Since the International Agency on Cancer Research’s monograph found glyphosate to be a likely carcinogen, the regulatory focus on the chemical has centred on this determinative criterion for regulatory action. Yet, other pertinent factors, such as the effects of glyphosate on fresh and ground water and ensuing effects on biodiversity, have received less attention as legitimate rationales for regulating the chemical. This underrepresentation prevents a wider policy discussion on the environmental and human health effects of the chemical and (...) fails to disrupt assumptions of path-dependently continuing on agriculture’s chemical treadmill. To avoid ad hoc post hoc chemical regulation, we assess four areas of chemical regulatory oversight in Europe with regard to glyphosate affecting water: (1) the undue emphasis on in laboratorio versus in situ testing; (2) assessing single chemicals (isolated glyphosate) versus admixtures (glyphosate plus surfactants and adjuvants) that are used in practice; (3) the tendency to downplay harms to non-human life; and (4) the lack of policy coherence in the existing regulatory framework. Focusing on European Union regulation of pesticide and water policy affecting aquatic environments, we conclude that issues of measurement and priority have become highly politicised in both science and policy, requiring preventative, precautionary frameworks utilising plural forms of measurement. (shrink)