Metanálise do efeito térmico de usinas nucleares costeiras sobre a biodiversidade local

Abstract

The rise in temperature due to climatic and anthropic factors has been considered one of the main causes of changes in aquatic ecosystems. In nuclear power plants it is necessary to supply large volume of water for its operation. This water is subsequently returned to the aquatic ecosystem at a higher temperature. The objective of this work was to evaluate the thermal impact caused by the operation of coastal nuclear power plants on local biodiversity and to estimate the magnitude of thermal variation between a site affected by the discharge of the effluent (impacted) and another maintained in natural conditions (reference). To this end, article searches on the Scopus and Web of Science platforms were performed and a meta-analysis was conducted using selection criteria according to the PRISMA methodology. From 853 articles found, 99 were included in the qualitative analysis and 75 were selected for the meta-analysis. The effect size of the temperature rise was calculated from the temperature difference between impacted and reference areas using a mixed-effect model. The moderators used were: 1 - number of reactors, 2 - electrical generation capacity and 3 - latitude of the plants. The overall effect size found was positive and significant, indicating a significant temperature increase in the discharge area. For this temperature difference, only the latitude moderator was found to be significant. Considering the studies included in the qualitative analysis, 31 nuclear plants were evaluated and were mainly distributed in China and the United States. The analysis of connectance showed low interaction between the authors and the most cited keywords were 'Daya Bay' and 'Phytoplankton'. The main effects reported in the organisms were those related to the structure and composition of aquatic communities, being abundance, distribution, dominance, density and species richness the most cited ones. Photosynthesizing microorganisms (i.e. phytoplankton and microphytobenthos) were the most cited among the affected groups, which may be related to their sensitivity to changes in hydrographic conditions due to the elevation of local temperature. The results showed that around the discharge of the thermal effluent the temperature reached higher temperatures, which may have lead to environmental changes and cascading effects in the aquatic ecosystem. These results can support environmental policies and improve methods for the installation and operation of nuclear power plants.