Table 4 Descriptive themes on exposure assessment & risk characterisation

Exposure assessment

Combining strategies for exposure assessment.

• All routes of exposure should be addressed (inhalation, dermal, oral).

• Use of biomonitoring in assessment of the total exposure

• Exposure can be estimated/modelled by assessing the used processes, volumes of chemicals used/produced and the physico-chemical characteristics, such as vapour pressure.

Reliable exposure assessment is challenging but necessary to reliably support maternity protection.

• General exposure assessment challenges

◦ Need for multiple measurements to reach adequate certainty about exposure levels.

◦ Judging the protective effect and reliability afforded by PPE.

◦ Intermittent and or (risk of) accidental exposures are hard to measure/predict.

• Limitations of biomonitoring

◦ Limited number of available biomarkers.

◦ Difficulties in procuring biomonitoring samples at end of shift/workweek.

◦ Challenges in accounting for synergistic effects of mixtures with individual biomonitoring markers.

Risk characterisation

Correct interpretation and use of occupational exposure limits (OEL) is essential.

• Understanding their origin and context: was reproductive health considered when the values were set?

• Threshold of effects are generally assumed for the dose-response relationships for reproductive toxicants, although some substances may have very low thresholds.

• No safe exposure level exists for genotoxic carcinogens or mutagenic substances, even when they have OELs.

Apply best practices of risk assessment.

• Hazards do not pose risks unless there is exposure.

• The more serious the hazards, the lower the tolerance for exposure.

• Risk assessment should be continuously updated and evaluated in a dynamic risk control system

Specific considerations for determining acceptable risk levels in pregnant workers.

• Application of extra uncertainty factors to OELs were often suggested, e.g. that a level of 10% of the OEL could be accepted.

• Exposures levels below those experienced by the general population were generally considered acceptable, e.g. for diesel engine exhaust.

• Biomonitoring was often suggested as a means of exposure assessment.

• Handling of some toxic chemicals under very controlled circumstances, e.g. use of very limited amounts in a fume cabinet, were considered acceptable in some guidelines.

• The precautionary principle was recommended to be used when data about the hazard or exposure is lacking, unclear or unreliable.