Antimony derived from brake linings in roadside soils, road run-off, and affected streams

锑（Sb）及其化合物被国家和国际环境当局（例如，世界卫生组织，美国环保署，欧洲共同体理事会），因为它们具有致癌潜力。然而，这种半金属被添加到制动衬片的摩擦材料中，并在制动过程中由于磨损而释放到环境中。本提案的目的是（一）产生详细的信息，总锑在彻底表征路边土壤的空间分布模式，及（二）提供一个更好的理解锑的流动性和形态（三与五价锑）及其空间分布模式。除了测定总锑微波消解使用强无机酸，连续提取程序将被应用于评估的流动性和生物利用度的Sb。该程序包括弱酸可溶性，可还原，可氧化，和残留馏分的测定。为了测定Sb（III）和Sb（V），必须从样品基质中可靠地定量提取Sb，而不对其物种进行任何降解或转化，但仍具有代表性的提取效率。我们将应用并调整已经测试过的提取方法，以适应更广泛和更多样化的土壤样本，以开发出一种对基质依赖性较小的程序。此外，（iii）形态和大小分级的锑在道路径流，和（iv）排放的道路径流的影响上的形态和大小分级的锑在排水流将进行调查。水质参数的变化，如pH值，离子强度，氧化还原电位，温度和溶解氧对水生系统中的金属形态的影响。我们将研究这些影响进行形态和大小分馏在两个道路径流在下雨的事件，和长期变化的排水系统下游的道路径流出口。粒度分级将提供更多的信息，锑在水生系统中的结合形式。已知Sb主要保留在低分子量（LMM）级分中。这是一个非常令人担忧的问题，因为LMM物质被认为比颗粒相关物质更具生物利用度。然而，这两种分析方法从未在路边径流及其受影响的排水系统中进行过。所有这些目标都有一个共同的目的：提供一个更好的了解如何制动衬派生锑存在于路边土壤和相关的排水系统。环境样品中Sb物种的分布对于评价毒性效应至关重要，因为Sb毒性取决于其氧化态。

Antimony (Sb) and its compounds are considered as a pollutant of high priority interest by national and international environmental authorities (e.g., WHO, US E.P.A., Council of the European Communities) as they have carcinogenic potential. Nevertheless, this semimetal is added to friction material in brake linings and released into the environment due to abrasion during the braking process. The objectives of this proposal are (i) to yield detailed information about the spatial distribution patterns of total Sb in thoroughly characterized roadside soils, and (ii) to provide an improved understanding of Sb's mobility and speciation (tri- versus pentavalent Sb) and its spatial distribution patterns in those. Besides the determination of total Sb by microwave digestion using strong mineral acids, a sequential extraction procedure will be applied to assess the mobility and bioavailability of Sb. The procedure includes the determination of the weak acid-soluble, reducible, oxidizable, and residual fractions. To determine Sb(III) and Sb(V), a reliable quantitative extraction of Sb from the sample matrix must be applied without any degradation or transformation of its species, but still with representative extraction efficiency. We will apply and adjust already tested extraction methods to a wider range and variation of soil samples in order to develop a less matrix-dependent procedure. Moreover, the (iii) speciation and size fractionation of Sb in road run-off, and (iv) the effects of discharged road run-off on the speciation and size fractionation of Sb in a drainage stream will be investigated. Variations in water quality parameter such as pH, ionic strength, redox potential, temperature, and dissolved oxygen have an influence on metal speciation in aquatic systems. We will study these effects by conducting speciation and size fractionation in both road run-offs during rain events, and long-term variations in a drainage system downstream of an outlet of road run-off. Size fractionation will provide more information about binding forms of Sb in aquatic systems. It is known that Sb mainly remains in the low molecular mass (LMM) fraction. This is of great concern, as LMM species are believed to be more bioavailable than particle-associated species. Nevertheless, both analytical approaches have never been conducted in roadside run-off and its affected drainage system. All these objectives share a common purpose: to provide a better understanding of how brake-lining-derived Sb is present in roadside soils and related drainage systems. Distribution of Sb species in environmental samples is crucial for the evaluation of toxic effects, since Sb toxicity depends on its oxidation state.