Temporal variations and bioaccumulation of heavy metals in different Suaeda salsa marshes of the Yellow River estuary,China

To understand the temporal variations and bioaccumulation of heavy metals in the coastal marshes, the concentrations of heavy metals (Cr, Ni, Pb, and Cu) in the two Suaeda salsa marshes [middle S. salsa marsh (MM) and low S. salsa marsh (LM)] of the Yellow River estuary were determined from May to November in 2008 by in situ sampling and inductively coupled plasma mass spectrometry (ICP-MS) analysis. Results showed that heavy metal concentrations in S. salsa of MM and LM were generally in the order of Cu?>?Cr?>?Pb?>?Ni, while those in sediments fell in the order of Cr?>?Ni?>?Cu?>?Pb. Heavy metal concentrations of S. salsa in MM and LM were different, and significant differences were observed in stems (F?=?4.797, p?=?0.046) and litters (F?=?6.799, p?=?0.026) for Ni. Litter was the main stock of heavy metals, and the allocations of Cr, Ni, and Pb reached 31.25–51.31, 28.49–42.58, and 29.55–66.79 % (in MM) and 36.73–48.60, 41.70–57.87, and 33.30–60.64 % (in LM), respectively. The ratios of roots/leaves (R/L) and roots/stems (R/S) for Cr and Ni in MM were mostly greater than 1, while those ratios in LM were mostly less than 1, indicating that Cr and Ni in S. salsa at LM had greater mobility compared with those at MM. Moreover, the [accumulation factor, AF]_plant of Cr, Ni, Cu, and Pb in LM, especially [AF]_root and [AF]_stem of Cr and [AF]_litter of Ni, was also higher than that in MM. These indicated that S. salsa grown in LM was more suitable for potential biomonitor or phytoremediation of Cr, Ni, Cu, and Pb if intertidal sediments were seriously contaminated with an increase of pollutant loading (especially heavy metals) in the Yellow River estuary. The use of biomonitor (S. salsa) living and growing in LM could yield valuable information not only on the presence of anthropogenic stressors, but, more importantly, on the adverse influence the stressors are having on the environment.     

闽江福州段湿地沉积物重金属吸附-解吸特征及其对酸沉降变化的响应

选择闽江福州段为研究对象,通过采集淡水河段(A、B)、城市河段(C、D)和河口区(E、F)6个样点的沉积物柱样,探讨了湿地沉积物重金属的吸附-解吸特征及其对酸沉降变化的响应.结果表明,Langmuir吸附等温方程可较好地拟合不同河段湿地沉积物吸附4种重金属(Ni²⁺、Cu²⁺、Zn²⁺和Cd²⁺)的热力学过程(R²≥0.71).不同样点对Ni²⁺、Cu²⁺、Zn²⁺和Cd²⁺的吸附能力整体以河口区最高,城市河段次之,淡水河段最低,解吸能力则与之相反,这主要与沉积物颗粒组成(黏粒)及pH值的差异有关.从淡水河段至河口区(A～F),不同样点0～40 cm土层对Ni²⁺、Cu²⁺、Zn²⁺和Cd²⁺的解吸量均随吸附量的增加而升高.随着pH值的增加,Ni²⁺、Cu²⁺、...