Toxic Chemical Levels Continue Falling

Toxic Chemical Levels Continue Falling

International and national efforts to reduce the level of exposure to some persistent toxic chemicals is working according to the latest results of a New Zealand study.

The chemicals, called persistent organic pollutants, are harmful to people and wildlife, accumulate in our bodies and are retained for long periods.

The latest study shows that the levels of persistent organic pollutants in our bodies has fallen by a further 40 percent in the past ten years. This follows the finding of an earlier study showing a 70 percent decline in the decade prior to the latest study.

The chemicals include the banned pesticide DDT; banned industrial chemicals such as PCBs; and unintended industrial by-products like dioxins and furans.

Similar declining rates have been shown in many other countries, though the study shows New Zealand has low relative levels compared to other similar countries.

The study was done through testing breastmilk in young mothers.

During the ten years to 2008:
• dioxin and furan levels in breast milk declined by 40%
• dioxin-like PCBs levels declined by 54%
• organo chlorine pesticides (like DDT) declined by 34-90%
• levels of dioxins, furans, PCBs and OCPs tended to be higher in rural areas
• levels of PBDEs (flame retardants) tended to be higher in urban areas.

This survey looked for the first time at breast milk levels of brominated flame retardants (BFRs) including PBDEs. The New Zealand levels of these compounds are moderate to low by international standards. Despite bans in some countries (US and Europe) many of these retardants remain in use internationally.

New Zealand’s level of these chemicals is lower than the US and Australia (we have half the levels found in Australia) and similar to or higher than European countries (Belgium has half our level). The researchers note that the levels of these flame retardant chemicals are likely to be considerably higher in our blood.

The Ministry intends to continue to monitor these chemicals.

New Zealand’s exposure to fire retardants is largely from retardants added to foam in imported furniture; to plastics and to electrical or electronic equipment. Flame retardants are added to products to reduce their ability to burn and help add vital seconds to the time required for people to get out of a burning building.

Younger mothers had lower levels of all dioxins, furans, PCBs and OCPs - but levels of flame retardants showed no link with age.

Exposure to many of these chemicals is unavoidable - through diet and inhalation - and the best approach to reducing exposure is through international and national efforts to reduce the overall levels in the environment. Some brominated flame retardants have been added to the list of chemicals targeted for elimination or reduction under an international agreement called the Stockholm Convention on Persistent Organic Pollutants and the European and US bans will encourage the use of different chemicals as flame retardants.

Further testing of chemicals in the blood, some of which is planned for next year, is expected to show a continued trend of a slow reduction in the level of these chemicals in New Zealanders. The tests will also give an indication about whether the levels of flame retardants are increasing or decreasing over time.

BACKGROUND
Persistent organic pollutants (POPs) are a group of organic compounds that remain intact in the environment for long periods and accumulate in the fatty tissue of living organisms. Due to human activities, POPs have spread around the world, even to areas where they were never used and most exposure now is primarily through our diet.

Toxic effects including cancer, damage to nerves and brain, reproductive and immune system disorders have been linked to POPs.
In 2001, New Zealand became a signatory to the global Treaty on Persistent Organo-Pollutants (POPs) which aims to eliminate or reduce POPs, where possible, from the environment.
Polybrominated diphenyl ethers are organobromine compounds used as flame retardants. PBDEs are used in building materials, electronics, furnishings, cars, plastics, foams and textiles. They are similar to PCB’s and concerns about their persistence and health effects have prompted them to be banned or their use reduced in some countries.
Breast milk is used as a marker for the presence of chemicals in human fat, because breast milk is high in fat. Breast milk is the healthiest food for baby and the Ministry of Health strongly recommends breast feeding. With time rates of chemical residues in children end up being roughly equal regardless of whether babies are breast or bottle fed.

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