lmplementation of a national regulatory framework for drinking water safety plans in Uruguay.

The establishment of national strategic frameworks for systematic scaling-up of water safety plans (WSPs) implementation needs to overcome major constraints: lack of legislation and policies, and the need for appropriate monitoring tools. In 2018, the Uruguayan regulator for energy and water services promulgated a regulation intended to ensure an ambitious and pragmatic strategy that supports and promotes WSP implementation and auditing at a national scale. The goal is to have all drinking water supply systems with their WSP implemented by 2030. For this, a demanding schedule was recommended considering the size of the drinking water supplies: (i) large systems serving more than 2,000 inhabitants and (ii) small and very small systems serving fewer than 2,000 inhabitants. A mandatory verification through internal and external audits was also established. This work describes the legal and regulatory framework as well as the challenges and opportunities that open up for the generalization of WSP implementation in Uruguay. Despite the impact of COVID-19 on working conditions for water suppliers, as for the year 2022, WSPs have been successfully implemented in 94 water systems serving more than 2.4 million people. Results of successful implementation and auditing processes are presented and discussed covering methods and outcomes.

Thermally reversible nanocellulose hydrogels synthesized via the furan/maleimide Diels-Alder click reaction in water.

The study deals with the synthesis of thermally reversible hydrogels from modified cellulose nanofibers via the Diels-Alder "click" reaction in an aqueous medium. "Never-dried" cellulose fibres derived from hardwood were submitted to shearing and surface TEMPO-oxidation before being modified with furfurylamine. The ensuing pendant furan moieties were reacted with a water-soluble bismaleimide via Diels-Alder coupling at 65 °C to produce a hydrogel, whose deconstruction was induced by the corresponding retro-Diels-Alder reaction carried out at 95 °C. Differential scanning calorimetry and rheological measurement were used to characterize the hydrogels. These aqueous cellulosic materials should provide original applications in such areas as strong paper-based artefacts and biocompatible gels.