Human health risk assessment is one of the rapidly evolving tools used in the management of contaminated aquifers. Health risk assessments have been traditionally based on the point estimate approach. Due to the uncertainty and variability inherent in subsurface properties and exposed human population characteristics, probabilistic risk assessment is becoming widely accepted. This study is focused on understanding the uncertainty in biokinetic parameters in describing biodegradation under natural and enhanced remediation conditions. The uncertain parameters considered in this work are key biokinetic parameters and the uncertainty is assessed using the predicted receptor maximum concentration, maximum of 30-year average concentration, time to reach maximum concentration, maximum mass of decay, and the time for maximum decay. The results of this analysis were extended to health risk assessment and risk-based economic analysis. The paper discusses the approach and methodology adopted in this study and the implication of uncertainty of key parameters on decision-relevant information.