Forever chemicals found in Vietnam’s fish, but regulation has yet to catch up

Vietnam’s rivers, lakes, and coastal waters are quietly accumulating one of the most stubborn classes of synthetic chemicals ever manufactured, and the country is only now beginning to grasp the scale of the problem. A comprehensive review published in Case Studies in Chemical and Environmental Engineering has, for the first time, pulled together every available study on per- and polyfluoroalkyl substances, or PFAS, in Vietnamese aquatic organisms, painting a picture of widespread but still poorly mapped contamination. The verdict from the literature is nuanced: concentrations in Vietnamese fish remain lower than those reported for heavily contaminated hotspots in Europe and North America, yet PFAS are detectable across freshwater, coastal, and marine species sampled to date, making them emerging contaminants of genuine national concern.

PFAS owe their nickname, forever chemicals, to a simple chemical fact. Their defining carbon-fluorine bonds are among the strongest in organic chemistry, which makes them essentially immune to hydrolysis, photolysis, and most abiotic degradation processes. Since the mid-twentieth century, industry has exploited this stability in everything from non-stick cookware and food packaging to firefighting foams, stain-resistant textiles, and water-repellent coatings. That durability, combined with high water solubility and an amphiphilic structure, means PFAS do not stay put. Short-chain compounds in particular dissolve readily and travel through surface waters, groundwater, and river networks, dispersing far from their emission sources. They have now been found everywhere from industrialized estuaries to the Norwegian Arctic, where long-range atmospheric and oceanic transport delivers them to ecosystems with no local industry at all.

What makes PFAS biologically unusual is where they end up inside an organism. Classical persistent pollutants such as PCBs and DDT are hydrophobic and lodge in fatty tissue, so their concentrations correlate with lipid content. PFAS flip that logic. Their molecules carry both a water-hating fluorinated tail and a water-loving head, allowing them to bind strongly to proteins such as serum albumin and liver fatty acid-binding proteins. As a result, they accumulate preferentially in protein-rich tissues, the liver, blood, and kidney, even when fat content is negligible. This also means lipid-normalization techniques used for decades to interpret legacy pollutant data simply do not work for PFAS, complicating comparisons with historical contamination studies.

Among the thousands of PFAS identified, a handful dominate aquatic contamination profiles worldwide. Perfluorooctane sulfonate, or PFOS, is consistently the most abundant compound in fish and other aquatic organisms, thanks to its extreme persistence and strong protein affinity. Long-chain perfluoroalkyl carboxylic acids, including PFOA, PFNA, PFDA, and PFUnDA, show similarly strong bioaccumulation potential because they bind serum proteins tightly and are eliminated slowly. Global monitoring data assembled in the review span a remarkable range: PFOS at roughly 2.2 micrograms per kilogram in the livers of Arctic fish in Norway, moderate levels of under 2 micrograms per kilogram in a tropical estuary in Bahia, Brazil, and staggering concentrations up to 777 micrograms per kilogram in organisms from a New York estuary contaminated by firefighting foam. In the Belgian North Sea, fish liver contained PFOS levels near 107 micrograms per kilogram, well above muscle tissue, and Swiss lake fish ranged from 0.1 to nearly 110 micrograms per kilogram.

Vietnam’s own data, though far sparser, follow the same pattern at lower intensities. A nationwide survey of waters, sediments, and biota, together with regional studies from Hanoi, major river basins, and the coast, recorded total PFAS in Vietnamese fish between roughly 0.08 and 16.9 nanograms per gram, depending on species and tissue. Freshwater fish muscle in northern Vietnam carried 0.08 to 8.06 nanograms per gram, while marine fish ranged from about 0.22 to 3.62 nanograms per gram. The single highest biota value, around 16.9 nanograms per gram, was PFUnDA in fish liver from a major river basin. In Hanoi’s urban lakes, blood concentrations in fish reached 5.2 to 29 nanograms per milliliter, exceeding liver, which in turn exceeded muscle. Marine studies along the Vietnamese coast found mollusks the most contaminated group at 22.68 nanograms per gram dry weight, likely a consequence of filter-feeding behavior that concentrates contaminated particles.

