The acute toxicity of chemical substances can be judged by the assistance of three impact categories: MAK (workplace threshold value, Maximale Arbeitsplatzkonzentration), hazard sign, or LD50-, LC50-values, respectively. Using logarithmic functions, similarly to the methodology in ‘claiming of resources’ (impact category substance price), weighting factors Q were assigned to MAK-, LD50-, LC50-value-ranges, respectively, which will be produced from the pair of value indicated.
Table 3 f(MAK) and f(LX50-value) with X = C or D and (x/y)-pairs of value 1 and 2 for the calculation of functions f(Q). (‘[]’ is the integer function of Gauß, i.e., e.g. [2.3] = [2.98] = 2)
f(MAK) and f(LX50-Wert) |
Pair 1 (Q / LX50) |
Pair 2 (Q / LX50) |
Q = [ln(MAK/28284)/-1.3246] |
Q = 2 / MAK = 2000 mg/m3 |
Q = 10 / MAK = 0.05 mg/m3 |
Q = [ln(LC50 inhal../68.39)/-0.6148] |
(Q = 2 / 20 mg/l
/4h) |
(Q = 8 / 0.5 mg/l
/4h) |
Q = [ln(LD50 oral/8615)/-0.7303] |
(Q = 2 / 2000 mg/kg) |
(Q = 8 / 25 mg/kg) |
Q = [ln(LD50 dermal/17230)/-0.7303] |
(Q = 2 / 4000 mg/kg) |
(Q = 8 / 50 mg/kg) |
f(MAK) and f(LX50-value) result from the exponential functions f(Q) = MAK = 28284 × e-1.3246×Q LC50 inhal. = 68.39 × e-0.6148×Q, LD50 oral = 8615 × e-0.7303×Q, and LD50 dermal= 17230 ×e-0.7303×Q. The hazard sign (Xn, T, or T+) were assigned to the values Q = 4, 7, and 10 (Table 4). The value-ranges for the workplace threshold value and the LD50-, the LC50-values, resp., are shown in Table 4 and Table 5.
Table 4 Assignment of MAK-value-ranges and symbols of danger to the weighting factor QHuman toxicity (acute)
Q |
|
MAK-range
[mg/m3] |
|
hazard sign |
||
1 |
7520.98 |
to |
1999.90 |
|
||
2 |
1999.90 |
to |
531.79 |
|
||
3 |
531.79 |
to |
141.41 |
|
||
4 |
141.41 |
to |
37.60 |
Xn |
||
5 |
37.60 |
to |
10.00 |
|
||
6 |
10.00 |
to |
2.66 |
|
||
7 |
2.66 |
to |
0.71 |
T |
||
8 |
0.71 |
to |
0.19 |
|
||
9 |
0.19 |
to |
0.05 |
|
||
10 |
0.05 |
to |
0.00 |
T+ |
||
Table 5 Assignment of LD50-, resp. LC50-value-ranges to a weighting factor Q
Q |
hazard sign |
|
way
of intake |
|
||||||||||
|
|
LC50
inhal. [mg/l /4h] |
LD50
oral [mg/kg] |
LD50
dermal [mg/kg] |
||||||||||
1 |
|
36.98 |
to |
20.00 |
4150.40 |
to |
1999.52 |
8300.80 |
to |
3999.03 |
||||
2 |
Xn » |
20.00 |
to |
10.81 |
1999.52 |
to |
963.30 |
3999.03 |
to |
1926.59 |
||||
3 |
Xn » |
10.81 |
to |
5.85 |
963.30 |
to |
464.08 |
1926.59 |
to |
928.16 |
||||
4 |
Xn » |
5.85 |
to |
3.16 |
464.08 |
to |
223.58 |
928.16 |
to |
447.16 |
||||
5 |
Xn, T » |
3.16 |
to |
1.71 |
223.58 |
to |
107.71 |
447.16 |
to |
215.42 |
||||
6 |
T » |
1.71 |
to |
0.92 |
107.71 |
to |
51.89 |
215.42 |
to |
103.78 |
||||
7 |
T » |
0.92 |
to |
0.50 |
51.89 |
to |
25.00 |
103.78 |
to |
50.00 |
||||
8 |
T+ » |
0.50 |
to |
0.27 |
25.00 |
to |
12.04 |
50.00 |
to |
24.09 |
||||
9 |
T+ » |
0.27 |
to |
0.15 |
12.04 |
to |
5.80 |
24.09 |
to |
11.60 |
||||
10 |
T+ » |
0.15 |
to |
0.00 |
5.80 |
to |
0.00 |
11.60 |
to |
0.00 |
||||
The weighting factors Q of the value-ranges presented in Table 5 fairly well agree with the assignment (made in Table 4) of the weighting factors Q to the hazard signs Xn, T, and T+, which were listed in the column ‘hazard signs’ according to the legal restraints from Table 6.
Table 6 Classification criteria and selection of hazard sign according to 67/548/EEC Appendix 6(2)
hazard sign |
|
way
of intake |
|
||||||||||||
|
inhal.
[mg/l /4h] |
oral
[mg/kg] |
dermal
[mg/kg] |
||||||||||||
T+ |
|
|
LC50 |
< |
0.5 |
|
|
LD50 |
< |
25 |
|
|
LD50 |
< |
50 |
T |
0.5 |
< |
LC50 |
< |
2 |
25 |
< |
LD50 |
< |
200 |
50 |
< |
LD50 |
< |
400 |
Xn |
2 |
< |
LC50 |
< |
20 |
200 |
< |
LD50 |
< |
2000 |
400 |
< |
LD50 |
< |
2000 |
The sequence of priorities prefers the program-internal use of MAK-values instead of the symbols of dangers and the symbols of dangers instead of the LD50-, resp. LC50-values.
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