A study using QSAR/QSPR models focused on the possible occurrence and risk of alloxydim residues from chlorinated drinking water, according to the EU Regulation.

Any active substance with phytosanitary capacity intended to be marketed in Europe must pass exhaustive controls to assess its risk before being marketed and used in European agriculture. Since the implementation of Regulation (EC) No 1107/2009, agrochemical companies have been obliged to study the formation of pesticide transformation products (TPs) during the treatment of drinking water containing pesticide residues. However, there is no consensus on how to address this requirement. In this research work, the open literature collection on alloxydim was used to propose potential chlorination paths from alloxydim isomers. Furthermore, several QSAR/QSPR models have been used to fill the of knowledge gap relative to some key parameters in the physico-chemical, environmental and ecotoxicological areas of potential alloxydim TPs from chlorinated water for which little information exists. In this way, it has been possible to estimate the state of aggregation of these TPs (they exist mainly as liquids) as well as their ease of transit between the different phases, to predict their possible behaviour in the three environmental compartments (e.g., thermophysical properties point to a change in their evolution with respect to the parent alloxydim isomers) and to anticipate their potential risk to human and animal health (e.g., all of them cause developmental toxicity). These and other results highlight that the hazards of several TPs, i.e., both chlorinated and nonchlorinated from parent alloxydim or from those obtained after cleavage of the N - O bond and the subsequent reaction with chlorine, should be seriously considered. The obtained results reopen the debate on the implications of the use of QSAR/QSPR models for pesticide risk assessment in the legislative framework.