The enrichment of chemical products in particular environmental compartments is termed accumulation. Organisms assimilate substances by their nourishment (bio-magnification), by the surrounding medium (bio-concentration), or by both ways (bio-accumulation). Ecological magnification, i. e., a substance’ concentration increase in an ecological system or a food chain at transition from a lower to the next higher trophic level, can result in consequence and, especially, jeopardize the human being situated at the end of the food chain, who mostly himself is the initiator of the immissions of problematic substances.
At the bio-accumulation we do not regard absolute concentrations but the
relation of the concentration in the organism to that of its environment. The
accumulation of substances in the organism depends on the environmental
concentration, the level of the internal assimilation, and the passive (diffusion
processes) or active (enzymatical detoxification) segregation. By the help of
freely accessible software, logKow-values (octanol/water-distribution
coefficients) of substances can be determined simply after input of their
structure and used for the estimation of the accumulation instead of BCF-values
to be gained expensively in an experimental way. According to the international
convention, a substance is classified as accumulating if the logKow > 3
(national logKow > 2.7 in Germany). Therefore, the assignment of
logKow-ranges to weighting factors Q in the EATOS program is made starting from
the lowKow-value 3 (Table 11) with the function
with
or logKow. The program-internal assignment of the substance-specific
weighting factor Q concerning the accumulation is made primarily according to
the BCF-value and – if this does not exist – according to the Kow-value. Table
11
represents this assignment.
Table
11
Assignment of
, resp. logKow-ranges to the weighting factor QAccumulation
Q |
|
log(BCF/0.048)- resp. logKow-range |
|
||
1 |
3.00 |
to |
3.33 |
||
2 |
3.33 |
to |
3.67 |
||
3 |
3.67 |
to |
4.00 |
||
4 |
4.00 |
to |
4.33 |
||
5 |
4.33 |
to |
4.67 |
||
6 |
4.67 |
to |
5.00 |
||
7 |
5.00 |
to |
5.33 |
||
8 |
5.33 |
to |
5.67 |
||
9 |
5.67 |
to |
6.00 |
||
10 |
6.00 |
to |
< |
||
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