Chemosphere 73 (2008) 1032–1035 0045-6535/$ - see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2008.08.010 Contents lists available at ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere 1. Introduction Fascioliasis is very common in the eastern Uttar Pradesh, 94% of buffaloes slaughtered in the local slaughter houses are infected with Fasciola gigantica (Singh and Agarwal, 1981; Agarwal and Singh, 1988). Snail Lymnaea acuminata is the intermediate host of F. gigantica. Grazing in water-logged area and the use of water plants as fodder are the primary cause of fluke infection. The con- tinuous and indiscriminate use of synthetic pesticides for pest control has created the problem of acute and chronic toxicity to man and other non-target animals (Shafer et al., 2005). Exposure of pyrethroids has been widely documented in humans, includ- ing exposure of pregnant women, infants, and children (Schettgen et al., 2002; Whyatt et al., 2002; Berkowitz et al., 2003; Heudorf et al., 2004). Primary mode of action of pyrethroids is on voltage- sensitive sodium channels in nerve cells (Agarwal and Singh, 1988; Shafer et al., 2005). The acute mammalian neurotoxicity of pyre- throids has been well characterized, and several comprehensive reviews of pyrethroids toxicity, metabolism and action are avail- able (Kaneko and Miyamoto, 2001; Narahashi, 2001; Ray, 2001; Soderlund et al., 2002; Shafer et al., 2005). The search therefore goes on for safer pesticides. As a group, synthetic parathyroids cause high pest mortality at lower doses (Ruzo et al., 1978; Reed et al., 1983; Wolansky et al., 2006) and are less toxic to non-tar- get animals, especially mammals (Matsumura, 1985). Even though considerable data on the effect of parathyroid on insects are avail- able, there is lack of information on the feasibility of using para- thyroid for the control of snails. Singh and Agarwal (1986, 1996) studied the effect of permethrin and cypermethrin on the snail L. acuminata. In this study, effect of binary combination of delta- methrin + MGK on the level of phospholipid and rate of lipid perox- idation in nervous and foot tissue of snail L. acuminata was studied to observe their mode of action. 2. Materials and method Adult L. acuminata (2.6 ± 0.3 cm in length) were collected locally and acclimatized to laboratory conditions for three days. Group of 10 experimental snails were then transferred to glass aquaria containing five liters of dechlorinated tap water. The experiments were carried out within a temperature range of 22–25 °C. The pH of the water was 7.1–7.3 and dissolved oxygen, free carbon dioxide and bicarbonate alkalinity were 6.5–7.2 mg L ¡1 , 5.2–6.3 mg L ¡1 and 102.0–105.0 mg L ¡1 , respectively. Dead snails were removed imme- diately from the aquaria to avoid any contamination. 2.1. Drug solutions Solutions of the desired strength of deltamethrin [(s)-a-cayno- 3-phenoxybenzyl (IR, 3R)-3-(2,2-dibromovinyl)–2, 2-1/m-dimeth- ylcyclopropane-carboxylate] (Evid and Company Chemicals Ltd., India) and MGK-264 (N-(2-ethylhexyl)-8,9,10-trinorborn-5ene- 2,3-dicarboximide) (McLaughlin Gormley King Co., USA) were prepared in acetone. Appropriate amounts of the drugs were mixed in 1:5 ratio and added to the aquarium water. Effect of binary combination of deltamethrin + MGK-264 on the levels of phospholipid and lipid peroxidation in the snail Lymnaea acuminata R.N. Singh, Pradeep Kumar, V.K. Singh, D.K. Singh * Department of Zoology, DDU Gorakhpur University, Gorakhpur, UP 273 009, India article info abstract Article history: Received 28 March 2008 Received in revised form 31 July 2008 Accepted 9 August 2008 Available online 17 September 2008 Effect of sublethal treatment of (40% and 60% of 48 h LC50) of deltamethrin + MGK on phospholipid level and rate of lipid peroxidation in nervous and foot tissue of Lymnaea acuminata were studied. Maximum reduction in phospholipid (24.10%) level and increase in rate of lipid peroxidation (586.8%) were observed in foot tissue of snail exposed to 60% of 48 h LC50 of deltamethrin + MGK 264 for 96 h. Alterations in the levels of phospholipids and rate of lipid peroxidation were time and concentration dependent. Use of MGK-264 with deltamethrin increases the toxicity of deltamethrin and their action on membrane phos- pholipids and rate of lipid peroxidation. © 2008 Elsevier Ltd. All rights reserved. Keywords: Deltamethrin + MGK Phospholipids Lipid peroxidation Lymnaea acuminata * Corresponding author. Tel.: +0551 2202187. E-mail address: dksingh_gpu@yahoo.co.in (D.K. Singh).