Platinum Group Elements in the Environment: Emissions and Exposure - Reviews of Environmental Contamination and Toxicology - page 112

ing in increased emissions and broader environmental distribution of PGEs in some
geographical regions. When released into the environment, PGEs accumulate first in
airborne particulate matter, road dust, soil, mud, and water; PGEs may then enter
organisms and subsequently undergo bioaccumulation. Scientific results from wide-
scale investigations support the thesis that concentrations of PGEs, especially plati-
num, are increasing in tissues and bodily fluids of humans exposed to these metals
(Minakata et al. 2006; Petrucci et al. 2005; Rudolph et al. 2005; Nygren and Lundgren
1997; Brook 2006). According to available data, the highest exposed groups
(Leœniewska et al. 2001) are individuals who work in refineries, chemical plants,
electronics plants, jewelry production, oncological wards (medical personnel), and
road maintenance; also highly exposed are women who have breast implants.
In general, metallic forms of PGEs do not enter the biochemical pathways of
organisms. However, some platinum salts such as hexachloro platinate and tetra-
chloro platinate have proven to be allergenic (Balcerzak 1997). The presence of
PGEs in a live organism may cause the following effects: asthma, miscarriage,
nausea, hair loss, skin diseases, and, in humans, other serious health problems.
Several review papers, in the literature, have addressed topics relevant to PGEs,
including their occurrence and applications (Rao and Reddi 2000), their environ-
mental distribution and speciation (Barefoot 1999), and the threats they pose to
human health as a result of anthropogenic emissions (Merget and Rosner 2001).
In this chapter, an attempt was made to synthesize the literature that addresses
emission sources and the bioavailability of PGEs in the environment.

2 Characteristics of PGEs

PGEs, also called platinum group metals (PGMs) in the international scientific
literature, encompass such metals as platinum (Pt), palladium (Pd), rhodium (Rh),
ruthenium (Ru), iridium (Ir), and osmium (Os). Average concentrations of these
metals in the earth's crust are presented in Table 1.

Table 1 Upper a and lower b continental crust concentrations of platinum
group elements (PGEs)

UCC a /LCC b concentration
(µg kg −1 ) c UCC concentration (µg kg −1 ) d
Pt 0.40 0.51
Pd 0.40 0.52
Rh 0.06 -
Ru 0.10 0.21
Ir 0.05 0.022
Os 0.05 0.031
Pt platinum, Pd palladium, Rh rhodium, Ru ruthenium, Ir iridium, Os osmium
a UCC-Upper continental crust
b LCC-Lower continental crust
c Wedepohl (1995)
d Peucker-Ehrenbrink and Jahn (2001)

Element