几种盐碱因子对青蛤的致毒效应

Toxic effects of several saline-alkali factors on Cyclina sinensis

盐碱水具有缓冲性能差、主要离子比例不稳定、碳酸盐碱度(Carbonate Alkalinity,CA)和pH高等特点。青蛤(Cyclina sinensis)生长快、抗逆性强、耐盐范围广,是一种在盐碱水中颇具养殖前景的品种。寄予为今后在盐碱水中开展青蛤养殖提供数据的目的,本文应用静态急性毒性实验的方法,研究了96 h内水体中不同K+、Ca2+、Mg2+浓度及CA和pH对青蛤死亡率的影响。结果显示:当K+浓度低于11.3 mg.L-1(对照水平的1/22)和高于838.7 mg.L-1(对照水平的3.34倍)时,青蛤的死亡率均超过了90%;其半致死浓度(LC50)分别为40.8 mg.L-1和541.2 mg.L-1。当Ca2+浓度为4.5 mg.L-1(对照水平的1/64)和4 600 mg.L-1(对照水平的16倍)时,其死亡率均为34%左右。当Mg2+浓度为0和3078 mg.L-1(对照水平的3.38倍)时,其死亡率均仅为8.5%左右。CA方面,其值低于40 mmol.L-1时,青蛤的死亡率不超过5%,其值为80 mmol.L-1时,青蛤的死亡率也仅为20%。而pH方面,其值超过9.5时,青蛤开始急剧死亡。研究认为:影响青蛤存活的主要限制因子为K+和pH。此外,青蛤对CA的耐受性较强,表明其确实具有在盐碱水中开展养殖的前景。

Saline-alkali water is a high pH type of water with poor buffer capacity,unstable proportion of major ions and high carbonate alkalinity（CA）.While clam Cyclina sinensis,with fast growth,strong resistance and wide salt tolerance,is a promising bivalve species for cultivation in the saline-alkali water.To provide data for the aquaculture possibility of introducting C.sinensis to saline-alkali water,the toxic effects of several saline-alkali factors,including K＋,Ca2＋,Mg2＋,CA and pH on C.sinensis within 96 h by static acute toxicity test were investigated.The results showed that the mortalities of C.sinensis were both more than 90% when K＋ concentration was lower than 11.3 mg·L-1（1/22 times that of control level） or was higher than 838.7 mg·L-1（3.34 times that of control level）.The semi-lethal concentrations（LC50） by low and high K＋ stress were 40.8 mg·L-1 and 541.2 mg·L-1,respectively.While the mortalities were both about 34% when the Ca2＋ concentration was 4.5 mg·L-1（1/64 times that of control level） or was 4 600 mg·L-1（16 times that of control level）.For Mg2＋,the mortalities were both only 8.5% when its concentration was 0 mg·L-1 or was 3 078 mg·L-1（3.38 times that of control level）.For CA,the mortality was less than 5% when its value was lower than 40 mmol·L-1,besides,even its CA value was 80 mmol·L-1,the mortality was just only 20%.Finally,for pH,C.sinensis died out rapidly when its value was over 9.5.In conclusion,the main limiting factors affecting C.sinensis survival were K＋ and pH.Moreover,C.sinensis has wide CA tolerance,further suggesting that it has potential prospects for aquaculture in the saline-alkali water.