The post-market environmental monitoring of GM maize in the EU has a limited capacity to identify adverse effects

Highlights: • Post-market environmental monitoring of GM crops is mandatory in the EU. • The current practice of PMEM limits its aim of detecting unforeseen adverse effects. • PMEM relies on famers' questionnaires and complaint system, and a literature survey. • Farmers lack the knowledge, time, and motivation to report impacts on biodiversity. • The use of environmental surveillance networks agreed by EFSA should be implemented. The EU legislation requests post-market environmental monitoring (PMEM) of a genetically modified (GM) organism even if its pre-market risk assessment indicated negligible risks. It has been claimed that the monitoring of the only currently commercially cultivated GM plant in the EU, Bt MON810 maize, has not revealed any adverse effects. However, the implementation of its PMEM has been criticised repeatedly by the European Food Safety Authority (EFSA). Although EFSA agreed with the monitoring plan consisting of four tools, as proposed by the company which markets MON810, in practice PMEM has relied on famers' questionnaires, a farmers' complaint system, and a literature survey. The fourth approach, environmental surveillance networks, has not been utilised yet. Furthermore, PMEM requires that farmers plant a refuge of non-Bt maize in order to sustain the efficiency of the plant in combating the targeted pest. This paper aims to contribute to improved PMEM by means of a critical evaluation of its implementation in the Czech Republic based on interviews and a questionnaire survey of farmers who cultivated MON810. The results indicate that a quarter of the farmers who were surveyed did not comply with the refuge requirement. Moreover, farmers often lacked the knowledge, time, and motivation to observe and report the potential impacts of Bt maize on biodiversity, which is supposed to be monitored by the PMEM farmers' questionnaire. The findings of this study compound the previous criticism and suggest that the current practice of PMEM limits its aim of detecting unanticipated adverse effects of MON810 maize cultivation on human and animal health and the environment. The PMEM plan should be revised before the approval process of the application for the renewal of the authorisation for MON810 cultivation in the EU continues.