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NEWS > STORIES

BREASTMILK TESTING IN AUSTRALIA

Harden, F., Muller, J., and Toms, L.
Organochlorine Pesticides (OCPs) and Polybrominated
Diphenyl Ethers (PBDEs) in the Australian population: Levels in Human Milk. January 2005, Environment Protection and Heritage Council.

This report has just been made available on the EPHC/NEPC website at: http://www.ephc.gov.au/ephc/ocp_pbde_human_milk.html  

Summary

The study collected and tested the pooled samples from 20 urban and rural areas around Australia. The levels of the brominated flame retardants, the polybrominated diphenylethers (PBDEs) are clearly higher than those observed in Europe and Japan but lower than those observed in North America and some parts of Canada. The European Union have banned both penta-BDE and octa-BDE.

In Australia, concentrations ranged from a minimum of 6.0 ng g-1 lipid detected in the Tasmanian pooled sample to a maximum of 18 ng g-1 lipid detected in the rural NSW pooled sample.

The study found that levels of organochlorine pesticides (OCPs) are low compared to international studies, which is consistent with the most of these chemicals being phased out in Australia. The highest concentrations of OCPs were found in the Sydney and the Melbourne samples.

The overall OCP concentration for all samples was dominated by beta (β)-HCH and p,p’-DDE, a degradation product of DDT.

A comparison of the Melbourne samples collected in 1993 with those collected in 2002/03 showed no significant differences in the concentrations of the OCPs over the ten-year period.

There had been small decreases in for HCB, α-HCH, aldrin, p,p’-DDD, heptachlor epoxide and dieldrin but small increases in β-HCH, γ-HCH, mirex, o,p’-DDT, oxychlordane, transnonachlor and p,p’-DDE.

Australia continues its use of mirex for termite control in mangoes, despite its inclusion in the Stockholm Convention on Persistent Organic Pollutants 2001.

_________________________________

Polybrominated Diphenylethers (PBDEs)

Prior to this study, PBDEs were detected in pooled blood samples from Australians aged 31-45 years. Overall concentration ranged from 6.7 ng g -1 lipid in a pooled sample collected from females from the South region to a maximum of 18 ng g -1 lipid in a pooled sample collected from males in the West region. The concentrations of PBDEs in Australian sera are high when compared to concentrations reported in European milk or blood. PBDEs have been shown to disrupt thyroid hormones, mimic oestrogen, and are linked with cancer and reproductive damage.(1)

Factors affecting the levels of PBDE compounds in human breast milk.

Factors that affect the levels of PBDEs in human breast milk and serum are not well understood. PBDEs levels vary substantially between countries’ populations and between individuals in a given country/region. There appears to be no clear relationship between the levels of PBDEs and age.

Explanations include:

• unclear exposure pathways with extreme ‘point sources’ or yet to be identified items

• shorter half-lives (which emphasise more recent exposure)

• shorter historic exposure (we may still be in a period where the human body burden increases for PBDEs whereas we have been decreasing body burdens for dioxins and PCBs over the last two decades).

Routes of exposure for PBDE compounds include dietary exposure, particularly of fish; inhalation of contaminated dust, dermal exposure and occupational exposure (computer/electronics repair, maintenance or dismantling). Exposure to PBDEs can also occur through maternal blood and through the amniotic fluid.

PBDEs are commercially available as three products: penta, octa, and deca BDEs. Two of these products (penta and octa) are mixtures of several congeners. Like most commercial chemical mixtures, the compositions of these products vary with manufacturer and with the year in which they were produced. The most common are Penta (BDE-47, -99, -100, -153, -154), Octa (BDE-183), Deca (BDE-209), hexabrominated biphenyl (BB-153) and hexabromocyclododecane (HBCD)

Table 1. Mean concentrations of PBDEs (ng.g -1 lipid) in blood (B) and breast milk (M) detected in other studies.(2)

a – current study, b- number of pools, c - median

PBDEs Breast Milk Results

The 2002/03 breast milk samples had a mean concentration of PBDEs of 11 ng.g -1 lipid. Concentration ranged from a minimum of 6.0 ng g-1 lipid detected in the Tasmanian pooled sample to a maximum of 18 ng g-1 lipid detected in the rural NSW pooled sample.

The highest concentrations were for BDEs 47, 99, 100, 153 and 154. For the three pooled samples collected in 1993, the mean concentration of PBDEs was 13 ng.g -1.

The levels of PBDE in Australian breast milk are clearly higher than those levels observed in Europe and Japan but lower than those observed in North America and some parts of Canada.

Table 4.10 PBDE concentrations in ambient human samples in ng g-1 lipid

Sources of PBDEs

PBDEs are not manufactured in Australia but are imported, either in manufactured goods or as raw material for incorporation into Australian-made products.

Penta-BDE is predominantly used as a flame retardant in polyurethane foam in furniture and electronics. In 2001, North America imported 7,100 tonnes of penta BDE, 95 % of the world market demand.

