Environmental fate and ecotoxicology of propanil: a review

The herbicide propanil, a synthetic anilide, was discovered in 1957 to control grasses and broad-leaf weeds in rice fields. It has been found to disrupt the electron transport chain by inhibiting the photosystem II, thus impacting plant growth. In the environment, photolysis represents a major degradation pathway, whereas volatilization is not a major route of dissipation from either water or moist soils. Propanil is rapidly degraded by microbes into the major degradation product 3,4-dichloroaniline. This degradation product has been highly detected in both groundwater and surface waters throughout the world. Propanil has been found to adversely impact many non-target organisms. It is toxic to some early life-stage aquatic organisms, in addition to being moderately toxic to the water flea (Ceriodaphnia dubia) and rainbow trout. In addition, it has been reported to pose a high acute and long-term risk to birds. In plants, growth rates are highly impacted; however, some plant species are becoming resistant to propanil.