Vertical distribution, environmental occurrence and risk assessment of organic pollutants in lacustrine sediments in southeast China

Abstract

To clarify environmental occurrence and ecological risks of Zhushan Bay in Taihu Lake, the characteristics of deposited organic materials (elements and 16 polycyclic aromatic hydrocarbons (∑16PAHs) in a 93-cm sediment core from Taihu Lake were determined. The results showed that the values of nitrogen (N), carbon (C), hydrogen (H), and sulphur (S) ranged from 0.08%~0.3%, 0.83%~3.6%, 0.63%~1.12%, and 0.02%~0.24%, respectively. Significant changes in most elements at 50 cm depth due to changes in endogenous input, accompanied by algal blooms. The concentration of ∑16PAHs was in a range of 1807.48 ~ 4674.83 ng g− 1, showing a downward trend with the deepening of the depth, accompanied by fluctuations. The 3-ring PAHs had obvious advantages in surface sediment. Affected by various factors, the change of PAHs concentration also mainly appeared at 50cm depth and it was estimated to occur in the 1900s. The ratio of PAH monomer and PCA results showed that the combustion of fossil fuels was the main source of PAHs in the sediments. The results of the toxicity analysis indicated that most of the PAH monomers had little impact on the ecology, and a small number of monomers were increasing year by year and close to the ERM value, which should be controlled and paid attention to.