Water treatment and disinfection by-products

Water treatment and disinfection by-products : A comparison of approaches for crop protection and biocidal products in the EU

Jan Achtenhagen, Sabine Dorn , Frauke Schnitzler
^{knoell Germany GmbH}

Regulation (EC) No 1107/2009 lays down the rules for the authorisation of crop protection products in Europe with the aim of protecting humans and the environment. During primary disinfection processes for central water treatment (e.g. ozonation, chlorination) certain active substances included in crop protection products and their metabolites have the potential to form unwanted by-products with e.g. toxic, carcinogenic and genotoxic characteristics. Notwithstanding that the EFSA (European Food Safety Authority), the scientific advisory body of the European Commission, has recently identified data gaps during the approval process of active substances, water treatment processes have not (yet) been implemented in the European data requirements (Reg 283/2013 or 284/2013) relevant for the authorisation of crop protection products. Further, no guidance document for experimental testing is available. With this information pending, addressing water treatment processes successfully becomes a challenge for applicants of crop protection products.

Biocidal Product Regulation (BPR)(EU) 528/2012 regulates the application of disinfectants for water treatment. Disinfection by-products (DBPs) are formed during the disinfection process using oxidizing, halogen containing biocidal products. According BPR (2012) the effect of residues, which includes per definition also reaction products like DBPs, should be further evaluated in the risk assessment, as known DBPs like trihalomethanes and haloacetic acids can be biologically active and stable in the environment.
A recently published guidance document, Guidance on the Biocidal Products Regulation, Volume V, Guidance on Disinfection By-Products (2017) (2) defines a stepwise approach for an environmental risk assessment (ERA) of DBPs and provides further guidance for testing strategies, like whole effluent testing.

Event: SETAC Europe 2021