CHAPTER ONE
INTRODUCTION
1.1 Background of the Study
Environmental pollution remains one of the most challenging burden in the world as a result of indiscriminate disposal of waste through industrial processes and other anthropogenic activities such as those taking place in automobile workshops. Environmental pollution which used to be the unique problem of the industrialized countries has now become the problem of the developing countries as a result of industrialization. Environmental pollution as a result of the release of potentially hazardous metals from automobile repair workshops has increased considerably in most urban cities of Nigeria in the past two decades due mainly to significant increases in the number of automobile, as well as increased transportation activities in those cities. Heavy metals is a general term used to describe a group of metals and metalloid with an atomic density greater than 5.0g/cm (Duffus 2017). One of the major source of increase in heavy metal concentration of the ecosystem in Nigeria is automobile workshop (Adewole and Uchegbu, 2015). Pollution effect of mechanic site activities in Nigeria have received limited attention even though these activities has been shown to produce harmful waste. Therefore, there is need to continually monitor their nature, volume, direct harmful effect and current methods of disposal as well as potential impact on the environment. Although Adams, Luter, Musa, and Umar (2013) reported that the two known source of metal accumulation in the environment are natural and anthropogenic. The natural sources which could be explained to be due to geological activities which man absolutely does not have control over, the anthropogenic activities can be adequately studied by determining the level of contamination, remote causing and possible remediation (Adamu et al.,2013) According to Fetherston (2018), automobile is a self –propelled vehicle used primarily on public road. George (2017),cited in Abwage (2017) defined automobile as self-propelled land vehicle usually having four wheels and an internal combustion engine, used for personal and public transportation.it is of different types according to styles, number of doors and the purpose of uses. However, when this vehicle develop one fault or the other, they are being taken care of in an automobile workshop, by a competent motor vehicle mechanics. A workshop according to jubril (2016), is a place, area, room or building where machines, equipment, hand tools, workbenches and materials are used in manufacturing or repairing of things. Therefore, an automobile workshop is a place where basic vehicle maintenance is being carried out by auto mechanic or motor vehicle mechanics. Pann (2018) defined an auto mechanic as a skilled personnel, trained in any of the trades in auto mechanics, which includes: Auto body repair and spray painting, auto electrical work, auto body mechanic work, auto body building (panel beating) and auto part merchandising. Atypical city in a developing country like Nigeria usually has a sizeable number of mechanic workshops sites, in proportion to its population and activities. Apart from an organized assemblage of sites, some industrial workshop are also observed in some isolated areas of these cities. Apart from automobile workshop, other site like motor park and highways are vulnerable to contamination by metal such as lead (pb), cadmium(Cd), zinc (Zn),and nickel (Ni), which often are used as a major or minor additives in gasoline and auto-lubricant (Onianwa et al, 2001). With these, the increasing accumulation of metal in these environment cannot be over emphasized. Utmost distributing is that, workers that are occupational exposed to substances containing toxic metal are unaware of their side effects, of which high level of some of the metal may deplete antioxidant in the blood apart from other health and environmental negative impact (Arinola and Akiibinu, 2016). Since the activities of automobile workshop is one of the major route through which heavy metal enter into environment, which may cause heavy metal contamination of soil, drinking water and crops. Monitoring heavy metals contamination of soils is therefore necessary. It is a known fact that automobile introduce a number of toxic metals into environment (Lonati et al., 2016). Auto tire wear, degradation of part and greases, peeling of part and metals in auto catalyst and source of heavy metal pollution (Pecheyran et al., 2015). Increase import of reconditioned automobile have led to increased wear and tear, mushrooming of open-air garage and elevated concentration by heavy metals in the soils (Iwegbue, 2017). Food chain contamination by heavy metals has become a burning in recent years because of their potential for accumulation in bio-system through contaminated water, soil and air. As observe by Begum et al. (2018), large quantity of pollutant have continuously been introduce onto ecosystem as a consequence of urbanization and industrial processes. Metals are persistence pollutant that can be biomagnified in the food chain, thereby becoming increasing dangerous to human being and wildlife. Therefore, assessing the concentration of pollutants in different components of the ecosystem has become an important task in preventing risk to natural life and public health. Due to the strong implication of pollution by automobile workshop on the environment and the cosmopolitan nature of Amawbia, this study is carried out to determine the concentration of heavy metals on the soil of the automobile workshop vicinities in the study area. The above constitute the background of the study. The temperature of Amawbia is generally 27-300
c between June and December but rises to 32-340
c between January and April with the last few months of dry season marked by intense heat. The coldest days are in the dry harmattan month of December particularly with dry and dusty wind which enters Nigeria in late December or in early part of January and it is characterized by a haze limiting visibility and blocking the sun rays. Annual rainfall is high in study area, varying from 1700mm to2100mm and has double maxima regime in july and October. It is concentrated in one season, with about four months of dryness, which is from November to February. The south western winds from Atlantic Ocean create eight months of heavy tropical rains which occurs between April and October. The vegetation of this region is forest interspersed with tall grasses. The trees are not too tall and include hardwood and softwood varieties. Domesticated trees such as the mango, palm tree, guava, orange and almond are found. Much of the natural vegetation has been felled and the land utilized for development. Farming is carried out at mainly subsistence level. The title surplus production is sold for money used to purchase non-farm commodities. Planting of food crops like yam (DioscoreaRofundata), Cassava (MainihotSpp), maize (Zea Mays) and cocoyam (Colocusia) among others are largely determined by weather conditions.Amawbia has one of the largest automobile workshop mareters in Awka South Local Government area and other surrounding towns. Due to this market, different automobile spare parts are sold and utilized in their numbers in the area. The communities also have a new tyre market where different types of tyres that serves different purposes are sold. They also engage in trading activities where different types of foodstuffs and other households’ equipment’s are sold. They also engage in farming activities where they grow and harvest varieties of crops.