Mutagenic activities of biochars from pyrolysis

Area of Science:

• Environmental Science
• Toxicology
• Materials Science

Background:

• Biochar, produced from pyrolysis of various organic materials, is gaining industrial significance.
• Developing reliable protocols for ecological monitoring of biochar quality is crucial.
• The Salmonella mutagenicity assay (Ames test) is a sensitive tool for assessing mutagenic potential, including with metabolic activation (S9).

Purpose of the Study:

• To validate the Ames test for analyzing mutagenic activities of biochar extracts.
• To investigate the influence of pyrolysis conditions and feedstock on biochar mutagenicity.
• To establish protocols for screening mutagenic residuals in biochar products.

Main Methods:

• Utilized the Ames test with Salmonella typhimurium strains TA98 and TA100.
• Tested biochar extracts in the presence and absence of rat liver extract (S9) for metabolic activation.
• Analyzed biochars derived from lignocellulose, agricultural residues, and various manures.

Main Results:

• Tester strain TA98 demonstrated higher sensitivity in detecting mutagenic biochar products.
• Pyrolysis temperature and time significantly impacted mutagenicity; biochar from lignocellulose at 400°C for 10min was mutagenic, unlike higher temperatures/longer times.
• Biochar from pig manure exhibited high mutagenicity, while poultry litter and grass-fed calf manure biochars showed low mutagenicity. Cow and milk-fed calf manure biochars, and industrial waste biochars had intermediate mutagenicities.

Conclusions:

• The Ames test, with S9 metabolic activation, is suitable for detecting mutagenic activities in biochar.
• Pyrolysis parameters and feedstock type are critical determinants of biochar mutagenicity.
• The outlined methods provide a basis for screening mutagenic residuals in diverse biochar products, informing safety assessments.