Duzgoren-Aydin N S, Li X D, Wong S C
Department of Earth Sciences, The University of Hong Kong, James Lee Science Bldg., Pokfulam Road, Hong Kong, China.
Environ Int. 2004 Apr;30(2):209-17. doi: 10.1016/S0160-4120(03)00175-2.
The source and the extent of Pb pollution in the urban environment of Hong Kong were investigated at five different urban settings selected on the basis of their annual average daily traffic (AADT) varying from less than 100 to 61,700. In addition, a small distant island without any traffic was selected to establish the possible baseline values. The surface environmental samples studied consisted of street and tunnel dusts, gully sediments, and a limited number of roadside topsoils. The analytical results clearly indicated variable degrees of Pb contamination in these urban settings. However, the level of contamination varied significantly among different types of samples collected at the same location. Pb concentrations of roadside topsoils (79+/-22 micrograms/g) and gully sediments (278+/-88 micrograms/g) were lower than those of the corresponding road dusts (327+/-54 micrograms/g). The Pb isotope compositions in different urban settings varied considerably. The bedrock in the small island had the lowest Pb concentration (12 micrograms/g) but with the highest 206Pb/207Pb ratio (1.2206), whereas the tunnel ceiling dusts with the highest level of Pb (1410 micrograms/g) had the lowest 206Pb/207Pb ratio (1.1062). Despite the significant differences in vehicle types and traffic volumes, and the presence of several different petroleum retailers in Hong Kong, the Pb isotope ratios of road dusts (206Pb/207Pb: 1.1553+/-0.0043, 208Pb/207Pb: 2.4408+/-0.0084) varied within a relatively narrow range among all the five urban sampling sites. On the other hand, the Pb isotopic compositions of gully sediments (206Pb/207Pb: 1.1515+/-0.0145, 208Pb/207Pb: 2.4322+/-0.0198) varied noticeably within the same setting, but were reasonably comparable across the different study sites. In general, the 206Pb/207Pb ratios of road dusts can be used to estimate the direct contribution from automobile emissions, whereas those of gully sediments might reflect the effects of the mixing of different anthropogenic sources. The Pb isotope signatures in the urban environment of Hong Kong clearly suggested that anthropogenic Pb in the environment originated from Pb ore with a low 206Pb/207Pb ratio (such as the Australian Pb ore and similar sources in Southeast Asia) were significantly different from those of the anthropogenic Pb present in the neighboring Pearl River Delta (PRD) region.
在香港城市环境中，基于年平均日交通量（AADT）从不足100至61,700不等，选取了五个不同的城市区域，对铅污染的来源和程度进行了调查。此外，还选取了一个没有任何交通流量的偏远小岛，以确定可能的基线值。所研究的地表环境样本包括街道和隧道灰尘、沟渠沉积物以及少量路边表土。分析结果清楚地表明，这些城市区域存在不同程度的铅污染。然而，在同一地点采集的不同类型样本中，污染水平差异显著。路边表土（79±22微克/克）和沟渠沉积物（278±88微克/克）中的铅浓度低于相应的道路灰尘（327±54微克/克）。不同城市区域的铅同位素组成差异很大。小岛上的基岩铅浓度最低（12微克/克），但206Pb/207Pb比值最高（1.2206），而铅含量最高的隧道顶部灰尘（1410微克/克）的206Pb/207Pb比值最低（1.1062）。尽管香港的车辆类型和交通流量存在显著差异，且有几家不同的石油零售商，但在所有五个城市采样点中，道路灰尘的铅同位素比值（206Pb/207Pb：1.1553±0.0043，208Pb/207Pb：2.4408±0.0084）在相对较窄的范围内变化。另一方面，沟渠沉积物的铅同位素组成（206Pb/207Pb：1.1515±0.0145，208Pb/207Pb：2.4322±0.0198）在同一区域内变化明显，但在不同研究地点之间具有合理的可比性。一般来说，道路灰尘的206Pb/207Pb比值可用于估算汽车排放的直接贡献，而沟渠沉积物的该比值可能反映了不同人为源混合的影响。香港城市环境中的铅同位素特征清楚地表明，环境中的人为铅源自206Pb/207Pb比值较低的铅矿石（如澳大利亚铅矿石及东南亚类似来源），这与邻近的珠江三角洲（PRD）地区存在的人为铅显著不同。
