INTERA Stakeholder Workshop 18th of November 2011 Brussels INTERA Project BTEX case study

INTERA Stakeholder Workshop 18th of November 2011 Brussels What is BTEX? Chemical nameCAS NoFormulaMWlog K ow Benzene C6H6C6H Toluene C 7 H 8 or C 6 H 5 CH Ethylbenzene C 8 H Xylenes C6H4C2 H6C6H4C2 H How are people exposed to BTEX? Exposure in the indoor environment is dominated by inhalation (ECB RAR’s). As BTEX is not is not one chemical, but a quaternary mixture of chemicals, exposure to BTEX involves a multi-chemical approach which has to take into account possible interactions between the four substances. BTEX health effects neurological impairment benzene (and more precise its toxic metabolites) can additionally cause hematological effects including acute myelogenous leukemia (AML)

INTERA Stakeholder Workshop 18th of November 2011 Brussels Personal exposure E T is given as a function of the concentrations C in the locations encountered, the time spent in these locations and the type of performed activity, which in turn affects the breathing rate where inh is the inhalation correction coefficient for each type of microenvironment encountered in the calculations Data acquisition BTEX concentrations for several types of locations Activity pattern data Physiological and biochemical parameters Exposure is the input for the BTEX PBPK model, taking into account the mixture interaction occurring at the level of BTEX metabolism (competitive inhibition) Case study work flow

INTERA Stakeholder Workshop 18th of November 2011 Brussels Average benzene concentrations in several EU locations

INTERA Stakeholder Workshop 18th of November 2011 Brussels Average toluene concentrations in several EU locations

INTERA Stakeholder Workshop 18th of November 2011 Brussels Average ethylbenzene concentrations in several EU locations

INTERA Stakeholder Workshop 18th of November 2011 Brussels Average xylenes concentrations in several EU locations

INTERA Stakeholder Workshop 18th of November 2011 Brussels Average BTEX intake across EU

INTERA Stakeholder Workshop 18th of November 2011 Brussels Exposure scenario assessed: Belgium, Adult male

INTERA Stakeholder Workshop 18th of November 2011 Brussels Exposure scenario assessed: Belgium, Adult male Intake probability distribution (MC analysis incorporating exposure and biokinetic variability)

INTERA Stakeholder Workshop 18th of November 2011 Brussels Exposure scenario assessed: Belgium, Adult male

INTERA Stakeholder Workshop 18th of November 2011 Brussels Conclusions There are significant data gaps with regard to indoor concentrations of BTEX across the EU. Exposure to TEX is significantly below the existing Exposure Limit values, thus the health concern of BTEX exposure is more closely associated to prolonged exposure to benzene. At the levels of environmental concentrations met in EU indoor locations, no mixture interaction at the metabolism level is manifested; thus, co-exposure to BTEX does not pose any reason for additional concern should these contaminants be assessed as individual substances.