Occurrence and Source of Chlorinated Polycyclic Aromatic Hydrocarbons (Cl-PAHs) in Tidal Flats of the Ariake Bay, Japan

Abstract

In this study, we hypothesize that natural photochemical reactions of polycyclic aromatic hydrocarbons (PAHs) in tidal flats are responsible for the occurrence of chlorinated polycyclic aromatic hydrocarbons (Cl-PAHs). This study aims to survey the impact of photochemical reactions using a combination of field surveys and lab-scale experiments. Concentrations and profiles of PAHs and Cl-PAHs in road dust and sediments collected from seven tunnels and two watersheds, respectively, were determined. In the lab-scale experiments, anthracene was irradiated with ultraviolet (UV) light under various salinity conditions. No detectable Cl-PAHs were found in the road dust. However, Cl-PAHs were detected in the sediments from 700 to 6.1 × 10(3) pg g(-1) and specifically from downstream sites. 2-Monochloroanthracene (2-Cl-ANT) and 9,10-dichloroanthracene (9,10-di-Cl-ANT) were dominant in the sediments. In the Domen River watershed, the ∑Cl-PAHs and the salinity showed a significant positive correlation (p < 0.01) in the sediments, while such a correlation was not found for PAHs. 2-Cl-ANT, 9-monochloroanthracene, and 9,10-di-Cl-ANT were identified as transformation products in the UV irradiation experiments. Production of these Cl-PAHs was dependent on the solution salinity. These results support our hypothesis, and we conclude that photochemical reactions significantly contribute to the occurrence of Cl-PAHs in the studied tidal flats.

Nontargeted Biomonitoring of Halogenated Organic Compounds in Two Ecotypes of Bottlenose Dolphins (Tursiops truncatus) from the Southern California Bight

“… 48 2,4,6-Tribromoanisole and the dichlorinated polycyclic aromatic hydrocarbon may have both natural and anthropogenic sources. 49 Methylene bis(trichloro)anisole, detected in all eight samples and not previously reported in the environment, is the methylated version of hexachlorophene, which was used as a disinfectant and banned in 1972. 50 Polybrominated dibenzofurans can be formed during the processing of PBDE-containing plastics or the incineration of waste containing brominated flame-retardants, 51 as well as from potentially natural hydroxy-PBDEs via photolysis.…”

Photochemical degradation of PAHs in estuarine surface water: effects of DOM, salinity, and suspended particulate matter

“…In addition to the effects on 1 O 2 and ·OH production at high salinity, Cl − may participate in the photodegradation of PAHs on its own. For example, based on a combination of field surveys and lab-scale experiments, Sankoda et al (2013) found the occurrence of chlorinated PAHs in tidal flats of the Ariake Bay, Japan, which was dependent on salinity.…”

Photochlorination of Polycyclic Aromatic Hydrocarbons in Acidic Brine Solution

“…The fates of PAHs in the environment are known to be significantly influenced by photodecay processes, including photo-oxidation (Lima et al 2005;Rubio-Clemente et al 2014). Recently, Sankoda et al (2013) reported that anthracene on glass beads simulated sedimentary particulate model was converted to chlorinated derivatives following UV irradiation, suggesting that photochemical reactions contribute significantly to the presence of ClPAHs in coastal environments. This finding also suggested that ClPAHs, formed via secondary reactions, may be present in coastal, aquatic and atmospheric environments.…”