4 Results and discussions for organic contaminants of emerging concern
4.6 Test of sampling methodology for volatile fluorinated substances and data mining . 70
substances, including those detected in data mining in 2018 (Table 17).
Table 17. Compounds, discovered by data-mining at Zeppelin in 2018.
CAS Concentration range (pg/m3) 1 1,1,2,3,4,4-hexachloro-1,3-Butadiene 87-68-3 4500-20 000
2 1,2-dichlorobenzene 95-50-1 3000-14 000
3 dichlorobenzene 95-50-1 890-3100
4 hexachloroethane 67-72-1 640-4600
5 1,4-dichloro-2-methylbenzene 19398-61-9 570-2500
6 1,2,4-trichlorobenzene 120-82-1 320-1600
7 hexachlorobutadiene, unknown isomer 340-1800
8 1,3,5-trichloro-2-methoxybenzene 87-40-1 270 1500
9 dichlorobenzene 95-50-1 240-1090
10 Hexachlorobenzene 118-74-1 160-1200
11 2,4-dichloro-1-methoxybenzene 553-82-2 150-750
12 1,2,4-trichlorobenzene 120-82-1 100-490
13 1,5-dichloro-2-methoxy-3-methylbenzene 13334-73-1 100-700 14 Ethane, 1,1,2,2-tetrachloro- 79-34-5 100-540 15 1,2,4-trichloro-3-methylbenzene 2077-46-5 80-470 16 1,2,4,5-tetrachloro-3,6-dimethoxybenzene 944-78-5 50-270 17 1,2-dichloro-4-(chloromethyl)-benzene 102-47-6 50-300 18 2,3-Dichloro-5-trifluoromethylpyridine 69045-84-7 50-220 19 1,5-dichloro-2-methoxy-3-methylbenzene 13334-73-1 60-370
20 1,2,4,5-tetrachlorobenzene 95-94-3 50-240
21 1,2,3,5-tetrachlorobenzene 634-90-2 40-200
Air samples were collected at NILU’s facilities at Kjeller using i) the same sampling methodology as in 2018 (ABN) but slightly modified, and ii) a new adsorbent (charcoal). The ABN method was modified with larger amounts of ABN and alternatives for extraction (Table 18). Two sampling campaigns were performed; one in spring (April-May) and one in winter (November-December).
Table 18. Sampling methodologies tested in 2019.
ABN 2018 ABN 2019, vers. 1 ABN 2019, vers. 2 Charcoal
Sorbent amount 140 mg 140 mg 250 mg 4 cm disk
Transportation
condition ambient ambient frozen frozen
Extragent 1 4 mL hexane 4 mL pentane 4 mL Ether 4 mL Ether
Extragent 2 none 4 mL ether +
4mL methanol 4 mL ethylacetate 4 mL ethylacetate Evaporation to 100 mL to 100 mL to 100 mL, advanced to 100 mL, advanced
The primary extracts (pentane in sampling campaign 1, April-May and ether in sampling 2, November-December) were analyzed for nine fluorine containing substances (Table 19). In addition, a total area of all peaks corresponding to an ion C3F5 (one of the characteristic ions for perfluoroaliphatic
subtances) was calculated to evaluate the part of undetected non-polar volatile PFAS. Results are summarized in table 20.
Table 19. Per- and polyfluorinated substances for analysis.
Short name Full name CAS number Formula
PFTBA Perfluorotributylamine 311-89-7 C12F27N
TCPFB Tetrachlorohexafluorobutane 375-45-1 C4F6Cl4
PFTPeA Perfluorotripentylamine 338-84-1 C15F33N
PFPHP Perfluoroperhydrophenanthrene 306-91-2 C14F24
PFBcH Perfluorobutylcyclohexane 374-60-7 C10F20
DCPFcH Dichloroperfluorocyclohexene 336-19-6 C6F8Cl2
PFBB pentafluorobromobenzene 344-04-7 C6F5Br
bisTFMBB 3,5-bis-(trifluoromethyl)bromobenzene 328-70-1 C8H3F6Br
DCTFP Dichlorotrifluoropyridene 1737-93-5 C5NF3Cl2
Total Fvol* C3F5 ion*
*This is a provisional parameter for evaluation of total content of perfluoroaliphatic substances in the air.
