts resulting in high-VOC biochar. In this study, it was tested to which extent VOCs are released from such high-VOC biochars when openly stored, which post-treatment measures are most effective in reducing phytotoxic potential and whether the VOC emissions could exceed human health-related threshold values. It was shown that the initial VOC release of high-VOC biochars can exceed occupational exposure limit values and even after 2 months, the biochars still emitted VOCs exceeding air quality guideline values. Consequently, these specific high-VOC biochars pose health risks when handled or stored openly. Simple open-air storage turned out to be insufficient for VOC removal. Low temperature treatment, on the other hand, removed VOCs from the high-VOC biochars effectively and alleviated any human health risks and phytotoxic effects. In addition to the high-VOC biochars, a low-VOC biochar was tested which did not emit any VOCs and was even able to sorb VOCs from the VOC-rich biochar to a certain extent. Thermal treatment and blending with low-VOC biochar are methods which could be used in practise to treat high-VOC biochar, reducing VOC emissions. This study revealed significant new findings on the topic of VOCs in biochar which highlights the need to include VOCs in the list of priority contaminants in biochar.


Biochar VOC Post-treatment Human health Phytotoxicity PAH 



Volatile organic compound


Polycyclic aromatic hydrocarbon

GC biochar

Gas contaminated biochar

LC biochar

Liquid contaminated biochar

NC biochar

Non-contaminated biochar


Low-molecular weight

Supplementary material

11356_2016_7112_MOESM1_ESM.docx (464 kb)
ESM 1 (DOCX 464 kb)


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Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.UK Biochar Research Centre, School of GeosciencesUniversity of EdinburghEdinburghUK

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