Seasonal and spatial variations of acid-volatile sulphide and simultaneously extracted metals in the Yangtze River Estuary

Abstract

Surface sediments were collected from the Yangtze River Estuary (YRE) in May 2012, August 2012, November 2012 and February 2013 to analyse the seasonal and spatial distributions of acid-volatile sulphide (AVS), simultaneously extracted metals (SEM) and the sediment toxicity. An optimised method was used for the AVS and SEM analysis and the results showed that the seasonal variations of AVS were positively correlated with changes in water temperature and the position of higher AVS was relatively fixed. The average of SEM was gradually increased from May 2012 to February 2013 and there were abnormally high values of SEM_Cu and SEM_Ni in the YRE. Concentrations of the five SEM components were in the following order: Cd < Pb < Cu ≈ Ni < Zn. The correlations among the concentrations of the five metals suggested that these metals in the sediments of the YRE did not have stable anthropogenic and/or natural origin. The mean values of AVS and SEM in the YRE were closer to those in the Huanghe Estuary and were lower than those in the Pearl River Estuary. The results of two sediment toxicity assessments showed that the sediments of most areas in the YRE had potential sediment toxicities, especially the Ni and Cu contamination.

Keywords:

• seasonal
• spatial
• acid-volatile sulphide
• metals
• Yangtze River Estuary
• sediments

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

We are grateful to Zhenyao Shen of Beijing Normal University for his advice about the structure of this article. We are also grateful for grants from the National Key Basic Research Development Program (‘973’ project) of China [No. 2010CB429006], the National Science Fund for Distinguished Young Scholars [No. 51225901], the Outstanding Youth Fund of Jiangsu Province [BK2012037] , the Research Fund for Innovation Team of Ministry of Education [IRT13061] and the Fundamental Research Funds for the Central Universities [2014B03814].