Tropical ecotoxicity testing with Ceriodaphnia cornuta

Area of Science:

• Environmental toxicology
• Aquatic ecology
• Invertebrate biology

Background:

• The Sai Gon-Dong Nai river system faces significant pollution from industrial, domestic, and agricultural sources.
• Toxicity assessment is a growing concern in Vietnam, necessitating region-specific ecotoxicological tools.
• Existing ecotoxicity tests often use non-native species, limiting their applicability to local aquatic ecosystems.

Purpose of the Study:

• To develop and validate a novel ecotoxicity test using an autochthonous organism relevant to Vietnamese aquatic environments.
• To establish a reliable culturing protocol and quality control criteria for the chosen test species.
• To assess the sensitivity of the new test system against standard ecotoxicological models.

Main Methods:

• Isolation and culturing of the microcrustacean Ceriodaphnia cornuta from the Sai Gon River.
• Development of a long-term reproduction protocol and quality control measures for C. cornuta.
• Acute toxicity testing of C. cornuta against pesticides (diazinon, methyl parathion) and metals (chromium, mercury), with comparisons to Daphnia magna and Vibrio fischeri.

Main Results:

• A successful protocol for culturing Ceriodaphnia cornuta with satisfactory long-term reproduction was established.
• Ceriodaphnia cornuta exhibited lower tolerance to salinity compared to Daphnia magna and Vibrio fischeri.
• Ceriodaphnia cornuta demonstrated higher sensitivity to potassium dichromate, diazinon, methyl parathion, and mercury than Daphnia magna and Vibrio fischeri.

Conclusions:

• Ceriodaphnia cornuta is a suitable autochthonous species for developing a relevant ecotoxicity test in Vietnam.
• The developed test system offers a valuable tool for assessing the impact of pollutants on local aquatic invertebrates.
• This research provides a foundation for more accurate and context-specific environmental risk assessments in the region.