Rethinking the effects of micro/nanoplastics from the global environmental change and systematic perspective: An aquatic environmental system-based comprehensive assessment approach of micro/nanoplastic impacts.

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.

Development of an SMR-induced environmental input-output analysis model - Application to Saskatchewan, Canada.

As an emerging power generation technology, small module reactors (SMRs) have the potential for development with its contribution to reducing greenhouse gas (GHG) emissions. In this study, an SMR-induced environmental input-output model (SEIOM) is proposed to simulate the environmental consequences of SMRs development and provide suggested schemes for SMRs deployment. A case study of Saskatchewan, Canada is conducted to demonstrate the proposed model. Specifically, key industries with high reduction potentials are first identified in the study; then, the power supply for three energy-intensive industries is assumed to be replaced by power generated from SMRs at various penetration degrees. The corresponding changes in direct and indirect GHG emissions and the interrelationships among multiple economic sectors associated with GHG flows are analyzed. The results indicate that there are close interdependences between various sectors and a small group of sectors could play a big role in GHG emission mitigation. In Saskatchewan, "Electricity power generation, transmission and distribution", "Oil and gas extraction", "Potash mining" and "Petroleum refineries" are key sectors for realizing GHG emission reduction targets. Meanwhile, it is estimated that replacing the power supply for "Oil and gas extraction" sector with SMRs would contribute the most to the reduction in GHG emission, which is much more than those for "Potash mining" and "Petroleum refineries" sectors. This study is expected to provide a basis for supporting the initiative and application of SMRs.