Xenobiotic contaminants in the equatorial Pacific near American Samoa

Abstract

In this study, I examined the spatial distribution and concentration of various xenobiotic contaminants in the waters of the equatorial Pacific near American Samoa. Using stateof- the-art mass spectral techniques, I determined if pollutant loads increase near urban environments, as well as how individual manmade contaminants present spatially. I collected water samples in the region around American Samoa from December 28th, 2023, to January 11th, 2024, then extracted pollutant chemicals from the sample via solid phase extraction using hydrophilic-lipophilic balance (HLB) cartridges and performed analysis of chemical concentrations using gas chromatography-mass spectrometry (GCMS). This was followed by a detailed spatial comparison of the chemical pollutants. Spatially, compound abundance was generally found to decrease moving away from urban environments. The highest concentration of a pollutant was 6.1 parts per billion of azelaic acid at Site 4. Industrial anthropogenic pollutants such as n-tridecane (0.065- 0.12 ppb) and benzyl butyl phthalate (0.065-4.0 ppb) were confidently found near the airport and fuel depot in American Samoa, the latter of which has been provided evidence of being toxic to humans. Assessing the spatial distribution of xenobiotic pollutants in relation to urban environments can help improve current understanding of how much manmade pollution is entering and persisting in the ocean, which can endanger ecosystems and human health.