Mobilization of toxic forms of aluminum (Al_i) have been one of the most harmful effects of acidic deposition on aquatic ecosystems. Large decreases in acidic deposition levels have resulted in decreases in Al_i concentrations in surface waters starting in the 1990s. However, recent studies indicate that fish communities are still being impaired by elevated Al_i concentrations in streams, suggesting the need for a present-day assessment of the recovery status of Al chemistry in impacted regions such as the Adirondack region of New York, United States. Therefore, the recovery status of Al was assessed from long-term high-frequency monitoring of three Adirondack streams up through 2019, and multiple resampling of 127 headwater streams throughout the Adirondack region between 2004/2005 and 2018/2019. Results indicated that concentrations of Al_i have continued to decrease throughout the Adirondack region, but that harmful conditions still exist in a substantial number of streams during spring snowmelt. In the western Adirondack region, 35 percent of streams during spring snowmelt, (typically the most acidic period), and 10 percent of streams during summer were still experiencing harmful concentrations of Al_i (>1.0 μmol L⁻¹) in 2018/2019. In the less-impacted east-central Adirondack region, 10 percent of streams during snowmelt, and 4 percent of streams during summer were experiencing harmful Al_i concentrations in 2018. Temporal decreases in Al_i concentrations were due in part to a shift in speciation from Al_i to non-toxic organically complexed Al as dissolved organic carbon concentrations increased, which was also a response to decreasing acidic deposition. Increased availability of calcium resulting from acid-neutralization processes such as weathering also contributed to the decrease in Al_i over the past 5–8 years. The current low levels of acidic deposition may have begun to enhance recovery by increasing the effectiveness of ambient acid-neutralization processes.

动员有毒形式的铝（Al _i）是酸性沉积对水生生态系统的最有害影响之一。从1990年代开始，酸性沉积水平的大幅度下降导致地表水中Al _i的浓度下降。但是，最近的研究表明，鱼类种群仍然受到Al _i升高的损害。浓度的变化，表明有必要对受影响地区（例如美国纽约的阿迪朗达克地区）的铝化学回收状况进行当今评估。因此，通过对直到2019年的三条阿迪朗达克溪流的长期高频监测，以及在2004/2005年至2018/2019年之间对整个阿迪朗达克地区的127个源头水流进行多次重采样，对铝的回收状态进行了评估。结果表明，Al _i的浓度在整个阿迪朗达克地区，这种现象一直在减少，但是在春季融雪期间，大量溪流中仍然存在有害条件。在阿迪朗达克（Adirondack）西部地区，春季融雪（通常是最酸性的时期）中有35％的溪流和夏季期间有10％的溪流仍在2018/2019年经历有害浓度的Al _i（> 1.0μmolL ^-1）。在-影响少东中央阿迪朗达克区域，融雪期间流的10％，和在夏季流的4％正经历有害的Al_我浓度在2018年时空以Al降低_我浓度部分是由于从在形态的移位人_我随着溶解有机碳浓度的增加，对无毒有机络合铝的吸收也增加，这也是对酸性沉积物减少的一种响应。在过去5-8年中，酸中和过程（如风化）导致钙的可用性增加，也导致Al _i的减少。当前的低水平酸性沉积可能已经开始通过提高环境酸中和过程的有效性来提高回收率。