There is currently a lack of scientific consensus on appropriate protective ecological guideline values for boron in the aquatic environment. Despite recent attention to the topic, existing promulgated guideline values for the protection of aquatic life vary by a factor of 10 and range from 10 mg/L to less than 1 mg/L. Many regulatory bodies, including the USEPA, currently have no promulgated ecological water quality guidelines for boron.
The variability in aquatic boron guideline values highlights the scientific uncertainty surrounding aquatic boron ecotoxicity. Although boron is a toxicant, it also an essential micronutrient that is required by plants, various phytoplankton species, and at least some fish, amphibians, and microorganisms. The dual role of boron as both a toxicant and an essential micronutrient leads to challenges in the regulatory sphere. Since boron is not a typical toxicant, it does not fit neatly into existing frameworks for quantifying toxicity.
At EHS Support, we are actively working to integrate the most recent advancements in the understanding of boron toxicity, deficiency, and essentiality to develop novel approaches for quantifying the related ecological risk. These approaches will allow us to keep pace with the state of the science and provide solutions to our clients despite current regulatory uncertainty. These solutions can also be implemented for other essential elements where regulatory consensus is lacking, allowing us to adapt this approach to specific client needs.
Austin Wilkes, Project Scientist