Emerging organic contaminants of concern - status and monitoring methods
There is global concern that the presence of emerging organic contaminants (EOCs) in the environment may lead to adverse effects on human and ecological health. This concern is primarily associated with the lack of knowledge of the fate and effects of EOCs. Many EOCs are linked explicitly to human activities and, with the world becoming increasingly urbanised, pressures from these contaminants will likely only increase if not addressed in the short term. The main sources of urban EOCs are wastewater effluent, stormwater, landfill leachate and some specific industrial and marine activities. Smaller loads of some EOCs may enter the environment through recreational activities, such as the application of sunscreen and insect repellent.
Dr Mike Stewart led a team of experts to review the current status of emerging contaminants internationally and nationally, with a focus on Auckland, Wellington and Canterbury Regional Councils. A major output of the resulting report was the recommendation for a tiered monitoring programme for emerging contaminants that Regional Councils can use for their State of the Environment Monitoring.
In a related project, Dr Stewart worked with Auckland Council, University of Otago and AsureQuality to develop passive sampling devices (PSDs) to measure bioavailable contaminant concentrations with a future goal to include in regulatory monitoring. Measuring “total” contaminant concentrations doesn’t always tell us about the portion that is actually able to be taken up by an organism (bioavailable). It is this bioavailable portion that is potentially toxic. High natural variability and cost in more “traditional” methods (such as shellfish monitoring) have led to the search for methods which provide more consistent (and hence reliable) results at lower costs. PSDs have this potential but their effectiveness hadn’t been demonstrated in New Zealand. A recent publication suggest PSDs show enormous potential for detecting very low concentrations of a range of chemicals of concern (including emerging organic contaminants); however more research is necessary before they can be used in a regulatory environment.