Acute Toxicity of an Emerging Insecticide Pymetrozine to Procambarus clarkii Associated with Rice-Crayfish Culture (RCIS).

Abstract

This study aims to evaluate the acute toxicity of pymetrozine to juvenile Procambarus clarkii. Two 96-h toxicity tests were conducted to assess the lethal concentration 50 (LC50) values, behaviors, and histopathology (at 50% of the 96 h LC50) after pymetrozine exposure. The results showed high toxicity of pymetrozine to juvenile P. clarkii in a dose and time dependent manner, with a decreasing LC50 from 1.034 mg/L at 24 h to 0.479 mg/L at 96 h. The maximum allowable concentration (MAC) of pymetrozine for P. clarkii was 0.106 mg/L. Behavioral abnormalities were observed in pymetrozine-treated crayfish, such as incunabular hyperexcitability, subsequent disequilibrium, lethargy, and increased defecation. Significant lesions were observed in all pymetrozine-treated tissues, including: (1) in gill, hemocytic infiltration and 33.27% of epithelial cells lesions; (2) in perigastric organs, 64.37%, 29.06%, and 13.99% of tubules with lumen atrophy, vacuolation, and cell lysis, respectively; (3) in heart, 2.5%, 8.55% and 7.74% of hemocytic infiltration, vacuolization, and hyperplasia, respectively; (4) in stomach, 80.82%, 17.77%, 6.98%, 5.24% of cuticula swelling, vacuolization, muscle fragmentation, hemocytic infiltration, respectively; (5) in midgut, 7.45%, 10.98%, 6.74%, and 13.6% of hyperplasia, tissue lysis and vacuolation, hemocytic infiltration, muscle fracture; and (6) in abdominal muscle, 14.09% of myofiber fracture and lysis. This research demonstrates that pymetrozine is highly toxic to juvenile P. clarkii, with significant effects on mortality, behavior and histopathology at concentrations of ≤1.1 mg/L, while the estimated practical concentration of pymetrozine in rice-crayfish culture water was around 20 times lower than the calculated MAC.

• Authors: Jixin Yu, Elvis Genbo Xu, Wei Li, Shiyu Jin, Ting Yuan, Jiashou Liu, Zhongjie Li, Tanglin Zhang
• Journal: International journal of environmental research and public health (Int J Environ Res Public Health) Vol. 15 Issue 5 (05 14 2018) ISSN: 1660-4601 [Electronic] Switzerland
• PMID: 29757963 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Insecticides
• Triazines
• pymetrozine

Topics

• Animals
• Aquaculture
• Astacoidea (drug effects)
• Insecticides (toxicity)
• Oryza
• Toxicity Tests, Acute
• Triazines (toxicity)