Department of Biology, McMaster University, Life Science Building 208, 1280 Main St. W., Hamilton, ON, L8S 4K1, Canada,
Ecotoxicology. 2014 Mar;23(2):147-62. doi: 10.1007/s10646-013-1159-5. Epub 2014 Jan 9.
Traditionally, water quality guidelines/criteria are based on lethality tests where results are expressed as a function of waterborne concentrations (e.g. LC50). However, there is growing interest in the use of uptake and binding relationships, such as biotic ligand models (BLM), and in bioaccumulation parameters, such as critical body residue values (e.g. CBR50), to predict metal toxicity in aquatic organisms. Nevertheless, all these approaches only protect species against physiological death (e.g. mortality, failed recruitment), and do not consider ecological death which can occur at much lower concentrations when the animal cannot perform normal behaviours essential for survival. Therefore, we investigated acute (96 h) Ni toxicity in two freshwater fish species, the round goby (Neogobius melanostomus) and rainbow trout (Oncorhynchus mykiss) and compared LC, BLM, and CBR parameters for various organs, as well as behavioural responses (spontaneous activity). In general, round goby were more sensitive. Ni bioaccumulation displayed Michaelis-Menten kinetics in most tissues, and round goby gills had lower Kd (higher binding affinity) but similar Bmax (binding site density) values relative to rainbow trout gills. Round goby also accumulated more Ni than did trout in most tissues at a given exposure concentration. Organ-specific 96 h acute CBR values tended to be higher in round goby but 96 h acute CBR50 and CBR10 values in the gills were very similar in the two species. In contrast, LC50 and LC10 values were significantly higher in rainbow trout. With respect to BLM parameters, gill log KNiBL values for bioaccumulation were higher by 0.4-0.8 log units than the log KNiBL values for toxicity in both species, and both values were higher in goby (more sensitive). Round goby were also more sensitive with respect to the behavioural response, exhibiting a significant decline of 63-75 % in movements per minute at Ni concentrations at and above only 8 % of the LC50 value; trout exhibited no clear behavioural response. Across species, diverse behavioral responses may be more closely related to tissue Ni burdens than to waterborne Ni concentrations. To our knowledge, this is the first study to link Ni bioaccumulation with behavioural endpoints. In future it would be beneficial to expand these analyses to a wider range of species to determine whether Ni bioaccumulation, specifically in the gills, gut and whole fish, may be a good predictor of behavioural changes from metal exposure; which in the wild can lead to ecological death.
传统上，水质准则/标准是基于致死性测试，其结果表示为水相浓度的函数（例如 LC50）。然而，人们越来越感兴趣的是使用摄取和结合关系，如生物配体模型 (BLM)，以及生物蓄积参数，如临界体残留值 (例如 CBR50)，来预测金属在水生生物中的毒性。然而，所有这些方法只能保护物种免受生理死亡（例如死亡率、招募失败），而不考虑生态死亡，当动物无法进行生存所必需的正常行为时，生态死亡可能会在更低的浓度下发生。因此，我们研究了两种淡水鱼类，圆鳍鱼（Neogobius melanostomus）和虹鳟鱼（Oncorhynchus mykiss）的急性（96 小时）镍毒性，并比较了各种器官的 LC、BLM 和 CBR 参数，以及行为反应（自发活动）。一般来说，圆鳍鱼更敏感。镍在大多数组织中的生物蓄积显示出米氏动力学，而相对于虹鳟鱼鳃，圆鳍鱼鳃的 Kd（更高的结合亲和力）较低，但 Bmax（结合位点密度）值相似。在给定的暴露浓度下，圆鳍鱼在大多数组织中积累的镍也多于鳜鱼。特定于器官的 96 小时急性 CBR 值在圆鳍鱼中往往更高，但在两种物种中，鳃的 96 小时急性 CBR50 和 CBR10 值非常相似。相反，LC50 和 LC10 值在虹鳟鱼中显著更高。关于 BLM 参数，两种物种的生物蓄积的鳃 log KNiBL 值比毒性的 log KNiBL 值高 0.4-0.8 个对数单位，而鳜鱼的 log KNiBL 值（更敏感）更高。圆鳍鱼在行为反应方面也更敏感，在镍浓度达到和高于 LC50 值的 8%时，每分钟的运动次数显著下降 63-75%；鳜鱼没有明显的行为反应。在不同的物种中，各种行为反应可能与组织中的镍负荷比水相中镍浓度更密切相关。据我们所知，这是首次将镍生物蓄积与行为终点联系起来的研究。在未来，将这些分析扩展到更广泛的物种范围将是有益的，以确定镍生物蓄积，特别是在鳃、肠道和整个鱼类中的蓄积，是否可以很好地预测金属暴露引起的行为变化；在野外，这可能导致生态死亡。
