CaCl_2、NaHCO_3和盐酸降pH的效果及其对水质的影响

PERFORMANCE OF CaCl_2, NaHCO_3 AND HYDROCHLORIC ACID INREDUCING pH VALUE AND THEIR EFFECTS ON WATER QUALITY

本文于1998年8—10月间选取山东省高青县赵店乡大芦湖养殖公司院内一口盐碱池塘的池水为实验用水，选用CaCl2、NaHCO3和盐酸作试剂，进行了这三种试剂的降pH值实验。实验结果表明：NaHCO3有降pH效果须高浓度使用，但会使水体缓冲能力下降，不宜作为降pH的试剂。盐酸能迅速降低pH，但持续时间较短，适合急救时使用。219kg．ha-1（14．6kg／亩）的用量可降低pH1．5个单位。能长期地降低pH值的理想方法是施用CaCl2。CaCl2能迅速降低pH，增强水体的缓冲能力，对浮游植物生物量无显著影响，但能提高浮游植物多样性；高浓度的钙离子会降低浮游动物生物量和多样性指数。用量为2190kg．ha－1（147kg／亩）可降低pH1个单位。

The experiment was conducted in Daluhu Aquaculture Company , Gaoqing County, Shandong Province during August and December, 1998. It was aimed at study on the performance of CaCl2,NaHCO3 and hydrochloric acid in the reduce of pH Value ,and the effects of application of CaCl2 on chemical and hydrobiology factors. The results show: Only by high application rates could NaHCO3 reduce pH, furthermore it decreased the buffering capacity of brackish water. Therefore it cannot be used to reduce pH value. Hydrochloric acid reduced pH rapidiy, but the duration was short. So it was fit to be used under emergent case. Application rates of 219kg.ha-1 can reduce pH by one and a half unit. The ideal method of reduching pH value was application of CaCl2. It reduced pH rapidly, at the same time raised the buffering capacity of brackish-water. No significant effects on plankton biomass had been observed, but it maintained the variety of plankton. High concentrations of calcium reduced the biomass and variety of zooplankton. So CaCl2 should be use at low concentrations. Application rates of 2190 kg.ha-1 can reduce pH value by one unit.