Geographically, the evidence is strikingly lopsided. Published monitoring studies cluster around Hanoi and the adjacent river systems of northern Vietnam, with additional work along major river basins and the coastline. The central coast and much of southern Vietnam remain essentially blank on the research map. The review’s authors stress that this uneven coverage means the absence of data should never be mistaken for the absence of contamination; current understanding of Vietnam’s PFAS burden is shaped more by where scientists have sampled than by where chemicals actually occur. Industrialization adds urgency: textile finishing, metal plating, paper and packaging production, leather processing, electronics manufacturing, and the use of aqueous film-forming foams at airports, military sites, and petrochemical facilities are all recognized PFAS sources, and all are concentrated in industrial provinces such as Ho Chi Minh City, Binh Duong, Dong Nai, Hai Phong, and Hanoi. Vietnam’s dense river networks then shuttle contaminants from urban centers toward biologically productive coastal aquaculture zones.

The health stakes are real, though current Vietnamese exposure estimates fall below international benchmarks. PFAS biomagnify through aquatic food webs, moving from algae to invertebrates to predatory fish, birds, mammals, and ultimately people who eat seafood, a staple of the Vietnamese diet. Ecologically, PFAS exposure has been linked to disrupted reproduction, impaired immunity, oxidative stress, and altered gut microbiomes in fish. In humans, chronic dietary exposure is associated with altered lipid metabolism, endocrine disruption, liver toxicity, immune impairment, and elevated risks of certain cancers. Regulatory bodies elsewhere have responded accordingly. The European Union sets a PFOS surface-water standard of 0.65 nanograms per liter and a biota threshold of 9.1 micrograms per kilogram in fish, while the European Food Safety Authority established a tolerable weekly intake of 4.4 nanograms per kilogram of body weight for four major PFAS combined. The US EPA’s 2022 drinking water advisories set 4 nanograms per liter for PFOA and PFOS and 10 nanograms per liter for GenX, PFHxS, and PFNA.

Vietnam, by contrast, has no PFAS-specific environmental quality standards or drinking water guidelines. National monitoring programs target conventional pollutants, so PFAS data come almost entirely from independent research groups rather than systematic government surveillance. The review identifies a chicken-and-egg problem in analytical capacity: several Vietnamese institutions own liquid chromatography-tandem mass spectrometry instruments, the workhorse technology for trace-level PFAS detection, but without mandated standards or compliance-driven demand there is little incentive to expand testing infrastructure or drive down costs. Isotope-labelled standards and certified reference materials remain expensive, further limiting routine surveillance. The 2020 Law on Environmental Protection offers a general legal framework that could eventually absorb PFAS into national monitoring, but the translation from law to laboratory has not yet begun.

The review also looks beyond the water’s edge, warning that PFAS contamination almost certainly extends into agricultural soils, crops, and livestock through irrigation with contaminated surface water, land application of sewage sludge, and atmospheric deposition. Short-chain PFAS move readily from roots into edible plant tissues, while long-chain homologues bind soil but accumulate in animal products, meaning exposure pathways shift depending on chemistry and land use. Vietnamese research on these terrestrial pathways is virtually nonexistent, even as wastewater reuse expands in water-scarce regions and aquaculture becomes increasingly intertwined with crop production. The authors advocate an integrated One Health monitoring framework spanning water, sediment, soil, crops, livestock, and aquatic organisms, alongside investment in remediation research, since microbial degradation still struggles to break the carbon-fluorine bond in terminal perfluoroalkyl acids. For a nation whose seafood culture and riverine identity are inseparable, the message of this first national synthesis is clear: the forever chemicals are already here, and Vietnam’s window for systematic monitoring before problems escalate is very much open, but it will not stay that way indefinitely.

Subject of Research: PFAS contamination and bioaccumulation in Vietnam's aquatic environments

Article Title: Current understanding of per-/polyfluoroalkyl substances (PFAS) contamination in aquatic environment in Vietnam

Article References: Van Tri, D., Quan, D. N., & Luu, T. L. (2026). Current understanding of per-/polyfluoroalkyl substances (PFAS) contamination in aquatic environment in Vietnam. Case Studies in Chemical and Environmental Engineering, 14, Article 101489. https://doi.org/10.1016/j.cscee.2026.101489

Image Credits: AI Generated

DOI: 10.1016/j.cscee.2026.101489

Keywords: PFAS, forever chemicals, Vietnam, bioaccumulation, aquatic ecosystems, PFOS, PFOA, water pollution, food safety, environmental monitoring, LC-MS/MS, One Health