Table 20. Concentrations of Volatile Fluorinated compounds (PFTBA-like) in air in Kjeller, weeks 15, 18, 19 and 48-50, 2019
PFTBA was found in high concentration in all samples and comprised 56-91% of the “Total FVol” (the ratio of peak area of ion 131 for PFTBA to combined area of all peaks of ion 131). The concentrations were higher in spring than in winter. In addition, there was variation between samples from the same season (ca 1.4 times in Spring and ca 2.5 times in Winter between maximal and minimal values). TCPFB and PFTPeA were detected in all but one sample, though at much lower levels (due to technical problems PFTPeA was not measured in Spring). PFPHP was detected in all but two samples. The other targeted substances were not detected (LOD: 1-57 pg/m3).
A careful conclusion can be made that PFTBA is likely a major contaminant of its class. Nevertheless, more careful search for other non-polar PFAS shall continue, as potentially ozon-depleting substance may not produce C3F5 ion during GC-MS analysis.
The results of the data mining shows that there is a clear advantage of using ABN as adsorbent for air sampling for non-target screening, as the aromatic substances were poorly detected on charcoal samples. The poor results for charcoal is due to high retention of such compounds on the charcoal sorbent.
Table 21. Levels of chlorinated substances from data-mining in the air using two different adsorbents at Kjeller in weeks 38-40, by order of concentration.
CAS ABN 1 ABN 2 ABN 3 Charcoal
1,1,2,3,4,4-hexachloro-1,3-Butadiene 87-68-3 773 525 668 261 264 378 1,5-dichloro-2-methoxy-3-methylbenzene 13334-73-1 596 429 338 2 3 2
1,2-dichlorobenzene 95-50-1 560 518 555 20 80 35 1,2,4,5-tetrachloro-3,6-dimethoxybenzene 944-78-5 72 23 32 2 <1 <1 1,5-dichloro-2-methoxy-3-methylbenzene 13334-73-1 72 134 87 1 5 2
1,2,4-trichlorobenzene 120-82-1 58 47 48 1 1 <1
1,2,4-trichloro-3-methylbenzene 2077-46-5 30 36 59 <1 <1 <1 2,3-Dichloro-5-trifluoromethylpyridine 69045-84-7 29 17 18 <1 <1 4 1,2,4,5-tetrachlorobenzene 95-94-3 28 20 24 <1 <1 <1
Hexachlorobenzene 118-74-1 23 11 22 <1 <1 <1
1,2,3,5-tetrachlorobenzene 634-90-2 20 11 15 <1 <1 <1 1,2-dichloro-4-(chloromethyl)-benzene 102-47-6 18 19 49 <1 <1 <1
Ethane, 1,1,2,2-tetrachloro- 79-34-5 0 45 10 2 7 7
The results from 2019 cannot be directly compared to those from 2018 due to different internal standard and different quantification approaches as well as different sampling locations (Kjeller in 2019 and Zeppelin in 2018). As already emphasized in 2018, results from 2018 are likely overestimates while the method established in 2019 is more accurate (e.g. consistent results) and applicable for future studies at the monitoring sites.
5 Conclusion for organic contaminants
The overall annual mean concentrations in outdoor background air from active air samplers for 17 different organic contaminant classes and three observatories in 2019 are presented in Table 22.
Table 22: Annual mean concentrations in air for all targeted organic contaminants in 2019.
The highest concentrations are marked with orange/pink while the lowest concentrations are marked with green.
The highest concentrations in air of all the targeted contaminants were observed for cVMS, phthalates, PAHs, SCCPs/MCCPs, and OPFRs. Also the volatile PFAS (FTOHs) were detected at high concentrations.
Most of these compounds are non-regulated contaminants that are still in use and the measured concentrations at Birkenes and Zeppelin are 100-10 000 times higher than the concentrations measured for the regulated POPs. In contrast, a few other non-regulated (i.e. nBFRs and dechloranes) contaminants were measured at low concentrations in Arctic air and at Birkenes.
The results from the air monitoring in 2019 show that the concentrations of most legacy POPs in air and precipitation are declining or have stabilized (reached temporal remote state conditions) during the last years. Significant for temporal remote state is that the primary emissions has stopped and that the long-term slow decline (removal rate) of a chemical in the environment is controlled by degradation rates in secondary repositories (Stroebe et al., 2004).
For HCB, an increase in concentrations has been observed at Zeppelin, Svalbard, during the last ten years, and at Birkenes during the last five years. However, the measurements from 2017-2019 suggests that the increasing trend for HCB has turned and is now apparently declining at Zeppelin and Birkenes.