Final opinion on potential risks to human health and the environment from the use of calcium cyanamide as fertiliser

The purpose of this Opinion is to assess potential risks to human health and the environment from the use of calcium cyanamide as fertiliser. Where appropriate, data on hydrogen cyanamide were also considered as this substance is a primary intermediate formed by the degradation of calcium cyanamide when applied as fertiliser or after organisms have been exposed to it. The SCHER has collected available data on physicochemical properties, agricultural practices and (eco) toxicology of this substance. These were used to derive an acceptable operator exposure level (AOEL) as well as the predicted no effect concentrations (PNECs). Subsequently the SCHER calculated predicted environmental concentrations (PECs) using the common application rates of the fertiliser and exposure models. The resulting PECs were compared to the PNECs to calculate the risk characterization ratios (RCRs) for environmental compartments. With regard to human health, the SCHER has calculated human health risks using worker exposure models for the use of calcium cyanamide as fertiliser, based on approaches used for registration of plant protection products. Exposure calculations were performed for both professional and private use scenarios and additionally for by-standers and residents, including children. The SCHER concluded that harmful effects for humans and for the environment could not be excluded when calcium cyanamide is used at the current rates of application.