Chemical Mixtures and Multiple Stressors: Same but Different?

Area of Science:

• Ecotoxicology and applied ecology, focusing on the impact of anthropogenic stressors on ecosystems.

Background:

• Ecosystems face numerous anthropogenic stressors, including chemical mixtures and nonchemical factors.
• Research on multiple stressors often neglects chemical mixtures, and chemical mixture studies often ignore other stressors.
• A lack of integrated frameworks hinders the prediction of combined effects from diverse environmental stressors.

Purpose of the Study:

• To provide an overview of research paradigms, tools, and methods in multiple stressor and chemical mixture research.
• To identify areas for cross-fertilization and discuss joint challenges between these research fields.
• To propose a framework for integrating the assessment of multiple chemical and nonchemical stressors.

Main Methods:

• Comparison of ecotoxicology and applied ecology paradigms to explain historical research divides.
• Analysis of methods for interaction identification, stressor characterization, and experimental design.
• Discussion of process-based and data-driven models for predicting effects on communities and food webs.

Main Results:

• Both research areas are overly focused on interactions and would benefit from improved null model selection.
• Stressor characterization is more costly for chemical mixtures, while nonchemical stressor research increasingly incorporates environmental context.
• Current experimental designs are often simplified, limiting the number of stressors and treatments studied.

Conclusions:

• Integrating chemical and nonchemical stressor research is essential for realistic ecological predictions.
• Advanced modeling approaches are promising for predicting the joint effects of multiple stressors.
• A proposed framework can guide the integrated assessment of multiple stressors and chemical mixtures in environmental toxicology.