The internal corrosion of cast iron and steel pipes is one of the main issues that drinking water distribution operators are facing. This study evaluated the relevance of 10 known corrosion indices according to their estimate of corrosion rate and iron particle release for 20 different water qualities. Pilot-scale contact trials were run over 45 days using cast iron and steel coupons. Corrosion rate was measured by coupon weight-loss and by an online linear polarization rate probe. Particle release was monitored by an online turbidimeter. The results showed that none of the indices properly predicted the level of risk associated with each water and that corrosion and particle release were not correlated. Two novel indices were developed to predict the corrosion and particle release risks independently of each other. The corrosion index showed a strong linear correlation with the corrosion rate of cast iron and slightly less reliable results for steel. The Particle Emission Index presented good correlation with turbidity in waters following contact with cast iron. These two indices thus showed interesting potential as tools to limit internal corrosion risks for metal pipes in water distribution networks.

Coastal landfills are poorly documented reservoirs of plastic waste that may release microplastics (MPs) directly to marine environments through erosion, marine flooding, and sea-level rise. This systematic review, conducted following the PRISMA 2020 guidelines, synthesizes current knowledge on MPs associated with coastal landfills, analytical practices, and potential export pathways. Among 211 publications addressing plastics and MPs in landfills, only seven provided quantitative MP data from coastal landfill systems or associated receiving environments. Reported mean abundances were 0.0043–79 MPs L⁻¹ in water and 410–12,300 MPs kg⁻¹ d.w. in solid matrices. Comparisons among studies were strongly limited by differences in sampled matrices, pretreatment protocols, analytical techniques, particle-size thresholds, and reporting units. Using the abundance measured in marine sediment adjacent to the Dollemard coastal landfill as a local proxy, annual number-flux scenarios ranged from 3.08 × 10⁹ to 4.10 × 10¹⁰ MPs yr⁻¹. Hypothetical scaling of these scenarios to approximately 100,000 coastal landfill sites worldwide yielded 3.08 × 10¹⁴–4.10 × 10¹⁵ MPs yr⁻¹, or 1.45 × 10⁻²–7.33 × 10⁻¹ Tg yr⁻¹. These first-order scenarios are not estimates of current global emissions but highlight the need to better quantify this understudied pathway in marine MP budgets.