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文章调查了东寨港红树林湿地近岸海水及潮间带表层沉积物汞(Hg)和砷(As)化学形态组成及分布。采用改进BCR逐级提取法分析沉积物中2种元素的化学形态。结果表明,海水中Hg和As主要以溶解态存在,夏季2种元素悬浮颗粒态的比例明显高于冬季,海水中ρ(Hg)明显超过国家一类海水水质标准,且夏季污染水平高于冬季。潮间带沉积物中w(Hg)为0.141~0.331 mg/kg,w(As)为10.226~27.020 mg/kg,采样点S6沉积物中w(Hg)和w(As)较其他采样点高,表现出受陆源输入影响;沉积物中Hg和As的化学形态组成存在差异,Hg主要以残渣态和酸可提取态存在,酸可提取态Hg的比例为21.0%~47.6%,存在一定的潜在环境风险。As主要以残渣态存在,环境风险相对较小。
In this paper, chemical composition and distribution of mercury (Hg) and arsenic (As) in sediment and intertidal zone of mangrove wetlands of Dongzhaigang were investigated. The chemical composition of two elements in sediment was analyzed by improved BCR stepwise extraction. The results showed that Hg and As in seawater mainly existed in dissolved state, and the proportion of suspended particles in the two elements was significantly higher in summer than in winter. The ρ (Hg) in seawater obviously exceeded the national first-class seawater quality standard and the pollution level in summer was higher than in winter . In the intertidal sediments, w (Hg) was 0.141-0.331 mg / kg and w (As) was 10.226-27.020 mg / kg. The w (Hg) and w , Which is affected by terrestrial input. The chemical composition of Hg and As in sediments is different. Hg mainly exists in residual and acid extractables, and the proportion of acid extractable Hg is 21.0% -47.6% Potential environmental risk. As mainly exists in the residue state, the environmental risk is relatively small.