Kevan S D, Dixon D G
Department of Biology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada.
Ecotoxicol Environ Saf. 1996 Dec;35(3):288-93. doi: 10.1006/eesa.1996.0113.
Thiocyanate (SCN-) is released to the aquatic environment as a result of the treatment of cyanide-bearing wastes from precious-metal mining activity. During continuous exposure alevin rainbow trout (1- and 10-day-old) were approximately 90% more tolerant of SCN- than juveniles (2-month-old). Pulse exposure of alevins for periods > or = 48 hr were required before postexposure stress reduced tolerance (by approximately 30%) in the 24-hr period following exposure. In contrast, stressing of juveniles after exposures of > or= 9 hr consistently reduced tolerance by approximately 60%. While coion (K+ or Na+ for SCN- derived from either KSCN or NaSCN) had no influence on SCN- toxicity for alevins, juveniles exhibited reduced tolerance in the presence on Na+. Although sudden death syndrome was apparent in juveniles, none occurred with alevins. Overall, juveniles were less tolerant of SCN- than alevins, possibly because of the enhanced efficiency of SCN- uptake by gill respiration versus the predominantly vitelline membrane respiration of alevins.
由于对贵金属开采活动中含氰废物的处理，硫氰酸盐（SCN-）被释放到水生环境中。在持续暴露期间，初孵虹鳟（1日龄和10日龄）对SCN-的耐受性比幼鱼（2月龄）高约90%。在暴露后应激使暴露后24小时内的耐受性降低（约30%）之前，需要对初孵虹鳟进行大于或等于48小时的脉冲暴露。相比之下，暴露9小时以上后对幼鱼施加应激会持续使耐受性降低约60%。虽然共离子（由KSCN或NaSCN产生的SCN-的K+或Na+）对初孵虹鳟的SCN-毒性没有影响，但在有Na+存在的情况下，幼鱼的耐受性会降低。虽然幼鱼中明显出现了猝死综合征，但初孵虹鳟中未出现。总体而言，幼鱼对SCN-的耐受性低于初孵虹鳟，这可能是因为通过鳃呼吸摄取SCN-的效率提高，而初孵虹鳟主要通过卵黄膜呼吸。
