SETAC Asia-Pacific 15th Biennial Meeting

Incorporating Metal Bioavailability Into Water Quality Criteria in the Asia-Pacific Region

Jenny Stauber; Ross Smith, Hydrobiology Pty. Ltd.; and Wataru Naito, National Institute of Advanced Industrial Science and Technology

10:00 a.m.–3:30 p.m. | Free but registration required

While metals occur naturally in the aquatic environment, and many are essential for living organisms, they can pose a risk if their concentrations exceed water-quality criteria. The ecotoxicological risk from certain metals is now understood to be associated with their bioavailability, i.e., the extent to which organisms in the water column are exposed to and able to absorb metals. The bioavailability and toxicity of metals in freshwaters is influenced by the water chemistry of the specific water body, including such Toxicity Modifying Factors (TMFs) as pH, hardness ions (calcium and magnesium) and dissolved organic matter. There are now a range of modelling approaches, including biotic ligand models and multiple linear regressions, which are used globally to derive bioavailability-based water quality criteria (e.g., Environmental Quality Standards, guidelines), together with online tools for their implementation. This helps reduce uncertainty in risk assessments and regulation of metals in freshwaters.

The aim of this workshop is to discuss the current status of metals guidelines in the Asia-Pacific region, with a view to determining what is needed to transition to bioavailability-based approaches. The workshop will introduce the concepts of metal bioavailability and the tools that are currently used to derive bioavailability-based criteria. Approaches used in the USA and Canada, Europe, Australia and New Zealand will be discussed, including the recent implementation of tiered frameworks to develop and implement criteria. Speakers include experts from Japan, China, Southeast Asia, USA, Great Britain and Australia. 

Hands-on Concentration-Response Modeling Using the Bayesian R Package

Rebecca Fisher, Australian Institute of Marine Science

10:00 a.m.–3:30 p.m. | Free but registration required

This hands‑on training workshop provides a practical introduction to concentration-response (CR) modeling in R, with a particular focus on modern Bayesian approaches using the bayesnec package. Participants will learn how to fit, interpret, visualize and compare concentration–response models, and they will be guided through examples using curated training datasets. The workshop builds on earlier SETAC Australasia training sessions and incorporates updated methods, tools and workflows. 

By the end of the workshop, participants will be able to:

• Understand the principles and applications of concentration-response modelling.
• Fit Bayesian CR models in R using the bayesnec workflow.
• Interpret key outputs, including no-effect concentration (NEC) and no-significant-effect concentration (NSEC) metrics, as well as model uncertainty.
• Apply reproducible R-based modeling workflows to their own environmental or ecotoxicological datasets.

• Participants should bring a laptop with R and RStudio installed, along with required packages (bayesnec and its dependencies).
• Access to the accompanying GitHub training repository will be provided for downloading workshop materials.

Legacy Mercury in a Changing Climate: From Isotopic Evidence to Action Under the Minamata Convention

Larissa Schneider, Australian National University, and Ruoyu Sun, Tianjin University

1:30 p.m.–4:00 p.m. | Free but registration required

To explore how legacy mercury sources are emerging as a dominant challenge under climate change, and to examine how multiple lines of evidence (including mercury isotopes, environmental data and policy frameworks) can inform adaptive management under the Minamata Convention.

As implementation of the Minamata Convention progresses, direct anthropogenic mercury emissions have declined in many regions. However, legacy mercury stored in contaminated sites, historic deposits and cryosphere is increasingly being remobilised under global warming. This raises critical questions about how to evaluate Convention effectiveness and adapt management strategies.

This workshop addresses the central question: How can we distinguish and manage the growing influence of legacy mercury under climate change to ensure effective policy outcomes?