黄海中部泥质区沉积物中重金属的 长期变化及其背景值的校正

Calibration of Long-Term Change of Heavy Metal Content and the Heavy Metal Background in the Muddy Area of the Middle Yellow Sea Sediments of China

中文关键词: 长期记录  沉积物  重金属  背景值  比表面积

英文关键词: Long sedimentary record  Sediment  Heavy metal  Background content  Specific surface area

中文摘要:

      为校正黄海中部泥质区沉积物中重金属的长期变化及其背景值，对采自黄海中部泥质区A03站位沉积剖面的年代学测定、比表面积和重金属(Cu、Pb、Cd和Zn)进行了测定，并在假定第一次工业革命以前的沉积环境基本未受污染的前提下，建立了其比表面积与重金属背景值的函数模型，进而反推出单位比表面积下重金属的长期变化特征。将重金属含量实测值和校正后单位比表面积下重金属含量长期变化比较发现，前者毫无规律可言，后者则在20世纪50年代以前，基本处于重金属含量背景值的合理波动范围之内，此后，逐渐背离背景值至今。可以推断，A03站位所代表的黄海中部泥质区受到外源重金属污染的起始年份约为1950年，4种重金属Cu、Pb、Cd、Zn单位比表面积下的背景值分别为26.31、22.11、0.20、63.21 mg/kg。许多研究表明，沉积环境的外源性污染、沉积颗粒的表面活性和粒度是重金属含量偏离背景值的3个主要原因。本研究应用相同沉积剖面，建立了第一次工业革命以前的比表面积与重金属背景值的函数模型，并对重金属含量的实测值进行了有效校正，无疑是能够同时满足上述3个主要条件的。研究表明，实际操作中，采取不同沉积类型区域，建立相应的重金属背景校正值，也是可行的。

英文摘要:

      In order to calibration the long-term change of heavy metal content and the heavy metal background in the muddy area of the middle Yellow Sea sediment of China, we combined with the contents of heavy metals (Cu, Pb, Cd, Zn), 210Pb data and the specific surface area (SS) of core A03 from the Huanghai Sea to structure the function models of the heavy metals (Cu, Pb, Cd, Zn) background. With the function models, we calculated the long-term change of the content of the heavy metals in the same SS in core A03. We compared with the content of the heavy metals in the same SS versus the content of heavy metals, showed a obvious demarcation point between them, in 100 cm. The trend is similar with a ideal sediment profile, which means that the starting point of contamination is around 100 cm. Calculated by deposition rate, the sediment age in the 100cm of the core is much older than 200 years. The average value of heavy metal contents under a single specific surface area (SS) below 100 cm without human pollution is taken as the background value of heavy metal Cu, Pb, Cd and Zn at station A03. The background of them are 26.31 mg/kg, 22.11 mg/kg, 0.20 mg/kg and 63.21 mg/kg, respectively. Compared with the nearby sea area, the background of heavy metals is similar. Compared with historical events, the variation characteristics of the heavy metals content under a single specific surface area correspond to major coastal historical events, which means that the estimation reduced the impacts from the provenance and particle characteristics of the sediments on the heavy metals content and that it provides a reference useful for increasing the veracity of evaluation of heavy metals contamination.