In situ arsenic speciation and the release kinetics in coastal sediments: A case study in Daya Bay, South China Sea

Jin-Jun Liu; Zeng-Hui Diao; Xiang-Rong Xu; Qun Xie; Zhi-Xin Ni

doi:10.1016/j.scitotenv.2018.09.389

In situ arsenic speciation and the release kinetics in coastal sediments: A case study in Daya Bay, South China Sea

Sci Total Environ. 2019 Feb 10;650(Pt 2):2221-2230. doi: 10.1016/j.scitotenv.2018.09.389. Epub 2018 Oct 2.

Authors

Jin-Jun Liu¹, Zeng-Hui Diao², Xiang-Rong Xu³, Qun Xie⁴, Zhi-Xin Ni⁵

Affiliations

¹ Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
³ Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China. Electronic address: xuxr@scsio.ac.cn.
⁴ Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; Guangdong Ocean University, Zhanjiang 524000, China; University of Chinese Academy of Sciences, Beijing 100049, China.
⁵ South China Sea Environmental Monitoring Center, South China Sea Branch of the State Oceanic Administration, Guangzhou 510300, China.

PMID: 30292115
DOI: 10.1016/j.scitotenv.2018.09.389

Abstract

In-situ study on arsenic speciation and the release kinetics in marine sediments was scarce. In this study, the distributions of labile As and their speciation in coastal sediments of Daya Bay were obtained by separate diffusive gradients in thin films (DGT) probes. Results showed that the DGT-labile As(V) was the main speciation in surface sediments (from -20 to 0 mm) with a concentration range of 0.07-3.05 μg·L^-1, while the labile As(III) was the main speciation in deep layers of sediments (from -100 to -20 mm). In coastal areas, mariculture farms was the most dominated contributor to As(V) contamination in surface sediments. Both the apparent diffusion flux estimation and the DGT induced flux in sediments (DIFS) simulation indicated that As(V) contamination in surface sediments of mariculture, harbor and petrochemical areas suffered the potential risk of As(V) release into the overlying water from sediments. DIFS modeling also found that the sediments of mariculture farms were the main sediment As pools. Linear regression analysis indicated that the mobility of As mainly attributed to the As(V) in sediments.

Keywords: Arsenic speciation; DGT induced flux in sediments (DIFS); Diffusive gradients in thin films (DGT); Release kinetics; Sediment.