Case Study - Alliance for Risk Assessment

1,3-Butadiene concentration parts per billion by volume (ppbv)43.1 1,3-ButadieneFigure 1 show the five sites in Texas with the highest 1,3-butadiene annual averageconcentrations (01/01/2010 to 12/31/2011). These measured 24-hr concentrations were almosttwo orders of magnitude below the 24-hr AMCV of 430 ppb based on decreased fetal bodyweight and maternal body weight gain. Adverse health effects would not be expected to occur.It should be noted that 24-hour AMCVs are based on noncancer effects and are not relevant to acancer assessment. However, as cancer is typically of some interest it is addressed here in thecontext of the data shown as solely a peripherally-related topic. When 24-hr measuredconcentrations were compared to the long-term AMCV for butadiene for 2010-2011 samplingdata, there were no exceedances of the long-term AMCV of 9.1 ppb (based on a 1x10 -5 lifetimeexcess risk goal for leukemia).20.018.016.0TCEQ 24-hr Air MonitoringComparison Value 430 ppb14.012.010.08.06.0TCEQ Long-Term AirMonitoring ComparisonValue 9.1 ppb4.02.00.0I Groves I Port Neches Ave L I Galena Park IJacinto PortIJefferson Co AirportFigure 3-4 Top five sites with the highest 1,3-butadiene annual average concentrations (01/01/2010 - 12/31/2011)Figure 1. Five Texas Sites with the Highest 1,3-Butadiene Annual Average Concentrations(01/01/2010 to 12/31/2011)3.2 AcroleinFigure 2 shows acrolein samples collected every 6th day between 10/6/2011 and 10/30/2012 attwo sites in Texas. The measured 24-hr values are well below the 24-hr AMCV of 1.2 ppb. Thus,no short-term adverse health effects would be expected based on an assumption of independentexposure to these individual 24-hour measurements.For acrolein, there were only five occasions where the 24-hr measured concentrations wereslightly above the chronic AMCV of 0.22 ppb (Karnack site). The annual average was below the