Influence of water pollution with copper and tributyltin on the physiological indicators of two Dreissenids (Dreissena polymorpha and D. bugensis)
Author: N. A. Berezina, A. N. Sharov, S. V. Kholodkevich & G. I. Kukhareva
Year: 2024
Digital Object Identifier: doi.org/10.1134/S2075111724700371
Type: Journal Article
Topic: Biology
This research focuses on the physiological indicators of zebra and quagga mussels, such as metabolic activity (oxygen consumption level), body mass index, and cardiac resistance (restoration of the heart rhythm after exercise), when the water is polluted with copper and tributyltin compounds. The results revealed differences in the physiological responses of two dreissenid mussel species (Dreissena polymorpha (Pallas, 1771) and D. bugensis (Andrusov, 1897)) to pollution of the aquatic environment with these substances. Quagga mussels were more vulnerable than zebra mussels to copper and tributyltin in terms of mortality, heart rate biomarkers, and metabolic activity. Exposure to these compounds also led to a decrease in body mass index in zebra mussels in some cases. Both dreissenid species exposed to copper exhibited similar levels of respiratory activity, with a dose-dependent bell-shaped response. Mollusks from the treatment with the lowest copper concentration (50 μg/L) and the control did not differ in the level of respiratory activity. However, at average copper concentrations of 100 and 500 μg/L, zebra mussels showed a statistically significant increase in respiration intensity, and at high copper levels (1 and 5 mg/L), they showed a significant decrease. Exposure to organotin compounds also significantly affected the respiratory activity of both dreissenid mussel species, leading to an increase in oxygen consumption by 1.5–1.7 times compared to the control. Quagga mussels were more sensitive to the presence of tributyltin than zebra mussels. As a result of the study, zebra mussel heart rate recovery time increased with increasing copper concentration (from 100 μg/L to 5 mg/L), such that mussels required 10–25 min longer to recover heart rate than the controls. In the case of quagga mussels, the time for recovery of heart rate at high copper concentrations (1000 μg/L) almost doubled (up to 103 min) compared to the control (56 min). Both dreissenid species showed significantly longer heart rate recovery times when exposed to tributyltin (10–100 ng/L) than the controls. The largest differences were observed at 100 ng/L tributyltin, with D. bugensis taking 27–35 min longer to recover heart rate than D. polymorpha. Our data showed that the better resistance of the zebra mussels to toxicants in water can contribute to its further expansion and successful competition with quagga mussels. However, quagga mussels may be more effective as an indicator species at monitoring of water pollution with copper and organotin compounds.