Phthalate-induced effects in algae and fishes: insights into environmental toxicology

Phthalic acid esters (PAEs) are ubiquitous environmental contaminants with endocrine-disrupting properties and increasing relevance for aquatic ecosystem health. This review synthesizes current evidence on PAEs' effects in fishes and micro- and macroalgae, integrating molecular, physiological and ecological responses across key trophic levels. In algae, PAEs impair photosynthesis, growth and metabolic homeostasis, while revealing a dual role as both targets of toxicity and potential contributors to environmental phthalate pools. In fishes, PAEs disrupt endocrine regulation, reproduction, development, metabolism and neurobehaviour, with emerging evidence of cardiotoxicity and epigenetic effects. By jointly analysing primary producers and vertebrate consumers, this review highlights species- and life-stage-specific vulnerabilities under environmentally realistic exposure scenarios, including chronic low-dose contamination, metabolite toxicity and mixture effects. Oxidative stress and endocrine signalling emerge as convergent mechanistic pathways. The review also evaluates algae-based bioremediation strategies, emphasizing species-dependent efficiencies and mixture-driven limitations. Major knowledge gaps include scarce long-term and multi-stressor studies and limited understanding of cross-trophic mechanisms. Overall, this integrated synthesis supports improved ecological risk assessment, informs regulatory frameworks and guides future multi-trophic and mechanistically driven research to mitigate PAEs pollution.