Effect of Pyrethrin Insecticides on Fish & Aquatic animals

Pyrethrins are extremely toxic to bees, fish, and other aquatic animals. Pyrethrin is extremely toxic to aquatic life, such as bluegill and lake trout while it is slightly toxic to bird species, such as mallards. Toxicity increases with higher water temperatures and acidity. Natural pyrethrins are highly fat soluble, but are easily degraded and thus do not accumulate in the body. www.pesticide.org/PyrethrinsPyrethrum.pdf & http://extoxnet.orst.edu/pips/pyrethri.htm

Pyrethrins are “extremely toxic to fish,” according to the Agency for Toxic Substances and Disease Registry.46 Median lethal concentrations (the concentration that kills half of a test population) range from 9 to 58 parts per billion. Pyrethrins are more toxic to fish in warm water than in cold water.47 Aquatic animals other than fish are also killed by low concentrations of pyrethrins. The scud (a fresh water crustacean) is killed by concentrations of 12 parts per billion.49 Static bioassays were made in the laboratory to determine lethal concentration of the pyrethroid pesticide fenvalerate for the freshwater catfish Clarias gariepinus and effects of sublethal concentrations of the pesticide on some biochemical parameters of the fish. Hepatosomatic index, liver glycogen, alkaline phosphatase of liver and ascorbic acid of blood, liver, and kidney decreased while haemoglobin (Hb) %, plasma glucose levels and acid phosphatase level of liver increased after 24 h exposure to 2.1 micro g/L fenvalerate. Longer exposure (96 h) to even a lower concentration (1.4 micro g/L) of fenvalerate resulted in reduction of all the parameters (except Hb %) tested as compared with control. Hepatosomatic index, liver glycogen, alkaline phosphatase of liver and ascorbic acid of blood, liver, and kidney decreased while haemoglobin (Hb) %, plasma glucose levels and acid phosphatase level of liver increased after 24 h exposure to 2.1 micro g/L fenvalerate. Longer exposure (96 h) to even a lower concentration (1.4 micro g/L) of fenvalerate resulted in reduction of all the parameters (except Hb %) tested as compared with control. 50 Chronic aquatic toxicity tests showed that cis-bifentrin (cis-BF) could significantly affect the reproduction of Daphnia magna, a water flea. 51

References:

46. Dept. of Health and Human Services. Public Health Service. Agency for Toxic Substances and Disease Registry. 2001. Toxicological profile for pyrethrins and pyrethroids. p. 159.

47. Johnson, W.W. and M.T. FInley. 1980. Handbook of acute toxicity of chemicals to fish and aquatic invertebrates. Washington, D.C.: U.S. Dept. of the Interior. Fish and Wildlife Service. p. 70.

48. Burridge, L.E and K. Haya. 1997. Lethality of pyrethrins to larvae and postlarvae of the American lobster (Homarus americanus). Ecotoxicol.

Environ. Safety 38: 150-154.

49. Sanders, H.O. 1969. Toxicity of pesticides to the crustacean Gammarus lacustris. Technical Paper No. 25. Washington, D.C.: U.S. Dept. of the Interior. Fish and Wildlife Service. Bureau of Sport Fisheries and Wildlife.

50. Toxicity of the pyrethroid pesticide fenvalerate to freshwater catfish clarias gariepinus: lethality, biochemical effects and role of dietary ascorbic acid. Bhattacharya M, Kaviraj A. J Environ Sci Health B. 2009 Aug;44(6):578-83.

51. Chronic toxicity and cytotoxicity of synthetic pyrethroid insecticide cis-bifenthrin. Wang C, Chen F, Zhang Q, Fang Z. J Environ Sci (China). 2009;21(12):1710-5.