An Assessment of the Robustness of the COSHH-Essentials (C-E) Target Airborne Concentration Ranges 15 Years on, and Their Usefulness for Determining Control Measures

Experimental Application of Semi-Quantitative Methods for the Assessment of Occupational Exposure to Hazardous Chemicals in Research Laboratories

Purpose

The aim of this study was to evaluate the application of some chemical risk assessment semi-quantitative methods and also to identify potential bias or differences originated by applying different methods to the same activities.

Methods

We collected the data related to the chemical agents used in three different activities of three laboratories of an Italian university; the methods we compared were: MoVaRisCh, COSHH Essentials, LaboRisCh and Datarisch.

Results

The input parameters requested by each method are shown for each activity and for each used chemical. We collected the results obtained since the application of the four different tools in three tables. The use of some chemicals (especially of the activity n° three) shows a not irrelevant risk for the users.

Conclusion

Our findings show that COSHH Essentials, MoVaRisCh and Datarisch tools are consistent in the identification of a risk level; the small differences are related to risk rating, to be considered in relation with the specific structure of the method applied. The differences detected in the risk rating may be overcome by applying, for each working activity we want to assess, two or more different semi-quantitative tools. This strategy can allow to reduce the exposure to chemicals of the workers.

Industry Derived Occupational Exposure Limits: A Survey of Professionals on the Dutch System of Exposure Guidelines

The Netherlands’ system for occupational exposure limits (OELs) encompasses two kinds of OELs: public and private. Public OELs are set by the government. Private OELs are derived by industry and cover all substances without a public OEL. In parallel, the regulation concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) has introduced an exposure guidance value similar to the OEL, namely the Derived No-Effect Level (DNEL) for workers’ inhalation exposure. This study aimed to investigate issues encountered by occupational health professionals regarding private OELs, and how they perceive the DNELs for workers in relation to private OELs. Towards this aim, we sent out a web-based questionnaire to the members of the Dutch professional organization for occupational hygienists (Nederlandse Vereniging voor Arbeidshygiëne [NVVA], n = 513) and to members of the Dutch professional organization for safety engineers (NVVK, n = 2916). Response rates were 27% (n = 139) and 7% (n = 198), respectively. More occupational hygienists (59%) than safety engineers (17%) reported to derive private OELs themselves. Our respondents reported several challenges with the derivation of private OELs. Fifty-one percent of the occupational hygienists and 20% of the safety engineers stated to see a role of REACH Registrants’ worker DNELs as private OELs. However, more than half of our respondents were undecided or unfamiliar with worker DNELs. In addition, stated opinions on where worker DNELs fit in the hierarchy of private OELs varied considerably. To conclude, both these professional groups derive private OELs and stated that they need more guidance for this. Furthermore, there is a lack of clarity whether worker DNELs may qualify as private OELs, and where they would fit in the hierarchy of private OELs.

Derivation of internal dose-based thresholds of toxicological concern for occupational inhalation exposure to systemically acting organic chemicals

This study aimed at deriving occupational thresholds of toxicological concern for inhalation exposure to systemically-acting organic chemicals using predicted internal doses. The latter were also used to evaluate the quantitative relationship between occupational exposure limit and internal dose. Three internal dose measures were identified for investigation: (i) the daily area under the venous blood concentration vs. time curve, (ii) the daily rate of the amount of parent chemical metabolized, and (iii) the maximum venous blood concentration at the end of an 8-hr work shift. A dataset of 276 organic chemicals with 8-hr threshold limit values-time-weighted average was compiled along with their molecular structure and Cramer classes (Class I: low toxicity, Class II: intermediate toxicity, Class III: suggestive of significant toxicity). Using a human physiologically-based pharmacokinetic model, the three identified dose metrics were predicted for an 8-hr occupational inhalation exposure to the threshold limit value for each chemical. Distributional analyses of the predicted dose metrics were performed to identify the percentile values corresponding to the occupational thresholds of toxicological concern. Also, simple linear regression analyses were performed to evaluate the relationship between the 8-hr threshold limit value and each of the predicted dose metrics, respectively. No threshold of toxicological concern could be derived for class II due to few chemicals. Based on the daily rate of the amount of parent chemical metabolized, the proposed internal dose-based occupational thresholds of toxicological concern were 5.61 × 10^-2 and 9 × 10^-4 mmol/d at the 10th percentile level for classes I and III, respectively, while they were 4.55 × 10^-1 and 8.5 × 10^-3 mmol/d at the 25th percentile level. Even though high and significant correlations were observed between the 8-hr threshold limit values and the predicted dose metrics, the one with the rate of the amount of chemical metabolized was remarkable regardless of the Cramer class (r² = 0.81; n = 276). The proposed internal dose-based occupational thresholds of toxicological concern are potentially useful for screening-level assessments as well as prioritization within an integrated occupational risk assessment framework.