Perylene in Lake Biwa sediments originating from Cenococcum geophilum in its catchment area

Perylene, which is composed of five benzene rings, is commonly found in sediments throughout the world at concentrations and distributions that are different from those of other polycyclic aromatic hydrocarbons. The only information available on the origin of perylene comes from 4,9-dihydroxyperylene-3,10-quinone (DHPQ), which originates from fungal component symbiosis or from parasites on plants; however, there is no direct evidence of a mechanism of perylene formation. In this study, we examined the relationship between sedimentary perylene and Cenococcum geophilum (C. geophilum) in a catchment area at Lake Biwa. Sclerotium grains of C. geophilum containing DHPQ were found in this catchment area (approximately 40 balls kg(-1) dried soil for >1 mm-phi), and small sclerotium grains were frequently found in the sediment. In the sediment sample, we also found broken particles containing perylene, and they had a porous structure characteristic of sclerotium grains. Furthermore, the particles contained DHPQ in different transformation stages to perylene via 3,10-perylenequinone (3,10-PQ). This finding was consistent with results from elemental analysis (oxygen/carbon). Because a remarkable amount of DHPQ originating from C. geophilum also exists in the humic acids of soils and because the inputs of compounds to the lake depend strongly on the rivers, perylene in the Lake Biwa sediment originates mainly from the DHPQ of C. geophilum in its catchment area. (C) 2012 Elsevier Ltd. All rights reserved.