Cadmium toxicity in aquatic organisms: A scientometric review (Part 1 - vertebrates and invertebrates)

Cadmium (Cd) is a toxic and bioaccumulative metal widely distributed in aquatic environments due to anthropogenic activities, posing significant risks to ecosystems and human health. This study presents Part 1 of a complementary two-part scientometric review on Cd toxicity in aquatic organisms, in which the global literature was organized into two major biological groups: (i) Aquatic vertebrates and invertebrates (Part 1) and (ii) photosynthetic aquatic organisms. A comprehensive literature search was conducted in the Web of Science database (1945-2024), retrieving 6,531 records, of which 3,837 were retained after refinement. The dataset was initially analyzed as a whole to identify global publication trends, research hotspots, and influential countries and institutions. Subsequently, a detailed scientometric analysis was performed focusing on aquatic vertebrates and invertebrates. The results revealed a substantial increase in scientific production over recent decades, with China leading in publication output and institutional influence. The most recurrent research themes were related to heavy metals, toxicity, and oxidative stress. Fish were the most studied vertebrate group, particularly Danio rerio, whereas among invertebrates, mollusks and crustaceans were the most frequently investigated groups, with Daphnia magna being the most commonly used model species. Bioaccumulation was the most frequently evaluated biological endpoint, while laboratory-based experiments predominated among study designs. Overall, the findings demonstrate a growing scientific concern regarding Cd contamination and its biological effects. Current research is strongly focused on mechanisms of toxicity, particularly oxidative stress and bioaccumulation, whereas future studies should prioritize integrated approaches and the development of effective remediation strategies to mitigate the environmental impacts of this metal.