Kim H S, Park J
Department of Environmental Engineering, Chungbuk National University, Cheongju, 361-763, Korea.
Environ Technol. 2008 Apr;29(4):375-80. doi: 10.1080/09593330801984571.
This paper describes a study on the role of limestone on the dissolution of phosphates when phosphate-containing sediments are put under anaerobic conditions. Anaerobic decomposition of organic substances produces both organic acids and carbonic acids which in turn could accelerate the dissolution of the phosphates. If limestone coexisted, both phosphate and limestone would compete as receptors of hydrogen ions so as to affect the dissolution of phosphate. A small quantity of calcium hydroxyapatite, alone or mixed with limestone powder, was put in contact with an aqueous solution of acetic acid or carbonic acid and the variations in phosphate concentration were determined over time. The results showed that the phosphate concentration was remarkably low in the case of limestone presence, in comparison with the case of limestone absence. This signifies that the coexistence of limestone suppresses the dissolution of phosphate by organic acid and/or carbonic acid. Separate experiments conducted by developing an anaerobic condition, after mixing lake sediments with dried leaves and limestone, allowed us to observe that the existence of limestone suppressed the dissolution of phosphate. It seems that the limestone acts as a material sacrificing to the leaching of hydrogen ions from the acids produced under anaerobic conditions. These results show that the application of limestone might be a useful measure to prevent deterioration of water quality through eutrophication, by breaking the internal loading of phosphates in eutrophic water bodies.
本文描述了一项关于当含磷沉积物处于厌氧条件下时，石灰石对磷酸盐溶解作用的研究。有机物质的厌氧分解会产生有机酸和碳酸，进而加速磷酸盐的溶解。如果石灰石共存，磷酸盐和石灰石都会作为氢离子受体相互竞争，从而影响磷酸盐的溶解。将少量羟基磷灰石单独或与石灰石粉末混合，使其与醋酸或碳酸水溶液接触，并测定随时间变化的磷酸盐浓度。结果表明，与不存在石灰石的情况相比，存在石灰石时磷酸盐浓度显著较低。这表明石灰石的共存抑制了有机酸和/或碳酸对磷酸盐的溶解。通过将湖泊沉积物与干树叶和石灰石混合后营造厌氧条件进行的单独实验，使我们观察到石灰石的存在抑制了磷酸盐的溶解。似乎石灰石充当了一种牺牲材料，用于消耗厌氧条件下产生的酸中的氢离子。这些结果表明，通过打破富营养化水体中磷酸盐的内负荷，施用石灰石可能是防止水质因富营养化而恶化的一种有效措施。
