Botanical Institute of Johann Wolfgang Goethe-University, Frankfurt/Main, Germany.
Environ Sci Pollut Res Int. 1997;4(3):131-9. doi: 10.1007/BF02986319.
The introduction of the 3-way catalytic converter is presently being acclaimed by different sources in Germany as the solution to the ozone problem. This hypothesis is viewed with scepticism: studies conducted in the USA, where the 3-way catalytic converter was introduced as early as 1975, show that the ozone problem has not been resolved by any means in that country. Moreover, the employment of the catalytic converter is associated with the emission of various elements occurring otherwise at extremely low background concentrations, e.g.the elements in the platinum group (Pt, Pd and Rh). A brief review of the literature reveals, for example, that platinum exhibited an unexpectedly high rate of accumulation in upper soil layers near highways in Germany within a few years of the introduction of catalytic converters. The focus of this paper is on impact research. My own studies have shown that water-soluble Pt 4. accumulates at a high rate in poplar roots. A six-week exposure of poplar cuttings to 34.8 ppb Pt 4+ results in disturbances affecting the water balance of the plants and, in conjunction with this, typical symptoms of moderate water stress. Cerium (Ce), another element released by catalytic converters, also displays a high degree of accumulation in plant roots. Water-soluble Pt4+ accumulates to an even greater degree in soil, giving rise to the following series arranged in order of decreasing affinity to platinum: soil > fine roots > coarse roots. In long-term experiments, even the metallic platinum contained in the active layer of catalytic converters accumulated in plant roots; the resulting distribution among soil, fine roots and coarse roots was comparable to that of water-soluble platinum. Possible uptake mechanisms are discussed. The first results of this study indicate that platinum apparently belongs to the elements with a strong affinity to humic matter, a fact which could possibly explain its especially heavy accumulation in upper soil layers.
三效催化转化器的引入目前在德国被不同的消息来源誉为解决臭氧问题的方法。这一假设受到了怀疑:在美国进行的研究表明,在美国,三效催化转化器早在 1975 年就已经引入,该国的臭氧问题根本没有得到解决。此外,使用催化转化器会导致排放各种其他情况下以极低背景浓度存在的元素,例如铂族元素(Pt、Pd 和 Rh)。文献综述表明,例如,在德国引入催化转化器后的几年内,铂在高速公路附近的上层土壤中以出乎意料的高速度积累。本文的重点是影响研究。我自己的研究表明,水溶性 Pt4+在杨树根中以很高的速度积累。杨树插条在 34.8ppbPt4+的条件下暴露六周,会导致影响植物水分平衡的干扰,同时伴有中度水分胁迫的典型症状。另一种由催化转化器释放的元素铈(Ce)也在植物根系中大量积累。水溶性 Pt4+在土壤中积累得更多,导致以下一系列按对铂亲和力递减的顺序排列:土壤>细根>粗根。在长期实验中,甚至催化转化器活性层中含有的金属铂也在植物根系中积累;在土壤、细根和粗根中的分布与水溶性铂相似。讨论了可能的吸收机制。这项研究的初步结果表明,铂显然属于对腐殖质亲和力很强的元素,这一事实可能解释了其在上层土壤中特别大量积累的原因。