2 Toxicological effects are believed to occur either: Non-Linearly (Threshold) Linearly(Non-Threshold) (low-dose extrapolation) 6 6 42 4 2 0 -NOAEL (the threshold") 0 2 4 6 0 2 4 68 DOSE DOSE 08i NOAEL:No Observable Adverse Effect Level OSU reoDOSE 0 2468 RESPONSE (malaise) 204 • Non-Linearly (Threshold) 6 8 NOAEL (the "threshold") DOSE 0 2468 RESPONSE (tumors) 2 0 4 •Linearly (Non-Threshold) (low-dose extrapolation) 6 8 Toxicological effects are believed to occur either: NOAEL: No Observable Adverse Effect Level