Diagnosing the Impact of Traffic on Roadside Soils Through Chemometric Analysis on the Concentrations of More Than 60 Metals Measured by ICP/MS - Highway and Urban Environment - page 303

Diagnosing the Impact of Traffic on Roadside
Soils Through Chemometric Analysis
on the Concentrations of More Than 60 Metals
Measured by ICP/MS
Jose Antonio Carrero, Naiara Goienaga, Oihana Barrutia, Unai Artetxe,
Gorka Arana, Antonio Hernández, José María Becerril,
and Juan Manuel Madariaga
Introduction
Road traffic is one of the most important environmental problems in many cities.
Its contribution to the global emission of environmental pollutants is increasing
every year [1] . However, the dispersion of those pollutants is affected by the climatic
conditions, placing finally in other areas such as the surrounding soil and water [2] .
There are many studies showing the contamination of roadside soils as a conse-
quence of traffic activity [2-5] . Among all possible pollutants originated by road
traffic, metals and polycyclic aromatic hydrocarbons (PAHs) are the most dangerous
ones. While organic compounds can be transformed or degraded by means of the
microbial action of the soil in others innocuous compounds such as water and CO 2 ,
metals can remain in the environment for a long time [6] .
According to the bibliography [2, 3, 5, 7] roadside soils have long been known
to contain high levels of heavy metals, Pb, Ba, Zn, Cd and Cu mainly. Well-known
road traffic related metal emission sources of concern are brake linings, tyres, road
pavement and exhaust fumes [8] . The metals of concern for emissions from brake
linings are Cd, Cr, Cu, Ni, Pb, Sb and Zn. Wear from vehicle tyres is another major
metal source, especially Zn and Ba. Tyres have traceable amounts of several other
metals, for example Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni and Pb. Metal emissions from
exhaust fumes derives from fossil fuels and the aging processes of engines and catalysts.
Combustion of leaded petrol was previously the major source. Since January 2000,
Pb has been banned as an anti-knocking additive in petrol in the EU. However,
there are still some emissions of Cd, Cr, Cu, Ni, Pb and V from fossil fuels [9] .