Assessment of nicotine and degradation products in cigarette butts leachates after detoxification by white rot fungi

Abstract

Cigarette butts (CBs) are widespread hazardous waste contaminating the environment due to the recalcitrance of the filter and the toxicity of the contaminants leached. This paper evaluated through analysis of contaminants and toxicity bioassays on Raphanus sativus seeds, the ability of four fungal strains of white rot fungi to treat cigarette butts, including 2 native strains of Trametes sp. (strains BAFC 4765 and BAFC 4767), one of Irpex lacteus (strain BAFC 4766) and one commercial strain of Pleurotus ostreatus (strain BAFC 2034). Each strain was grown in a medium of water-soaked CBs in axenic conditions at Erlenmeyer-scale during six weeks, analyzing leachate samples periodically by HPLC-MSⁿ. Temporal evolution of nicotine as well as the transformations of tobacco alkaloids and other contaminants generated by the different fungal treatments were characterized. Nicotine was degraded significantly by the end of the treatments although variations were found among the fungal strains, proposing a degradation mechanism based on the 12 tobacco alkaloid transformation products identified. Leachates from CBs showed a total inhibition of germination on Raphanus sativus seeds whereas those obtained after 6 weeks of treatment displayed a significant decrease of phytotoxicity (7-20% inhibition of germination) exhibiting sublethal effects. The results obtained in this work support the development of CBs fungal treatment for waste detoxification on a larger scale.