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EHC 226: Palladium
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Depending on the distance from the mineral deposit, palladium con-
centrations in twigs from dwarf birch ranged from 8.5 (background) to
4014  µg/kg   ash,  and  concentrations  in  leaf  tissue of Labrador tea
ranged from 37.8 (background) to 2523 µg/kg ash.
Biomonitoring values  from different areas  of Italy  using epiphytic
lichens  as   bioaccumulators   were   below  the  detection  limit  of  the
inductively coupled plasma atomic  emission spectrometry (ICP-AES)
technique of 2.5 µg/kg (Guidetti & Stefanetti, 1996;  Zocchi et al., 1996).
Palladium  concentrations  below  or  at  the  limit  of  detection
(0.25 µg/kg dry weight) were found in the US NBS standard reference
sample of orchard leaves (SRM 1571) (Eller et al., 1989).
The uptake  of traffic-related PGMs by plants  has  been determined
by Schäfer et al. (1998). Palladium concentrations in spinach, cress and
phacelia grown on palladium-contaminated soil (5.7 and 6.5 µg
palladium/kg) collected from areas  adjacent to a German highway were
close to the detection limit of the AAS method (~0.7 µg palladium/kg
dry material), whereas  concentrations in stinging nettle (Urtica dioica)
reached up to 1.9 µg palladium/kg.
In 1995, palladium concentrations in grass from sampling locations
near German highways were  between <0.5 and 0.6 µg palladium/kg dry
weight (Hees et al., 1998).
2) 
Aquatic plants
Yang (1989) analysed annual fronds from 22 species of marine
macrophytes collected from California  (USA) in 1986 using GF-AAS.
Mean palladium concentrations for the different types of algae are
listed in Table 13.
5.1.7.2
Animals
Concentrations of palladium were  quantified in body segments of
different  size   classes   of  the  spot  prawn   (Pandalus  platyce r o s )
collected from various locations in British Columbia (Canada). The
concentration  of  absorbed  palladium  was   highest  in  the  abdomen

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Environmental Levels and Human Exposure
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Table 13. Average palladium concentrations in seaweeds
a
Algal type
Concentration (µg/kg)
Brown
0.11
Non-calcareous red
0.44
Calcareous red
0.17
Green
0.27
a
 
Table adapted from Yang (1989).
carapace (6 mg/kg dry weight) and the head (5.64 mg/kg  dry weight).
The lowest  concentration (0.02 mg/kg  dry  weight) was  found in the
hatched larvae. The data of this field sampling study suggested an
accumulation of palladium during the growth and development of
marine invertebrates (Whyte & Boutillier, 1991).
In muscles of feral pigeon (Columba  livia),  a  concentration  o f
0.511 mg palladium/kg dry weight was measured (Abbasi, 1987).
5.2
Exposure of the general population
5.2.1
Levels found in the general population
Exposure  of the general population is through palladium in air,
food and water and through release of palladium from dental restor-
ations containing palladium.
A t present, the low detection sensitivity for analysis in biological
matrices is still a problem. If current tissue data vary  by a factor of 2 or
more from older data, this  can reflect different trace levels  as  well as the
analytical reliability of the detection method. 
In  earlier  reports,  palladium concentrations in serum, blood,
faeces, hair and urine of persons without occupational exposure were
below the detection limits (Gofman et al., 1964; Johnson et al., 1975b,
1976). A  pool of 282 blood samples indicated concentrations of less
than 0.01 µg/100 ml blood for palladium (Johnson et al., 1975b). More
recent  backgroun d  levels   for  urine  do  not  s h o w  a  general
concentration trend in the overall population over the last 25 years. 

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EHC 226: Palladium
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Some   levels   of  palladium in blood, hair, urine and faeces in non-
occupationally exposed persons are shown in Table 14.
Measured concentrations of palladium in various tissues were
reported  in  a  study completed in 1974 (before the introduction of
catalytic  converters). Concentrations in autopsy “wet” tissue samples
(liver, kidney, spleen, lung, muscle, fat) from five men and five women
12–79 years of age who died from a variety of causes in Los Angeles,
California (USA), were below the limit of detection for different tissue
materials by the applied A A S technique — i.e., less than 0.6–6.7 µg/kg
(Johnson et al., 1976).
The investigations of Begerow et al. (1998a, 1999b) showed that
direct exposure  to traffic  has  no verifiable  influence on the background
burden of the population.
It is  probable  that the baseline concentrations of palladium in the
body fluids of unexposed people  are <0.1 µg/litre blood and 
#
0.3 µg/li-
tre urine (Table 14).
5.2.2
Food
Little information was found in the literature, and only  one total
diet study was  available. The actual concentrations of palladium in
food from various countries vary widely depending on the food
product and the growing conditions (soil).
The following mean palladium concentrations per kg wet weight
were   measured  in  different  meat  samples:  chicken,  0.6  µg/kg;  beef,
0.7  µg/kg;  and  pork,  0.5  µg/kg.  The  highest  concentration  of  2  µg
palladium/kg was in ham (Koch & Roesmer, 1962).
A  concentration of 0.5 µg palladium/kg was found in a US NBS
standard  reference sample  of bovine liver (SRM  1577) (Eller et al., 1989).
Nineteen honey samples collected from several polluted areas in
Florida and New York State (USA) were analysed before the intro-
d uction of catalytic  converters  in the USA  (Tong et al., 1975) .   T h e
background concentration range of palladium was <1–15 µg/kg fresh

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