Polychlorinated alkanes in paired blood serum and breast milk in a Swedish cohort study: Matrix dependent partitioning differences compared to legacy POPs

Bo Yuan; Anders Bignert; Patrik L Andersson; Christina E West; Magnus Domellöf; Åke Bergman

doi:10.1016/j.envint.2024.108440

Polychlorinated alkanes in paired blood serum and breast milk in a Swedish cohort study: Matrix dependent partitioning differences compared to legacy POPs

Environ Int. 2024 Jan:183:108440. doi: 10.1016/j.envint.2024.108440. Epub 2024 Jan 12.

Authors

Bo Yuan¹, Anders Bignert², Patrik L Andersson³, Christina E West⁴, Magnus Domellöf⁵, Åke Bergman⁶

Affiliations

¹ Department of Environmental Science (ACES), Stockholm University, SE-106 92, Stockholm, Sweden; Department of Chemistry, Norwegian University of Science and Technology, NO-7491, Trondheim, Norway. Electronic address: bo.yuan@ntnu.no.
² The Swedish Museum of Natural History, SE-104 01, Stockholm, Sweden. Electronic address: anders.bignert@gmail.com.
³ Department of Chemistry, Umeå University, SE-901 87, Umeå, Sweden. Electronic address: patrik.andersson@umu.se.
⁴ Department of Clinical Sciences, Umeå University, SE-901 87, Umeå, Sweden. Electronic address: christina.west@umu.se.
⁵ Department of Clinical Sciences, Umeå University, SE-901 87, Umeå, Sweden. Electronic address: magnus.domellof@umu.se.
⁶ Department of Environmental Science (ACES), Stockholm University, SE-106 92, Stockholm, Sweden; Department of Science and Technology, Örebro University, SE-701 82, Örebro, Sweden. Electronic address: ake.bergman@oru.se.

PMID: 38232504
DOI: 10.1016/j.envint.2024.108440

Abstract

Background: Polychlorinated alkanes (PCAs) constitute a large group of individual congeners originating from commercial chlorinated paraffin (CP) products with carbon chain lengths of PCAs-C_10-13, PCAs-C_14-17, and PCAs-C_18-32, occasionally containing PCAs-C_6-9 impurities. The extensive use of CPs has led to global environmental pollution of PCAs. This study aimed to quantify PCAs in paired serum and breast milk of lactating Swedish mothers, exploring their concentration relationship.

Methods: Twenty-five paired samples of mothers' blood serum and breast milk were analysed and concentrations were determined for PCAs C_6-32 and compared to 4,4'-DDE, the PCB congener 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153), and hexachlorobenzene (HCB).

Results: The median concentrations of PCAs-C_6-9, PCAs-C_10-13, PCAs-C_14-17, PCAs-C_18-32 and ΣPCAs in serum were 14, 790, 520, 16 and 1350 ng/g lipid weight (lw), respectively, and in breast milk 0.84, 36, 63, 6.0 and 107 ng/g lw. Levels of 4,4'-DDE, CB-153 and HCB were comparable in the two matrices, serum and breast milk at 17, 12 and 4.9 ng/g lw. The results show significant differences of PCAs-C_10-13 and PCAs-C_14-17 in breast milk with 22- and 6.2-times lower lw-based concentrations than those measured in serum. On wet weight the differences serum/breast milk ratios of PCAs-C_6-9, PCAs-C_10-13, PCAs-C_14-17, PCAs-C_18-32 and ΣPCAs were 1.7, 3.2, 1.0, 0.4 and 1.6, respectively, while the ratio for 4,4'-DDE, CB-153 and HCB were each close to 0.1.

Conclusion: Swedish lactating mothers had high serum concentrations of PCAs-C_10-13 and PCAs-C_14-17, with the ΣPCAs median serum concentration of 1350 ng/g lw. The breast milk concentration, although considerably lower at 107 ng/g lw, still surpassed those of 4,4'-DDE, CB-153 and HCB, suggesting an exposure risk of infants to PCAs. The variation in blood and breast milk accumulation between PCAs and studied legacy POPs, is rarely discussed but warrants further studies on partitioning properties as well as associated toxicological implications.

Keywords: Human exposure; Lactation; Milk/serum partitioning; NorthPop; POPs.

MeSH terms

Cohort Studies
Environmental Pollutants*
Female
Hexachlorobenzene
Humans
Hydrocarbons, Chlorinated* / analysis
Infant
Lactation
Milk, Human / chemistry
Polychlorinated Biphenyls*
Serum / chemistry
Sweden

Substances

2,4,5,2',4',5'-hexachlorobiphenyl
Environmental Pollutants
Hexachlorobenzene
Polychlorinated Biphenyls
Hydrocarbons, Chlorinated