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Trace Elements in Abiotic and Biotic Environments
above 440 μg/kg, is in roadside soil samples from Perth, Australia (Whiteley 2005).
For the most soils along heavy traffic roads of various countries, the maximum Pd
contents are reported as follows (in μg/kg): Austria, 50; Brazil, 58; Germany, 47;
Greece, 126; Hawaii, 105; Italy, 110; Poland, 42; and the United States (California),
115. High Pd contents are also reported for road tunnel dust, from 20 to 207 μg/kg
(Helmers et al. vide Kabata-Pendias 2011).
Due to the use of Pd in car converters, its steady increased levels in environments
along roads, as well as in sewage sludge, have been observed. Its content in sewage sludge may vary from about 10 to 20 in rural and industrial areas, respectively.
Sewage sludge ashes contain Pd within the range of <100–600 μg/kg (Pyrzyńska
vide Kabata-Pendias and Mukherjee 2007).
32.3 WATERS
Palladium concentrations in the Pacific Ocean vary from 0.04 to 0.06 ng/L (Nozaki
2005). Its world average contents in river water are from 1 to 30 ng/L, at the average
of 2.8  ng/L (Gaillardet et  al. 2003). Rainwater collected in Sweden, during 1999,
contains Pd at the average value of <1 ng/L, and its wet deposition is calculated for
<11 mg/ha/yr (Eriksson 2001a). In water, Pd may occur in both species, hydroxide,
Pd(OH) 2 and chloride, PdCl 2 .
According to the data of the WHO (2002a), the common ranges of its concentration are as follows (in ng/L): freshwater, 0.4–22; salt water, 19–70; and drinking
water, <24.
In water contaminated with road dust, an increased Pd concentration is noticed,
and its elevated mean amount in eels, up to 0.18 μg/kg fresh weight (FW), is observed
(Sures et al. 2001).
Sediments in some water reservoirs along German highway contain Pd up to
35 μg/kg (Gower and Zereini vide Sures et al. 2001).
32.4 AIR
Palladium concentrations in air vary commonly from <270 to 280 pg/m 3 . However,
air above some cities and industrial regions may contain much higher Pd amounts,
for example, 12,700 and 56,600 pg/m 3 , in Chicago, Illinois, and Chernivtsi, Ukraine,
respectively (Ravindra et al. 2004). The average Pd concentration in air of the United
States is <1 pg/m 3 and varies from <0.06 to 110 pg/m 3 (WHO 2002a).
32.5 PLANTS
Palladium is most available to plants, among other PGMs. Its contents in various
shrubs and trees are in the range of 30–400 μg/kg ash weight (AW). Twigs of birch
trees grown close to the mineral deposits of PGMs in Canada accumulate Pd up to
4014 μg/kg AW (WHO 2002a). In contaminated regions (e.g., PGMs ore deposits
in Canada), twigs of birch trees contain Pd within the range of 30–400 μg/kg AW.
A great variation has been observed in Pd contents in various trees, within the range
of 30–400 μg/kg AW, due to variable climatic conditions and stage of growth.