Dioxins

Breast Milk Survey

How does the level of dioxins in the breast milk of New Zealand women compare to other countries?

New Zealand submitted the first two samples collected for its 1988 national breast milk study to the 1988 WHO breast milk survey of dioxins. Participating countries followed the same study protocol as far as possible. The purpose was to compare the total toxic burden (TEQ) in breast milk in different countries and in some instances different areas within countries. Outside the European region the lowest TEQ levels were reported from New Zealand, Thailand and north Vietnam (Hanoi). The highest values were reported in some areas of south Vietnam although large differences were reported between areas of Vietnam. Large differences for TCDD levels were also reported between areas of Vietnam, including within south Vietnam.

TCDD levels (ppt) in breast milk in certain countries (WHO breast milk survey)

	TCDD (ppt)
Vietnam (Song Be)	17
Belgium	9.7
Vietnam (Ho Chi Minh)	7.1
Netherlands	5.3
United Kingdom	5.5
Poland	3.6
USA	3.3
Vietnam (Hanoi)	2.2
New Zealand	1.4
India	<1
Thailand	<1

The average TCDD level in the 1988 New Zealand breast milk study which sampled 38 women who were breastfeeding their first child was 5.1 ppt (range 0.9-13).

Comparison of breast milk dioxins results from different studies are not valid unless the study protocols for collecting and analysing the samples are consistent. For example,breast milk dioxins decrease over the period of lactation and generally are lower as the parity (or number of children) of the woman increases.

A further national breast milk study which includes participation in a WHO breast milk survey is currently being undertaken in New Zealand.