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New Research Reveals How Chemical Exposure Affects Developing Zebrafish

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New Research Reveals How Chemical Exposure Affects Developing Zebrafish

JUNE 9, 2025 — A 2025 publication, “Exposure to the Polychlorinated biphenyl mixture Aroclor 1254 elicits neurological and cardiac developmental effects in early life stage zebrafish (Danio rerio),” reports on research carried out by the University of North Texas, NOAA’s Office of Response and Restoration Assessment and Restoration Division, and other partners. The paper evaluates the effects of the PCB mixture Aroclor 1254 on the early life stages of zebrafish. This research builds on existing studies examining how PCBs affect fish.

“This work is a great example of how a university works with a federal agency in a research partnership,” says Aaron P. Roberts, Ph.D., a professor within the Department of Biological Sciences at the University of North Texas and senior author of the publication. “The results of the work are important for assessment of chemicals in the environment, and interactions with federal scientists provide university students real-world experience needed for the job market.”

Legacy contaminants, such as PCBs, bioaccumulate through the food chain from invertebrates to fish and wildlife, causing harm to both wildlife and humans who consume a contaminated organism. These contaminants can negatively affect development, growth, and reproduction of organisms in the ecosystem. Zebrafish (Danio rerio) are a common environmental toxicological model species, making them ideal for comparisons across multiple studies.

The goal of this study was to compare the bioaccumulation of different doses of Aroclor 1254 in zebrafish embryos to associated cardiac and neurologic outcomes under different test conditions. Establishing effect concentrations for cardiac and neurotoxic effects of PCBs in early life stage fish is challenging due to the non-reporting of measured concentrations in fish eggs for lab experiments, the lack of standard exposure methods, and the difficulty conducting experiments with PCBs. By reporting tissue concentrations in fish embryos, this research will support standardization across different tests and may improve the accuracy of effect threshold estimates.

The results of this study showed:

  • novel neurologic effects (eye tremors) in zebrafish exposed to PCBs,
  • cardiac effects (brachycardia, pericardial edema) from exposure to Aroclor 1254 are much less than elicited by PCB 126, confirming results from other studies,
  • and the importance of measuring PCB concentrations in water (exposure medium) and receptors (fish tissue).

These findings underscore the importance of understanding how legacy contaminants like PCBs continue to affect aquatic life at critical stages of fish development as scientists work to protect and restore ecosystems impacted by hazardous waste and oil spills.

Magnified image of a juvenile zebrafish.
Zebrafish are a freshwater fish commonly used to study diseases and contaminant effects in humans and other organisms. Image credit: University of North Texas.
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What’s New in ERMA®: Service Feeds, Dashboard Enhancements, and More

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What’s New in ERMA®: Service Feeds, Dashboard Enhancements, and More

Expanded Capabilities for Data Display, Analysis, and Processing

With the latest release, ERMA has transitioned to a new data loader that significantly enhances the display of external data streams, such as live weather. Previously, data from external sources offered limited options for editing and querying. The new data uploader creates a table "copy" of the feed, which supports a wider variety of data types. This allows us to customize map symbology, calculate statistics for display in dashboards, and query data for these external data streams. Even though a copy is being used, ERMA still automatically updates the data and refreshes the table copy.

Enhanced Map Card Filtering In Dashboards

Within the Dashboard map card, ERMA users can now filter cards based on a custom-drawn polygon. This feature enables users to draw and select an area on the map to improve the relevance of the metrics and data showcased in the dashboard. This selection allows the dashboard to filter and display data within the defined region, making it easier for users to analyze information that is most pertinent to their needs.

For example, in the screenshot below of an ERMA dashboard displaying active cases from NOAA’s Damage Assessment, Remediation, and Restoration Program, users can draw an area of interest by selecting “Add” at the top of the map card.

An ERMA dashboard displaying active cases from NOAA’s Damage Assessment, Remediation, and Restoration Program. This example highlights a total of 147 active cases, with case details for "68th Street Dump/Industrial Enterprises" in Baltimore. A pie chart indicates the majority of cases are hazardous waste sites. The interactive map on the right highlights case locations across the Northeast U.S., with icons marking oil spill and hazardous waste sites.
An ERMA dashboard displaying active cases from NOAA’s Damage Assessment, Remediation, and Restoration Program. Image credit: NOAA.
 
Updated view of NOAA’s Damage Assessment, Remediation, and Restoration Program dashboard with a user-drawn polygon filter active on the map. The same case details for "68th Street Dump/Industrial Enterprises" in Baltimore are shown. The case count in the selector has changed to 14, reflecting filtered results. The pie chart remains similar, and the map displays a dashed polygon boundary filtering visible site locations across the mid-Atlantic region.
An ERMA dashboard displaying active DARRP cases with an area of interest polygon drawn around a selection of cases. Image credit: NOAA.

With the area of interest now drawn, use select mode to modify or highlight specific drawings and remove them, as needed. Cards on the left will change only to reflect the sites chosen in the area of interest. This is also reflected at the bottom left of the card with the rectangular icon.

The active DARRP cases card does not have this icon, so nothing has changed with the area of interest polygon filter added. This new feature ensures that your chosen area of interest is reflected across chosen dashboard cards, making analysis more intuitive and tailored to user needs.

An ERMA dashboard displaying active cases from NOAA’s Damage Assessment, Remediation, and Restoration Program.
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