Project Abstract

<p> The study investigated the levels of organochlorine pesticide residues in both cocoa beans<br>and soils of cocoa plantations in selected farms in Ondo State. Soil samples and cocoa pods<br>were collected from four major farms in the State. The pesticide residues were extracted,<br>cleaned up and analysed using Gas Chromatography-Electron Capture Detector (GC-ECD).<br>In the analysed cocoa samples, the ranges of the mean concentrations of the organochlorine<br>pesticides were α-HCH (ND-0.094 mg/kg), β-HCH (ND-0.371 mg/kg), γ-HCH (ND-0.032<br>mg/kg), δ-HCH (ND-0.032 mg/kg), heptachlor (ND-0.272 mg/kg), heptachlor-epoxide<br>(0.040-0.185 mg/kg), aldrin (ND-0.117 mg/kg), dieldrin (0.052-1.110 mg/kg), endrin (0.297-<br>1.516 mg/kg), endosulfan I (1.719-10.689 mg/kg), endosulfan II (0.028-0.570 mg/kg),<br>endosulfan sulphate (ND-3.865 mg/kg), p,p’ DDT (ND-0.100 mg/kg), cis-permethrin (0.078-<br>0.662 mg/kg), trans-permethrin (0.085-0.927 mg/kg). However, the levels of aldrin, dieldrin,<br>endrin and endosulfan in the cocoa samples analysed were found to be high and above<br>Maximum Residual Limits (MRLs) established by WHO/FAO (HCH isomers, heptachlor,<br>heptachlor-epoxide, aldrin, endrin and dieldrin (0.020 mg/kg) and endosulfan I, II and<br>sulphate (0.100 mg/kg)) and European Union (α-HCH, β-HCH and δ-HCH isomers,<br>heptachlor, heptachlor-epoxide, and dieldrin (0.020 mg/kg), γ-HCH (1.000 mg/kg), p,p’-<br>DDT, aldrin (0.050 mg/kg) and endosulfan I, II, cis- and trans-permethrin (0.100 mg/kg)) . In<br>the soil samples analysed, the ranges of the mean concentrations of the organochlorine<br>pesticides were α-HCH (ND-0.064 mg/kg), heptachlor-epoxide (0.059-1.384 mg/kg), aldrin<br>(ND-0.450 mg/kg), dieldrin (0.041-0.066 mg/kg), endrin (0.136-0.567 mg/kg), endosulfan I<br>(0.319-1.451 mg/kg), endosulfan II (0.033-0.113 mg/kg), endosulfan sulphate (0.764-1.711<br>mg/kg), cis-permethrin (0.077-0.259 mg/kg), trans-permethrin (0.079-0.151 mg/kg) The<br>mean concentration of aldrin, dieldrin, endrin, endosulfan (I and II) in the soil sample<br>analysed were above the MRLs of the analytes established by Netherlands<br>aldrin(0.0025mg/kg),dieldrin(0.0005mg/kg),endrin(0.001mg/kg),endosulfanI(0.050mg/kg),en<br>dosulfanII(0.050mg/kg). p, p’ DDT was below detection limit (10-4 mg/kg) in 50% of the<br>analysed cocoa and all the soil samples. Similarly, HCH isomers and p,p’ DDT were below<br>detection limit (10-4 mg/kg) in the soil samples analysed except Oluji-1 where α-HCH was<br>detected. The results of the bioaccumulation factors showed that endosulfan, dieldrin, endrin<br>heptachlor, heptachlor-epoxide, cis- and trans-permethrin were bioaccumulated in the cocoa<br>samples from the selected farms. The high bioaccumulation factors of endosulfan I (7.367 in<br>Oluji-1, 3.084 in Oluji-2 and 14.525 in idanre), Dieldrin (27.073 in Oluji-2, 7.477 in Owena),<br>and cis- and trans-permethrin (1.8 and 11.734 in Owena, 8.597 and 8.429 in Idanre<br>respectively) give cause for concern considering the adverse health hazards pose by high<br>accumulation of these pesticides on man. This indicated recent use of these pesticides despite<br>the ban imposed on their use. The results of ANOVA showed that there was no significant<br>difference between the mean concentrations of the pesticide residues in all the cocoa samples<br>(p&lt;0.05). Similarly, no significant difference was observed between the mean concentrations<br>of the analytes in all the soil (p&lt;0.05). <br></p>

Project Overview

<p> 1.0 INTRODUCTION<br>Cocoa is an important tropical tree crop which does not only provide farmers with<br>much desired income to meet their basic family needs1 but also serves as aforeign exchange<br>earner for many West African countries like Nigeria, Ghana, Côte d’Ivoire, Cameroon and<br>Togo.Its botanical name, Theobroma Cacao, given by Swedish natural scientist Carl Von<br>Linne denotes its rich taste and high nutritional value which make it irresistible to both young<br>and adult especially when processed into diverse products such as chocolate, sweet, cocoa<br>drink, cocoa biscuit, cocoa bread, cocoa cake, cocoa flakes, cocoa popcorn, cocoa jam, cocoa<br>jelly, cocoa cream, cocoa wine and spirit, etc.2-4<br>Cocoa was believed to have originated in the hot, humid region near the source of the<br>River Amazon in South Africa and introduced into Nigeria in 1874.1,5In Nigeria, Cocoa is<br>grown mostly in Southern States such as Ondo, Oyo, Ogun and Osun. It is a tropical lowland<br>crop which flourishes best where the annual rainfall is at least 1140mm with mean<br>temperature below 170C. It requires shade to reduce moisture evaporation especially at the<br>nursery and the early stages of its establishment in the field. It also requires a deep, fertile and<br>well aerated loamy soil which must beloose and friable. The cocoa plant when mature<br>reaches a height of 7.5 to 10.5m.6<br>Before 1960, exportation of cocoa accounted mainly for the agricultural