1.1 本试验方法涵盖了在pH为4和加入酸性缓冲液后老化3小时的萃取程序测定水中生物可利用铝。 1.2 该测试方法使用现有的分析方法测定水中的铝，仅提供了一种新的提取程序，旨在回收水样中存在的铝的生物可利用部分。 1.3 该测试方法旨在评估水样中铝对水生生物的潜在毒性。 1.4 本试验方法适用于含有溶解、聚合和矿物形式铝的水，适用浓度范围为0.01 mg/L至5 mg/L。 1.5 该测试方法在天然地表水和含有悬浮固体的废水上进行了测试。用户有责任确保本测试方法对未测试基质水的有效性。 1.6 已经获得了天然水、废水和试剂水的精密度和偏差。用户有责任确保本测试方法对未测试基质水的有效性。 1.7 单位- 以SI单位表示的值将被视为标准值。本标准不包括其他计量单位。 1.8 本标准并不旨在解决与其使用相关的所有安全性问题（如果有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践并确定法规限制的适用性。 1.9 本国际标准是根据国际公认的标准化原则制定的，该原则载于世界贸易组织技术性贸易壁垒委员会。 ======意义和用途====== 5.1 最近的研究结果调查了水化学和铝对水生生物的毒性之间的关系。毒性显示为pH、溶解有机碳（DOC）和硬度的函数。毒性试验中的生物反应与溶解的金属无关，因为在环中性水中（pH 6至8.5），铝以氢氧化物或矿物颗粒的形式存在，这两者都通过过滤去除。因此，过滤去除一些导致毒性的金属物质。 5.2 美国环境保护署(EPA)制定了铝的水质标准。美国许多州已采用这些标准，并要求排放者满足其排放许可证中规定的水质标准。在慢性毒性研究中，溶解的铝与多种水生生物的毒性之间没有直接关系。然而，毒性确实与使用pH 4提取方法获得的铝测量值相关。 5.3 天然水和废水通常含有大量的悬浮固体（25毫克/升至300毫克/升），这些悬浮固体含有高铝矿物质。监管机构通常建议测量总可回收铝，这使用强酸和热消化。该消化过程导致悬浮固体中存在的大部分或全部惰性无毒铝被溶解，并且金属被报告为“总或总可回收”。 5.4 开发了当前的方法（pH 4提取）以提供一种测量与悬浮固体无关的水性生物可利用铝的方法。支持使用该方法评估毒性的数据可在Rodriguez等人的出版物中找到。 4 5.5 目前pH 4提取方法提供的分析结果通常大于相同水样中的溶解金属浓度且小于总可回收浓度。在没有或很少悬浮固体的水样中，pH 4提取浓度和总铝浓度通常相同。 5.6 铝盐经常用作饮用水厂和废水处理厂的絮凝剂。 5.7 铝在一些工业废水和酸性矿山（岩石）排水中很常见。

1.1 This test method covers the determination of bioavailable aluminum in water using an extraction procedure at a pH of 4 and an aging period of 3 h following the addition of an acidic buffer. 1.2 This test method uses existing analytical methods for the determination of aluminum in water and only presents a new extraction procedure designed to recover the bioavailable fraction of aluminum present in a water sample. 1.3 This test method is designed to be used to assess the potential for aluminum in water samples to be toxic to aquatic life. 1.4 This test method is applicable to waters containing dissolved, polymeric, and mineral forms of aluminum and is applicable to concentrations ranging from 0.01 mg/L to 5 mg/L. 1.5 This test method was tested on natural surface waters and wastewaters containing suspended solids. It is the user’s responsibility to ensure the validity of this test method for waters of untested matrices. 1.6 Precision and bias have been obtained on natural waters, wastewaters, and reagent waters. It is the user’s responsibility to ensure the validity of this test method for waters of untested matrices. 1.7 Units— The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Recent research results investigating the relationship between water chemistry and aluminum toxicity to aquatic organisms are available. Toxicity was shown to vary as a function of pH, dissolved organic carbon (DOC), and hardness. Biological responses in toxicity tests do not correlate with dissolved metal because in circumneutral waters (pH 6 to 8.5) aluminum occurs as a hydroxide species or mineral particulate, both of which are removed by filtration. As such, filtration removes some of the metal species responsible for toxicity. 5.2 The U.S. Environmental Protection Agency (EPA) established water quality criteria for aluminum. Many U.S. states have adopted these criteria and require dischargers to meet water quality standards placed in their discharge permit. No direct relationship between dissolved aluminum and toxicity was shown for a wide variety of aquatic organisms in chronic toxicity studies. Toxicity does, however, correlate with aluminum measurements obtained using the pH 4 extraction method. 5.3 Natural water and wastewater frequently contain significant levels of suspended solids (25 mg/L to 300 mg/L) containing minerals high in aluminum. Regulatory authorities typically recommend measurement of total recoverable aluminum, which uses a strong acid and heat digestion. This digestion procedure results in most or all of the inert non-toxic aluminum present in suspended solids being dissolved and the metal reported as “total or total recoverable.” 5.4 The current method (pH 4 extraction) was developed to provide a method that measures aqueous bioavailable aluminum not associated with suspended solids. The data supporting the use of this method to assess toxicity can be found in the publication by Rodriguez et al. 4 5.5 The current pH 4 extraction method provides analytical results that are typically greater than the dissolved metal concentration in the same water sample and less than the total recoverable concentration. In water samples with no to very little suspended solids, the pH 4 extracted concentration and the total aluminum concentration are often the same. 5.6 Aluminum salts are frequently used as flocculants in drinking water plants and wastewater treatment plants. 5.7 Aluminum is common in some industrial wastewaters and acid mine (rock) drainage.