Emerging Organic Contaminants: What Are They and Should We Be Concerned?

Emerging organic contaminants (EOCs) are gaining increasing attention across the globe. But what are they and should we be concerned?

What are they?

EOCs are a diverse range of compounds that are found in water and wastewater and stormwater that can adversely affect the environment and/or people. These chemicals come from a range of sources, such as pharmaceuticals, flame retardants, surfactants, preservatives, pesticides, plasticisers, and more. The most commonly recognised are the perfluorocarbons (PFCs), flame retardant chemicals that have been used in firefighting and are now being found in groundwater at airports and other firefighting sites.

This paper describes the New Zealand context and how work done around the world can be used to inform the risk of EOCs the environment and people in New Zealand. It also describes the treatment of selected EOCs using common wastewater treatment technologies employed in New Zealand drawing on various large scale, international, peer reviewed research from Europe and North America. The paper describes how EOCs vary between catchments, as well as over time (diurnally, weekly, and seasonally).

Should we be concerned?

EOCs are complex molecules, capably of undergoing different chemical reactions depending on the environmental conditions. This increases the complexity of understanding EOCs and the risk they pose to the environment and people. The potential for the formation of intermediate compounds, which may be more or less hazardous than the original EOC chemical requires consideration.

A key challenge for New Zealand is identifying and agreeing a robust set of EOCs that can be used as indicators and allow direct comparisons between studies as well as an underpinning benchmark for regulations. This paper discusses what guidance is currently available in current New Zealand regulations and proposes