Platinum [Pt, 78]
245
Platinum levels in drinking water have been estimated to be 0.1 ng/L. In some tap
water, however, it is reported to be very high, up to 60 ng/L (WHO 1991b).
In marine algae, Pt contents vary from 0.08 to 0.32 μg/kg. It is relatively easily
bioaccumulated, and in some crustaceans, it may be concentrated up to 38 μg/kg
(WHO 1991b).
33.4 AIR
There are only a few data on Pt concentration in air, prior to the introduction of
motor vehicle catalytic converters. Data from that time may reflect Pt background
levels and are <0.05 pg/m 3 in air samples taken near freeways in California and
<0.6–1.8 pg/m 3 in rural areas of Germany. Data taken in Germany for the twentieth
century (in pg/m 3 ) are as follows: rural areas, <0.6–1.8; traffic roads, <1–13; and
city road dust, on average, 730 (WHO 1991b). The average Pt content in airborne
particles of roadsides of some EU countries is approximately 15 pg/m 3 (Gómez
et al. 2002).
Maximum Pt concentration in air recommended in Germany for the occupational exposure is 2 pg/m 3 (Hoppstock and Sures vide Kabata-Pendias and
Mukherjee 2007).
Platinum contents of moss sampled in Finland are up to 12.2 μg/kg, whereas in
moss sampled from areas of Ni industries, it may be above 6000 μg/kg (Reimann
and Niskavaara 2006).
33.5 PLANTS
Apparently, plants easily take up mobile Pt species, which are mainly its complexes
with soluble OM. It is accumulated in roots. Platinum may be bound by some proteins and is relatively highly toxic, especially Pt 2+ , which is more toxic than Pt 4+ .
The contents of Pt in crop plants vary highly between the kind of plants and
growth sites. Grasses from rural regions contain Pt within the range of 0.1–0.3 μg/kg,
whereas from areas close to traffic roads, they contain 0.8–96.0 μg/kg (KabataPendias 2011). Some plants from the roadsides may contain Pt up to above 800 μg/kg
(Ravindra et  al. 2004). Platinum emitted from motor vehicles (its main pollution
sources) is deposited mainly as suspended particles on the plant surface.
Cereal grains from Sweden contain Pt from 0. 2 to 0.9 μg/kg (Eriksson 2001a),
whereas corn grains have Pt from 80 μg/kg in Germany to 642 μg/kg in Austria.
Relatively high Pt contents are in radish roots (530 μg/kg) and the highest tobacco
leaves (23,300 μg/kg) (Ravindra et al. 2004). The authors reported that barks of trees
grown in remote and urban areas contain Pt from 0.07 to 38 μg/kg, respectively, and
in pine needles from a town, its content is up to 102 μg/kg.
33.6 HUMANS
The total amount of platinum in the human body is not known, but low, and it has no
known biological role (Emsley 2011). The natural levels of Pt significantly fluctuate
in the human body fluids of various types. The values of 0.8–6.9 ng/L and 0.56 μg/L