International Journal of Environment, 5(1): 8–13 (2015) ORIGINAL ARTICLE Impacts of Sumithion on Blood Glucose and Some Hematological Parameters in Common Carp Sabrina Hossain, Mst. Halima Khatun, Md. Khalilur Rahman, Zahid Parvez Sukhan, Md. Shahjahan ,* ISSN: 2186- 6872 (print) ISSN: 2186-0009 (online) http://www.BENJapan.org/IJE ARTICLE HISTORY Received: 12 May 2015 Revised: 17 November 2015 Accepted: 8 December 2015 Published online: 13 December 2015 Abstract An experiment was conducted to assess the effects of an organophosphorous pesticide sumithion on blood glucose and some hematological parameters in common carp, Cyprinus carpio. The experiment was conducted with three treatments, each having three replications. Treatment one (T1) was used as control (0 ppm) and two concentrations, such as 0.85 ppm and 1.70 ppm were used as Treatment two (T2) and Treatment three (T3), respectively. Fish were sacrificed at 7, 14, and 21 days after start of exposure. The sexual dimorphic changes in blood glucose levels were observed in the present study. In male, the blood glucose levels were significantly (P<0.05) increased with the toxicity of sumithion at 7, 14, and 21 days of exposure periods in higher concentrations (T2 & T3) compared to control (T1), while only tended to increases were observed in female. The Hb (g/dL) tended to decrease with toxicity of sumithion though significantly decreased in males at 7 and 14 days of exposure in T3. The RBCs (×10 6 /mm 3 ) were decreased significantly (P<0.05) during the toxicity of sumithion at 7, 14, and 21 days of exposure periods in higher concentrations (T3), whereas Hct (%) showed no significant changes in both concentrations (T2 & T3). On the other hand, WBC were significantly (P<0.05) increased in higher concentrations both in male and female. The present investigation highlighted that sumithion has adverse effects on the metabolism of macromolecules of fish. Key words: Organophosphorous; Environment; Pesticide; Fish; Toxicology.  2015, International Journal of Environment. All rights reserved. I. INTRODUCTION 1 The use of pesticides for the safety of humans and to increase agricultural production is alarming for their harmful effects on other non-target animals like fish. Contamination of water by pesticides, either directly or indirectly can lead to fish kills, reduced fish productivity. Several hundred types of pesticides and insecticides are used for crop protection in agriculture in Bangladesh. Among them, sumithion, the O, O Dimethyl O-(3- AUTHORS INFO Sabrina Hossain Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh-2202. Mst. Halima Khatun Department of Fisheries Biology and Genetics, Bangladesh Agricultural University, Mymensingh-2202. Md. Khalilur Rahman Bangladesh Fisheries Research Institute, Freshwater Station, Mymensingh, Bangladesh. Zahid Parvez Sukhan Department of Marine Fisheries & Oceanography Patuakhali Science & Technology University Dumki, Patuakhali 8602, Bangladesh Md. Shahjahan ,* Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh-2202. *Corresponding author e-mail: mdshahjahan@bau.edu.bd Tel:+88-01718590903; Fax: +880-91-61510 methyl-4-nitrophenyl) is important one which falls under the organophosphate groups. It is effective to control wide range of important insects and certain other arthropod pests. It is mainly used to control brittle in paddy field. It is also used in larval rearing fish pond to control tiger bug. Since sumithion is widely used for crop protection and for eradication of aquatic insects in aqua-ponds, it is very important to know the extent of damage made by this chemical to fish. Sumithion is considered somewhat toxic to fish [1]. The pesticides affect the aquatic ecosystem by interrupting the aquatic food chain resulting in the loss/shift in abundance of natural species in the aquatic environments [2 and 3]. Fish appear to possess the same biochemical pathways to deal with the toxic effects of endogenous and exogenous agents as mammalian species does [4]. Hematological parameters like hemoglobin, hematocrit, and blood cell counts can be used to find physiological response of contaminated environment [5]. Therefore, the blood parameters are often measured when a clinical diagnosis of fish physiology is applied to determine the sub-chronic effects of pollutants [5]. In the present study, the changes in blood glucose, hemoglobin, RBCs, WBCs and hematocrit values were monitored after sub-lethal exposure of this pesticide to the common carp (Cyprinus carpio), an economically important freshwater fish. II. MATERIALS AND METHODS A. Animals and chemicals The fish was collected from Bangladesh Catfish Limited, Valuka, Mymensingh and maintained in aquaria at the wet laboratory of the Faculty of Fisheries, 8