Module 2 - New tools for the management of organic micro-contaminants

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Water reclamation and reuse can offer a win-win scenario for the environment and agriculture. However, the willingness of agricultural consumers to use recycled water is dependent on their confidence that recycled water is safe to use and that the intended applications will be managed to promote sustainable environmental outcomes. Consumer confidence and trust is fragile and likely to only be built over time.

This project focuses on new tools for the environmental safety of recycled water (of whatever origin, e.g. municipal waste water treatment plants, factory discharges, dairy effluents etc), and the risk to aquatic ecosystems of off-farm migration of highly biologically active trace organics at the sub-ng/L to sub-ng/L level. Increasingly, stakeholders are asking for cheaper, faster monitoring tools. The tools this project will assess include time integrated passive samplers and yeast-based bioassays.

Following several concept and project development meetings with stakeholders, the DPI project team has:

(a) Critically reviewed existing information/studies related to the risks posed by the transport of steroid hormones from agroecosystems.

(b) Is adapting to local conditions two world’s best practice passive sampler techniques (using the Chemcatcher™ system, and solvent-filled bags). The latter have already been successfully deployed in industry co-funded research collaborations.

Time integrated passive sampling offers reduced sampling frequency (and hence lower cost). Unfortunately, many laboratories lack the necessary knowledge to achieve their aims, both of the need for sample preparation to remove potential confounding agents, and of the methodology itself. In addition, there is little calibration data, even for common pesticides, making risk assessment problematic. The project is:

Validating commercially available passive samplers for polar pesticides and hormones in water.
Developing LC-MS/MS methods for emerging contaminants.

One of the biggest hurdles in modeling and monitoring the levels of chemicals in complex mixtures, such as WWTP effluent, is an inability to properly characterize the complex mixtures. The use of yeast-based assays ‘solves’ this problem by not attempting to characterize mixtures at all. Such assays, rather, give a broad brush, but still sensitive indication of contaminant hormone receptor activity, which can then be compared to trigger levels for further detailed study by more traditional techniques.

The project is establishing a suite of yeast-based assays capable of providing a rapid (4 h) assessment of contaminant activity of recycled and natural waters. These bioassays can be used to measure the migration of hormonally active materials, including steroid hormones and pesticides, off-farm and into natural waters.

The project team is heavily involved in a Department of Human Services (DHS) funded collaboration with RMIT University, Murdoch Children’s Institute Royal Children’s Hospital, and Phytotox Pty Ltd, "A health risk assessment for cyanobacterial toxins in seafood from the Gippsland Lakes."

This project will review alert levels for cyanobacterial toxins in seafood from the Gippsland Lakes by assessing existing trigger levels, investigating bioaccumulation of nodularin by biota and correlating toxin levels with Nodularia cell counts. Results will be incorporated into a health risk assessment to provide acceptable residue levels for cyanobacterial toxins in seafood (in the event of a bloom).

Chemcatcher passive sampler systems after a month in the field - some return cleaner than others!

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