Toxicological approaches for the quantitative inhalation risk assessment of toxic metals from tobacco smoke: application on the deterministic and probabilistic inhalation risk assessment of cadmium for Austrian smokers

Abstract

Objective

The objective of this study was the assessment of risks from inhalation exposure of Austrian smokers to cadmium through established toxicological approaches with emphasis on the exposure assessment component, which is challenging regarding the actual amount of metal that is inhaled and the simulation of the smoking pattern.

Materials and methods

Exposure assessment comprised an estimation of the proportion of cadmium inhaled through smoking and actual occurrence data in tobacco products and survey smoking habits, which were integrated in alternative scenarios through a deterministic and a probabilistic Monte Carlo simulation method. Risks were characterized through the comparison of the exposure with health-based guidance values, as well as through the assessment of the excess lifetime cancer risk (ELCR), the non-cancer hazard quotient (NCHQ), and the margin of exposure (MOE). The strengths, the uncertainties, and the limitations of the different methodologies were discussed.

Results and discussion

Upper exposures are close or exceed the Permitted Daily Exposure. Respiratory ELCRs are unacceptable compared to the benchmark range of 1.0E–06 to 1.0E–04. Renal and respiratory NCHQs exceed the target value of 1.0 by 3- to 17-fold. MOEs are not protective enough for cancer and non-cancer effects. The amount of cadmium that reaches the lung is a key source of uncertainty.

Conclusion

Probabilistic estimates provide a refined capture of the actual inhalation exposure. Risk estimates and gender and age profiles are alarming, especially for young smokers. Application of toxicological approaches, combined with realistic assessment of the inhalation exposure levels, can support risk communication and management.

Keywords:

• Cadmium
• inhalation exposure
• smoking
• risk assessment
• Monte Carlo
• probabilistic
• margin of exposure
• excess lifetime cancer risk
• hazard quotient

Acknowledgements

The authors wish to thank the European Food Safety Authority (EFSA), as this work was part of the risk assessment on cadmium, implemented by the Austrian Agency for Health and Food Safety (AGES) within EFSA’s EU-FORA Fellowship Programme. The first author was hosted as a fellow of the 2018–2019 cohort at the Department of Risk Assessment of the Data, Statistics and Risk Assessment Division of AGES in Vienna. Tobacco products samples were collected within the framework of the Official Control and Inspections in Austria. Chemical analyses were conducted in the laboratories of the AGES Institute for Food Safety in Vienna.

Disclosure statement

No potential conflict of interest was reported by the author(s).