Freshwater acidification is characterised by elevated concentrations of aqueous aluminium. Global emissions of acidifying agents are reduced due to international agreements, and freshwater acidification has shifted from chronic to a more episodic character. The recovery of fish populations in acidified areas is likely to depend on the individual’s ability to recover from short-time aluminium exposures. We exposed brown trout (Salmo trutta) to an Al-rich medium, nominal concentration 600 µg L^–1, for 0.5, 2, 6, 8 and 11 hours, before transfer to circumneutral Al-poor water for recovery. As controls, fish were either exposed for 11 hours to an acidified Al-poor medium or to untreated water. Some mortality during the first 24 hours of the recovery period occurred in fish exposed for 11, 8 and 6 hours to aluminium. No mortality during recovery was observed in the remaining groups. Aluminium exposure led to increased haematocrit and plasma lactate concentration, decreased plasma chloride concentration, deposition of aluminium on gill surfaces, and morphological alteration of the gill structures. The responses depended on exposure time. Aluminium deposited on the gill disappeared and plasma lactate levels were at control levels after 1 day in the recovery water, while haematocrit and plasma chloride levels were at control levels after 14 days of recovery. Gills in fish exposed to aluminium for 11 hours were almost fully recovered after 14 days. We conclude that the toxic response in brown trout exposed to an acutely toxic aluminium challenge is reversible. Moreover, the first 24 hours after aluminium exposures is the most critical period for the fish recovery. Further, it takes no more than 14 days for brown trout to fully recover from an acute toxic aluminium exposure, and only 1 day if the aluminium challenge is moderate.

淡水酸化的特点是铝水溶液浓度升高。根据国际协议，全球范围内酸化剂的排放量有所减少，淡水酸化已从长期性转变为更具偶发性。酸化地区鱼类种群的恢复可能取决于个人从短期铝暴露中恢复的能力。我们将鳟鱼（Salmo trutta）暴露于标称浓度为600 µg L ^–1的富铝培养基中转移0.5、2、6、8和11小时，然后转移至贫铝的水中以进行回收。作为对照，将鱼暴露在酸化的贫铝培养基中或未处理的水中11个小时。在铝暴露11、8和6小时后，鱼在恢复期的前24小时内发生了一些死亡。在其余组中未观察到恢复期间的死亡率。铝暴露导致血细胞比容和血浆乳酸浓度增加，血浆氯化物浓度降低，铝在g表面的沉积以及ill结构的形态变化。反应取决于暴露时间。1天后，在回收水中沉淀在ill上的铝消失了，血浆乳酸水平处于控制水平，恢复14天后，血细胞比容和血浆氯化物水平处于对照水平。14天后，暴露于铝中11小时的鱼中的几乎完全恢复了。我们得出结论，暴露于急性毒性铝挑战的褐鳟的毒性反应是可逆的。此外，铝暴露后的最初24小时是鱼类恢复的最关键时期。此外，褐鳟从急性有毒铝暴露中完全恢复所需的时间不超过14天，如果铝挑战为中度，则仅需要1天。铝暴露后的最初24小时是鱼类恢复的最关键时期。此外，褐鳟从急性有毒铝暴露中完全恢复所需的时间不超过14天，如果铝挑战为中度，则仅需要1天。铝暴露后的最初24小时是鱼类恢复的最关键时期。此外，褐鳟从急性有毒铝暴露中完全恢复所需的时间不超过14天，如果铝挑战为中度，则仅需要1天。