Analysis of traces of precious metals in soils

铂族金属是汽车催化转化器中常用的活性元素。主要是将高度分散的铂（Pt）、钯（Pd）和铑（Rh）纳米颗粒（NPs）涂在陶瓷支撑材料上，由于热磨损和机械磨损，部分纳米颗粒随排气排出。每公里最多可排放约100毫微克的铅，主要以特定物质的形式排放。这些颗粒中有三分之一的重量小于5纳米。排放出的微粒在道路旁沉淀，并以迄今未知的方式渗入路边的土壤。该项目的目的是评估PGM在土壤中的迁移和积累。因此，将研究pgm在表土中运移的深度，它们在哪些土壤类型和层中积累，以及是否要估计其对地下水的渗透。从沿不同交通密度道路的入渗盆地取几个样品，测定不同土壤深度的Pd、Pt和Rh浓度。为此，将进一步开发一种用于Pd预富集的流动注射分析系统，以分析Pt和Rh的痕量。本文将对该方法进行优化和验证。这些项目的结果将有助于评估PGM-NPs在一般环境中的风险。

Platinum group metals (PGMs) are used as active elements in car catalytic converters. Mainly highly dispersed platinum (Pt), palladium (Pd), and rhodium (Rh) nanoparticles (NPs) on ceramic support materials are applied and are partly emitted with the exhaust due to thermal and mechanic abrasion. Up to some 100 ng PGMs per kilometre can be emitted mainly as particular matter. Up to a third of the weight of these particles are smaller than 5 nm in size. The emitted particles settle beside roads and are infiltrated in so far unknown manner in roadside soils. The aim of the proposed project is to evaluate the transport and accumulation of PGM in soils. Thereby, it will be investigated in what depths the PGMs are transported in topsoil, in which soil types and layers they are accumulated and whether infiltration into ground water is to be estimated. Several samples from infiltration basins along roads with different traffic densities will be taken and Pd, Pt, and Rh concentrations will be determined in different soil depth. For this purpose a flow injection analysis system for pre-concentration of Pd traces will be further developed in order to analysis traces of Pt and Rh. This new method will be optimized and validated. The results of this projects will contribute to the risk assessment of PGM-NPs in the environment in general.