The PBDEs are used by the electronics industry and include the penta-BDE, octa-BDE, and deca-BDE. Deca-BDE is the most commonly used in electronic products. Deca-BDE has recently been shown to have the potential to break down in the environment and in animals to the smaller, more toxic penta-BDE that is more bioaccumulative in the environment. (3)

In June 2004, deca-BDE, previously claimed not to bioaccumulate, was found in Arctic animals, providing further evidence of the persistency of BFRs and their ability to travel far from their original source.(4) PBDEs have now been found in umbilical cord blood, breast milk, breast fat, as well as adult blood and fat.(5)

This year, the US government’s National Institute of Standards and Technology has found high levels of PBDEs in dust from 27 homes.(6) The levels of the chemical components of deca, the most widely used of the PBDE mixtures, ranged from 160 parts per billion to 8,700 ppb. Levels of penta, the second-most widely used mixture, ranged from 200 to 25,000 ppb. The source of the contamination is likely to be the off gassing of treated domestic products and furnishings, a process referred to as ‘blooming’.

The report, Brominated Flame Retardants In Dust on Computers released in June 2004, reports on ‘wipe samples’ taken from computers which found toxic PBDE residues in every sample.(7)

These studies raise new concerns about potential health risks to young children. Toddlers who crawl on the floor and have a lot of hand to mouth activity, generally have a far greater exposure to household dust than adults. Research indicates that PBDEs can effect a child’s development and may also place them at greater risk of cancer. A Norwegian study of PBDEs found higher levels in 4-year-olds than in adults.(8)

There are no reliable estimates of quantities of BFRs in Australia. Australia faces the ultimate disposal of contaminated articles including the growing quantities of ‘technotrash’ (computer waste, white goods waste, etc). When electronic wastes are incinerated or combusted they can form the highly toxic brominated dioxins. The World Health Organization's International Program on Chemical Safety has concluded that (and brominated flame retardants are significant sources of polybrominated dioxins and furans. Their report concluded that they should not be used where suitable replacements are available.(9)

The two forms of BFRs, BFRs; penta-BDE and octa-BDE have been banned by the European Union and a number of US states.

Organochlorine Pesticides (OCPs)

The overall OCP concentration for all samples was dominated by beta (β)-HCH and p,p’-DDE, a degradation product of DDT.

A comparison of the Melbourne samples collected in 1993 with those collected in 2002/03 showed no significant differences in the concentrations of the OCPs over the ten-year period but with small decreases in for HCB, α-HCH, aldrin, p,p’-DDD, heptachlor epoxide and dieldrin and small increases in β-HCH, γ-HCH, mirex, o,p’-DDT, oxychlordane, transnonachlor and p,p’-DDE.

The overall OCP concentration for all samples was dominated by beta (β)-HCH and p,p’-DDE, a degradation product of DDT. The highest concentrations of OCPs were found in the Sydney pool A and the Melbourne pool A samples. An elevated concentration of HCB was also detected in the sample from rural Queensland.

The study found that levels of OCPs are low compared to international studies, which is consistent with the most of these chemicals being phased out in Australia. However, Australia does use mirex for termite control in mangoes, under an exemption in the Stockholm Convention on Persistent Organic Pollutants 2001.

The study collected and tested 173 pooled samples from 12 regions of Australia during October 2001 and September 2003. To allow direct comparison with previous World Health Organisation studies, volunteering mothers were selected using the following criteria: • A primapara (first-time) mother with a baby aged two to eight weeks (IVF babies are fine); • Exclusively breastfeeding; • Willing to provide a minimum of 100mls (preferably 150mls) of expressed milk. This volume was to be collected over the six week period (2-8 weeks post-partum); • Healthy pregnancy, mother and child; and • A resident of the area for the past five years.

As a result the breast milk study was skewed as it only accepted “healthy pregnancy, mother and child” and samples “pooled”. Inclusion of a less selective group could alter the results considerably. More targeted studies using older first time mothers could produce more meaningful results.

Dioxins were detected in all pooled samples, with mean and median levels (expressed as TEQ) of 9.0 pg WHO-TEQ g-1 lipid and 8.9 pg WHO-TEQ g-1 lipid, respectively. A higher level of dioxin-like chemicals was detected in the Brisbane pool (15.2 pg WHO-TEQ g-1 lipid) which the authors state may have been due to the lower (2.8%) lipid content found in this sample.

For samples collected in 1993, the mean and median levels, expressed as TEQ were 16 pg WHO-TEQ g-1 lipid and 16.4 pg WHO-TEQ g-1 lipid, respectively. International levels of PCDD/Fs and PCBs in pooled human milk.
 

Health Risk Assessment

Infants and toddlers have the highest intake of dioxins relative to weight via breast milk and other foods, dermal exposure and though inhalation (including passive smoking).

The Human Health Risk Assessment of Dioxins in Australia (Technical Report No. 12) gives the estimated lower and upper bound mean intakes of PCDD/Fs, PCBs and total dioxins for breast-fed and non-breast-fed Australian infants at 3 and 9 months of age, breastfed Australian infants are consuming many times the Tolerable Monthly Intake for dioxins and furans.

In 2002, Australia recommended a Tolerable Monthly Intake (TMI) for Australians of 70pg TEQ/kg bodyweight from all sources combined, and including polychlorinated dioxins, polychlorinated furans and dioxin-like PCBs (NHMRC/TGA, 2002).

