Polynuclear aromatic hydrocarbons (PAHs) in global background soils.

The levels and distribution of polynuclear aromatic hydrocarbons (PAHs) were investigated in global background soil samples. Total PAH concentrations (sum of 15 compounds) ranged over 5 orders of magnitude, from North America > Asia > Oceania > Africa > South America. Proximity to long-term emissions sources and locations susceptible to high atmospheric depositional inputs tended to have higher concentrations. A broad positive correlation was obtained between population density and soil PAH concentrations (i.e. source-related factors). However, concentrations were also influenced by the holding capacity of the soils (i.e. sink-related factors) with statistically significant correlations observed between PAHs and soil organic matter (SOM), and black carbon (BC)

Relationships between organic matter, black carbon and persistent organic pollutants in European background soils : implications for sources and environmental fate.

Black carbon (BC) and total organic carbon (TOC) contents of UK and Norwegian background soils were determined and their relationships with persistent organic pollutants (HCB, PAHs, PCBs, co-planar PCBs, PBDEs and PCDD/Fs) investigated by correlation and regression analyses, to assess their roles in influencing compound partitioning/retention in soils. The 52 soils used were high in TOC (range 54–460 mg/g (mean 256)), while BC only constituted 0.24–1.8% (0.88%) of the TOC. TOC was strongly correlated (p < 0.001) with HCB, PCBs, co-PCBs and PBDEs, but less so with PCDD/Fs (p < 0.05) and PAHs. TOC explained variability in soil content, as follows: HCB, 80%; PCBs, 44%; co-PCBs, 40%; PBDEs, 27%. BC also gave statistically significant correlations with PBDEs (p < 0.001), co-PCBs (p < 0.01) and PCBs, HCB, PCDD/F (p < 0.05); TOC and BC were correlated with each other (p < 0.01). Inferences are made about possible combustion-derived sources, atmospheric transport and air–surface exchange processes for these compounds. Total organic carbon and black carbon fractions can play an important role in the storage and cycling of persistent organic pollutants in background soils

The impact of polybrominated diphenyl ether prohibition:a case study on the atmospheric levels in China, Japan and South Korea

Abstract The atmosphere is an important medium which could directly reflect the changes of pollutant sources. Worldwide, the commercial products of polybrominated diphenyl ethers (PBDEs) have been officially restricted and subsequently prohibited. For the purpose of evaluating their concentration after prohibition, passive air samplers (PASs) were therefore deployed again across the East Asia during two periods in 2008 after the initial deployment 4 years ago. When compared with the data in 2004, the atmospheric concentrations of PBDEs have declined significantly. Spatially, the PBDE level in China was still the highest, with a mean value of 15.4 pg m− 3, and in Japan was the lowest (2.47 ± 1.12 pg m− 3) in the East Asia. Moreover, the relatively high concentrations were observed at sites where there are electronic or e-waste recycling industries, and this is particularly true in China, suggesting that illegally imported e-waste is still a typical source of PBDEs in this region

PAHs in background soils from western Europe : influence of atmospheric deposition and soil organic matter.

The levels and distribution of polynuclear aromatic hydrocarbons (PAHs) were determined in soil samples from background locations in the UK and Norway, to investigate their spatial distribution and the controlling environmental factors. Concentrations ranged between 42 and 11 200 μg kg−1 (geometric mean 640 μg kg−1) and 8.6 and 1050 μg kg−1 (150 μg kg−1) dry weight in the UK and Norwegian soil, respectively. Proximity to sources and locations susceptible to high atmospheric depositional inputs resulted in higher concentrations. Statistically significant relationships were observed between PAH and total organic carbon (TOC) in the Norwegian samples. High molecular weight PAHs correlated with black carbon (BC) in UK-woodland soil. These observations support the hypothesis that TOC plays an important role in the retention of PAHs in soil and that PAHs are often combined with BC during combustion emissions. PAHs with 4 and more rings comprised 90% of total PAHs in the UK soil, but only 50% in the Norwegian soil. The mixture of PAHs implied that fractionation occurred during long-range atmospheric transport and deposition. The lighter PAHs with lower Kow values more readily reached the most remote sites. The heavier PAHs with higher Kow values remained in closer proximity to sources

Passive air sampling of PCBs, organochlorine compounds and PBDEs across Asia.

