Keywords: deterministic estimates, probabilistic estimates, dose, exposure, health risk assessment, uncertainty, risk management, risk communication, environmental engineering, risk modelling, risk estimation, hazardous substances, toxic substances
Risk uncertainty matters: an engineer's view
Risk assessment is a multi-disciplinary endeavour that synthesises scientific, social and economic factors and protects public health and natural resources. This paper assesses the literature and discerns the impact of risk uncertainty on human risk assessment, risk management and risk communication. This literature assessment is illustrative rather than comprehensive and regards risk assessment from the point of view of the environmental engineer. This paper puts forward exposure, dose and risk models used to estimate carcinogenic and non-carcinogenic deterministic (point estimates) or probabilistic risk and uncertainty values. The emphasis is on the uncertainty of risk estimates, uncertainty taxonomy and estimation of parameter uncertainty and uncertainty associated with selection of models and scenarios of exposure. This paper attempts to assess the current scientific schism among proponents of deterministic risk estimation and supporters of probabilistic risk and uncertainty estimates and asserts that either may be used as a factor of the risk assessment objectives and available data.