export, which<br>made over 80% of the Gross National Product (GNP) of the Nigerian economy.7This showed<br>that cocoa was the chief source of foreign exchange earnings for Nigeria before the discovery<br>and exploration of crude oil. Despite the oil boom experienced in Nigeria, cocoa still serves<br>as the major agricultural export crop and accounted for about 38% of agricultural export in<br>1997.8Being an important agricultural produce, cocoa provides employment for the farmers<br>xv<br>in the remote villages and millions of individuals all over the world involved in its<br>processing, marketing and distribution. It is imperative to note that large scale production of<br>cocoa can solve the problems of unemployment in Nigeria. This is because the world demand<br>for cocoa and its derived products is ever increasing and remains insatiable. Eighty-five<br>percent (85%) of the cocoa demand of the European Nations is from West Africa where<br>Nigeria is one of the major exporters5. This showed that the final destination of West African<br>cocoa is Europe.<br>Although, the cocoa producing Nations in West Africa derive revenue from the export<br>of cocoa to Europe, much more revenue could be derived if the exported cocoa is being<br>processed within the West African region and the finished products is exported for the<br>consumption of the European nations after the satisfaction of the local demands. This could<br>only be achieved if laws are enacted and necessary provisions are made to provide a very<br>conducive environment for the farmers and the local processing industries to strive.However,<br>the discovery of abundant natural resources, such as crude oil in Nigeria, gold in Ghana,<br>probably led to the reduction in effort of most African Governments to make available these<br>required provisions. Consequently, cocoa farming is now left mostly to smallholder farmers<br>(with farm size less than 5 hectares) who rely on the crop as the primary source of income.8<br>Many of these farmers are geographically isolated, illiterate, poorly informed and have very<br>limited resources for proper crop management. This development has caused a sharp decline<br>in cocoa production as many of the farmers still adopt the traditional methods of farming<br>which is very inefficient and pose high risk to the farmers8.<br>Unfortunately, the enormous effort of these farmers at sustaining production under<br>high risk conditions was not most often reflected in their output as pests and diseases largely<br>contributed to decline in cocoa production.9In Nigeria, decline in cocoa production started in<br>1971 and 1972 with yield of 255,000 and 241,000 metric tonnes respectively5. The lowest<br>xvi<br>yield in the 70’s was recorded in 1978 with output of 137,000 metric tonnes5. Yields declined<br>further from a peak of about 350,000 metric tonnes in the mid 80’s to about 58,700 metric<br>tonnes in 19865. According to THISDAYLIVE Newspaper report issued on 21st January, 2014,<br>the cocoa production in Nigeria was 250, 000 metric tonnes in 2011, 300, 000 metric tonnes<br>in 2012, and 350, 000 metric tonnes in 2013. This showed an annual increase in production<br>by 50, 000 metric tonnes but when compared to the annual cocoa production from other West<br>African countries in the same period (Ghana cocoa production was between 850, 000 – 1,<br>000, 000 metric tonne per annual and Cote d’Ivoire cocoa production was in the range 1.2 –<br>1.4 million metric tonnes per annual), it would be obvious that the growth rate was not only<br>insignificant but also the annual output was too small for the most populated black Nation<br>(Nigeria) that is expected to champion the course of self sustenance in food production in<br>Africa.<br>Major contributors to this decline were pests as 25-30% loss in yield of cocoa was attributed<br>to the cocoa mired, Sahlbergella singularis while about 17% was lost through the feeding of<br>the cocoa pod borer Characoma strictigrapta10, 11. The collective efforts of minor pests (such<br>as the shield bug, Bathycoelia thalassina, the pod miner, Mamara species, the root-feeding<br>termites, Macrotermes bellicosus,Mesohomotoma tessmanniand the cacao thrips,<br>Selenothrips rubrocinctus)could become significant especially under suitable conditions in<br>young cocoa or ageing cocoa plantations.