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• A multi-stochastic SMR siting model is developed to handle multiple uncertainties • Environmental-economic trade-offs related to SMR siting are analyzed systematically • The competitive relationships among SMRs, CCS, and CCGTS are analyzed • Multi-scenario analysis provide policy supports for decision-makers Existing electric power systems have been being faced with great concerns on climate change mitigation through the reduction of greenhouse gas emissions in recent decades. Small modular reactors (SMRs) are considered the next generation of power technologies, offering stable, safe, and environmental-friendly power. This research initially establishes a multi-stochastic SMR siting model (SSMRS) based on a dynamic mixed-integer left-hand-side chance-constrained multistage programming (DMLCM) method, aiming to provide solid bases for electric power system management to promote GHG mitigation under uncertainties and advance the practical application of SMRs in a regional electric power system. The model is applied to emission-intensive Saskatchewan power systems, which have a high reliance on fossil fuels. The commissioned coal-fired and gas-fired power plants in Saskatchewan are identified as potential sites for employing SMRs. A series of scenarios regarding technical development and carbon policies are analyzed to study the interrelationships among technological competition, policy efficiency, and system-failure risk. This is the first attempt to apply an optimization-based modeling approach for siting SMRs in Saskatchewan with detailed consideration of other new-emerging emission reduction technologies. We found that a carbon tax ranging from 30 to 40$/tonne might be reasonable in Saskatchewan after 2030 while the SMR would be partly commercially viable, occupying ∼>15% of total installed capacity. The solution obtained could provide scientific bases for decision-makers to determine optimal schemes for power supply, capacity expansions, and system costs under environmental targets, and particularly identify construction schemes for SMRs at specific sites in different periods under various risk levels. [ABSTRACT FROM AUTHOR]

The study on micro/nanoplastic pollution should embrace complexity. Here, we aim to develop an aquatic environmental system-based comprehensive assessment approach of micro/nanoplastic impacts (ACAM) to evaluate the effects of micro/nanoplastics on aquatic ecosystems from the global environmental change (GEC) and systematic perspective. A case study for freshwater systems in Saskatchewan, Canada was conducted to evaluate the comprehensive effects of multiple GEC factors (polystyrene-nanoplastics (PS-NPs), N, P, salinity, dissolved organic matter (DOM), pH, hardness) on Asterococcus superbus based on ten ecologically relevant endpoints. It is found that at the cellular level, PS-NPs and N had an antagonistic interaction on microalgal growth in the Saskatchewan freshwater ecosystem; at the molecular level, the PS-NP-induced changes in lipid composition in microalgae were regulated by P, DOM, and pH. The significance ranking of factor effects suggested that instead of PS-NPs pollution, the fluctuations in pH level, DOM and N concentrations should be paid attention to first in Saskatchewan. Under the combined impact of PS-NPs and other GEC factors, microalgae at station 14 (Qu'Appelle River near highway 56) might have the minimum growth rate with [−0.048, 0.094] d-1 in Saskatchewan. These findings demonstrate the efficacy of the developed ACAM in a more comprehensive and context-specific assessment of MNP risks, providing new insight for the management of MNP pollution. [Display omitted] • A systematic assessment method for MNP impacts is developed embracing complexity. • Interactions among MNPs and other global environmental change factors are revealed. • The significance of MNP pollution and other environmental problems is prioritized. • Composite effects from multiple global environmental change factors are assessed. [ABSTRACT FROM AUTHOR]

Small modular reactor (SMR) is an emerging clean technology that is expected to help decarbonize power systems and mitigate climate change in the future. However, previous SMR siting methods were unable to take the multi-complexities of the power system into account. To deal with such a shortage, a factorial optimization-based SMR siting (FOSS) model is developed in this study. The main advantage of the developed FOSS model is its capability of comprehensively examining the SMR siting issue within a general electricity-system framework under multi-complexities. The optimized SMR siting schemes and power-systems transition plans can be then provided. The developed approach was applied to the power systems in Saskatchewan, Canada. The results indicate that replacing conventional coal-fired plants with SMRs can be a beneficial alternative to promote GHG mitigation and meet the growing power demand. The SMR deployment would enable a transition to a low-carbon power system in Saskatchewan with at least 65.6% emissions reduction by 2045 from 2018 level. Factorial and scenario-based analysis can provide policy makers with reference points to formulate specific decarbonization policies of power systems. The FOSS model can be adapted for electricity systems in different countries and this research provides a promising way to promote a transition towards long-term sustainability in global energy systems. [Display omitted] • A FOSS model that can solve multiple complexities is developed. • SMR siting issue is analyzed within a general electricity-system framework. • Contrastive and multi-scenario analysis provide policy support for decision-makers. • Replacing coal-fired power plants with SMRs is a potential siting method. • SMR siting and the transition in future power systems can promote GHG mitigation. [ABSTRACT FROM AUTHOR]

The potential ecological risks of nanoplastics (NPs) may be inaccurately assessed in some studies as they fail to consider the impact of environmental factors and their interactive effects. Here, the effects of six representative environmental factors (N, P, salinity, DOM (dissolved organic matter), pH and hardness) on NPs' toxicity and mechanism to microalgae are investigated based on the surface water quality data in Saskatchewan watershed, Canada. Our 10 sets of 2 6-1 factorial analysis reveal the significant factors and their interactive complexity towards 10 toxic endpoints from cellular and molecular levels. This is the first time to study the toxicity of NPs to microalgae under interacting environmental factors in high-latitude aquatic ecosystems of Canadian prairie. We find that microalgae become more resistant to NPs in N-rich or higher pH environments. Surprisingly, with the increase of N concentration or pH, the inhibitory effect of NPs on microalgae growth even became a promotion effect with the decreased inhibition rate from 10.5 % to -7.1 % or from 4.3 % to -0.9 %, respectively. Synchrotron-based Fourier transform infrared spectromicroscopy analysis reveals that NPs can induce alterations in the content and structure of lipids and proteins. DOM, N*P, pH, N*pH and pH*hardness have a statistically significant effect on NPs' toxicity to biomolecular. The toxicity levels of NPs across Saskatchewan watersheds are evaluated and we find that NPs could have the greatest inhibition on microalgae growth in Souris River. Our findings indicate that multiple environmental factors should be considered during the ecological risk assessment of emerging pollutants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)