CEA presented 16 posters at SETAC Dublin in April/May 2023. We will be showcasing each of these presentations in a series of ‘SETAC Spotlight’ articles. This week it is:

Copper deficiency in aquatic organisms: How should this be considered as part of the PPP risk assessment?

Authors: Sarah Priestly1, Amy Brooks1, ; Robert Morris2 and Ann Orth2
1Cambridge Environmental Assessments, Boxworth, UK; 2Albaugh LLC, Ankeny, IA, USA.

The EU regulation for authorising plant protection products (Regulation (EC) 1107/2009) uses a tiered risk assessment approach for aquatic organisms. Under this approach, if an active substance fails the lower-tier, more conservative risk assessment, then intermediate or higher tier approaches can be used to demonstrate low risks to aquatic organisms. Higher tier refinements can include the derivation of toxicity endpoints from more realistic test systems, such as mesocosm studies. Assessment factors (AFs) are then applied to those toxicity endpoints to derive a regulatory acceptable concentration (RAC) for use in the risk assessment. There is some flexibility in terms of the AF value applied by regulators to derive the RAC, which can increase or decrease the conservatism of the risk assessment.  

Copper is widely used in a variety of industrial applications as well as for plant protection products and it has been documented that Copper is toxic at high concentrations (worst case). However, Copper is also an essential nutrient that is required at low concentrations and if these levels are too low this may cause adverse effects (deficiency). In regulatory risk assessments the focus is usually based on toxicity at these high levels but there is little or no consideration for the impacts of deficiency at lower levels. For example, would the AF assigned by regulators drop the RAC below the required level for normal growth and development and should deficiency be considered by regulators for nutrients such as copper? This issue of essential metals having a U-shaped dose-response curve is mentioned in the EFSA statement on transition metals (EFSA 2021), but not in the context of AF-setting. 

Based on this, a literature search was conducted to investigate the evidence available for copper deficiency, with particular focus on the critical taxa of aquatic invertebrates and fish. This poster discusses if this could then be used to support use of a reduced assessment factor in the aquatic risk assessment for essential nutrients including copper. 

If you would like to discuss any of the topics raised in this article, feel free to contact us.

The poster is available for free download.

You can find all of the other posters that CEA presented at SETAC Dublin here. You can also find all of our publications from previous conferences and links to journal articles we have authored on our library page.

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