The Use of Exposure Models in Assessing Occupational Exposure to Chemicals

Humans do often experience occupational exposure to chemicals, which could lead to negative health effects if the risks aren’t managed. Proper risk assessments of exposure to chemicals is needed and can be performed in different ways. The exposure assessment part of the risk assessment can be performed by exposure measurements or by using exposure assessment models. The use of exposure assessment models is recommended by the authority of the REACH-legislation ECHA. It is of great importance that these exposure assessment models are studied and continues to develop. The genral aim of this thesis was to study the use of three exposure assessment models: ECETOC TRA, Stoffenmanager ® and the Advanced REACH Tool (ART), when performing exposure and risk assessments. We collected all data (input parameters for the models and exposure measurements) while visiting work places in a total of 7 types of indusries. The between user reliability was low when 13 users used Stoffenmanager ® assessing 11 exposure situations which the users were studying simultaneously visiting the 4 workplaces. The lack of agreements were calculated for Stoffenmanager ® and ART (50 th percentile) when assessing 29 exposure situations in 11 companies in 7 types of industries. The GM of measured exposures were used for comparison. The lack of agreement was higher for ART. ART underestimated the exposure in general but mostly for exposure situations concerning solids. Stoffenmanager ® overestimated exposures with low measured exposure and underestimated exposures with high measured exposures. Stoffenmanager ® estimated solids better than liquids. The level of protection was calculated for the same exposure situations as for the lack of agreements but the 90 th percentile of the models were used for comparison with the GM of the measurements. ECETOC TRA had lowest level of protection with 31 % of the measured exposure exceeding the modelled exposure, Stoffenmanager ® 17 % and ART 3 %. When comparing the outcomes from the models (90 th percentile) with limit values, ECETOC TRA had most false safe situations (the risk was considered safe by the model when in fact it was unsafe using measurements) compared to the other models. The risk assessment approach under REACH legislation was studied by the comparison between observed RCRs (calculated with the three models) and registered RCRs (presented in the e-SDS). The data was collected when visiting companies studying situations at the work places. In general, the registered RCRs were much higher than the observed RCRs but still about 12 % of observed RCRs were above 1 using Stoffenmanager ® . The observed RCRs above 1 had significant (p < 0.001) lower DNEL values and higher vapour pressures compared to observed RCRs below 1. When combing the results of our studies, ECETOC TRA shouldn’t be recommended as a protective (Tier 1) model since it has lowest level of protection, highest amount of false safe situations and didn’t present the most situations with RCRs > 1. Generic exposure scenarios (under REACH) may not provide safe use of chemicals based on our results.