A total of 92 samples of street dust were collected in Luanda, Angola, were sieved below 100 urn, and analysed by ICP-MS for 35 elements after an aqua-regia digestion. The concentration and spatial heterogeneity of trace elements in the street dust of Luanda are generally lower than in most industrialized cities in the Northern hemisphere. These observations reveal a predominantly "natural" origin for the street dust in Luanda, which is also manifested in that some geochemical processes that occur in natural soils are preserved in street dust: the separation of uranium from thorium, and the retention of the former by carbonate materials, or the high correlation between arsenic and vanadium due to their common mode of adsorption on solid particles in the form of oxyanions. The only distinct anthropogenic fingerprint in the composition of Luanda's street dust is the association Pb-Cd-Sb-Cu (and to a lesser extent, Ba-Cr-Zn). The use of risk assessment strategies has proved helpful in identifying the routes of exposure to street dust and the trace elements therein of most concern in terms of potential adverse health effects. In Luanda the highest levels of risk seem to be associated (a) with the presence of As and Pb in the street dust and (b) with the route of ingestion of dust particles, for all the elements included in the study except Hg, for which inhalation of vapours presents a slightly higher risk than ingestion. However, given the large uncertainties associated with the estimates of toxicity values and exposure factors, and the absence of site-specific biometric factors, these results should be regarded as preliminary and further research should be undertaken before any definite conclusions regarding potential health effects are drawn.

No abstract

No abstract

No abstract

We review the evolution, state of the art and future lines of research on the sources, transport pathways, and sinks of particulate trace elements in urban terrestrial environments to include the atmosphere, soils, and street and indoor dusts. Such studies reveal reductions in the emissions of some elements of historical concern such as Pb, with interest consequently focusing on other toxic trace elements such as As, Cd, Hg, Zn, and Cu. While establishment of levéis of these elements is important in assessing the potential impacts of human society on the urban environment, it is also necessary to apply this knowledge in conjunction with information on the toxicity of those trace elements and the degree of exposure of human receptors to an assessment of whether such contamination represents a real risk to the city's inhabitants and therefore how this risk can be addressed.

No abstract

This study characterizes the elemental composition of street dust and soils in Avilés (N. Spain), a medium-size city of approximately eighty thousand inhabitants, where industrial activities and traffic strongly affect heavy metal distribution. A total of 112 samples of street dust were collected within a 7-km(2) area, encompassing residential and industrial sites (ferrous and non-ferrous plants). Elevated geometric mean concentrations of zinc (4,892 microg x g(-1)), cadmium (22.3 microg x g(-1)), and mercury (2.56 microg x g(-1)) in street dust were found in samples located near industrial areas. Two types of anthropic influence were distinguishable: the first and most important one is that related to metallurgical activity and transportation of raw materials for local industries. Secondly, exhaust emissions from traffic are an important source of lead concentration in areas with high vehicular density (geometric mean: 514 microg x g(-1)). The zinc content in the dust samples decreased with the distance from a zinc smelter located in the northern part of the city. The same trend was found for other elements in association with zinc in the raw materials used by the smelter, such as cadmium and mercury. A simultaneous research campaign of urban soils, that involved the collection of 40 samples from a 10-km(2) area, revealed geometric mean concentrations of 376 microg x g(-1) Zn, 2.16 microg x g(-1) Cd, 0.57 microg x g(-1) Hg, and 149 microg x g(-1) Pb, and distribution patterns almost identical to those found for street dust.

No abstract