Page 173 - 00. Complete Version - Progress Report IPEN 2014-2016

Nuclear Science and Technology | Progress Report 173

Environmental term cumulative health effects, making them
applications of neutron priority pollutants. Several authors studied

activation analysis metal contamination in soils under and in the
vicinity of discarded vehicle scrapyards, me-
chanic workshops and vehicle dismantlers.
Trace elements status in the terrain Most of them observed moderate to high con-
of an impounded vehicle scrapyard tamination by Cd, Cu, Cr, Fe, Mn, Ni, Pb and

Zn in the top layer of soil (0-10 cm), decreas-
Urban soil contamination varies considerably ing with depth.
depending on different anthropogenic activ-
ities within city perimeters. However, one of In Brazil, in spite of the increasing number
the most common sources of pollution pres- of IVS, the consequent soil metal contamina-
ent in most cities is vehicular. Over the past tion has still received little attention. There-
decade, worldwide vehicle production has in- fore, studies on metal contamination in soils
creased rapidly and tends to continue to rise of Brazilian vehicle impound scrapyards may
due to demand. In Brazil, the number of li- provide valuable information to support re-
censed vehicles has increased by 118% over mediation procedures, as well as encourage
the last decade, totaling a fleet of 89 million improvements in the management practices
vehicles in 2015. Impounded vehicle scrapy- of these areas.
ard (IVS) overcrowding has become a problem
in many Brazilian cities. Brazilian law states The aim of this study was to evaluate topsoil
that apprehended vehicles must not remain samples from an IVS located in Ribeirão Pires,
longer than 90 days in an impound yard. How- São Paulo, for potentially toxic elements (PTEs),
ever, in spite of this, they remain longer than such as As, Ba, Co, Cr, Cu, Mo, Ni, Pb, V and Zn,
that and suffer from weathering action. Most- and rare earth elements. Mass fractions of all
ly, the ground of these areas is not imperme- elements, except for Co, Cu, Mo and Zn, were
able. The main sources of pollution are liquid higher than reference values. Hot spots were
residue spills, leachates produced by rainwa- observed for most elements suggesting ve-
ter leaching and particulate material result- hicular source. The geoaccumulation index
ing from vehicle decomposition. showed moderate pollution of As. The enrich-
ment factor pointed to a significant enrich-
Metals and some metalloids are important ment of As, Mo and Pb. The normalization of
pollution sources in different parking areas. REEs to Earth’s crust values indicated a posi-
Many metals are present at different levels in tive anomaly of Ce. The results indicate a po-
leaded and unleaded gasoline, diesel oil, an- tential risk to the soil quality of the scrapy-
ti-wear substances added to lubricants, brake ard. (Partnership: Instituto de Geociências da
pads, and tires, as well as emitted by vehicle UNICAMP; Financial support: CNEN, CNPq).
exhausts. The main components of automo-
biles are steel materials, including those that Potentially toxic elements in tunnel
contain alloys and are composed by elements dusts from São Paulo city
such as Al, Co, Cr, Cu, Fe, Mn, Mo and Ni . Met-
als are non-degradable in soil, and their high The vehicle traffic is the major source of air pol-
toxicity and persistent nature in the environ- lution in São Paulo, one of the largest megaci-
ment, even at low levels, may result in long- ties in the world (20 million inhabitants in an