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Nickel is the 28th element in the periodic table. It is a silver-white
metal found in several oxidation states (ranging from -1 to +4), however,
the +2 oxidation state [Ni(II)] is the most common in biological systems
(DENKHAUS, SALNIKOW 2002). Nickel easily forms nickel-containing alloys, which
have found an ever increasing use in modern technologies for over a hundred
years now. Global input of nickel to the human environment is approximately
150 000 and 180 000 metric tonnes per year from natural and anthropogenic
sources, respectively, including emissions from fossil fuel
consumption, and the industrial production, use, and disposal of nickel compounds
and alloys (KASPRZAK et al. 2003).
SOURCES OF NICKEL
Nickel is widely distributed in the environment, and can be found in
air, water, and soil. Natural sources of atmospheric nickel include dusts
from volcanic emissions and the weathering of rocks and soils. The level of
nickel in ambient air is small (about 6-20 ng⋅m-3), but levels up to
150 ng Ni⋅m-3 could be present in air contaminated by anthropogenic sources.
In water, nickel derives from biological cycles and solubilization of nickel
compounds from soils, as well as from the sedimentation of nickel from the
atmosphere. Uncontaminated water usually contain about 300 ng Ni⋅dm-3.
Farm soils contain approximately 3-1000 mg Ni⋅kg-1 soil, but the Ni concentration
can reach up to 24 000-53 000 mg⋅kg-1 Ni in...