Figure 3
Vertical variations of the selected PAC concentration ratios for source identification in (A) the Huguangyan Maar Lake (HGY) and (B) the Chaohu Lake (CH). (A1 and B1) concentration ratio of low-molecular-weight (LMW) PAHs to high-molecular-weight (HMW) PAHs; (A2 and B2) ∑15OPAHs/∑28PAHs concentration ratios; (A3 and B3) concentration ratio of indeno[1,2,3-cd]pyrene (IcdP) to the sum of IcdP and benzo[g,h,i]perylene (BghiP); (A4 and B4) concentration ratio of anthracene (ANT) to the sum of ANT and phenanthrene (PHE); (A5 and B5) concentration ratio of fluoranthene (FLUA) to the sum of FLUA and pyrene (PYR). Note: Low- molecular-weight (LMW) PAHs include naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene and anthracene; High- molecular-weight (HMW) PAHs include fluoranthene, pyrene, benzo[a]anthracene, chrysene+triphenylene, benzo[b+j+k]fluoranthene, benzo[e]pyrene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, dibenzo[a,h]anthracene, benzo[g,h,i]perylene and coronene. Note: The chronologies older than 1850 were obtained by assuming the average accumulation rate of the upper layers because the 210Pb method can only produce reliable chronologies of 150–170 years. Consequently, the older dates have a high uncertainty.
