HAO Feng，QIN Yong，YU Ningxiao，WANG Fushun
（School of Environmental and Chemical Engineering, Shanghai University, Shangda Road 99, Baoshan, Shanghai 200444, China）

Abstract: At present, the determination of the biogenic silica (BSi) content in sediments is problematic in terms of time-consuming, cumbersome steps, large workload and lack of internationally uniform standard samples. In this paper, the alkaline continuous extraction method was used to analyze the BSi content of surface sediments in reservoirs of the Guizhou Karst Area. The result found that the measured contents of BSi by different extraction solutions of 0.1mol/L, 0.5 mol/L and 1mol/L Na2CO3 were consistent, and the accuracy of the Demaster slope intercept method was verified by the silicon-aluminum intercept method. The results showed that 0.1 mol/L Na2CO3 solution is the most suitable for extraction and determination of biogenic silica in sediments from this area. At the same time, this study compared advantages and disadvantages of the multi-point method and the single-point method, and pointed out that, when the extraction time is set within 15 to 30 minutes, in addition to saving analysis time, the single-point method gives the more accurate result of the biogenic silica content than the traditional 5 h extraction method.

Key words：Biogenic silica；silicon-aluminum slope method；multi-point method；single-point method

EARTH AND ENVIRONMENT Vol.47, No.6, Tot No.332, 2019, Page 864