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[Display omitted] • Great concentration of SMCs and siloxanes were entered into Geum River through WWTP. • They widespread with a different trend depending on the distance from WWTP. • The δ15N of amino acids provided high resolution foodweb and accurate TP forTMF. • The TMFs of compounds were consistent at the both sites and seasons. • The trophic magnification of these compounds was not occurred in this study. Despite the extensive usage of synthetic musk compounds (SMCs) and siloxanes in various personal care products (PCPs), trophic magnification of such chemicals in aquatic environments remains unexplored. In June and September 2020, eleven SMCs and nineteen siloxanes were measured in water, sediments, and biota. Samples were collected from two sites where levels were expected to be influenced by the distance from the wastewater treatment plant (WWTP) in the Geum River, Republic of Korea, were expected. High concentrations of SMCs and siloxanes entered through WWTP were measured in water, sediment, and biota at the both sites and both seasons. The δ15N of amino acids provided a high-resolution food web and accurate trophic position (TP), which is an important factor for determining the trophic magnification factor (TMF). Among 24 TMFs, 19 of them were <1, ranging 0.7–0.8 for 1,3,4,6,7,8‑hexahydro‑4,6,6,7,8,8‑hexamethyl‑cyclopenta‑γ‑2‑benzopyran (HHCB), 0.6–0.8 for 6-Acetyl-1,1,2,4,4,7-hexamethyltetralin (AHTN), 0.7–0.8 for 4-tert-Butyl-3,5-dinitro-2,6-dimethylacetophenone (MK), 0.7–0.9 for octamethylcyclotetrasiloxane (D4), 0.1–0.4 for decamethylcyclopentasiloxane (D5), and 0.04–0.8 for dodecamethylcyclohexasiloxane (D6), and the remaining ones including HHCB, AHTN, MK, and D4 showed values close to 1 or slightly higher (TMF range: 1.0–2.3) indicating no or a little trophic magnification. The TMFs of these compounds were constant across sites and seasons. The TMF values of PCPs might be affected by species specificity and food web structure rather than by chemical properties such as log K ow , which describes a wide range of TMF values in various environments. This study presents valuable implications for assessing risk and managing environmental fate and trophic transfer of SMCs and siloxanes in freshwater environments. [ABSTRACT FROM AUTHOR]

• Compound specific isotope analysis of amino acids is remarkable for calculating trophic position. • Trophic positions of fish were compared based on the δ15N of bulk and amino acids. • The concentrations of PCB, PBDE and OCPs in fish were increased with trophic position in Masan bay. • Trophic magnification factors are governed by trophic position. The trophic magnification of persistent organic pollutants (POPs), which is the relationship between POP concentration and the trophic position (TPs) of an organism, is considered an important factor for prioritizing chemicals of concern in the environment. Organismal TPs are typically based on nitrogen isotope ratios of bulk tissue (δ15N bulk). In this study, nitrogen isotope ratios of amino acids (δ15N AAs), a more precise approach for TP estimation (TP AAs), was applied and compared with estimations of TP based on δ15N bulk (TP bulk) in marine organisms living in Masan Bay, South Korea. Compound-specific isotope analysis of the amino acids (CSIA-AAs) in fish samples allows us to calculate robust TPs by correcting the variation in baseline isotope values with use of the δ15N bulk technique. In a benthic food chain, this approach reveals more significant magnification trends for POPs [polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCPs)] than those revealed by analysis of the relationship between TP bulk and POPs. The trophic magnification factors (TMF) associated with TP AAs were significant for some POPs, especially pp′ -DDD and chlordane. The results presented in this study suggest that TP calculations based on δ15N AAs are an effective tool for characterizing trophic magnification trends related to the fates of various pollutants. [ABSTRACT FROM AUTHOR]