Dioxins and Fatty Acids in Breast Milk of Primiparas in Yonago District, Tottori Prefecture, Japan

We analyzed the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in breast milk collected 1 week after childbirth from 8 primiparas in Yonago district, Tottori Prefecture, and investigated the relationship between PCDDs or PCDFs and fatty acids in concentration, and the relationship between dioxin concentration and kind of daily foods. The mean total content of dioxins (PCDDs and PCDFs) was 0.48 pg-toxic equivalent (TEQ)/g (range 0.12?1.04 pg-TEQ/g) in breast milk, and 16.7 pg-TEQ/g-fat (range 9.6?32.7 pg-TEQ/g-fat) in total lipids of breast milk. The 8 primiparas showed a low mean dioxin concentration: the levels were lower in 6 of them and higher in 2 of them than in primiparas living in other cities in Japan. For 1 of the 2 mothers, the reason for the high level was thought to be her poor intake of vegetables in the diet. The total dioxin content was well correlated with the total lipid content ranging from 1% to 3%. Fatty acids with C16:0 and C18:1 dominated those with C12:0, C14:0, C16:1, C18: 2 and C18:0, which were commonly detected. The amount of fatty acids with C10:0, C20:1, C20:2, C20:3, C20:4, C22:5 and C22:6 was small. Gas chromatograms of these fatty acids generally showed similar distributions in breast milk of the 8 primiparas. The contents of fatty acids ranged from 17.1 to 31.3 mg/g (average 24.0 mg/g) in bulk breast milk. No clear correlation was found in concentration between PCDDs or PCDFs and specific fatty acids in breast milk.