Diazinon(R): Chronic Toxicity to, and Brain Acetylcholinesterase Inhibition in, the Sheepshead Minnow, Cyprinodon variegatus
- 1 September 1979
- journal article
- research article
- Published by Oxford University Press (OUP) in Transactions of the American Fisheries Society
- Vol. 108 (5) , 479-488
- https://doi.org/10.1577/1548-8659(1979)108<479:dr>2.0.co;2
Abstract
We investigated the toxicity of Diazinon to sheepshead minnows continuously exposed in flow‐through toxicity tests. In the 96‐hour acute test, a measured concentration of 1,400/ μg/liter was lethal to 50% of the juvenile test animals. In the partial life‐cycle test, we also investigated uptake of Diazinon by sheepshead minnows and effect of Diazinon on brain acetylcholinesterase (AChE) activity. Average measured concentrations in the partial life‐cycle test were nondetectable (control), 0.47, 0.98, 1.8, 3.5, and 6.5 μg of Diazinon per liter of seawater. Although the number of eggs spawned by continuously exposed fish was significantly reduced (α = 0.05) in all concentrations, no concentration tested significantly affected parental survival or fertility of eggs, nor were survival and growth of progeny affected in a subsequent 28‐day test. Fish exposed to 0.47 μg/liter spawned 22.6 eggs/female‐day, or 69% of control production (32.8 eggs/female‐day). The number of eggs spawned by fish exposed to 6.5, 3.5, 1.8, and 0.98 μg/liter Diazinon was similar (14.9–17.9 eggs/female‐day), averaging 45–55% of production by control fish. Egg production by fish that had been previously exposed to 3.5 μg/liter did not change significantly following deputation for 23 to 31 days. AChE activity varied inversely with exposure concentration, fish in the highest concentration (6.5 μg/liter) averaging 71% inhibition. The concentration of Diazinon measured in adult fish exposed to 1.8, 3.5, and 6.5 μg/liter averaged 169 times the concentration measured in the water. Diazinon was not consistently detected (<0.05 mg/kg) in fish exposed to 0.98 and 0.47 μg/liter. The maximum acceptable toxicant concentration (MATC) for sheepshead minnows continuously exposed to Diazinon, based on reduced fecundity, is <0.47 μg/liter; the application factor (MATC ÷ 96‐hour median lethal concentration) is <0.0003.This publication has 1 reference indexed in Scilit:
- A Method for Establishing Acceptable Toxicant Limits for Fish—Malathion and the Butoxyethanol Ester of 2,4-DTransactions of the American Fisheries Society, 1967