<br>It is important to note that several concerted research efforts have been made to<br>develop various control techniques (such as cultural, biological and chemical) which could be<br>adopted for integrated management of the major and minor pests of cocoa in Nigeria. It is<br>however quite unfortunate to note that many of the findings of such research hardly reached<br>the local farmers and when they did eventually, the inability of the farmers to read and write<br>often hindered the proper interpretation of those findings. Despite the various mechanisms<br>xvii<br>developed for pest management, the farmers rely greatly on the use of pesticides (chemical<br>control technique) because it provides immediate and quicker remedy in the periods of<br>serious pest outbreaks.11<br>There are over seven hundred (700) chemicals in use as pesticides, which are<br>formulated into about thirty-five thousand products classified as insecticides, herbicides,<br>fungicides and rodenticides.12Although, pesticides are known to be very efficient in pest<br>control, reliance and prolonged application of thesesynthetic chemicals had given rise to<br>numerous problems which affected the food chain and posed negative impact on biological<br>diversity. It has been established that pesticides application could lead to serious health<br>hazard ( such as epilepsy, stroke, respiratory disorders, leukemia, convulsion, brain and liver<br>tumors ) and environmental pollution as it is often manifested in the disturbance of the<br>ecosystem,which include destruction of some natural vegetation, pollution of the important<br>water bodies (ground water, river water, drinking water), soil and air as well as reduction and<br>extinction of some aquatic species and wildlife population.13-15<br>In Nigeria, cocoa farmers use different insecticide formulations including the very<br>notorious organochlorine types. Due to their bioaccumulation throughout the food chain and<br>prolonged persistence in the environment coupled with numerous associated health risk, food<br>and environmental regulatory bodies in many developed and developing nations,including<br>National Agency for Food and Drug Administration and Control (NAFDAC) in Nigeria,<br>place ban on the use of most pesticides especially those with organochlorine formulations in<br>line with the new European Union Legislation on pesticide use.16 Despite, the ban on these<br>chemicals, the hazards associated with them still remain for long period as many of them<br>possess extended half-life especially the organochlorines which are very stable and persist for<br>a long period of time.The problem is further complicated as these compounds have many<br>xviii<br>derivatives which are very soluble in body fat and can move with relative ease through the<br>food chains.<br>It is therefore very expedient to provide adequate quantitative and qualitative<br>information on these banned pesticidesand their derivatives in soil, farm produce (e.g. cocoa)<br>and water. This is to assist; the farmers (who use these pesticides), government (in the<br>formulation of policy)and the general public (to make the consuming populace aware of the<br>associated danger inherent in consumption of farm produce and water contaminated<br>withpesticides). These can only be achieved through concerted research effort tailored and<br>targeted towards acquiring this much important information.<br>1. 1 STATEMENT OF PROBLEM<br>Use of Pesticide in Nigeria has been on the increase since its introduction in early 50s<br>for cocoa production. To attain acceptable levels of crop production, Nigerian cocoa<br>production is strongly dependent on pesticides. The campaign against mired attack on cocoa,<br>which followed the recommendation of Lindane in 1957, lead to highly significant increase in<br>cocoa production from an average of 103,000 tons per annum in 1961- 67 periods to 212,000<br>tons per annum in 1961-65 periods.16 This shows to a large extent that the use of some<br>pesticides is of significant importance to the production of cocoa. Since cocoa is one of the<br>major cash crops that contribute towards the Gross Domestic Product (GDP) of Nigeria<br>through foreign exchange, increasing the productivity of cocoa is tantamount to an indication<br>of economic development. However, most recently, the developed nations discovered<br>increase in the case of cancer among their citizens. This prompted the European Union to be<br>conscious of the quality of food products meant to be consumed among her citizens. This<br>development is in connection to pesticide residue observed to be high in most imported<br>agricultural produces and products. Thus, within the European Union (EU), as in many parts<br>of the world, legislation regulates the supply and use of pesticides. It has two important<br>xix<br>components: Directive 91/414, which defines active substances permitted for use in the EU;<br>and Regulation 396/2005, which defines the maximum levels of residues (MRLs) permitted<br>in food and feedstuffs in the EU. Regulation 396/2005 came into force on 1st September,<br>2008 and has significant implications.17 From 1st September 2008, any foodstuffs, including<br>cocoa as an imported commodity, containing pesticide residues above the temporary<br>maximum levels of residues (tMRLs) is considered illegal in the EU. In the new legislative<br>framework, tMRLs have been set on beans but also apply to cocoa and chocolate products. In<br>the light of this development, it is imperative for cocoa exporting countries like Nigeria to<br>make concerted effort to ensure their cocoa produce meet up with the set standards as Europe<br>is the final destination of cocoa produce in most developing nations.