Documents\Palladium-contents. Pdf

Table 5 (contd).
Matrix/medium
Sample treatment
(decomposition/separation)
Determinatio
n method
a
Limit of detection
b
Comments
c
References
Urine
adjustment to pH 4, conversion to the
pyrrolidinedithiocarbamate complex,
extraction into 4-methyl-2-pentanone
ETA-AAS 
0.02 µg/litre
Begerow et al. (1997a)
Urine
acidification with nitric acid
quadrupole
ICP-MS
0.03 µg/litre
no further sample
treatment other than
calibration
Schramel et al. (1997)
Whole blood,
urine
samples mixed with hydrogen
peroxide/nitric acid; digestion by UV
photolysis
sector field
ICP-MS
0.2 ng/litre
cleaning of all materials
resulted in a drastic
reduction of blanks
Begerow et al.
(1997b,c)
Other biological materials
Meat
dry ashing of homogenized meats
(11–12 kg); decomposition with aqua
regia/hydrofluoric acid
NAA
0.5 µg/kg meat 
radionuclide 
103
Pd
Koch & Roesmer (1962)
Human organ
material, blood
wet mineralization with sulfuric acid/
nitric acid/hydrogen peroxide;
extraction with diethylammonia-
diethyldithiocarbamate in chloroform
ESA
2.5 µg/g
1 g organ material
Geldmacher-von
Mallinckrodt & Pooth
(1969)
Human hair,
faeces
digestion with nitric acid/perchloric
acid; aspiration into air–acetylene
flame 
AAS
20 ng/g (hair),
1 ng/g (faeces)
Johnson et al.
(1975a,b)

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Table 5 (contd).
Matrix/medium
Sample treatment
(decomposition/separation)
Determinatio
n method
a
Limit of detection
b
Comments
c
References
Rice, tea, human
hair
digestion with perchloric acid/nitric
acid; cathodic stripping voltammetric
determination by mixed binder
carbon paste electrode containing
dimethylglyoxime
VD
0.1 µg/g
samples spiked with Pd
2+
were examined; simulta-
neous determination of
Hg, Co, Ni, Pd
Zhang et al. (1996)
Biological
materials, fresh
waters
extracted with N-p-methoxyphenyl-2-
furylacrylohydroxamic acid in isoamyl
alcohol at pH 2.7–3.5
spectro-
photometry
0.1 µg/litre
enrichment of Pd(II) 15
times
Abbasi (1987)
Marine
macrophytes
dry ashing and wet digestion;
purification with an anion-exchange
resin
GF-AAS
0.11 µg/kg
d
 
Yang (1989)
Ash of plant tissue
ashing at 870 °C and digestion in
hydrofluoric acid/aqua regia
ICP-MS
0.5–1 µg/kg
Rencz & Hall (1992)
Various foods
digestion with nitric acid; calibration
with rhodium and rhenium as internal
standards
ICP-MS
0.9 µg/kg (peanut
oil), 0.1 µg/kg
(water)
0.5-g samples
Zhou & Liu (1997)
Release from dental alloys
Cell culture
medium
centrifugation
FAAS
35 µg/litre
the supernate of the cell
culture medium was
analysed
Wataha et al. (1992)
Cell culture
medium
direct measurement of cell culture
extracts
FAAS
20 µg/litre
Wataha et al. (1995a)

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Table 5 (contd).
Matrix/medium
Sample treatment
(decomposition/separation)
Determinatio
n method
a
Limit of detection
b
Comments
c
References
Artificial saliva
direct measurement of the solution
AAS
30 µg/litre
Pfeiffer & Schwickerath
(1995)
Miscellaneous material
Diverse samples
digestion in aqua regia; separation
on anion-exchange and concentrator
column; eluants: sodium perchlorate/
hydrochloric acid
UV-D
1 µg/litre
Rocklin (1984)
Catalytic converter
block
catalytic converter sample leached in
hydrochloric acid/sodium chloride for
12 h; separation of the chloride
complexes by electrophoresis
CZE-UV
1.4 µg/ml
simultaneous
determination of Pd
2+
and Pt
4+
Baraj et al. (1996)
a
 
AAS  =  atomic absorption spectrometry; CZE-UV = capillary zone electrophoresis, using direct UV absorbance detection; ESA = emission
spectrochemical analysis;  ETA-AAS = atomic absorption spectrometry with electrothermal atomization; FAAS = flame atomic absorption spectrometry;
GF-AAS  =  graphite  furnace  atomic  absorption  spectrometry; ICP-AES = inductively coupled plasma atomic emission spectrometry; ICP-MS =
inductively coupled plasma mass spectrometry; NAA = neutron activation analysis; UV-D = ultraviolet detection; VD = voltammetric determination;
XRF = X-ray fluorescence analysis; ZAAS = Zeeman graphite furnace atomic absorption spectrometry.
b
 
The limit of detection normally represents the concentration of analyte that will give a signal to noise ratio of 2.
c
 
No information about the oxidation state is given, except it is stated that palladium(II) was determined.
d
 
Lowest value indicated.

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30
3. SOURCES OF HUMAN AND ENVIRONMENTAL
EXPOSURE
3.1 
Natural occurrence
PGMs  occur naturally in very low concentrations ubiquitously in
the  environment  (Table  6).  The  fraction  of  palladium  within PGMs is
approximately 20% (Renner & Schmuckler, 1991; Renner, 1992).
A  concentration  of  palladium below 1 µg/kg in the upper conti-
nental crust is estimated. This is in accordance with a mean value of 0.4
µg  palladium/kg  proposed  by  Wedepohl  (1995).  Together  w i t h   t h e
other PGMs, palladium occurs at a concentration below 1 ng/kg in sea-
water.
3.2
Anthropogenic “sources” of palladium
3.2.1
Production levels and processes for palladium metal
Nearly all of the world’s supply of PGMs is extracted from depos-
its  in  four  countries:  the Republic of South Africa, Russia, Canada, and
the  USA.  The  primary  production  of  palladium  for  these  and  other  pro-
ducing countries is listed in Table 7.
The  largest  fraction  of  palladium  is  recovered as a by-product of
copper  and  nickel  sulfide  ore  refining  (Russia  and Canada) or as alloys
of the PGMs from primary PGM  deposits (South Africa, USA). PGMs
are generally found in mixtures of varying proportions.
  Because  PGMs  are  very  expensive  to  mine  and  purify,  a  high
proportion  of  PGMs  are  recycled  by  the  users  or  by  the  producers
(e.g.,  catalysts)  and  do  not  appear  on  the  market.  Averaged over all the
PGMs,  the quantity recycled amounts at present to about 20% of pri-
mary  production,  with  the  greatest  emphasis  on  platinum  and  palladium
(Loebenstein,  1996).  Therefore,  supply   figures  essentially reflect only
mined products and sales from the former Soviet Union/Russia.

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