برآورد میزان مواجهه شغلی با هگزان نرمال در پاسخ معیار بر اساس اسیب به دید رنگ

Background and aims: Exposure to the normal hexane can induce dysfunction of the nervous system and color vision impairment. Occupational risk assessment is established according to no observed adverse effect levels (NOAEL). Recently, because of the NOAEL’s limitations, the benchmark responses were applied for risk assessment. The study’s aim is an analysis of benchmark response in occupational exposure to the normal hexane by color vision impairment. Methods: In this study, inhalation exposure to the normal hexane of some shoemakers was evaluated based on the OSHA ID-07 method. Two samples performed for each subject and cumulative exposure was estimated. Acquired color vision impairment was assessed by a D-15 technique in the both exposed and control groups. A dose-response curve was plotted by normal hexane cumulative exposure and color vision impairment according to the BMDS EPA software. Results: Exposure to the normal hexane in all studied workers was lower than OELs. It was found that 33% of the exposed groups had acquired color vision impairment. A dose-response curve was evaluated by five exposure groups in the range concentration of 0, 10.82, 11.97, 15.11 and 18.55 mg/m3.The results show Log Logistic model is the best model for the benchmark response prediction. Occupational exposure in 10% of responses (benchmark response) was determined 19.54 mg m-3 with a lower limit of 12.15 mg m-3. Conclusion: Neurological toxicity occurred in the levels of airborne exposure lower than occupational exposure limit. Accordingly, can be concluded that the new occupational exposure level can be established by further studies and concentrated researches for neurotoxicity of n-hexane through inhalation exposure.