Worldwide, 10 to 40 million tons of microplastics (MPs) are emitted annually into the environment, redistributing across environmental compartments and affecting organisms. Current life cycle impact assessment (LCIA) methods partially account for their impacts on ecosystem quality by considering a limited number of compartments and particles. This study advances the work of the MarILCA group by introducing the PEBBLE method which integrates physical effects of MPs, tire and road wear particles (TRWPs), and cellulosic microfibers across environmental compartments into life cycle assessment (LCA).Characterization factors (CFs) are developed for 10 conventional polymers, 6 biodegradable polymers, 6 cellulosic materials, and TRWPs, for multiple shapes and sizes. Particle fate is modelled using the SimpleBox object-oriented (SBoo) model for microparticles, computing fate factors (FFs) in air, terrestrial, freshwater, and marine environments at continental and global scales, following USEtox regionalization. SBoo was improved to account for size and shape effects, refined degradation data, regional marine currents, and biofouling.FFs are combined with exposure and effect factors in water, sediments, and terrestrial environments to obtain updated CFs. Uncertainty is quantified using Monte Carlo simulation, and time-horizon-dependent CFs are computed. Results are provided for different LCIA methods: for IMPACT World+ and ReCiPe, CFs representing regional species loss are derived, while for GLAM, the Global Extinction Probability is applied to derive CFs representing global species loss. The results support environmental decision-making for plastics and their alternatives, and aim to be the consolidated version of MarILCA CFs for microparticles, ready for implementation in LCA tools and methods.
Grain nitrogen (N) content is an important indicator of grain protein content and nutritional quality, and it is also an essential parameter for calculating nitrogen use efficiency (NUE) in cropping systems. Despite the potential influence of fertilizer, grain N content is often treated as a constant for a given crop, and few studies have evaluated its variability under different fertilization practices over the long term. In this study, we analyzed historical data from 11 long-term experiments in China to assess how fertilization practices impact grain N content and to quantify potential bias in NUE assessments arising from assuming a fixed grain N content. N inputs were not strictly equalized among treatments. N application significantly increased grain N content by 19% in wheat and 20% in maize relative to the unfertilized control. However, the increase diminished for wheat and stabilized for maize over the long term in synthetic fertilizer treatments. Compared with synthetic NPK fertilizer alone, the incorporation of manure effectively enhanced grain N content over the long term, despite a short-term reduction. Ignoring changes in grain N content led to an underestimation of wheat NUE by 11% and overestimation of maize NUE by 17%, underscoring the critical need to track grain N contents over time and across different fertilizer practices.
Multi-objective optimization has been widely applied to low-carbon mortar mix design, but comparatively few studies have simultaneously incorporated an experimentally measured chloride-related durability indicator and explicit carbon-pricing scenarios into cementitious binder optimization. To address these limitations, this study proposes a multi-objective optimization framework for oyster shell powder–calcined clay–cement (OC³) mortar based on a simplex-centroid design. Mechanical properties, hydration heat, ultrasonic pulse velocity, and surface electrical resistivity (SER) were experimentally measured and fitted as response models. SER was used as a comparative durability indicator, and carbon pricing was incorporated into the total cost function. Results show that adding durability as an objective markedly increases the optimized calcined clay content, accompanied by higher SER. Higher carbon prices further reduce cement content and carbon emissions per unit volume. This framework provides a practical approach for designing durable, low-carbon cementitious materials under carbon pricing scenarios.
