浙江近岸海域海水和沉积物中铬形态分布特征研究

Study on the distribution characteristics of chromium speciation in seawater and sediments in the Zhejiang coastal area

本研究在浙江近岸4个海域开展同步采样和观测,分析海水和沉积物中铬(Cr)形态分布特征。结果表明,表层海水总Cr浓度范围为0.405~0.653μg/L,Cr(Ⅵ)浓度范围为0.009~0.087μg/L;底层海水总Cr浓度范围为0.426~0.638μg/L,Cr(Ⅵ)范围为0.005~0.099μg/L,海水中Cr形态含量分布与深度无相关性。沉积物中Cr含量范围为50~82 mg/kg,以残渣态为主;有效态Cr的含量大小依次为有机结合态Cr>铁锰氧化物结合态Cr>离子交换态Cr>碳酸盐结合态Cr;沉积物中水溶态Cr(Ⅵ)含量范围为2.99~11.71μg/kg,小于0.02 mg/kg。上述结果表明,浙江近岸海域环境存在一定程度的Cr污染,但水溶态Cr(Ⅵ)含量低,潜在风险较小。

Simultaneous sampling and observation were conducted in Zhejiang coastal area. The distribution characteristics of chromium in water and sediments were analyzed. The results showed that the total contents of chromium in surface water and bottom water were 0.405~0.653 μg/L and 0.426~0.638 μg/L, respectively.And the contents of Cr(Ⅵ) in surface water and bottom water were 0.009~0.087 μg/L and 0.005~0.099 μg/L.The distribution of chromium species in seawater had no correlation with depth. The effective state and residue state chromium were the main existing form of chromium in sediments, and the residual chromium accounts for more than 85%. The content of different forms of effective state chromium in the sediment was organic bound state chromium > iron-manganese oxide bound state chromium > ion exchangeable state chromium > carbonate bound state chromium. The total contents of chromium in sediments was 50~82 mg/kg and the contents of Cr(Ⅵ) in sediments was 2.99~11.71 μg/kg, less than 0.02 mg/kg. The above results indicate that there was a certain degree of chromium pollution in Zhejiang coastal area, while the content of water-soluble hexavalent chromium was low and the potential hazards of chromium was small.