<br>Since cocoa produce that has its pesticide residue far above the minimum required<br>level stated by EU are restrained in the foreign exchange market, this implies that those local<br>farmers that are not aware of this legislation are only producing for themselves. Knowing<br>well that the market of cocoa is not only situated within the country but extends outside this<br>country, hence farmers that are still using the banned chemicals will definitely be running at a<br>loss. Information available at theFederal Environment Protection Agencyindicated that the<br>Federal Government of Nigeriarecognizes the problems of pesticides use andhas put in place<br>legal and administrativeprocedures aimed at regulating and monitoringpesticide manufacture,<br>importation, distribution,use and disposal so as to protect users as well as the nation’s<br>environment from the effects of thesepesticides.16 However, the marketing of pesticides in<br>Nigeria is very much unorganized and lacks proper legislative control. This has made it<br>difficult to determine the various market sizes, types, and shares of pesticides in use. Hence<br>there is no dependable official statistics on the type and amount of pesticides imported into<br>the country.18This is indeed a pathetic situation that requires immediate attention, which can<br>only come from well structured and organized research.<br>xx<br>1. 2 OBJECTIVE OF THE STUDY<br>The intensive use of pesticides leads to environmental problems such as<br>contamination of soil, farm produce and underground water. On application of pesticides to<br>destroy pests and pathogens, only 15% of the applied amount hits the targeted pests, with the<br>remaining 85% being distributed in the soil and air.19 The soil is the main matrix for pesticide<br>disposition and the bulk of pesticide residues are generally confined to the upper 20cm of the<br>top soil.20 Pesticide residue in the soil can move from the surface when they dissolve in<br>runoff water, or percolate down through the soil, and eventually reach the groundwater.<br>Plants take up pesticides dissolved in water. These pesticides are distributed in most part of<br>the plants especially in fruits rich in fat like cocoa beans. Most farmers are only interested in<br>protecting their crops from pests in order to get good harvest but have little concern for the<br>detrimental effects of these pesticides on the soil, environment and their health.20 In order to<br>comply with the maximum residue limit regulation and produce high quality cocoa beans for<br>exportation, it becomes expedient to assess organochlorine – α-HCH, β-HCH, γ-HCH,<br>Heptachlor, Heptachlor-epoxide (B), Aldrin, Dieldrin, Endrin, Endosulfan (I, II and<br>sulphate), DDT, cis- and trans-Permethrinresidue in cocoa beans and soil from selected<br>cocoa plantations in Ondo State, Nigeria.<br>The general objective of the study is to determine organochlorine pesticides residue<br>in both cocoa beans and soil of cocoa farm, and assess the pesticide management practices<br>among farmers in selected cocoa plantation in Ondo state, Nigeria. The specific objectives<br>are to:<br>(i) Identify pesticide management practices adopted by the farmers in the study area<br>(ii) Determine the level of organochlorine pesticides residue in the cocoa beans from the<br>selected farms<br>xxi<br>(iii) Determine soil physicochemical parameters (soil organic matter / total organic carbon,<br>particle size analysis and pH)andthe level of organochlorine pesticides residue in the top soil<br>of the selected cocoa farms<br>(iv) Evaluate the bioaccumulation factor<br>(v) Compare the values of the organochlorine pesticides in cocoa and soil with the accepted<br>Maximum Residual Limits (MRLs) established by international organisations<br>(vi) Provide required suggestions and make useful recommendations based on the findings of<br>this research to both the farmers and the Government.<br>1. 3 JUSTIFICATION OF THE STUDY<br>Until recently, environmental pollution monitoring and control have not received<br>much attention in most part of cocoa producing States in Nigeria. One important aspect of<br>this is the availability of adequate and reliable data on the levels of key pollutants resulting<br>from applications of pesticides. The occurrence, persistence, and consequences of<br>organochlorine pesticides in the environment will continue to represent an environmental<br>issue for contemporary and future generations. To address this issue, it is necessary to<br>determine the levels of organochlorine pesticides in some areas of likely predominance. This<br>informs the choice of the selected study area, Ondo State. This is a major cocoa producing<br>area in Nigeria where large cocoa plantations are situated. Thus, the findings of this research<br>can serve as a basis on measure of the presence and persistence of organochlorine pesticides<br>in major cocoa farms in Nigeria.<br>xxii <br></p>