Assessment of the influence of traffic-related particles in urban dust using sequential selective extraction and oral bioaccessibility tests

Abstract

Urban dust is a heterogeneous mix, where traffic-related particles can combine with soil mineral compounds, forming a unique and site-specific material. These traffic-related particles are usually enriched in potentially harmful elements, enhancing the health risk for population by inhalation or ingestion. Urban dust samples from Estarreja city and traffic-related particles (brake dust and white traffic paint) were studied to understand the relative contribution of the traffic particles in the geochemical behaviour of urban dust and to evaluate the long-term impacts of the metals on an urban environment, as well as the risk to the populations. It was possible to distinguish two groups of urban dust samples according to Cu behaviour: (1) one group with low amounts of fine particles (<38 µm), low contents of organic material, high percentage of Cu in soluble phases, and low Cu bioaccessible fraction (Bf) values. This group showed similar chemical behaviour with the brake dust samples of low- to mid-range car brands (with more than 10 years old), composed by coarser wear particles; and (2) another group with greater amounts of fine particles (<38 µm), with low percentage of Cu associated with soluble phases, and with greater Cu Bf values. This group behaved similar to those found for brake dust of mid- to high-range car brands (with less than 10 years old). The results obtained showed that there is no direct correlation between the geoavailability of metals estimated by sequential selective chemical extraction (SSCE) and the in vitro oral bioaccessibility (UBM) test. Thus, oral bioaccessibility of urban dust is site specific. Geoavailability was greatly dependent on particle size, where the bioaccessibility tended to increase with a reduction in particle diameter. As anthropogenic particles showed high metal concentration and a smaller size than mineral particles, urban dusts are of major concern to the populations' health, since fine particles are easily re-suspended, easily ingested, and show high metal bioaccessibility. In addition, Estarreja is a coastal city often influenced by winds, which favours the re-suspension of small-sized contaminated particles. Even if the risk to the population does not represent an acute case, it should not be overlooked, and this study can serve as baseline study for cities under high traffic influence.

Lead and zinc concentrations in household dust and toenails of the residents (Estarreja, Portugal): a source-pathway-fate model

“…Since the 1950s, the complex has produced a variety of organic and inorganic compounds, such as nitric acid, aniline, nitrobenzene, chlorate compounds from rock salt, polyurethanes and others. 34,42 In the early years, sulphide ores were used in fertiliser production, which was one of the primary activities of the CCE, yet one of the most polluting for PTEs such as arsenic (As) and Pb. In the late 1990's the area was remediated and industrial wastes containing hazardous materials such as pyrite ashes, mercury-enriched muds, and organochlorine compounds, were buried and sealed near the complex.…”

“…42,46 Hot-dip galvanising for zinc coating or the production and assembly of carbon steel, stainless steel, and aluminium tubing are industrial processes taking place in the CCE likely to emit PTEs to the atmosphere. Indeed, the Zn concentrations reported in different studies focusing on groundwater, soils, home-grown foodstuffs and street dust 34,44,45 suggest elevated levels of environmental Zn in the region.…”

“…29 A few studies on indoor residential environments have examined indicators specic to indoor sources, such as wood burning in replaces, 30 and cooking. 31,32 Urban studies on the composition of street dust have identied elemental tracers and source signatures typically associated with primary urban sources 33,34 (e.g., vehicular traffic, waste incineration). Potentially toxic elements (PTEs), such as Pb and Zn, introduced into the environment through different sources, nd their way into residential homes either as airborne dust or through items used or activities carried out within the house.…”

Using 206/207Pb isotope ratios to estimate phosphorus sources in historical sediments of a lowland river system

“…This group of elements is typical of elements found as waste water outputs from STWs and includes Cd, P, Sb, Cu, Pb, Zn and Cr, and suggests that P concentration increases along with the concentration of the trace element assemble, particularly those associated with road wash-off. In particular, the presence of Sb is a key indicator of STW source as the major likely source is from road dust where it is a component of brake disc linings (Patinha et al 2015). It was found that 206/207 Pb isotope ratios had a strong negative correlation to this group of elements ( Supplementary Information Fig.…”

Human bioaccessibility and absorption by intestinal cells of potentially harmful elements from urban environmental matrices

“…Mn (50%) in sediments, and Zn (82%) > Cd (58%) > Cu (54%) > Mn (47%) > Pb (45%). The groups of samples containing considerable proportions of PHE in the mobile and reducible phases were likely to be derived from anthropogenic sources, while the less mobile (oxidizable and residual) were linked to geogenic sources (Patinha et al, 2015).…”