Question

How/why does the chemical species F- (fluoride) at concentrations 3.22 ppm cause fish death? Explain your answer in a typed paragraph.

Answer 1

Fluorides are common in lake, river and sea water. Concenteration of 0.1 ppm is common but conc. exceeding 1.0 ppm is harmful. Most of the fluorides occur naturally. They are leached from fluoride, cryolite, apaptite, sedimentary phosphate rocks by precipitation and ground water. Pollution both aerial and hydric also contribute to the aquatic enviornment.

Fluoride ions are directly toxic to aquatic life, and accumulate in the tissues, at concentrations where absorption rates exceed excretion rates. The toxic action of fluoride resides in the fact that fluoride ions act as enzymatic poisons, inhibiting enzyme activity and, ultimately, interrupting metabolic processes such as glycolysis and synthesis of proteins. Fluoride toxicity to aquatic invertebrates and fishes increases with increasing fluoride concentration, exposure time and water temperature, and decreases with increasing intraspecific body size and water content of calcium and chloride