Evaluating the phytotoxicity of dissolved organic matter derived from black carbon

Dissolved organic matter (DOM) derived from black carbon (BC) can migrate from soil to river by rainfall or snow melting in nature. Because of the incomplete biomass combustion, BC produced at various temperatures is mixed, which is hard to divide the DOM at single temperature. Then it is difficult to explore the properties and risks of DOM in detail. Therefore, corn straws were selected to prepare BC under different heating temperature (200 degrees C, 250 degrees C, 300 degrees C, 350 degrees C, 400 degrees C and 450 degrees C). Germination index combined the excitation-emission matrix-parallel factor (PARAFAC) and two-dimensional correlation spectra was employed to clarify the phytotoxicity and the PARAFAC components of DOM derived from BC at single temperature. Results showed that BC was hard to dissolve in water, but most of its DOM were toxic. Heating temperature promoted the formation of simple and complex fluorescent components. Combined with volume integration, it is the complex peaks of fluorescent components to determine the phytotoxicity of DOM derived from BC. These results would help to build a deep understanding of the fluorescence characteristics and toxicity of BC at different temperatures and emphasize the importance of reducing straw by burning. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study found that black carbon was insoluble in water, but most of its DOM was toxic, and heating temperature promoted the formation of simple and complex fluorescent components.