Coastal water quality is threatened by the ever-increasing list of novel chemicals produced and used in our modern lives. These chemicals are commonly incorporated into pharmaceuticals and household items, and subsequently discharged into coastal areas from a broad range of point sources, such as sewage and industrial wastes.

For many of these chemicals, our understanding of their environmental concentrations and biological effects is limited. When new scientific information emerges to suggest that a particular contaminant may harm the environment, we then refer to this as a contaminant of emerging concern (CEC).

As new chemicals are constantly being produced and used in our daily lives, a plethora of chemical contaminants are being detected in marine waters, sediments, and biota, yet the impacts of many of these chemicals on marine organisms and ecosystems are not yet defined.

Contaminants of Emerging Concern (CECs) are chemicals which have been flagged as potentially hazardous. Generally, CECs are poorly understood: there is limited data about their environmental occurrence and biological effects, but emerging research suggests they have the capacity to be toxic.

The scientific uncertainty surrounding CECs makes regulating these contaminants challenging. In Australia, a range of stakeholders contribute to CEC management. This includes the Commonwealth government, which establishes national CEC policies and objectives, and state and territory governments which regulate environmental CEC emissions in their respective jurisdictions. Government policy makers and regulators are supported by researchers and academics, who generate the scientific evidence to inform government actions.

With an increasing list of CECs detected in the environment, important questions remain unanswered around which contaminants and scientific knowledge gaps should be prioritised. This project engaged CEC stakeholders from academic research, government, water utilities, and non-government organisations to collaboratively identify priority CEC issues in Australia’s marine ecosystems.

Approach and findings

The project found that stakeholders typically deal with mixtures of several CECs, including antimicrobial compounds, per- and poly-fluoroalkyl substances (PFAS), microplastics, nutrients and heavy metals. The exact nature of CEC mixtures in the environment is likely to vary seasonally and regionally, according to local human activities. Although CECs are, by their nature, poorly understood, information is particularly sparse about the ecological effects of CECs in marine environments, as online CEC databases primarily focus on the effects of CECs in freshwater ecosystems.

Stakeholders identified the need to:

  • Identify CEC sources, fates and behaviours, and how these may affect CEC exposure pathways for marine organisms.
  • Develop analytical methods to quantify CECs in the environment, and establish environmental CEC baselines that account for regional and seasonal variation.
  • Determine the ecological effects of CECs, with a focus on understanding the effects of chronic CEC exposures and environmentally-relevant CEC mixtures.
  • Develop toxicity thresholds and consider risk assessment methodologies that enable stakeholders to prioritise CECs.

Existing databases and methodologies could be adapted to incorporate marine environments. Laboratory studies are needed to develop standard biomarker protocols, which can assess the effects of CECs, and their mixtures, at the levels of individual organisms, organism populations, and ecosystems.

Field studies are needed to establish standard CEC sampling and analytical methodologies, and subsequently establish environmental CEC baselines that incorporate regional and seasonal fluctuations. These baselines will populate CEC databases and facilitate CEC risk assessments. Field studies are also required to assess ecological effects of CECs in estuarine and marine environments with different receiving water contexts.


Research users from the research community, government, water utilities, and non-government organisations have a new, shared understanding of priority issues relating to CECs in Australia’s marine ecosystems. The identification of priorities for CEC management in marine environment, along with suggested desktop, laboratory and field studies provides guidance for future research.

Project location