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Effects of Calcium Content and Humic Substances on the Toxicity of Acriflavine to Juvenile Zebrafish Danio rerio
Author(s) -
Meinelt Thomas,
Rose Alexander,
Pietrock Michael
Publication year - 2002
Publication title -
journal of aquatic animal health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 52
eISSN - 1548-8667
pISSN - 0899-7659
DOI - 10.1577/1548-8667(2002)014<0035:eoccah>2.0.co;2
Subject(s) - acriflavine , danio , toxicity , calcium , acridine orange , acridine , chemistry , biology , zebrafish , biochemistry , toxicology , apoptosis , organic chemistry , gene
Acriflavine, a fluorescent acridine dye, is one of the most universal dyes used in fisheries to treat external bacterial and protozoan diseases of fish. However, there is only limited information on the influence of physicochemical water parameters on acriflavine toxicity. Therefore, we conducted laboratory experiments to test the combined effects of water hardness (calcium ion content or Ca 2+ ) and humic substances (HS) on acriflavine toxicity to embryos and larvae of zebrafish Danio rerio , also known as zebra danio, as a test model. Developing fish embryos (prehatch) were exposed to different concentrations of acriflavine (0, 0.2, 0.4, 0.8, 1.6, and 3.2 mg acriflavine/L) in test media containing various combinations of Ca 2+ and HS for a period of 144 h. The test media were high (↑) Ca 2+ (2 mmol/L) without (−) HS, ↑Ca 2+ with (+) HS (5 mg C/L), low (↓) Ca 2+ (0.2 mmol/L) −HS, and ↓Ca 2+ +HS. Mortality was observed every 24 h up to 144 h. The increasing toxicity ranking of acriflavine based on LC 50 values in the different test media was 0.229 mg/L in ↑Ca 2+ −HS, 0.473 mg/L in ↓Ca 2+ −HS, 2.059 mg/L in ↑Ca 2+ +HS, and 2.339 mg/L in ↓Ca 2+ +HS. The −HS groups were significantly different from the +HS groups. Because the anion of acriflavine is positively charged, it can bind to the functional groups of the HS, subsequently reducing the amount available for uptake by fish. Calcium ions are able to elevate the toxicity of the dye while HS is reducing. The toxicity, and therefore the therapeutical index, is modified by the content of Ca 2+ and HS in the waters.