They were asked to pass a list with the number and the names of the persons within their organization that were willing to participate. After that, they received the necessary sampling material
from the WIV-ISP (Scientific Institute of Public Health). The blood samples themselves were taken by the occupational health physician of each organization. In addition, an e-mail address was opened ([email protected]) for any questions check details related to the biomonitoring study in Wetteren. Emergency responders who presented themselves spontaneously but were not on the lists, were also accepted for the study. The study protocol was approved by the Ethical Committee of the Ghent University Hospital and an informed consent was signed by all participants prior to their participation in the study. The sampling took place from May 21 until June 28, i.e., days 17–55 after the train accident. The data collection was organized in collaboration with the occupation health services. Each participant provided venous blood, collected in a tube filled with EDTA for the determination of N-2-cyanoethylvaline (CEV). Urine samples were collected for the measurement of cotinine because smoking may influence the CEV concentration. All Obeticholic Acid cost emergency responders also filled in a short questionnaire, including (i) demographic information,
i.e., name, address, gender and date of birth; (ii) smoking status (non-smoker, ex-smoker, occasional smoker and daily smoker); (iii) some specific variables related to the sampling, i.e., the day and the hour at which blood and urine sampling took Unoprostone place; (iv) a table with detailed information
on where participants had been in the night of and in the days following the train accident, i.e., <50 m, 50–250 m, 250–500 m, 500–1000 m, and >1000 m away from the train accident; by day between May 4–10; and (v) the use of respiratory protection (yes/no) in the night of and in the days following the train accident, by day between May 4–10. The function of the participants was provided by the emergency responder organizations. In total, 1054 emergency responders participated in the biomonitoring. Persons with missing value in either blood CEV measurements, urinary cotinine measurements, questionnaire (spatial and temporal information of the presence on-site between May 4–10), or transmission of the function, were omitted from the analyses of this article. The final study population consisted therefore of the 841 emergency responders. Blood samples were pre-treated within 24 h to obtain a lysate of erythrocytes. The pretreated samples were stored at −20 °C. Because of the need for substantial analyzing capacity, blood samples were sent on dry ice to three different laboratories specialized in CEV analyses where a modified Edman degradation was used for adduct dosimetry (Tornqvist et al., 1986 and Van Sittert et al., 1997).