珠江口沉积物中生物有效性硅的赋存形态及释放研究

Study on the Species of Silica Bioavailability in Pearl River Estuary Sediment and Release Experiments

运用ATessier逐步化学连续提取法,研究了珠江口沉积物中各种生物有效性硅:Ⅰ-可交换离子态、Ⅱ-碳酸盐结合态、Ⅲ-铁锰氧化物结合态、Ⅳ-有机质和硫化物结合态。研究表明:表层沉积物中,Ⅲ为优势赋存态。在沉积柱C2中,Ⅲ>Ⅳ>Ⅱ>Ⅰ,Ⅰ、Ⅱ随深度变化无规律性,Ⅲ随深度先升高后下降,Ⅳ表层含量较高,到达一定深度(18cm左右)后骤降。释放试验表明:振荡在一定时间内有利于硅释放;而盐度对硅释放的影响比较复杂,低盐度(5‰以内),随盐度升高,释放量下降。当盐度继续升高时释放量又增加,但高盐度对硅释放影响不大;硅的释放在pH值=3～8范围内随着pH值升高而减少。

A Tessier sequential chemical extraction methods have been introduced to study the distribution of species of silica bioavailability in Pearl River Estuary sediment： Ⅰ -exchangeable, Ⅱ-bound to cachonates, Ⅲ -bound to Fe-Mn oxides and IV-bound to organic matter and sulfide, m is predominant over the rest of other species. The content of four different species in sediment core C2 is Ⅲ〉Ⅳ〉 Ⅱ 〉 Ⅰ. Ⅰ and Ⅱ contained in the core C2 vary irregularly with the increase of depth. Ⅲ first tends to increase and then decrease. Ⅳ near the surface is relatively high, after reaching the depth of 18 cm, it drops sharply. In the release experiment, vibration helps to release silica within a certain period; the influence of salinity on the release of silica is relatively complex, in low salinity scope （about within 5‰）, the content of released silica varies negatively with the increase of salinity, subsequently dissolved silica tend to increase in line with ascending salinity, but relatively high salinity have little influence on silica release. While pH places an significantly opposite role on the release of silica with the increase of pH between 3 - 8.