Impact of Endocrine Disruptors on Reproductive Physiology of Aquatic Fauna: A Review

Endocrine-disrupting chemicals (EDCs) have become major pollutants in aquatic environments worldwide, presenting serious threats to the reproductive function, development, and survival of aquatic organisms. They originate from diverse sources such as industrial discharges, agricultural runoff, pharmaceuticals, pesticides, plastics, and domestic wastewater, and are notable for their persistence, lipophilic nature, and strong tendency to bioaccumulate in organs including the liver, gonads, and brain. EDCs disrupt endocrine homeostasis by mimicking or antagonizing endogenous hormones, modifying receptor activity, interfering with the hypothalamic–pituitary–gonadal axis, and triggering epigenetic alterations. Consequences include disturbed sex hormone balance, vitellogenin production in males, intersex conditions, compromised spermatogenesis and oogenesis, feminization, masculinization, sex reversal, and developmental deformities across fish, amphibians, reptiles, mollusks, and crustaceans. Such physiological impairments lead to reduced reproductive success, biased sex ratios, delayed development, decreased offspring survival, and, under extreme exposure, population declines. Through biomagnification, EDCs propagate along trophic chains, adversely affecting top predators and disrupting aquatic food webs, as evidenced by reproductive failure in fish exposed to synthetic estrogens, imposex in gastropods caused by tributyltin, and endocrine dysfunction in reptiles exposed to organochlorine pesticides. Advanced analytical tools including LC-MS/MS, GC-MS, ELISA, ER-CALUX bioassays, qPCR, and omics approaches support accurate detection and mechanistic insights. Although international regulations such as the Stockholm Convention, REACH, and EPA guidelines define exposure thresholds, effective control is constrained by low-dose effects, chemical mixture toxicity, and limitations of conventional treatment systems. Current mitigation approaches emphasize advanced wastewater treatment, phytoremediation, bioremediation, green chemical alternatives, and enhanced public awareness. Integrating robust monitoring, strengthened regulatory measures, and sustainable chemical management is essential to safeguard aquatic reproductive health, ecosystem stability, and biodiversity through coordinated, interdisciplinary efforts.