Toluylendiisocyanate – Addendum zur Ableitung eines BAT-Wertes (original) (raw)

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area re-evaluated 2,4-toluene diisocyanate (2,4-TDI) [584-84-9], 2,6-toluene diisocyanate (2,6-TDI) [91-08-7] and toluene diisocyanates, mixture [26471-62-5] and derived a biological tolerance value (BAT value) for the combined urinary con centration of the two metabolites 2,4-toluenediamine (2,4-TDA) and 2,6-toluene diamine (2,6-TDA) to characterise the internal exposure at the workplace. The evaluation of the BAT value was based on the relationship between 2,4-/2,6-TDI uptake by inhalation at the level of the MAK value and the corresponding urinary excretion rate of 2,4-/2,6-TDA. Biomonitoring field studies were applied in which the excretion of 2,4-and 2,6-TDA in urine of persons occupationally exposed to 2,4-/2,6-TDI was examined as well as the concentration of TDI in the air. An eight-hour exposure to the present MAK value of 0.001 ml 2,4-/2,6-TDI/m³ (7 µg 2,4-/2,6-TDI/m³) correlated with a mean urinary sum of 2,4-and 2,6-TDA concentration (after hydrolysis) of approximately 5 µg/g creatinine. Therefore, a BAT value of 5 µg Σ 2,4-and 2,6-TDA (after hydro lysis)/g creatinine was evaluated. Sampling time is at the end of exposure or the end of the working shift.