IOSR Journal of Applied Chemistry (IOSR-JAC) e-ISSN: 2278-5736.Volume 12, Issue 6 Ser. I (June. 2019), PP 32-41 www.iosrjournals.org DOI: 10.9790/5736-1206013241 www.iosrjournals.org 32 |Page Assesment of pesticide residues in water and sedimet in Njuwa Lake, Yola Adamawa State, Nigeria * U.U Modibbo 1 , H.M. Maina 1 , O.N. Maitera 1 and M.Halilu 2 1( Departmnet of Chemistry, Modibbo Adama University of Technology, P.M.B, 2076 Yola, Adamawa State Nigeria) 2 ( Department of food science, Modibbo Adama University of Technology, P.M.B, 2076 Yola, Adamawa State Nigeria) Correspnding author (Musa Halilu) Abstract: Pesticides residues in both water and sediment could be a health risk in the fishes consume from Njuwa Lake Yola, Adamawa State Nigerial. The Levels of pesticides residues in water and sediments in lake Njuwa Yola wasinvestigated. The analytical methods usedinvolved solvent extraction of the pesticides residues by soxhlet extraction, cleaning and their subsequent quantification using hyphenation of gas chromatography mass spectromatry (GC-MS). In this technique, mass spectrometer acts as a detector for the compounds separated by a gas chromatography. Result of the Mean concentrations (μg/l) of pesticides residues in water ranged from (0.15 – 0.92). The mean concentrations (μg/g) of pesticides residues in sediment at south, north,west, and eastern sites of the Lake were ranged from (0.91 – 1.21), (0.92 – 1.07), (0.73 – 1.21) and (0.82 – 1.03), respectively. The pesticide residues found in the present study are generally above the maximum residues limit (MRL) set by FAO/WHO bodies. This indicate that the pesticides residues could pose a health risk to the consumers of the fishs from lake Njuwa. Keywords:pesticides,Herbicides, Insectides,Gas Chromatography, Mass Spectrometry. --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 27-05-2019 Date of acceptance: 11-06-2019 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction During the past five decades, the use of agrochemicals including pesticides has contributed to a sgnificant increase in major crop production [1]. Pesticides are used in agriculture for three main purposes, to produce a larger yield of crop, to produce a crop of better quality and to reduce the input of labour and energy into crop production. Even now, approximately 25% of the potential production of the world’s crop is destroyed by pest, weeds and diseases, either by direct attack upon the growing crop or damage and destruction to the stored harvest [2]. In practice, the appropriate use of pesticides has been responsible for increase in the productivity of agriculture, both in terms of output per unit area and output per man employed. In Nigeria, less and less number of persons are engaged in agriculture, in terms of total population of the country, every passing year, but there is regular increase of food production [3]. This increase in efficiency is clearly not solely related to the pesticides, the progressive mechanization of farm operations and the development of high-yielding crop varieties being other important factors. However, pesticides use has undoubtedly played a part in the maintenance of this trend.The use of increased quantities of fertilizsers and pesticides, which has done so much to improve agricultural production in recent years, also involves a considerable energy input in relation to the extraction and synthesis of chemicals[4]. The extent to which different types of pesticides are used to control agricultural pests is now increasing everyday several kinds of insecticides such as DDT are used in large quantity to control diseases like malaria and filarial [2,3]. These chemicals are poisonous and are washed into rivers and lakes endangering fish life. The pesticides and insecticides used are DDT, eldrine, dieldrine benzene hexachloride., endosulphan, endrex, folidol, demeton, and phosphamidon [6]. Chemical fertilizers are used in agricultural fields like urea and superphosphates are washed down into fishery ponds and nursery tanks, this are prove to be harmful to all sorts of organism [5]. Studies indicates that organochlorine pesticides (OC 5 ) are far more toxic than organophosphorus compounds (OP 5 ) [6,7,8,10]. It has also been shown by laboratory experiments [9] that a mixture containing pesticides belonging to different groups (OP 5 and OP 9 ) is far more toxic to fishes than when they are alone. This is called joint toxicity[1,3]. Application of pesticides to aquatic environemt inevitable result in some of the pesticides being diluted and dispersed, without necessarily reaching the target organism, at least in effective concentrations. Pesticides may accidentally enter water and in some cases the soil and sediment by spillage, misuse, cleansing or disposal of containers and from industrial and domestic effluents.However such factors may