Research
| Title： | Distribution Pattern of Dioxins in Sediment Cores from the Xiangxi River, a Tributary of Three Gorges Reservoir, China |
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| First author： | Zhou, Bei; Zhu, Kongxian; Bi, Yonghong; Henkelmann, Bernhard; Bernhoeft, Silke; Mi, Wujuan; Schramm, Karl-Werner |
| Journal： | WATER |
| Years： | 2023 |
| DOI： | 10.3390/w15010057 |
| Abstract： | Sediment cores were collected from the Xiangxi River, a tributary of the Three Gorges Reservoir, the deposition time in the longest sediment core (90 cm) was measured by radiometry (Cs-137, Pb-210) activities and polychlorinated dibenzo-p-dioxins/furan (PCDD/F) concentrations in different depths of the sediment core were measured. The results indicated that the mean deposition rate was 1.01 cm/a. The total PCDD/F concentrations ranged from 19.28 to 70.07 pg/g d.w. with a mean of 35.06 pg/g d.w. PCDD/Fs in the 1960-1990s were higher than others, which were significantly different in the various layers and cores (p < 0.05). PCDD occupied 63.42-87.33% of PCDD/Fs, and octachlorianted debenzo-p-dioxin (OCDD) was the predominant congener. The ratio of PCDD to PCDF was 2.26-8.08. PCDD/Fs significantly correlated with total organic carbon (TOC) (p < 0.01). The toxic equivalent (TEQ) ranged from 0.15 to 0.98 pg/g d.w. No significant difference was found in TEQ (p > 0.05). It was concluded that the spatio-temporal heterogeneity determined by hydrodynamics and total organic carbon (TOC) was the distribution pattern of PCDD/Fs in the sediment cores of Xiangxi River, the concentrations of PCDD/Fs were low, with a low environmental pollution risk, and by-products of sodium pentachlorophenate might be the main source. |
