潮滩沉积物重金属污染的色度反演方法初探

A new assessment method of heavy metal pollution in tidal flat sediments using color indexes

为了探求快速评估土壤重金属污染的方法,以崇明岛东滩低、中、高潮滩沉积物为研究对象,用色度仪测量其色度参数(明度L*、红度a*、黄度b*),并对照化学分析数据,初步探讨了潮滩沉积物的色度特征与重金属元素(Cu、Cr、Pb、Zn、Mn、Fe)含量之间的相关关系.同时,运用回归分析分别建立了重金属元素含量与色度参数(明度L*、红度a*、黄度b*)之间的定量关系模型,并对模型进行验证.结果表明,在崇明岛低、中、高潮滩的沉积物中,Cu、Pb、Zn与L*之间负相关,相关系数最高可达rCu=-0.97、rPb=-0.88、rZn=-0.98;Cu、Pb、Zn与a*之间正相关;而Cr与a*之间负相关.在河口水体中重金属含量稳定的条件下,色度信息可以定量地反演潮滩沉积物重金属元素的含量,为大范围的潮滩重金属污染研究提供了一项实用有效的辅助手段.

Environmental monitoring methods for environmental protection of tidal flats is an important topic in wetland research. To search for a rapid assessment method of soil heavy metal contamination, in this work a color index system （ L＊ , a ＊ , b ＊ ） was designed to evaluate the concentration of heavy metals （Cu, Cr, Pb, Zn, Mn, Fe ） in the sediments of Chongming Dongtan. The results indicated a strong correlation between the color indexes and heavy metal contents in sediments, which implies that the content of heavy metals in sediments can potentially be quantitatively deduced from the sediment color indexes. Regression models between the color indexes and the heavy metal concentrations were established and tested. In the low, middle and high beach sediments of Chongming Dongtan, there were significant negative correlations between Cu, Pb, Zn and L＊ , with the highest correlation coefficient of Cu being -0.97, of Pb being -0.88 and of Zn being -0. 98 ; there were significant positive correlations between Cu, Pb, Zn and a＊ , but there were significant negative correlations between Cr and a ＊. This work shows that when the heavy metal content in the estuary is stable, the color indexes can be rapid, efficient and useful proxies for detailed, large - scaled surveys or monitoring of heavy metal pollution in tidal flat sediments.