New laboratory research on QZ achieves control of quagga mussels twice as quickly as zebra mussels

by Jan 2, 2024

Recently published research on EarthTec QZ shows that high dose rates achieve total mortality of quagga mussels twice as quickly as zebra mussels, which can help product applicators optimize treatment solutions.

ROGERS, AR  – New research on EarthTec QZ tests the effectiveness of the copper-based molluscicide at different doses against zebra and quagga mussels. The study measured the mortality rates of quagga and zebra mussels through “cost-effective and environmentally acceptable doses of copper.” The research was performed by RNT Consulting in partnership with Earth Science Laboratories, and Next Game Solutions, with assistance from the Iowa State University Veterinary Diagnostic Laboratory.

Zebra and quagga mussels collected from Lake Ontario were jar tested at three different dose rates at the RNT laboratory in Picton, Ontario, Canada. As mussels died, tissues were collected for subsequent analysis by the Veterinary Diagnostic Laboratory to determine the copper concentration in the flesh of the deceased mussels. After 10 days of exposure to the highest dose, quagga mussels experienced a 100% mortality rate after accumulating 30 mg/kg of copper. In contrast, zebra mussels had less than a 20% mortality rate after accumulating 1,000 mg/kg of copper. The results show that zebra mussels have a higher tolerance for copper, but further research is needed to explain their protection mechanism.

The experiment continued until all test animals reached mortality at 22 days. The dose-mortality data revealed that quagga mussels treated with EarthTec QZ died faster than zebra mussels treated with the same concentration. The disparity in their time to mortality increased with the increasing levels of copper.

The research findings can help managers optimize the dose of copper they apply to control dreissenids, especially quaggas. With a better understanding of its impact, low-dose ionic copper products like EarthTec QZ can prevent over-application of the product. This results in better control with less copper being added to the environment. Read the full study for free here.

Earth Science Laboratories Inc. develops and manufactures sustainable chemical water treatment products for use in municipal, agricultural, and recreational waters. EarthTec QZ is an EPA-registered molluscicide used to control zebra and quagga mussels in pipelines and open waters. It is NSF certified to Standard 60 as an additive to drinking water. More information is available at