A brief history of risk assessment for agrochemicals

Risk assessment of pesticides has its roots in the same process for chemicals in general, both of which are relatively recent. Pesticides such as oxides of sulfur and some minerals were also used by early civilizations but the concepts of dose-response and risk as a probability were only documented in the literature (books) in the 1500s and 1600s, respectively. Formal use of toxic dose and safety factors for humans was developed as inorganic and organic pesticides entered the market after the 1930s, but only made use of simple hazard ratios to characterize danger. This approach continued until adoption of the concept of probability of exposure of humans to pesticides via dietary exposure, but not sensitivity of humans. It was in 1980s–90s that the use of probability was suggested as a way of characterizing variation in sensitivity of species in the environment as well as the exposures in environmental matrices. As we move into the future, risk assessment of agrochemicals will evolve to include new frameworks and approaches for dealing with conflicting data, such as Weight of Evidence.