Objective: To investigate the levels of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD-Fs) in human breast milk of the mothers who lived in non-directly persistent organic pollutants (POPs) polluted area in Shenzhen, and the correlation of exposure risk factor was analyzed.
Methods: From July to November in 2007, 60 primiparas by vaginal delivery after parturition 3 weeks to 2 months were sampled for breast milk who aged from 20 - 34 years old and has lived in Shenzhen non-directly POPs polluted areas over 5 years. PCDD-Fs were extracted from the frozen-dried samples with accelerated solvent extraction (ASE), cleaned up by fluid management system (FMS) and quantified by high-resolution gas chromatography-high resolution mass spectrometry (HRGC-HRMS) using isotope dilution methodology. TEQ were calculated. The correlation relationship among infant's birth weight and length, participatory's dietary, age, inhabitation period, environment and the body burden of PCDD-Fs in mother was statistically analyzed by SPSS 13.0.
Results: The participants aged from 20 - 34 years old (28 years on average) and lived in Shenzhen for 5 - 29 years (10 years on average). The concentration of PCDD-Fs in 60 breast milk samples were 26.957 143 - 669.583 333 pg/g fat (mean: 7.224 817 pg/g fat, median: 84.176 062 pg/g fat), and TEQ-PCDD-Fs in samples were 2.420 793 - 29.014 277 pg/g fat (mean: 8.645 992 pg/g fat, median: 7.751 804 pg/g fat). 2, 3, 4, 7, 8-PeCDF, 1, 2, 3, 7, 8-PeCDD, 2, 3, 7, 8-TCDD were the dominant contributors to the total TEQ, which were 3.691 654 pg/g fat (42.689 378%), 2.478 315 pg/g fat (28.652 356%), and 0.980 995 pg/g fat (11.343 995%) respectively. Significant positive correlations were found among age (r = 0.26, P < 0.05), inhabitation period (r = 0.49, P < 0.05), the consumption of fish (r = 0.37, P < 0.05) and the concentrations of TEQ-PCDD-Fs in the study.
Conclusion: The levels of dioxin chemicals in the breast milk samples in non-directly POPs polluted areas of Shenzhen are high. Significant positive correlations were found among age, inhabitation period, the consumption of fish and the concentration of PCDD-Fs.