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Updated: Jun 2, 2026
Small Molecule Screening and Toxicity Testing in Early-stage Zebrafish Larvae
Published on: March 7, 2025
Acute toxicity and bioconcentration of pyrimorph in zebrafish, Brachydanio rerio
Chunqing Zhao1, Boqian Liu, Jing Wang
1Key Laboratory of Pesticide Chemistry and Application Technology, Ministry of Agriculture, College of Science, China Agricultural University, Beijing, China.
Background:
Pyrimorph is a novel fungicide being developed in China that shows high antifungal activity against diseases caused by Phytophthora infestans, Phytophthora capsici, Rhizoctonia solani, Peronophythora litchi and Pseudoperonospora cubensis. Until now, no information on the toxicity of pyrimorph to untargeted organisms has been reported. To assess the potential environmental impacts of pyrimorph in fish, the acute toxicity and bioconcentration of pyrimorph in zebrafish were studied in this paper.
Results:
When tested by the semi-static method, the 48, 72 and 96 h median lethal concentration (LC50 ) values of pyrimorph to zebrafish were 24.33, 22.61 and 19.79 mg L(-1) respectively. To study the bioconcentration of pyrimorph in zebrafish, the fish were exposed to sublethal concentrations of pyrimorph (2.00 and 0.25 mg L(-1) ) for 192 h, a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method was applied to extract pyrimorph from samples and the residues of pyrimorph in the water and fish were determined by high-performance liquid chromatography (HPLC). The highest bioconcentration factor (BCF) of pyrimorph in the fish was 1.07 × 10(2) (144 h) and 23.1 (96 h) after exposure to 2.00 and 0.25 mg L(-1) of pyrimorph respectively.
Conclusions:
The novel fungicide pyrimorph has low toxicity to zebrafish; however, it showed medium BCF to zebrafish. Therefore, more attention should be paid to the residue of pyrimorph in fish, as well as to its long-term ecological effects.
Insights
The novel fungicide pyrimorph exhibits low toxicity to zebrafish but has a medium bioconcentration factor. Further research is needed on pyrimorph residues in fish and its long-term ecological impact.
Area of Science:
- Environmental toxicology
- Aquatic toxicology
- Fungicide research
Background:
- Pyrimorph is a new Chinese fungicide with high efficacy against plant pathogens like Phytophthora infestans.
- No prior studies have investigated pyrimorph's toxicity to non-target aquatic organisms.
- This study assesses pyrimorph's environmental risk by examining its toxicity and bioaccumulation in zebrafish.
Purpose of the Study:
- To determine the acute toxicity of pyrimorph in zebrafish.
- To evaluate the bioconcentration potential of pyrimorph in zebrafish.
- To inform the environmental risk assessment of pyrimorph.
Main Methods:
- Acute toxicity tests using semi-static methods to determine median lethal concentration (LC50) values.
- Exposure of zebrafish to sublethal pyrimorph concentrations (2.00 and 0.25 mg L⁻¹) for bioconcentration studies.
- Quantification of pyrimorph residues in water and fish using high-performance liquid chromatography (HPLC) after modified QuEChERS extraction.
Main Results:
- The 96-hour LC50 of pyrimorph to zebrafish was 19.79 mg L⁻¹, indicating low acute toxicity.
- Bioconcentration factors (BCF) ranged from 23.1 to 107, suggesting medium bioaccumulation potential.
- Pyrimorph residues were detected in fish tissues after exposure.
Conclusions:
- Pyrimorph demonstrates low acute toxicity to zebrafish.
- The fungicide exhibits a medium bioconcentration factor in zebrafish.
- Further investigation into pyrimorph residues and long-term ecological effects in aquatic environments is warranted.
