EFFECT OF POISONOUS CHEMICAL ON BEANS PRESERVING
CHAPTER ONE
INTRODUCTION
1.1Â Â Â Â Background of Study
Cocoa (Theobroma cacao L.) is one of the most important cash crops in Ghana and the industry is the mainstay of the Ghanaian economy as it provides 30 percent of Ghana’s total export earnings making it the second largest source of export earnings (Gakpo, 2012). According to the Bank of Ghana, cocoa bean and products export receipts for the first quarter of 2011 was $859.4 million, accounting for about 61 percent of total export earnings as compared with $682.5 million at 48.8 percent in 2010 (Marcela and Ashietey, 2012). In September 2011,cocoa production in Ghana reached a record One Million (1,000,000) metric tonnes (MT), the highest ever. This record was 35.7 percent higher than the full-year record of 740,000 MT, obtained in the 2005/06 season (Marcela and Ashietey, 2012). Much of the increase in cocoa production could be attributed to their response to increased use of fertilizers and pesticides (Afrane and Ntiamoah, 2011).
The cocoa plant, like all living organisms, is susceptible to attack by a wide range of pests and diseases. Preventive and curative measures are therefore necessary in the cocoa industry to maintain and even increase output (Akrofiand Baah, 2007). While non-chemical means of managing pests and diseases in the industry are widely recommended for health and environmental reasons, the use of chemicals in the form of fertilizers, insecticides and fungicides is unavoidable in the effective management of cocoa farms (Moy and Wessel, 2000; Opoku et al., 2007; Adjinah and Opoku, 2010). Pesticides are widely used in most sectors of the agricultural production to prevent losses by pests and thus improve yields as well as quality of the produce (Cooper and Dobson, 2007). There are many kinds of benefits that may be attributed to pesticides, but these benefits often go unnoticed by the general public (Damalas,2009). Thus, pesticides can be considered as an economic, labor-saving, and efficient tool of pest management with great popularity in most sectors of the agricultural production.
Cocoa farmers therefore use a wide range of pesticides to limit losses from pests and diseases in cocoa agriculture. Prominent among these are: Copper sulphate (a fungicide popular in the treatment of black pod infection; Benzene hexachloride (BHC) (an insecticide for control of cocoa mirids); aldrin/dieldrin or aldrex 40 (to control mealy bugs); propoxur (an insecticide which is effective in controlling cocoa mirids in West African countries). Others are lindane, diazinon, clofenotate, DDT, and brestan, most of these chemicals have been banned for use on cocoa in Ghana. Pesticide use is associated with risk and can be hazardous if not handled properly (Owusu-Ansah et al., 2010).
In developing countries, farmers face great risks of exposure due to the use of toxic chemicals that are banned or restricted in other countries, incorrect application techniques, poorly maintained or totally inappropriate spraying equipment and inadequate storage practices (Asogwa and Dongo, 2009). Obviously, exposure to pesticides poses a continuous health hazard, especially in the agricultural working environment. By their very nature most pesticides show a high degree of toxicity because they are designed to kill certain organisms and thus create some risk of harm to humans and the environment (Berny, 2007; Power, 2010). Although pesticides have been developed to function with reasonable certainty and minimal risk to human health and the environment, published results are not always in agreement with this fact (Damalas, 2009; Burger et al., 2008). Considering that, the toxicity and quantity of a pesticide one is exposed to, are risk factors that directly affect human health, a greater risk is expected to arise from high exposure to a moderately toxic pesticide than from little exposure to a highly toxic pesticide. However, whether or not pesticide residues found in food and drinking water sources is a potential threat to human health when consumed, is still the subject of great scientific controversy (Magkos et al., 2006). In addition, inappropriate use of pesticides has been linked with, adverse effects on non-target organisms, watercontamination from mobile pesticides or from pesticide drift, air pollution from volatile pesticides, injury on non-target plants from herbicide drift, injury to rotational crops from herbicide residues remained in the field and crop injury due to high application rates, wrong application timing or unfavourable environmental conditions at and after pesticide application (Mariyono,2008).
Despite continuing disagreements over the degree of risk posed by pesticides, it appears that people have become increasingly concerned about pesticide use and particularly about their impacts on human health and environmental quality (Damalas, 2009). According to the Ghana Statistical Service, between 2002 and 2006 for instance, pesticide importation into the country increased from 7,763 metric tons to 27,886 metric tons with over 141 different types of pesticide products registered (Ghana EPA, 2008). However research has indicated that, there is an overuse, misuse and abuse of pesticides in farming mainly due to illiteracy and ignorance of the health effects of these chemicals (Ntow et al.,2006). A number of unapproved pesticides are in use on farms in Ghana most of which have been banned from use due to their environmental persistence. Pesticides such as Lindane, DDT, Aldrin, Dieldrin, Heptachlor, BHC and Endosulfan were found to be environmentally persistent ( Owusu-Ansah et al., 2010). However due to a combination of factors including weak enforcement of bans on pesticide importation and application as well as ignorance of its harmful effects, these chemicals are available to the farmer and often used on cocoa farms ( Fajewonyomi, 1995). The quality of cocoa imported into the EU and elsewhere is assessed based on traces of pesticides and other substances that have been used in the supply chain (Afrane and Ntiamoah, 2011). In 2010, over 20,000 MT of cocoa beans was rejected by Japan alone due to the presence of the following pesticides [(Fenvalerate Japanese MRL 0.01ppm, was found to be 0.07ppm), Endosulfan (MRL 0.1ppm), found to be 0.38ppm, Pirimiphos-methyl (MRL 0.05ppm), found to be 0.17ppm, Chlorpyrifos (MRL 0.05ppm), found to be 0.14 ppm, and 2,4-Dichlorophenoxyacetic acid (MRL 0.01ppm), found to be 0.06ppm]. above the Maximum Residue Levels (MRL) (Kaminaga, 2011).
1.2 Â Â Â Statement of Problem
Despite the popularity and beneficial use of pesticides, there are serious concerns about health risks arising from the exposure of farmers when mixing and applying pesticides or working on treated fields and from residues in food and in drinking water (Soares and Porto, 2009). The afore mentioned incidences have caused a number of accidental poisonings, and even the routine use of pesticides can pose major health risks to farmers both in the short and the long run and can degrade the environment ( Fajewonyomi, 1995). There are repeated cases of excessive levels of pesticide residues on agricultural produce and the safety of these products has become an issue of concern ( Moy and Wessel, 2000).
Recent changes in regulations in the European Union (EU), North America and Japan have called for a reflection on crop protection practices in cocoa and other commodity crops (ICCO, 2007). The pesticides of interest on cocoa in these countries include Chlorpyriphos, Fenvalerate, Pirimiphos-methyl, Endosulphan, Permethrin, Methamidophos, Fenitrothion and Dimethoate. These pesticides according to the new regulations on pesticides residues in foodstuffs of vegetables and animal origin imported into their countries should not be used on cocoa (ICCO, 2007).
