Figure 2

(Historical variations of concentrations and mass accumulation rates (MARs) of BC, char and soot, char/soot ratios, parent-PAHs (∑28PAHs), oxygenated PAHs (∑15OPAHs) and azaarenes (∑4AZAs)in (A) the Huguangyan Maar Lake (HGY) and (B) the Chaohu Lake (CH). A1 and B1) BC, char and soot concentrations; (A2 and B2) BC, char and soot MARs; (A3 and B3) char/soot ratios; (A4 and B4) concentrations of parent-PAHs (∑28PAHs), oxygenated PAHs (∑15OPAHs) and azaarenes (∑4AZAs); (A5 and B5) MARs of ∑28PAHs, ∑15OPAHs and ∑4AZAs. 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.