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EFFECTS ASSESSMENT<br />

Table 21 Default BMF values <strong>for</strong> organic substances<br />

log Kow of substance BCF (fish) BMF<br />

8 – 9 2,000-5,000 3<br />

>9 < 2,000 1<br />

3.8.3.5 Calculation of the predicted no-effect concentration (PNECoral)<br />

Only toxicity studies reporting on dietary <strong>and</strong> oral exposure are relevant as the pathway <strong>for</strong><br />

secondary poisoning is referring exclusively to the uptake through the food chain. Secondary<br />

poisoning effects on bird <strong>and</strong> mammal populations rarely become manifest in short-term studies.<br />

There<strong>for</strong>e, results from long-term studies are strongly preferred, such as NOECs <strong>for</strong> mortality,<br />

reproduction or growth. If no adequate toxicity data <strong>for</strong> mammals or birds are available, an<br />

assessment of secondary poisoning cannot be made.<br />

For new substances, the results of mammalian repeated-dose toxicity tests are used to assess<br />

secondary poisoning effects. For existing substances <strong>and</strong> biocides, toxicity data <strong>for</strong> birds (e.g.<br />

OECD test 205 (1984h) (LC50, 5-day acute avian dietary study) or OECD test 206 (1984i)<br />

(chronic)) may also be present. Extrapolation from such test results gives a predicted no-effect<br />

concentration in food (PNECoral) that should be protective to other mammalian <strong>and</strong> avian<br />

species.<br />

Acute lethal doses LD50 (rat, bird) are not acceptable <strong>for</strong> extrapolation to chronic toxicity, as<br />

these are not dietary tests. Acute effect concentrations (e.g. OECD 205 (1984h)) <strong>for</strong> birds are<br />

acceptable <strong>for</strong> extrapolation. The results of the available mammalian or avian tests may be<br />

expressed as a concentration in the food (mg .kgfood -1 ) or a dose (mg .kg body weight .day -1 )<br />

causing no effect. For the assessment of secondary poisoning, the results always have to be<br />

expressed as the concentration in food. In case toxicity data are given as NOAEL only, these<br />

NOAELs can be converted to NOECs with the following two <strong>for</strong>mulae:<br />

Explanation of symbols<br />

128<br />

NOEC = NOAEL ⋅CONV<br />

bird<br />

bird<br />

bird<br />

(77)<br />

mammal,<br />

food _ chr = NOAELmammal,<br />

oral _ chr CONVmammal<br />

(78)<br />

NOEC ⋅<br />

NOECbird NOEC <strong>for</strong> birds (kg . kgfood –1 )<br />

NOECmammal, food chr NOEC <strong>for</strong> mammals (kg . kgfood –1 )<br />

NOAELbird NOAEL <strong>for</strong> birds (kg . kg bw . d -1 )<br />

NOAELmammal, oral chr NOAEL <strong>for</strong> mammals (kg . kg bw . d -1 )<br />

CONVbird conversion factor from NOAEL to NOEC (kg bw . d . kgfood –1 ) Table 22<br />

CONVmammal conversion factor from NOAEL to NOEC (kg bw . d . kgfood –1 ) Table 22

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