State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2017 Nov 15;598:900-909. doi: 10.1016/j.scitotenv.2017.04.070. Epub 2017 Apr 27.
A number of studies have revealed ammonia to be toxic to aquatic organisms; however, little is known about its effects under natural conditions. To elucidate the role of ammonia, we conducted 96-h acute toxicity tests as well as a whole-ecosystem chronic toxicity test for one year in ten 600-m ponds. Three common cyprinids, silver carp Hypophthalmichthys molitrix Val. (H.m.), bighead carp Aristichthys nobilis Richardson (A.n.), and gibel carp Carassius auratus gibelio Bloch (C.g.), were used as test organisms. The 96-h LC values of un-ionized ammonia (NH) for H.m., A.n., and C.g. were 0.35, 0.33, and 0.73mgL, respectively. In the ponds, annual mean NH ranged between 0.01 and 0.54mgL, with 4 ponds having a NH higher than the LC of A.n. (lowest LC in this study). No fish were found dead in the high-nitrogen ponds, but marked histological changes were found in livers and gills. Despite these changes, the specific growth rate of H.m. and A.n. increased significantly with NH. Our pond results suggest that fish might be more tolerant to high ammonia concentrations in natural aquatic ecosystems than under laboratory conditions. Our finding from field experiments thus suggests that the existing regulatory limits for reactive nitrogen (NH) established from lab toxicity tests might be somewhat too high at the ecosystem conditions. Field-scale chronic toxicity tests covering full life histories of fish and other aquatic organisms are therefore encouraged in order to optimize determination of the effects of ammonia in natural environments.
已有多项研究表明氨对水生生物具有毒性；然而，目前对于其在自然条件下的影响知之甚少。为了阐明氨的作用，我们在 10 个 600 平方米的池塘中进行了为期一年的 96 小时急性毒性试验和全生态系统慢性毒性试验。三种常见的鲤科鱼类，包括白鲢 Hypophthalmichthys molitrix Val.（H.m.）、鳙鱼 Aristichthys nobilis Richardson（A.n.）和异育银鲫 Carassius auratus gibelio Bloch（C.g.）被用作试验生物。H.m.、A.n.和 C.g.的非离子氨（NH）96 小时 LC 值分别为 0.35、0.33 和 0.73mgL。在池塘中，年平均 NH 浓度在 0.01 至 0.54mgL 之间，有 4 个池塘的 NH 浓度高于本研究中 A.n.的 LC（最低 LC）。在高氮池塘中没有发现鱼类死亡，但在肝脏和鳃中发现了明显的组织学变化。尽管存在这些变化，但 H.m.和 A.n.的特定生长率随着 NH 的增加而显著增加。我们的池塘结果表明，鱼类在自然水生生态系统中可能比在实验室条件下更能耐受高氨浓度。因此，我们从野外实验中得出的结论表明，根据实验室毒性试验确定的活性氮（NH）的现有监管限值在生态系统条件下可能有些过高。因此，鼓励进行涵盖鱼类和其他水生生物完整生命史的现场慢性毒性试验，以便优化对自然环境中氨影响的确定。
