Biomedical subjects

Peter M J Bos

Publications and source records attributed to Peter M J Bos.

3 recordsLinked to original sources

PubMed2005

Probabilistic risk characterization: an example with di(2-ethylhexyl) phthalate.

While probabilistic methods gain attention in hazard characterization and are increasingly used in exposure assessment, full use of the available probabilistic information in risk characterization is still uncommon. Usually, after probabilistic hazard characterization and/or exposure assessment, percentiles from the obtained distributions are used as point estimates in risk characterization. In this way, all information on variability and uncertainty is lost, while these aspects are crucial in any risk assessment. In this paper, we present a method to integrate the entire distributions from probabilistic hazard characterization and exposure assessment into one risk characterization plot. This method is illustrated using di(2-ethylhexyl) phthalate as an example. The final result of this probabilistic risk assessment is summarized in a single plot, containing two pieces of information: the confidence we may have in concluding there is no risk, and the fraction of the population this conclusion applies to. This information leads to a better informed conclusion on the risk of a substance, and may be very useful to define the necessary measures for risk reduction.

Adult↗

PubMed2004

Risk assessment of peak exposure to genotoxic carcinogens: a pragmatic approach.

Short-term exposures to relatively high concentrations or doses are a regular cause of concern. Since carcinogenicity is often of great personal and social relevance the question arises whether short-term exposure (1-10 days) to a carcinogenic substance may contribute to tumour development and, if so, whether this contribution to the cancer risk can be quantified. The present object was to explore the possibility of a pragmatic estimation of the cancer risk of peak exposure to a genotoxic carcinogen relative to the cancer risk of the same cumulative dose of this carcinogen distributed over lifetime. A report published by the Health Council of The Netherlands served as point of departure. Published data strongly suggests that short-term or single exposure can indeed give rise to tumour formation in animal experiments. The application of a dose-rate correction factor (DRCF), defined as a factor by which the tumour incidence caused by a specific dose of a chemical carcinogen at low-dose rates is multiplied to derive the tumour incidence at high-dose rates, appears to be a feasible approach. Theoretical models calculated maximum values for the DRCF of up to seven for a young child acutely exposed to an initiator or first-stage carcinogen. A maximum value of 8.3 was calculated from animal experiments. A decision tree is presented which allows the pragmatic assessment of the carcinogenic risk following short-term exposure to genotoxic carcinogens. It is recommended to validate this decision tree with model-substances.

Age Factors↗

PubMed2002

Evaluation of the sensory irritation test (Alarie test) for the assessment of respiratory tract irritation.

Within the framework of risk assessment of existing substances in the EC the irritating properties on the respiratory tract should be considered. Since no standardized test is available it was studied whether the Alarie test could be used for this purpose, as proposed by the Technical Guidance Document for new and existing substances. The available literature on respiratory tract irritation, seen as a local inflammatory response and/or tissue damage, after single and repeated (few-day) exposure was evaluated and compared with data on sensory irritation. No relation was found between the sensory irritation potential (as measured by the Alarie test) and local tissue damage (histopathological changes) in the respiratory tract after single or repeated exposure. It was concluded that the Alarie test is inappropriate to evaluate respiratory tract irritation. In addition, the available data do not support a quantitative potency ranking for man based on the RD50 obtained with experimental animals.

Administration, Inhalation↗