Use of Information on Reproductive Toxicity in Hazard Identification

The adverse reproductive effects are considered as being threshold effects, i.e., effects for which there are expected to be a threshold of substance concentration below which the effects will not be manifested. For the hazard and risk assessment, it is important to identify those dose levels at which adverse reproductive effects are observed, and the dose level at which adverse reproductive effects are not observed, i.e., to derive a NOAEL for reproductive toxicity. Crucial in the derivation of the NOAEL and/or LOAEL, is the definition of adverse effects (Section 4.2.2). In the derivation of the NOAEL and/or LOAEL, a number of factors need to be considered these issues are addressed in detail in Sections 4.2.3 and 4.2.4. An alternative approach to the derivation of the 

Toxicological Risk Assessments of Chemicals A Practical Guide 

the BMD concept, and the limitations of its applicability are addressed in Section 4.2.5. Attention is brought to the fact that the BMD approach has been studied most widely in the contexts of developmental toxicity endpoints (Falk Filipsson et al. 2003). 

Human studies on altered sexual function/fertility provide the most direct means of assessing risk, but data are often unavailable (WHO/IPCS 2001b). 

If it is possible to identify a NOAEL from well-reported and reliable human smdies, this value may be used preferentially in the risk assessment. However, it is expected that this will rarely be the case. 

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