Endocrine disrupting chemicals in Aotearoa New Zealand

^{Common bully, Gobiomorphus cotidianus, Shaun Lee, iNaturalist}

Hormone disruption

What's the problem?

In living things, the endocrine system sends hormones to most organs in the body. Hormones play a crucial role in metabolism, growth and development, immune function, sexual characteristics and reproduction.

Some chemicals can affect this system. That may be purposeful, say in the case of medications, or it may be accidental if these chemicals are present in the environment. How big any unwanted interference is, and what the wider consequences are for our natural environment are not well understood.

Worldwide, about 140 chemicals have been recognised as endocrine disrupting. Most of these are pesticides, industrial solvents and pharmaceuticals. However, thousands of chemicals are still to be fully assessed for their potential endocrine disrupting properties and the impact they might have on exposed humans and biota.

Over the course of his investigation into the fate of chemicals in the environment, the Parliamentary Commissioner for the Environment noted the lack of knowledge and information about endocrine disrupting chemicals in Aotearoa New Zealand and their potential impact on living things.

As a result, he commissioned Cawthron Institute to review endocrine disrupting chemicals and what is known about their potential impact on our natural environment.

What did the report find?

The Cawthron Institute report, Overview of endocrine disruption – An Aotearoa New Zealand perspective, provides valuable insight into the complex, still poorly understood yet nonetheless potentially threatening impact of endocrine disrupting chemicals in our environment.

It outlines international evidence for the influence of endocrine disruptors on population collapse in fish, developmental abnormalities in alligators, deformities in frogs and impaired reproduction in sheep, among other examples.

It also dives into uncertainties around sources of endocrine disruptors and exactly how they affect exposed organisms. The report explains that while scientists have progressed their understanding of how these chemicals impact hormonal processes, this knowledge is still far from being comprehensive. We know there are multiple ways endocrine disrupting chemicals can interfere with body functions, but most of these have barely been studied across different living organisms.

From the studies that have been undertaken, most methods used to detect the effects of endocrine disrupting chemicals occur at a cellular level. While this information is vital, it may not always be able to predict how the effects on cells translate into adverse effects on whole animals or populations.

Until this connection is understood and robustly demonstrated, regulations specific to endocrine disruptors will be difficult to develop and implement.

What’s the situation in Aotearoa New Zealand?

The report found that research into endocrine disruptors in Aotearoa New Zealand is limited. Most studies have focused on the presence and activity of endocrine disrupting chemicals in urban sewage and dairy effluents, groundwater and sediments. To date, there has been no evidence of endocrine disruption in exposed biota.

But is this evidence of absence or absence of evidence? The authors of the report suggest the latter. There is substantial information worldwide on the impact of endocrine disrupting chemicals on ecosystems, and, as similar chemicals are used here, it is very likely that evidence would apply to our environment too.

What next?

While much remains to be studied, technological advances (including the adverse outcome pathway framework and models that predict the likelihood of substances affecting hormonal processes) are creating more robust ways to use data to support regulatory decision making. But these methods are time and resource intensive to develop and implement.

Some scientists predict that inadequate regulation could have serious adverse consequences for future generations, so how we monitor and manage endocrine disrupting chemicals will be critical to mitigating the negative effects they have on humans and animals.

The report argues for a precautionary approach to the registration and use of chemicals in New Zealand. It recommends more stringent assessment of the potential for endocrine disruption, better characterisation of the sources of pollution, the need for a multi-disciplinary approach to manage the risk posed by endocrine disruptors, and engagement across the community to raise awareness of downstream impacts.