Environmental concentrations of emerging contaminants in coastal stormwater

There is a need for CECs to be incorporated into contaminant guidelines for wastewater treatment in Australia. Two previous Marine and Coastal Hub projects took steps towards identifying the evidence base required to update contaminant guidelines. Project 1.16 identified a need for data on environmental concentrations of CECs and an assessment of their impact on ecological communities. Project 2.4 determined environmental concentrations and potential ecological effects of CECs at selected wastewater-treatment-plant outfalls. Research users have identified a need to repeat this sampling and analysis at more locations.

This project will engage with the Department of Climate Change Energy the Environment and Water (DCCEEW) and water quality specialists to determine specific research-user needs. This will guide a tailored program of increased spatial and temporal sampling of CECs in coastal environments. The sampling will yield a better understanding of the concentrations of these pollutants in coastal stormwater and wastewater effluent on a seasonal basis. It will present a fuller picture of the scale and significance of the issue to help the DCCEEW scope the research needed to determine guideline values, and to support the management of coastal water quality. 

The National Outfall Database is also being maintained under this project. This involves collating, analysing and presenting data from water treatment authorities on outfall flows, pollutant concentrations and loads.

Approach

The field research will focus on two locations: Gamay (NSW) and Glenelg (South Australia).

In consultation with NSW Department of Planning and Environment (DPE) and Sydney Water, the project team will conduct sampling at sites within Towra Point Nature Reserve, swimming and fishing sites used by the Gamay community, and at Foreshore Beach. At each site, water and sediment samples will be collected at fixed distances from stormwater drains. The project team is also engaging with the Gamay Rangers and La Perouse Local Aboriginal Land Council with the view to involving them in the project.

Contaminant levels will be quantified in water and sediment samples using the same techniques used in Project 2.4. Concentrations of CECs, such as pharmaceuticals (for example, antibiotics), will be quantified using high-performance liquid chromatography and mass spectrometry. Microplastic (<5 mm) concentrations and characteristics (for example fragment/fibre) will be measured using best-practice techniques including visual inspection and infrared spectroscopy. Physico-chemical data including temperature, salinity, dissolved oxygen, chlorophyll a, dissolved nutrients and metals will also be collected.

Potential marine ecological impacts will be examined by investigating the responses of microbial assemblages in the water column and in sediment samples. Microbes are excellent diagnostic sentinels for impact because of their fast generation times and highly sensitive metabolisms. This makes them sensitive indicators of impact. Ecogenomic approaches, including next generation sequencing, will define the composition of microbial assemblages. PCR approaches will be used to quantify antimicrobial resistance genes. Microbe populations will be quantified using flow cytometry protocols.

The project team will work collaboratively with relevant Indigenous organisations (Gamay Rangers, La Perouse Local Aboriginal Land Council, South Australia First Nations Sea Country Research Alliance) to communicate about the project in a respectful and culturally appropriate way.

National Outfall Database

This part of the project will collect and report on 2022/2023 wastewater treatment plant discharge data in the National Outfall Database. Additional data on proposed capital works, license variations and technology by water treatment authorities will be integrated into the database (with permission).

Water authority data providers will be engaged to determine their interest in assisting with future sample collection, and whether there are planned infrastructure upgrades. Such plans would help to locate before-after control-impact studies to determine how effectively waste water treatment plants remove regulated contaminants and CECs.

Governance

A project steering committee will be set up to provide a mechanism for regular communication between end-users, contributors and researchers. It will include members from DCCEEW, NSW DPE, Sydney Water, SA Water, the Gamay Rangers, and University of Technology Sydney.

Expected outcomes

A broader understanding of the scale, distribution and potential ecological impacts of CECs will support decision-making about wastewater treatment and the protection and management of Australian coastal waters. The DCCEEW will be better positioned to scope the research required to determine contaminant guidelines.

Benefits will also flow to managers of state and commonwealth marine parks around areas of human amenities, coastal restoration in areas receiving stormwater inputs, Ramsar wetlands in urban settings such as Gamay (Botany Bay, NSW), and Indigenous communities who rely on a healthy environment to maintain cultural practices.

Continued collection, analysis and reporting of wastewater treatment plant discharge data in the National Outfall Database will maintain the visibility and public access of information on regulated contaminants in Australian coastal environments.

Project location

The field research will focus on two locations: Gamay (NSW) and Glenelg (South Australia).