Keinänen M, Peuranen S, Tigerstedt C, Vuorinen P J
Finnish Game and Fisheries Research Institute, Helsinki, Finland.
Ecotoxicol Environ Saf. 1998 May-Jun;40(1-2):166-72. doi: 10.1006/eesa.1998.1658.
Anadromous whitefish [Coregonus lavaretus (L.)] were exposed during the yolk-sac phase to combinations of pH values of 6.0, 5.5, 5.0, 4.5, and 4.0 and nominal Al concentrations of 0, 100, 200, and 400 micrograms liter-1 for 4 days. The test waters were: (1) lake water diluted 1:1 with ion exchanged water (DLW) and (2) artificial water (AW). The major differences were: [Ca2+] 0.069 mmol liter-1 in DLW versus 0.034 mmol liter-1 in AW, [Na+] 1.5 and [Cl-] 1.8 times higher in DLW, with no dissolved organic material in AW. The fry were sampled daily for the analysis of exchangeable body Na+ and Cl- contents, and the swimming activity and mortality were registered. Aluminum initially protected yolk-sac fry against acidic water at pH 4.0 both in DLW and in AW. Generally, however, an increase in [Al] and a decrease in pH increased the adverse effects, seen as decreased exchangeable body Na+ and Cl- content, decreased swimming activity, and increased mortality. The effects of Al were more pronounced in AW compared with DLW. In AW, the Na+ and Cl- content of the fry already decreased after 1 day of exposure to a level that predicts mortalities. There was a time trend in DLW toward decreasing exchangeable body Na+ and Cl- concentrations as a function of increasing acidity and [Al]. In DLW, mortalities occurred primarily at pH 4.0; at that pH value in AW, the mortality rate was even higher, and mortalities also occurred after 2 to 4 days at all other pH values. There was a threshold limit in exchangeable body Na+ and Cl- concentrations at which yolk-sac fry became passive; it was at approximately 0.3 mumol per fry in DLW and was slightly higher in AW. In the DLW control with moderate ionic strength, the Na+/Cl- ratio was above 1 from the second exposure day on but remained closer to 1 in soft AW control. The Na+/Cl- ratio was predominantly > 1 in AW when the fry were exposed to moderate acidities but approached 1 at pH values < 5.0. The Na+/Cl- ratio was mostly < or = 1 in DLW, irrespective of the exposure, indicating cation selectivity of ion leakage pathways in slightly harder water.
溯河洄游型白鲑[Coregonus lavaretus (L.)]在卵黄囊期暴露于pH值为6.0、5.5、5.0、4.5和4.0以及名义铝浓度为0、100、200和400微克/升的组合环境中，持续4天。试验用水为：(1)用离子交换水按1:1稀释的湖水(DLW)和(2)人工水(AW)。主要差异在于：DLW中的[Ca2+]为0.069毫摩尔/升，而AW中的为0.034毫摩尔/升，DLW中的[Na+]和[Cl-]分别高出1.5倍和1.8倍，且AW中没有溶解有机物质。每天对鱼苗进行采样，分析其体内可交换的Na+和Cl-含量，并记录游泳活动和死亡率。在DLW和AW中，铝最初都能保护卵黄囊期鱼苗免受pH 4.0的酸性水影响。然而，总体而言，[Al]的增加和pH的降低会增加不利影响，表现为体内可交换的Na+和Cl-含量降低、游泳活动减少以及死亡率增加。与DLW相比，铝在AW中的影响更为明显。在AW中，鱼苗暴露1天后，其Na+和Cl-含量就已降至预测死亡率的水平。在DLW中，随着酸度和[Al]的增加，体内可交换的Na+和Cl-浓度有下降的时间趋势。在DLW中，死亡率主要发生在pH 4.0时；在该pH值下，AW中的死亡率更高，并且在所有其他pH值下，2至4天后也会出现死亡。体内可交换的Na+和Cl-浓度存在一个阈值，低于该阈值卵黄囊期鱼苗会变得被动；在DLW中约为每尾鱼苗0.3微摩尔，在AW中略高。在具有中等离子强度的DLW对照中，从第二次暴露日起Na+/Cl-比值就高于1，但在软AW对照中更接近1。当鱼苗暴露于中等酸度时，AW中的Na+/Cl-比值主要>1，但在pH值<5.0时接近1。无论暴露情况如何，DLW中的Na+/Cl-比值大多≤1，这表明在略硬的水中离子泄漏途径具有阳离子选择性。
