Burden and Risk of Polychlorinated Naphthalenes in Chinese Human Milk and a Global Comparison of Human Exposure

Abstract

Polychlorinated naphthalenes (PCNs) are carcinogenic contaminants. Residues from historical production and ongoing unintentional releases from industrial thermal sources have led to the ubiquitous presence of PCNs in the environment. Our previous study has revealed that unintentional releases may be the main sources of PCNs in human milk from China. However, an assessment of PCN burden in human milk and exposure differences between historical residues and unintentional release exposure has not been conducted. In this study, we performed the first comparison of human exposure to PCNs and evaluated the differences between the estimated health risks from historical residues and unintentional releases. Three characteristic PCN congener patterns found in Chinese human milk specimens collected from 100 cities/counties can be considered characteristic of PCN exposures in regions with unintentional industrial releases as the main PCN sources. The health risk assessment suggested potential noncarcinogenic health effects in infants aged 0–6 months. The hazard index calculated for infants in Sweden indicates a strong impact of historical residues that nonetheless decreases over time, and a comparison of the hazard indices calculated for China and Ireland suggests that ongoing unintentional formation and release of PCNs from industrial processes should be a matter of public health concern.

Comprehensive Evaluation of Dietary Exposure and Health Risk of Polychlorinated Naphthalenes

“…Figure S5 shows the mass concentration of the 75 congeners by food category and the concentrations in human milk reported in our previous work. 40,47 Tri-CN24/14 and Di-CN5/7 were also the most abundant congeners in our food samples, and DiCNs and TriCNs were the dominant homologues. This indicates that raw feed may be an important source of PCNs in animal-origin food.…”

“…Unintentional release of PCNs from combustion-related activities may be the primary source of PCNs in food; our previous study on PCNs in human milk also supports this opinion. 40,47 Figure 3 displays the contribution of the six combustion-associated congeners with fewer than four chlorine atoms (Tri-CN24/14, Tri-CN17/25, Tri-CN13, Tri-CN18), which have rarely been studied, to the total PCN mass concentration. The contribution of these congeners to the total mass concentration was in the range of 21−44%, which means that the previously less studied, less chlorinated combustionassociated congeners should be included in assessments of dietary exposure in countries with the unintentional release from the thermal process being the main PCN source.…”

“…Instrument parameters have been described in the Supporting Information and also reported in our previous studies. 40,47 At least one blank was analyzed in each batch of samples. A small amount of MoCNs, DiCNs, and TriCNs was measured in the blanks, which was lower than 20% of the PCN contents measured in food samples.…”

“…However, the influence of PCN source diversity on human exposure has seldom been reported and requires more attention. Although PCNs are also known as byproducts of polychlorinated biphenyls, PCNs emitted from the use of polychlorinated biphenyl in China are estimated to account for only 0.005% of the historical production of PCNs. , There is evidence indicating that industrial emissions are a more and more important source of environmental PCNs, , as the influence of the historical use and production of commercial PCNs has decreased over time.…”

Distribution of Polychlorinated Naphthalenes in Sediment From Industrialized Coastal Waters of Korea With the Optimized Cleanup and GC-MS/MS Methods

“…These include waste incineration, steel and coking industries, and chlor-alkali and copper smelting processes (Liu et al, 2010(Liu et al, , 2014Hu et al, 2013;Waheed et al, 2020). PCNs are also released from the use of PCB technical mixtures as impurities contained (Huang et al, 2015;Li et al, 2021). Although there has been no consumption of technical PCN mixtures (Park et al, 2010), several PCN congeners have been detected in multiple matrices, such as air, soil, freshwater biota, and human serum (Lee et al, 2007;Park et al, 2010;Kim et al, 2019a).…”