Human exposure to polychlorinated naphthalenes in food: estimated dietary intake in Korean population

Abstract

Polychlorinated naphthalenes (PCNs) are persistent organic pollutants (POPs) unintentionally emitted from thermal processes or technical mixtures. From 1910 to 1980s, PCNs were widely produced and used as capacitor dielectrics, insulators, oil additives, lubricants, and preservatives. PCNs are known to have toxic effects and bioaccumulate persistently. In particular, dietary intake is considered as the main pathway of exposure to PCNs. There have been a few studies on PCNs in food; however, most of them have focused on fishery products, and only a single study has been done in Korea. In this study, 55 PCN congeners from tri-CNs to octa-CN were analyzed in agricultural products, fishery products, and processed foods. The 30 food items were collected from markets in Seoul, Busan, and Pohang. The samples (n=208) were extracted using Soxhlet extractors, treated with sulfuric acid, cleaned up using multi-silica gel columns, and then analyzed using gas chromatograph/high-resolution mass spectrometer (GC/HRMS). From the results, contamination levels, and correlationship of PCNs in food were investigated and dietary intakes from food were estimated. Additionally, the total combined dietary intakes of PCNs, PCDD/Fs, and DL-PCBs among the Korean population were estimated using previous results. The mean Σ55 PCN concentrations were 9.12 pg/g ww, 70.71 pg/g ww, and 48.00 pg/g ww in agricultural products, fishery products, and processed foods, respectively. The concentration levels of PCNs in food groups of this study are similar to those in other countries. Tri-CN was a predominant homologue, followed by tetra-CN and penta-CN. Significant correlations exist among the concentrations of PCN congeners, PCDD/F congeners, and dioxin-like PCB congeners in food, reflecting that these lipophilic POPs have similar exposure pathways. The relative composition of hexa-CNs was the highest for Σ TEQPCN in food due to their high relative potencies. The highest sum of dietary intake of Σ11 TEQPCN was found in agricultural products (0.263 pg-TEQ/day), followed by livestock (0.247 pg-TEQ/day), fishery products (0.149 pg-TEQ/day), and processed foods (0.077 pg-TEQ/day). The sum of intake of Σ20 TEQPCN was mostly higher for males than females, and the highest intake was observed in youngest females, although they did not exceed the tolerable weekly intake (TWI) of Ministry of Food and Drug Safety (14 pg-TEQ/kg bw/week). The sum of total combined dietary intakes from food were also under the TWI, whereas it exceeded the suggestion of European Food Safety Authority (2 pg-TEQ/kg bw/week). Therefore, it is necessary to investigate more PCN congeners in various kinds of foods and estimate the dietary intakes. On the basis of this study, it would be possible to establish a system for the intake levels of PCNs and manage the dietary habits of the Korean population.