Asia is of global importance economically, yet data on ambient persistent organic pollutant levels are still sparse for the region, despite international efforts under the Stockholm Convention to identify and reduce emissions. A large-scale passive air sampling survey was therefore conducted in Asia, specifically in China, Japan, South Korea, and Singapore. Polyurethane foam disks were deployed simultaneously at 77 sites, between Sept 21 and Nov 16, 2004, and analyzed for polychlorinated biphenyls (PCBs), organochlorine compounds (hexachlorobenzene (HCB), dichlorodiphenyltrichloroethanes (DDTs), chlordane), and polybrominated diphenyl ethers (PBDEs). The meteorological conditions prevailing in the region at this time facilitated the assessment of local/regional differences in atmospheric emissions, because large-scale advection effects due to monsoons or dust storms did not occur. Air concentrations estimated assuming an average sampler uptake rate of 3.5 m3/day ranged as follows (pg m-3): PCBs, 5−340; HCB, 10−460; DDTs, 0.4−1800; chlordanes, 1−660; PBDEs, <0.13−340. South Korea and Singapore generally had regionally low concentrations. Elevated concentrations of PCBs, DDTs, and HCB occurred at sites in China, higher than reported in a similar recent sampling campaign in Europe. Chlordane was highest in samples from Japan (which also had elevated levels of PCBs and DDTs) and was also elevated in some Chinese locations. PBDE levels were generally low in the region

Atmospheric Short-Chain Chlorinated Paraffins in China, Japan, and South Korea

This study presents the first investigation of concentrations and congener group patterns of atmospheric short-chain chlorinated paraffins (SCCPs) throughout East Asia. Based on an absorption rate calibration experiment, a spatial survey of SCCPs was performed using passive air samplers in China, Japan, and South Korea during two separate periods in 2008. The atmospheric concentrations of SCCPs in China were clearly greater than those in Japan and South Korea, both of which exceed the levels determined for other regions of the world. C-10 components were the most abundant type of SCCPs in China, whereas C-11 components were dominant in Japan and South Korea. With respect to the total chlorine content, Cl-6 and Cl-5 were the predominant compounds in China and Japan; however, Cl-6 and Cl-7 were predominant in South Korea. A similar pattern was also found for remote sites within China, Japan, and South Korea, respectively. Together with the back-trajectories calculated for the remote sites, the results indicate that the SCCPs in the air of East Asia were mainly influenced by local sources due to their relatively low long-range atmospheric transport potential compared to other POPs.This study presents the first investigation of concentrations and congener group patterns of atmospheric short-chain chlorinated paraffins (SCCPs) throughout East Asia. Based on an absorption rate calibration experiment, a spatial survey of SCCPs was performed using passive air samplers in China, Japan, and South Korea during two separate periods in 2008. The atmospheric concentrations of SCCPs in China were clearly greater than those in Japan and South Korea, both of which exceed the levels determined for other regions of the world. C-10 components were the most abundant type of SCCPs in China, whereas C-11 components were dominant in Japan and South Korea. With respect to the total chlorine content, Cl-6 and Cl-5 were the predominant compounds in China and Japan; however, Cl-6 and Cl-7 were predominant in South Korea. A similar pattern was also found for remote sites within China, Japan, and South Korea, respectively. Together with the back-trajectories calculated for the remote sites, the results indicate that the SCCPs in the air of East Asia were mainly influenced by local sources due to their relatively low long-range atmospheric transport potential compared to other POPs