20 Oct 2011 ... and tetramethrin on carp (Cyprinus carpio L. 1758) ... Cyfluthrin and tetramethrin
are extensively used synthetic pyrethroid pesticides. The.
J. Black Sea/Mediterranean Environment Vol. 17(3): 260-268 (2011) RESEARCH ARTICLE
A comparative study on the acute toxicity of cyfluthrin and tetramethrin on carp (Cyprinus carpio L. 1758) Elif Güneş Günde1 and Sedat V. Yerli2* 1 2
Department of Biology, Aksaray University Aksaray, TURKEY Department of Biology, Hacettepe University, Beytepe-Ankara, TURKEY
*Corresponding author:
[email protected] Abstract Cyfluthrin and tetramethrin are extensively used synthetic pyrethroid pesticides. The present study was designed to compare the responses of two synthetic pyrethroids in carp (Cyprinus carpio). The experiments were repeated 3 times and 96-h LC50 values were determined for the carps. Lethal doses of the insecticides were determined using LC 50 software programme of US EPA based on Finneys Probit Analysis statistical method. Behavioral changes of carps were also observed. The 96-h LC50 values of cyfluthrin and tetramethrin were estimated as 21.5 µg/L and 14.84 µg/L, respectively. Keywords: acute toxicity, Cyprinus carpio, cyfluthrin, tetramethrin, pyrethroid insecticides
Introduction Insecticides which are used commonly in agriculture cause the death of the target insects within a few hours by inflicting irrevocable damage on the peripheral and central nervous systems (Leake et al. 1985; Reddy and Philip 1994). Synthetic analogues of the pyrethrins extracted from the ornamental Chrysanthemum cinerariaefolium, have become much more popular than other insecticides in recent years due to their high photostability, low toxicity on mammals and long persistence in the natural medium (Leake et al. 1985; Reddy and Philip 1994). The pyrethroids used against mosquitos in lake and riverside areas are carried into wetlands by rainwater and flood from where they were applied (Dhawan and Kaur 1996; Nemcsok et al. 1987). Pollutants can react with each other and develop new forms when entering the water, and they have undesirable toxic effects on living organisms, i.e., fish and arthropods (Moore and Waring 2001). Pyrethroids are generally safe in mammals and birds but are highly toxic to fish and aquatic invertebrates. Low solubility in water and high lipophillic properties of pyrethroids cause fast seizing by gills, and lack of hydrolithic enzymes can cause serious harm to fish (Hill 1989; Haug and Hoffman 1990). 260
Cyfluthrin, cyano (4-fluoro-3- phenoxyphenyl) methyl-3-(2,2 dichloroethenyl) 2,2-dimethylcyclopropanecarboxylate) is a broad spectrum synthetic type II pyrethroid insecticide. Cyfluthrin is a synthetic pyrethroid insecticide that has both contact and stomach poison action. First registered by EPA in 1987, cyfluthrin is found in both restricted use (RUP) and general use insecticides (US EPA, 1987). Cyfluthrin containing products may be classified by EPA as acute Toxicity Category II (bearing the signal word "Warning") or Toxicity Category I (bearing the signal word "Danger") based on its potential to cause eye damage (Meister 1995). Tetramethrin (Cyclopropanecarboxylic acid, 2, 2-dimethyl-3-(2-methyl-1propenyl (1,3,4,5,6,7-hexahydro-1,3-dioxo -2H-isoindol-2-yl) methyl ester), a synthetic pyrethroid insecticide, was first registered to EPA in 1968. It is a fast working contact insecticide used to target a range of flying and crawling insect species. Tetramethrin has very low toxicity to birds but is toxic for honey bees. Because tetramethrin is rapidly degraded, and provided its use is limited to buildings, as recommended, the potential that it has for producing effects on the environment is unlikely to be realised. Tetramethrin is highly toxic to fish, amphibians, and aquatic invertebrates. The present study was designed to compare the acute effects of cyfluthrin and tetramethrin, synthetic pyrethroid pesticides on carp (Cyprinus carpio) using the static test system. Materials and Methods Carp (16.4-19.8 cm) were obtained from Bolu, Turkey, and within 2 hours, with sufficient air, brought to the laboratory one month before the study. The fish were kept in glass aquaria and all the aquaria were aerated by air compressors. Test chambers were filled 25 L of dechlorinated tap water. The temperature of the aquaria was regulated at 25 ± 1 ºC with the help of aquarium heaters. Some characteristics of this aquarium water were: dissolved oxygen concentration, 7.2-7.9 mg/L, pH 7.5-7.7 and conductivity 0.212-0.260 mS. (Pullin 1986; Weirich et al. 1993). Following the preliminary experiment, all the tests were repeated three times. Each aquarium contained ten fish, which were selected randomly. Feeding was done once a day and was stopped 48 h before the experiment. After 48 h of adaptation, different concentrations of cyfluthrin and tetramethrin were added to the experimental aquaria. Technical grade cyfluthrin (98 %) and tetramethrin (98 %) were supplied from Sigma Aldrich. Stock solutions were prepared by weighing a certain amount analytical grade pesticides, stored at +4ºC, dissolved in acetone. Test concentrations were prepared by using appropriate amount of stock solutions to give the dosing concentration 15, 20, 25, 30, 40 µg/L of cyfluthrin and 10, 15, 20, 25, 30 µg/L of tetramethrin. The control groups received acetone at the 261
maximum acetone volume used in the dissolving of the dosing concentration. The bioassay systems were as described in standardized methods (Greenberg et al. 1985) and the national regulation (Turkish Official Gazette 2006). The selected species is also as recommended in these references. LC 50 values of pesticides and 95 % confidence limits were calculated using Finneys Probit Analysis by a computer program (US EPA 1999). The statistical significance of the difference between LC50 values for the cyfluthrin and tetramethrin was evaluated by a parametric Wilcoxon test, using SPSS 15.0 programme. The significance of the results was ascertained at p
