Multiple persistent organic pollutants in mothers' breastmilk: Implications for infant dietary exposure and maternal thyroid hormone homeostasis in Uganda, East Africa
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Date
2021
Journal Title
Journal ISSN
Volume Title
Publisher
Science of The Total Environmen
Abstract
Persistent organic pollutants (POPs) are ubiquitous contaminants with adverse health effects in the ecosystem.
One of such effects is endocrine disruption in humans and wildlife even at background exposure concentrations.
This study assessed maternal breastmilk concentrations of POPs; brominated flame retardants (BFRs),
polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), and the potential
health risks posed to the nursing infants. We also evaluated the association of these POPs with total 3,3′,5-
triiodo-L-thyronine (T3), L-thyroxine (T4), and 3,3′,5′-triiodo-L-thyronine (rT3) levelsmeasured in human breast
milk. Thirty breastmilk samples were collected from Kampala, Uganda between August and December 2018. Hexabromobenzene was not detected while the maximum level of 2,2′,4,4′,5,5′-hexabrombiphenyl was 64.7 pg/g
lw. The median levels of total indicator PCBs, PBDEs, dioxin-like PCBs, and PCDD/Fs in the samples were 159 pg/g
lw, 511 pg/g lw, 1.16 pg TEQ/g lw, and 0.4 pg TEQ/g lw, respectively. These levels were lower than those reported
in other countries. Owing to their bio accumulative nature, PCBs −81, −169, andΣPCDD/Fs increased with increase
in maternal age. Estimated dietary intakes for dioxin-like PCBs and PCDD/Fs were lower than those reported
elsewhere but were higher than the WHO tolerable daily intakes suggesting potential health risks to
nursing infants. In adjusted single pollutant models, PCB-126, PCB-169, andΣPCBTEQ were negatively associated
with T3, while 1,2,3,4,5,7,8-HpCDF was positively associated with rT3. Although these associations did not persist
in multi pollutant models, our findings suggest potential thyroid hormone disruption by POPs in mothers. This
may reduce the levels of thyroid hormones transferred from the mother to the neonates and, hence, adversely influence
infant growth. A temporal study with a bigger sample size is required to corroborate these findings
Description
Keywords
Persistent organic pollutants, Breastmilk, Dietary exposure, Thyroid hormones, Africa
Citation
Matovu, H., Li, Z. M., Henkelmann, B., Bernhöft, S., De Angelis, M., Schramm, K. W., ... & Ssebugere, P. (2021). Multiple persistent organic pollutants in mothers' breastmilk: Implications for infant dietary exposure and maternal thyroid hormone homeostasis in Uganda, East Africa. Science of The Total Environment, 770, 145262. https://doi.org/10.1016/j.scitotenv.2021.145262