Sedimentary record and risk assessment of polycyclic aromatic hydrocarbons in the northern Taihu Basin

抄録

Polycyclic aromatic hydrocarbons (PAHs) accumulate and persist ubiquitously in natural environment during Anthropocene. This study was conducted in a heavily industrialized and urbanized Taihu basin of the lower reaches of Yangtze River. The concentrations of 15 priority PAHs were measured in the sediment core (49.5-cm length). Multiple source apportionment methods were used to trace the pollution history and sources, spanning the last ca. 116 years (1902∼2018). The PAHs concentration in the sediment increased from 428.70 to 1486.60 ng·g^-1. Three representative periods with characteristics of high PAHs level were divided: the 1952 peak was linked to the beginning of industrial development under the first Five-Year-Plan (1951∼1955); the 1979 peak was closely related to the industrial boom by the application of Reform and Opening policy since 1978. The highest PAHs value in 2008 and then decreased indicated the enhanced pollution treatment after Water Crisis event in Wuxi City (2007). The toxic equivalent quantity (TEQ) value for the PAHs indicated that toxicity in 79% of samples exceeded the environmental standard set from 1980s~2010s. The results of diagnostic ratios and a positive matrix factorization (PMF) model show that the contribution of coal combustion and vehicle emissions to the PAHs compounds account for 41% and 26%, respectively throughout the sedimentary period.