In recent years, the insidious infiltration of endocrine-disrupting chemicals (EDCs) into aquatic ecosystems has emerged as a pressing environmental and public health concern. These synthetic or natural compounds have the unique ability to mimic or interfere with the hormonal systems of living organisms, precipitating a cascade of physiological disturbances and ecological imbalances. A new comprehensive study focusing on the National Aquatic Germplasm Resources Reserves (NAGRRs) in the South China Sea offers unprecedented insight into the prevalence and ecological risks posed by EDCs within vital marine protected areas (MPAs).
EDCs encompass a wide spectrum of substances, including industrial chemicals, pesticides, plasticizers, and pharmaceuticals. Their pervasive utilization in commercial products and personal care items amplifies their presence in wastewater and effluent. Once released into aquatic environments, these compounds persist and bioaccumulate, ultimately threatening the integrity of diverse marine species, ranging from microscopic plankton to complex benthic organisms. The South China Sea, an ecologically rich and economically pivotal region, is particularly vulnerable to such chemical intrusions due to its proximity to heavily industrialized urban centers.
The study rigorously examines thirty-one frequently encountered EDC compounds within three strategically designated NAGRRs in the Guangdong−Hong Kong−Macao Greater Bay Area. These reserves are critical sanctuaries established to protect important tidal flats and coastal zones that serve as spawning and nursery grounds for numerous marine species. Given this area’s complex amalgamation of dense human population, expansive industrial activity, and delicate coastal ecosystems, the research addresses longstanding knowledge gaps regarding spatial and temporal patterns of EDC contamination.
Sampling campaigns revealed a stark contrast between dry and wet seasons in terms of contaminant levels. The dry season registered substantially elevated concentrations of EDCs, a phenomenon likely attributed to reduced dilution efficacy and altered hydrodynamic conditions. Such seasonal variability underscores the complex interactions between environmental factors and contaminant distribution, necessitating dynamic monitoring strategies rather than static assessments.
Spatial heterogeneity was another defining characteristic of the pollutant distribution. Variations among different reserves and adjacent coastal waters reflected localized sources, hydrological influences, and anthropogenic pressures. Noteworthy among the detected compounds were environmental estrogens, a subgroup of EDCs known for their potent endocrine activity. Specifically, molecules such as 17α-ethinylestradiol, norgestrel, bisphenol A (BPA), bisphenol B (BPB), bisphenol F (BPF), and 4-tert-octylphenol demonstrated significant prevalence. These substances disrupt hormonal signaling pathways essential for growth, reproduction, and development, potentially inducing reproductive failure and population declines in affected species.
The detection of synthetic progestins like norgestrel adds complexity to the contamination profile, as these chemicals often exhibit persistent bioactivity even at low environmental concentrations. Similarly, bisphenols, commonly employed in plastic manufacturing, are notorious for leaching into aquatic systems, thereby exacerbating the endocrine disruption cascade. The synergistic effects of these compounds remain an area of active toxicological research, with emerging evidence indicating compounded ecological risks when mixtures rather than isolated chemicals are considered.
In response to these findings, the researchers advocate for a multi-tiered approach targeting pollution at its source. Upgrading sewage treatment infrastructure to incorporate advanced secondary treatment modalities, such as aerobic bioreactors, could markedly reduce the influx of EDCs into marine environments. Aerobic bioreactors enhance microbial degradation efficiency, breaking down complex organic contaminants and minimizing their environmental release. Parallel initiatives to incentivize chemical manufacturers towards the adoption of greener, less harmful alternatives are vital to curtail long-term exposure risks.
Furthermore, the study highlights the pressing need to intensify investigative efforts into the toxicological impacts of EDCs on benthic marine organisms, which occupy essential niches within the coastal food web. Benthic fauna often serve as bioindicators due to their sensitivity to pollution and exposure to sediment-bound contaminants. Understanding sub-lethal effects, reproductive impairments, and potential bioaccumulation mechanisms will deepen insight into ecosystem-level consequences and inform risk assessment models.
On a regulatory and policy front, the establishment and enforcement of enhanced monitoring and early warning systems within marine protected areas are paramount. These systems should utilize a combination of chemical analyses, biomonitoring, and ecological surveillance to detect emergent threats promptly. Incorporating environmental EDC indicators into criteria for site selection when designating new NAGRRs is recommended to ensure future reserves are optimally positioned away from pollution hotspots such as sewage treatment plants and densely urbanized coastal cities.
This integrative research underscores a broader paradigm shift in marine conservation strategy, recognizing that protected status alone does not confer immunity against chemical pollution. Instead, the ecological health of MPAs is intricately linked to effective watershed management and multi-sectoral collaboration, encompassing environmental engineers, ecotoxicologists, policymakers, and industry stakeholders. Holistic stewardship informed by cutting-edge scientific evidence is essential to safeguard biodiversity and maintain resilience of marine ecosystems under mounting anthropogenic pressures.
In sum, the comprehensive assessment elucidates the intricate dynamics governing EDC pollution within three key aquatic reserves in the South China Sea and their surrounding coastal environments. By charting seasonal trends, identifying priority pollutants, and prescribing actionable mitigation pathways, the study materially advances the agenda for environmentally sustainable management of marine resources in one of the world’s most economically vital and ecologically sensitive regions. Continued surveillance, coupled with technological innovation and policy foresight, will be indispensable in confronting the challenges posed by endocrine disruptors and preserving the vitality of marine habitats for generations to come.
Subject of Research: Occurrence and ecological risks of endocrine-disrupting chemicals in marine protected areas of the South China Sea
Article Title: Occurrence and ecological risks of endocrine-disrupting chemicals in three National Aquatic Germplasm Resources Reserves in the South China Sea
Web References: http://dx.doi.org/10.1016/j.enceco.2025.08.011
Image Credits: CHONG CHEN
Keywords: Marine protected areas, endocrine-disrupting chemicals, environmental estrogens, South China Sea, National Aquatic Germplasm Resources Reserves, sewage treatment, ecotoxicology, bisphenol A, 17α-ethinylestradiol, benthic organisms, aquatic pollution
