Polychlorinated dibenzo-dioxin/furan and polychlorinated biphenyl concentrations in the human milk of individuals living near municipal waste incinerators in the UK: Findings from the Breast milk, Environment, Early-life, and development (BEED) human biomonitoring study

The objective of this study is to report recent PCDD/F and PCB human milk concentrations in the United Kingdom (UK) and relate these to two proxies for exposure to municipal waste incinerator (MWI) emissions. As part of the Breast milk, Environment, Early-life, and Development (BEED) study, primiparous individuals were recruited from within 20 km of English MWIs between 2013 and 2015 and asked to provide human milk samples. The samples were analysed for quantitative concentrations of 17 PCDD/F and 12 PCB congeners. Linear regression models were used to investigate the association between two proxy measurements for exposure to MWI emissions: (i) log average modelled daily ground-level PM10 from MWIs (modelled PM10) and (ii) residential proximity to nearest MWI and the toxic equivalents (TEQs), ∑TEQ2005-PCDD, ∑TEQ2005-PCB and ∑TEQ2005-PCDD/F + PCB. Samples from 194 participants were analysed for PCDD/Fs and 150 for PCBs. Overall ∑TEQ2005-PCDD/F + PCBs ranged from 1.76 to 25.1 pg/g lipid with a geometric mean of 5.81 (Geometric standard deviation: 1.64). A doubling in modelled PM10 was significantly associated with an average increase of 9.71% (95% CI: 2.91%–16.5%) in ∑TEQ2005-PCDD/Fs + PCB, 9.14% (95% CI: 1.79%–16.5%) in ∑TEQ2005-PCDD/Fs and 9.02% (CI:1.57%–16.5%) in ∑TEQ2005-PCBs. MWI proximity was not associated with an increase of ∑TEQ2005-PCDD/Fs, ∑TEQ2005-PCBs, or ∑TEQ2005-PCDD/Fs + PCBs. The results from this study suggest that MWI emissions may make a small contribution to the body burden of toxic PCDD/F and PCB mixtures. Enhanced environmental monitoring and human biomonitoring of PCDD/Fs and PCBs near MWIs would be needed to investigate this further.