Even at the lower bound limit, 3 month old babies are consuming at least 17 times the TMI of total dioxins.

References :

(1)Fire Retardant, Polybrominated diphenyl ethers (PBDEs), UNEP Chemicals, Regional Reports of the Regionally Based Assessment of Persistent Toxic Substances Program (2002) UNEP Chemicals 11-13, chemin des Anemones, CH-1219 Chatelaine, GE Switzerland. Available from <http://www.chem.unep.ch/pts>

(2)Determination of the levels of Polybrominated Diphenylethers (PBDEs) in pooled blood sera obtained from Australians aged 31-45 years., Fiona Harden, Leisa Toms,  John Jake Ryan,  Jochen Müller,  National Research Centre for Environmental Toxicology, The University of Queensland, 39 Kessels Road, Coopers Plains, Queensland 4108, Australia, Health Canada, Health Products and Food Branch , Banting 2203D, Ross Ave Ottawa, Ontario K1A 0L2 Canada

(3)Stapleton, H. et al. Debromination of the flame retardant Decabromodiphenyl Ether by Juvenile Carp (Cyprinus carpio) following Dietary Exposure. Env. Sci & Tech 38 (1) pp. 112-119, 2004

(4)‘ Hazardous substance in the Arctic’ (3/6/2004) , Norwegian Pollution Control Authority (SFT), the Norwegian Polar Institute, National Veterinary Institute of Norway/Norwegian School of Veterinary Science; Available at <http://www.sft.no/english/news/dbafile11556.html> [Accessed 10/6/2004] Also see’ Brominated Flame Retardants (BFRs) in the Artic Marine Food Chain’ Bjørn Munro Jenssen, Eugen G. Sørmo, Maria P. Salmer, Kine Bæk, and Janneche U. Skaare, Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; Norwegian Veterinary Institute, PO Box 8146, NO-0033 Oslo, Norway. Presentation to the Third International Workshop on BFRs, Uni. of Toronto, Canada 6-9 June 2004

(5)See Choi JW, Fujimaki TS, Kitamura K, Hashimoto S, Ito H, Suzuki N, Sakai S, Morita M (2003) Polybrominated dibenzo-p-dioxins, dibenzofurans, diphenyl ethers in Japanese human adipose tissue. Environ Sci Technol; 37 (5):pp817-21; Guvenius DM, Aronsson A, Ekman-Ordeberg G, Bergman A, Noren K (2003) Human prenatal and postnatal exposure to poly-brominated diphenyl ethers, poly chlorinated biphenyls, polychlorobiphenylols and pentachlorophenol. Environmental Health Perspective; 111(9) pp1235-41; Hardell L, Lindstrom G, van Bavel B, Wingfors H, Sundelin E, Liljegren G (1998) Concentrations of the flame retardant 2,2’4,4-tetrabrominated diphenyl ether in human adipose tissue in Swedish persons and the risk for non-Hodkin’s lymphoma. Oncol Res;10(8) pp429-32; Mazdai A, Dodder NG, Abernathy MP, Hites RA, Bigsby RM (2003) Polybrominated diphenyl ethers in maternal and fetal blood samples. Environmental Health Perspective;111(9):1249-52; She J, Petreas M, Winkler J, Visita P, Mc Kinney M, Kopec D (2002) PBDEs in San Francisco Bay area: Measurements in harbor seals blubber and human breast adipose tissue. Chemosphere; 46(5) pp697-707

(6)Heather M. Stapleton, Michele Schantz and Stephen Wise (2004) Polybrominated Diphenyl Ether Measurements in Household Dust, Institute of Standards and Technology. Presentation to the Third International Workshop on BFRs, Uni. of Toronto, Canada 6-9 June 2004; Also see Sharp R, Lunder S,(2004) In the dust; Toxic Fire Retardants in American Homes, Environmental Working Group Available at <http://www.ewg.org/reports/inthedust/> [Accessed 4/6/2004] The studies found high levels of PBDEs in dust samples taken from houses in the Washington metropolitan area. The levels of the chemical components of deca, the most widely used of the PBDE mixtures, ranged from 160 parts per billion to 8,700 ppb. Levels of penta, the second-most widely used mixture, ranged from 200 to 25,000 ppb. The EWG study also found high PBDE levels in dust samples from 10 home around the country. The average combined levels of deca, penta and octa _ a third commercial mixture _ for nine of the homes was over 4,600 ppb.

(7)Alexandra McPherson, Beverly Thorpe & Anne Blake (2004) Brominated Flame Retardants in Dust on Computers; The Case For Safer Chemicals and Better Computer Design. Available at <www.computertakeback.org>

(8)Thomsen C, Lundanes E, Becher G. 2002. Brominated flame retardants in archived serum samples from Norway: a study on temporal trends and the role of age. Environmental Science and Technology. 6(7):1414-8.[18]

(9)World Health Organization. International Programme on Chemical Safety, Environmental Health Criteria 205: Polybrominated dibenzo-p-dioxins and dibenzofurans.