POTASSIUM CHLORIDE CAS N°: 7447-40-7

OECD SIDS POTASSIUM CHLORI
Date: 30-MAR-2003
3. Environmental Fate and Pathways Substance ID: 7447-40-7
The pool of exchangeable K is particularly
important for plants, and the main site of
exchangeable K is the clay. Various types of clay
binding K at different strengths, from weak
surface binding that do not hold K against
leaching (e.g. kaolinite clays), to a binding
that restricts plant availability (e.g. illitic
and smectite clays).
Most soils contain a mixture of the different
clay minerals; the proportion in which they occur
dictate the way the soil will behave as far as K
is concerned. The larger the amount
of clay in a soil the higher will be its capacity
to adsorb K and the better this will be able to
replenish the K in the soil solution when this is
depleted. Organic and light sandy soils have low
capacity for binding K. If such soils should
contain more K than the plant can take up, the K
ions are easily washed out or leached beyond the
range of crop roots. Heavier soil has an
advantage in that the clay holds much K, and any
temporary excess over the plant’s immediate
requirement is not easily leached.
The organic matter in soil (humus) also has
exchangeable properties, somewhat similar to
those of clays. While in most temperate mineral
soils containing clay, the contribution of
organic matter to the pool of exchangeable K is
not very important, it is very important in sandy
soils and in soils where the clay minerals are
predominantly of the kaolinitic type, as in many
tropical soils.
K is in general less mobile and less prone to
leaching than anions in soil, such as chloride
and nitrate (NO 3 - ), but more so than phosphate.
Chloride binds only weakly to soil particles, and
therefore follows water movement. Anions do not
leach alone, but always together with a counterion
(cation). Hence, chloride and nitrate
leaching may deplete soils of nutrients such as
K. Leaching can be minimized by keeping the land
covered by crops.
Source:
Norsk Hydro ASA
Reliability: (1) reliable without restrictions
Flag:
Key study for SIDS
01-MAR-2001 (37)(49)
3.3.2 Distribution
Media:
air, water, soil and sediment
Method: Fugacity Level I.
Generic Model of OECD (FUGMOD, 1992).
Result:
Environmental distribution of potassium chloride
using a Generic Level I Fugacity Model under three
emission scenarios showed the same result
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