Dioxins

Breast milk survey

New Zealand’s Breast Milk Study - Investigation of Breast Milk for Persistent Organic Pollutants (POPs)

In this section:

Introduction
Aims of the study
Study areas
Criteria for potential donors
Chemicals to be tested
International Obligation
What are POPs?
Toxic effects of POPs
Progress reports

The Ministry of Health commissioned the Massey University, Centre for Public Health Research to assess the levels of POPs in human breast milk. The study has commenced in October 2006 and is expected to be completed in mid-2008. That date has been extended to the end of December 2008 due to difficulties in recruiting mothers, and to complete the collection of breastmilk from 50 mothers.

Aims of the study
The study is aimed to obtain data on current levels of POPs in breast milk in New Zealand and compare these levels with previous New Zealand studies and detect trends in POPs exposure; to study the determinants of elevated levels of POPs in breast milk; and to provide recommendations for prioritising POPs for remedial action in New Zealand.

Scope of the study

The study will:

survey and interview 250 possible participants
select 50 eligible participants as well as about 10 alternates
collect and handling of samples (including one pooled sample that will be sent to WHO)
sample analysis of:
- one pooled sample for basic and advanced POPs (see list below).
- one pooled sample for optional POPs, ie polybrominated diphenyl ethers (PBDEs), polybrominated and mixed halogenated dioxins and furans, hexabromocyclododecane (HBCD)
- analysis of 50 individual samples (basic POPs only).
provide advice and information to the Ministry of Health, and to other agencies on behalf of the Ministry of Health, including timely advice on any emerging national and international advice issues that may impact on public health
report on delivery of services, emergent issues and other relevant information.

Study areas
Participants are to be recruited in the North Island, Wellington (urban) and the Wairarapa (rural) and Christchurch (urban) and North Canterbury (rural) for the South Island. There will be 25-30 women from rural areas and 25-30 women in urban areas from both the North and South Islands.

Criteria for potential donors

The following criteria must be met by the participants:

be primiparous (have one child only)
be aged 20–30
have had a normal pregnancy and apparently healthy mother and child
mother planning to breastfeed only
residential history: apart from holidays the mother should have lived in the same area for the last five years
speak English
have a freezer at home for storage of milk samples.

Chemicals to be tested

Basic persistent organic pollutants (POPs): aldrin, dieldrin, DDT, heptachlor, hexachlorobenzene, hexachlorocyclohexane (HCH), mirex, polychlorinated biphenyls (PCBs) (marker PCBs) (total expressed in WHO Toxic Equivalency Factors (TEFs)).

Advanced POPs: polychlorinated dibenzodioxins (PCDDs) (total expressed in WHO TEFs, polychlorinated dibenzofurans (PCDFs) (total expressed in WHO TEFs, PCBs mono-ortho PCBs and non-ortho PCBs (total expressed in WHO TEFs).

Optional POPs: polybrominated diphenyl ethers (PBDEs).

Lipids will be determined for all samples.

International Obligation
New Zealand is a Party to the Stockholm Convention on POPs, which aims to reduce the amount of these substances in the environment and in humans. One of the activities in the protocol is to assess the levels of POPs found in human milk so that a National Implementation Plan for each country can better identify and prioritise POPs for remedial action. The WHO has co-ordinated a number of international studies on levels of organochlorine contaminants in breast milk. Therefore the results of this study can be used to provide international comparison. This Convention addresses an initial list of 12 chemicals.

What are POPs?
POPs are chemical substances that persist in the environment, bioaccumulate through the food chain, and pose a risk of causing adverse effects to human health and the environment. They are a group of chemicals which have been intentionally or unintentionally introduced and widely distributed in the environment.

Toxic effects of POPs
Due to their stability and fat solubility, they have a capacity to accumulate in many fat-containing foods, including human milk. POPs have been of health concern, both for their acute and chronic toxic effects. Long-term exposures have been linked to increased incidence of cancer, reproductive, endocrine and immune dysfunction, as well as neurobehavioural disorders.

Progress reports
First quarterly progress report (1 October – 31 December 2006)

The study protocol, study questionnaire have been completed and the ethical approval has been sought and approved from the Multi-Region Ethics Committee. Two research nurses have been identified for the North and South Islands and started approaching midwives in the Wairarapa study area.

Second quarterly progress report (1 January 2007-31 March 2007)

CPHR have started collaborating with a third research nurse and contacts with midwives of the Wairarapa area have been established. Contacts with midwives from the Wellington area and a meeting with the Wellington midwives to discuss the study will be set-up.

Two mothers have agreed to participate in the Wairarapa area but they did not fit the criteria specified in the protocol.

Page last updated 24 May 2007