The research, published in the Archives of Environmental Contamination and Toxicology, was designed around a deceptively simple question: if you sample the water moving away from industrial zones before it disperses into the ocean, what does it contain? The team collected water samples from drainage channels that transport stormwater and greywater runoff from areas surrounding industrial sites on Viti Levu. Rather than relying on visual identification alone, which has historically inflated microplastic counts in some studies, the researchers applied a rigorous analytical pipeline. Samples were first digested with hydrogen peroxide to strip away organic matter that could obscure plastic particles. Density separation was then used to float the low-density plastic particles away from heavier mineral and biological debris, a technique that exploits the fact that most common plastics are less dense than the salt solutions used in the separation step.

The recovered material was filtered through aluminum oxide Anodisc membrane filters with a pore size of 0.2 micrometers, ensuring that even very small particles were captured on the membrane surface. Each filter was then examined under a microscope to record the presence, size and morphology of the particles. Crucially, the team did not stop at morphology. Particles measuring 100 micrometers or larger were confirmed using attenuated total reflectance Fourier transform infrared spectroscopy, or ATR-FTIR, a technique that identifies the chemical bonds within a material and produces a spectral fingerprint unique to each polymer type. The result of this verification step was striking: 93.4 percent of the particles examined in this size range were confirmed as genuine microplastics, giving the researchers high confidence that what they were counting was plastic rather than natural fibers or other lookalike material.

Across all sampling locations, the study recorded an average microplastic concentration of 2.23 plus or minus 0.78 particles per liter of water. That average, however, conceals considerable spatial variation. The highest abundance, 3.08 particles per liter, was measured at Site 5, while the lowest, 1.26 particles per liter, occurred at Site 2. This kind of spatial heterogeneity is exactly what one would expect if contamination is driven by localized industrial activity rather than by uniformly distributed background pollution, and it underscores the value of sampling drainage channels directly rather than inferring sources from offshore measurements alone. Every liter of runoff, in effect, functions as a conveyor belt delivering plastic particles from factory floors, storage yards and packaging waste streams toward the reef systems that fringe the island.

The shape of the particles told its own story. Fragments accounted for the largest share of the microplastics found, at 48.08 percent, followed very closely by fibers at 47.83 percent, with films making up the remaining 4.09 percent. This near-even split between fragments and fibers is analytically meaningful. Fragments are typically produced by the mechanical breakdown of larger plastic items, consistent with the handling, cutting, grinding and weathering of plastic materials in industrial settings. Fibers, by contrast, are strongly associated with synthetic textiles, rope, and abrasion of fabric-based materials, sources that are well documented in the global literature on microplastic pollution. The small proportion of films suggests that thin packaging sheeting, while ubiquitous in the waste stream, contributes less to the suspended particle load in these channels than the sturdier debris that fragments into discrete particles.

Size distribution added a further layer of concern. The majority of the microplastics recovered, 52.30 percent, were smaller than 500 micrometers, meaning that most of the particles leaving these industrial areas are small enough to be ingested by a wide range of marine organisms, from zooplankton and filter-feeding shellfish up to fish that form the basis of local diets. Particle size matters because it governs which animals can mistake a particle for food, and because smaller particles present a larger surface area relative to their volume for the adsorption of other contaminants. Research cited by the authors has shown that microplastics can act as carriers for persistent organic pollutants and trace metals, effectively concentrating toxins in the very particles most likely to enter the food web.

Polymer identification through ATR-FTIR revealed which plastics dominate the industrial footprint. Polyethylene was the most prevalent polymer, accounting for 46.29 percent of identified particles, followed by polystyrene at 33.76 percent. Together these two polymers represent roughly four-fifths of the confirmed microplastic load. The authors attribute this dominance to the extensive use of both materials in packaging, a conclusion consistent with global studies showing that food packaging and single-use items are major pathways for microplastic generation, including the particles shed simply by opening plastic packaging. The polymer profile is therefore not an accident of chemistry but a direct reflection of consumption and industrial practice: where polyethylene and polystyrene packaging is manufactured, stored, discarded and fragmented, those polymers appear in the water leaving the site.

What makes the findings particularly actionable is the policy context in Fiji. Polystyrene has already been completely banned as a single-use plastic in the country, while polyethylene is restricted under certain conditions. Yet the study shows that both polymers remain the dominant contaminants in industrial runoff, demonstrating that existing restrictions have not yet eliminated these materials from the environment. The authors argue that the logical next step is to extend the ban to include polyethylene and polystyrene packaging materials specifically, a measure they say would accelerate the elimination of these plastics from Fiji’s environment. Because the polymer signature in the drainage channels matches the polymers targeted by policy, the study offers regulators a direct line of sight from legislative action to environmental outcome: remove the source materials, and the particle signature in the runoff should change accordingly.

The study also fits into a rapidly growing body of Pacific-focused research that has documented microplastics throughout Fiji’s coastal and freshwater systems. Previous work has found microplastics in the subsurface coastal waters along the southern coast of Viti Levu, in freshwater aquaculture systems on the island, in oysters, water and sediment from Laucala Bay, and in numerous coastal marine fish species caught by fishing communities. Comparable studies have documented contamination in fish from the remote atoll nation of Tuvalu, demonstrating that no Pacific community is too distant to be affected. By identifying the drainage channels around industrial sites as concentrated conduits of contamination, the new research adds a critical upstream perspective to this body of work, pointing to interventions that can occur before plastics ever reach the reef.

For a nation whose economy and food security are tightly bound to the health of its reefs and fisheries, the implications extend well beyond academic interest. Microplastics have been documented to cause physical harm to marine organisms, to bioaccumulate in edible species, and to enter drinking water systems, with recent Fijian research by overlapping author teams measuring microplastic consumption through drinking water drawn from freshwater and groundwater sources. The present study provides the kind of source-specific, chemically verified evidence that environmental managers need to prioritize interventions. Its message is ultimately one of tractable optimism: unlike diffuse global pollution, the microplastic load in these drainage channels has identifiable industrial origins, identifiable polymer signatures and identifiable policy levers. Extending Fiji’s existing plastic bans to packaging materials, the authors conclude, offers a concrete and scientifically grounded route to reducing the industrial microplastic footprint flowing from Viti Levu into the Pacific Ocean.

Subject of Research: Microplastic contamination of industrial stormwater runoff and its pathway into Fiji's marine environment

Article Title: Tracing Industrial Microplastics Footprint in Fiji’s Marine Environment

Article References: Rohindra, D., Patel, T., Lata, R., Waqainabete, T., & Chang, R. (2026). Tracing Industrial Microplastics Footprint in Fiji’s Marine Environment. Archives of Environmental Contamination and Toxicology, 91(3), Article 24. https://doi.org/10.1007/s00244-026-01226-0

Image Credits: AI Generated

DOI: 10.1007/s00244-026-01226-0

Keywords: microplastics, Fiji, Viti Levu, industrial runoff, polyethylene, polystyrene, ATR-FTIR, marine pollution, stormwater drainage, small island developing states, plastic ban, University of the South Pacific