Chemical and ecotoxicological properties of three bio-oils from pyrolysis of biomasses

• The fast pyrolysis oil from pine wood had the lowest water and nitrogen content.
• The intermediate pyrolysis from poultry litter had the highest nitrogen content.
• All the tested oils were biodegraded by activated sludge bacteria.
• All the tested oils were scarcely toxic to crustaceans and green algae.
• Toxicity, though low, could not be predicted from the substances detected in the oils.

In view of the potential use of pyrolysis-based technologies, it is crucial to understand the environmental hazards of pyrolysis-derived products, in particular bio-oils. Here, three bio-oils were produced from fast pyrolysis of pine wood and intermediate pyrolysis of corn stalk and poultry litter. They were fully characterized by chemical analysis and tested for their biodegradability and their ecotoxicity on the crustacean Daphnia magna and the green alga Raphidocelis subcapitata. These tests were chosen as required by the European REACH regulation. These three bio-oils were biodegradable, with 40–60% of biodegradation after 28 days, and had EC50 values above 100 mg L−1 for the crustacean and above 10 mg L−1 for the alga, showing low toxicity to the aquatic life. The toxic unit approach was applied to verify whether the observed toxicity could be predicted from the data available for the substances detected in the bio-oils. The predicted values largely underestimated the experimental values.