Environmental Engineering Reference
In-Depth Information
times their weight at birth or hatching. Compared to both human and cow's milk,
milks of both platypus (Griffiths
1988
) and some non-specified marsupial (most
likely grey giant kangaroo) contain 50-100 times as much iron (20-30 mg/l). Obvi-
ously, milk has to cover all the metal demands of young platypuses directly from
delivery onward. Data for Mn, Zn, Mo or other metals are lacking. While the body
weights of humans and giant kangaroos (grey or red) are similar when exclusive
milk nutrition comes to an end (of order 5 kg), the Fe depot in a human newborn
of about 1 g is identical to the entire weight of a newborn kangaroo, material bal-
ances being correspondingly much different. African summon-primates other than
humans can also be raised/nursed with infant milk formulae based on cow's milk,
implying the situation (existence of metal depots) is similar in the great apes—even
including gorillas which feed on plants only. This agrees with the DGE stating there
is no Fe demand whatsoever for the “pure” (human) phase of breast-feeding (< 4
months).
Nickel (Ni) also interacts with numerous other elements; though it is coordinated
e.g. to albumin, this complex is so labile in both kinetic and thermodynamic terms
that Ni
2+
will be transferred to the latter already upon addition of simple amino acids
(Tabata and Sarkar
1992
), suggesting intense interactions. Unlike Mn, Ni will not
undergo redox reactions in aerobic organisms, rendering effects by other heavy met-
als by generation of oxidizing radicals unlikely. Nevertheless, increased maternal
administrations of Cu, Cd, Co and Zn, here lower TF
Ni
once again. Mangenese (Mn)
exerts an unsymmetrical effect: Manganese (Mn) lowers transfer of Ni but not the
reverse. Such kind of asymmetry is to be anticipated in exactly those cases where
transport of some pair of elements is accomplished using different pathways and/
or carriers. There are similar asymmetries with obviously the same reasons in the
element couple Cu/Fe.
With respect to their effect on the flow of matter and of energy in the food
chain, plants represent an important link between the atmosphere and the soil on
the one hand and between consumers from the first to the highest order (animals
and humans) on the other. Frequently, pollutants are introduced into the food chain
via plants which have taken them up from the soil or the atmosphere, and these
pollutants often cause irreversible damage to individual organisms or to entire
communities as a result of accumulation and exclusion processes (Fargašová and
Beinrohr
1998
; Szárazová et al.
2008
). Therefore highest quality on the control of
the influence on soil chemistry and microbial activities has to be given in the future.
Quantitatively, the uptake of substances is adequately characterized by the inten-
sity and scale of the uptake up to a particular point in time. For a defined nutrient,
the uptake by the plant is dependent on the amount of the nutrient in the medium
taken up and its availability. As a rule, the plant has no positive influence on the
supply, but it does have an effect on the material and spatial availability of the nutri-
ents. For example, from a material aspect, the nutrient availability can be changed
by modifying the pH of the soil solution.
