Occurrence, profile and possible sources of PCNs in Hong Kong soils, and a comparison with PCBs, PCDDs and PCDFs

Abstract

Polychlorinated naphthalenes (PCNs) have been proposed for inclusion in the annexes of the Stockholm Convention by the European Union, signifying a probable increase in monitoring PCN levels at a global level. Investigations on PCN levels in the environment of Hong Kong have not been reported. In this preliminary investigation, PCN levels in surface soils samples were determined by isotope dilution HRGC/HRMS techniques, and compared with those of polychlorinated biphenyl (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). The concentrations of PCNs in the soil samples were 35-883 pg g −1 (average, 201; and median, 94 pg g), which were lower than those of PCBs PCDDs and PCDFs. This comparison suggested that PCNs are currently not priority POPs compared with dioxins and PCBs in Hong Kong soils. PCDDs were the most important contributor to the sum of toxic equivalents of PCNs, PCBs, PCDDs and PCDFs. OCDD was the most dominant dioxin congener in Hong Kong surface soils. PCB-118 was the most abundant in 12 dl-PCB congeners. PCN congeners indicating thermal related sources (CN52/60, CN66/67 and CN73) were relatively abundant in their respective homologs, which suggested PCN contamination from thermal sources. The ratio of CN73 to CN74 in soil samples suggested the contribution of PCN contaminations in soils from both thermal-related sources and evaporative emissions of technical PCN mixtures.

Risks for animal and human health related to the presence of polychlorinated naphthalenes (PCNs) in feed and food

“…These are related to waste and coal combustion from industries that use thermal processes including metal ore smelting and refining, secondary metal smelting processes or cement and coke production. They can also be found in environmental samples such as pine needles, lake sediment cores and soil (Hanari et al, 2004;Horii et al, 2004;Liu et al, 2014;Orlikowska et al, 2009;Wyrzykowska et al, 2007Wyrzykowska et al, , 2009. The mechanism of PCNs formation during thermal processes was reviewed by Liu et al (2014) and formation pathways resulting from de novo synthesis during combustion have been documented suggesting that the chlorination of the naphthalene occurs on the active surface of fly-ash (Fernandes et al, 2017).…”

“…These are related to waste and coal combustion from industries that use thermal processes including metal ore smelting and refining, secondary metal smelting processes or cement and coke production. They can also be found in environmental samples such as pine needles, lake sediment cores and soil (Hanari et al., 2004 ; Hanari, Falandysz, Nakano, et al., 2013 ; Hanari, Falandysz, Petrick, et al., 2013 ; Horii et al., 2004 ; Liu et al., 2014 ; Orlikowska et al., 2009 ; Wyrzykowska et al., 2007 , 2009 ). The mechanism of PCNs formation during thermal processes was reviewed by Liu et al.…”

“…The mechanism of PCNs formation during thermal processes was reviewed by Liu et al. ( 2014 ) and formation pathways resulting from de novo synthesis during combustion have been documented suggesting that the chlorination of the naphthalene occurs on the active surface of fly‐ash (Fernandes et al., 2017 ). A study of sediment cores from Jiaozhou bay (China) showed that the contribution from the municipal solid waste incineration source of PCNs has been more important in more recent years than other sources (Pan et al., 2012 ).…”

3D-QSAR/HQSAR-based analysis of bioconcentration and molecularmodification of monophenyl aromatic compounds

“…Some aromatic compounds have been listed as persistent organic pollutants by the Stockholm Convention, including pentachlorobenzene (PeCB), 1 hexachlorobenzene, 2 polychlorobiphenyls, 3 and polychlorinated naphthalenes. 4 Furthermore, nitrobenzene and PAHs have been listed as priority pollutants by the US Environmental Protection Agency. 5 As an important class of chemical raw materials and intermediates, aromatic compounds are widely used in food, dyes, petroleum, plastics, organic synthesis, and other industries.…”

Profiling of small molecule metabolites and neurotransmitters in crustacean hemolymph and neuronal tissues using reversed‐phase LC‐MS/MS

“…High‐throughput detection and identification of small molecules face tremendous challenges due to their diverse physiochemical properties and wide range of abundance levels. To address these challenges, a plethora of separation techniques (e.g., CE, GC and LC) and detection methodologies (e.g., NMR and MS), have been developed and integrated to obtain enhanced chemical information for more confident assignment . MS imaging (MSI) has provided another powerful approach due to its ability to enable visualization of molecular distributions within anatomical context .…”