The sediment-water diffusion and risk assessment of PAHs in different types of drinking water sources in the Yangtze River Delta, China

Abstract

PAHs are hazardous and ubiquitous pollutants in the aquatic environment. Understanding their flux, diffusion and environmental risk is very important for the sustainable development of drinking water sources. Thus, PAHs residues were measured with isotope dilution mass spectrometry in sediments, and overlying water of different types of drinking water sources such as rivers, lake, and river networks of Yangtze River Delta. These water bodies are important sources of drinking water, fish, and ecological habitats of various species. The results showed that the ΣPAHs were ranged from 4.25 to 407 ng/L in water, ranked in order as follows: rivers > river networks > lake. ΣPAHs were ranged from 149 to 8023 ng/g dry weight in sediment, ranked in order as follows: river networks > lake > rivers. Low molecular weight PAHs were dominant compounds in water, while high molecular weight PAHs were dominant compounds in sediment. The ffSW values revealed a net resuspension of naphthalene (Nap), acenaphthylene (Dih), fluorine (Flu), phenanthrene (Phe), anthracene (Ant), and benzo[a]pyrene (BaP) from sediment to water in all kind of water sources; indeno[1,2,3-c,d]pyrene (Ind), benzo[b]fluoranthene (BbF), and benzo[k]fluoranthene (BkF) were transferred from water to sediment in Qiantang river but these compounds were at sediment-water equilibrium in Yangtze River, Huangpu River, Jiaxing River Network and Taihu Lake. Acenaphthene (Ace), fluoranthene(Fla), benzo[a]anthracene (BaA), chrysene (Chr), benzo[g,h,i]anthrancene (BPY) were at sediment-water equilibrium at Qiangtang River. PAHs were mainly derived from a mixed source of combustion and petroleum through source resolution. According to quality guidelines, PAHs in sediment posed a potential ecological threat at one site, however, drinking water did not pose any carcinogenic and non-carcinogenic risks.