EFFECT OF HEAVY MATERIAL ON HUMAN RESPIRATORY SYSTEM ABSTRACT: Several heavy metals are found naturally in the earth crust and are exploited for various industrial and economic purposes. Among these heavy metals, a few have direct or indirect impact on the human body. Some of these heavy metals such as copper, cobalt, iron, nickel, magnesium, molybdenum, chromium, selenium, manganese and zinc have functional roles which are essential for various diverse physiological and biochemical activities in the body. However, some of these heavy metals in high doses can be harmful to the body while others such as cadmium, mercury, lead, chromium, silver, and arsenic in minute quantities have delirious effects in the body causing acute and chronic toxicities in humans. The focus of this study is to determine the effect of heavy metals on human respiratory system by describing the various mechanism of intoxication of some selected heavy metals in humans along with their health effects. Therefore it aims to highlight on biochemical mechanisms of heavy metal intoxication which involves binding to proteins and enzymes, altering their activity and causing damage. More so, the mechanism by which heavy metals cause neurotoxicity and affect respiratory and human health are discussed and recommendations are made. TABLE OF CONTENTSCONTENT PAGETITLE PAGE - - - - - - - - - - IAPPROVAL - - - - - - - - - - IIDEDICATION - - - - - - - - - - IIIACKNOWLEDGEMENT - - - - - - - - - IVABSTRACT - - - - - - - - - - VCHAPTER ONE1.0 INTRODUCTION1.1 BACKGROUND TO THE STUDY1.2 STATEMENT OF PROBLEM1.3 PURPOSE OF THE STUDY1.4 RESEARCH OBJECTIVES1.5 SIGNIFICANCE OF THE STUDY1.6 SCOPE AND LIMITATION/DELIMITATION OF THE STUDY1.7 DEFINITION OF TERMSCHAPTER TWO2.0 LITERATURE REVIEW2.1 HISTORICAL REVIEW2.2 CURRENT DISCOVERY2.4 SOURCES OF HEAVY METAL EXPOSURE TO HUMANS2.3 ROUTE OF EXPOSURE, BIO-UPTAKE AND BIOACCUMULATION OF HEAVY METALS IN HUMANS2.4 EFFECTS OF HEAVEY METALS ON HUMAN HEALTH2.5 THE HUMAN RESPIRATORY SYSTEMCHAPTER THREE3.0 RESEARCH METHODOLOGY3.1 MATERIALS AND TOOLS USED3.2 MODE OF DATA COLLECTION3.3 LOCATION AND SOURCES OF DATA COLLECTED3.3 RESEARCH DESIGN3.4 METHOD OF DATA ANALYSISCHAPTER FOUR4.0 RESULTS OF THE FINDING4.1 IMPACT OF THE RESEARCH TO THE IMMIDIATE COMMUNITY4.2 CHARTS AND DIAGRAM4.1 MECHANISM OF HEAVY METAL TOXICITY4.2 HEALTH EFFECTS OF HEAVY METAL TOXICITY IN HUMANSCHAPTER FIVE5.0 SUMMARY5.1 DISCUSSION5.2 RECOMMENDATION5.3 REFERENCESCHAPTER ONE1.0 INTRODUCTION1.1 BACKGROUND TO THE STUDYHeavy metals include both non-toxic and toxic elements. Iron (Fe), Cobalt (Co) Copper (Cu) Manganese (Mn) Molybdenum (Mo) and Zinc (Zc) Magnesium(Mg) are the trace elements and are required in a very minute amount, whereas other metals are non-essential, toxic to animals and even fatal when accumulated these metals includes; Mercury (Hg), Arsenic (As), Lead (Pb) Plutonium (Pu), Vanadium (v), Tungsten (w) and Cadmium (Cd), (Deevikaet al., 2012).Heavy metals with established toxic action to humans include cadmium (Morrow, 2010 and Hayes, 2007) lead (Eric, 2013 and Patrick, 2006 and mercury (Bojorklund, 1995).Each of these has been studied in isolation for toxicity (Morrow, 2010; Patrick,2006 and Clarkson, and Magoss. 2006). But in the ecosystem, be it air, (atmosphere, land and water) where they occur they do not exist in isolation. They occur in close association with other metal and non-metallic elemental pollutants. Among the metallic pollutant could be calcium, copper, zinc, magnesium, manganese, iron and others. Metals are known to interact with one another. Interaction can bring about two element together include proximately and could cause out right displacement with one another. When ingested in food and water they can antagonize each other. When it comes to intestinal hand and pulmonary absorption it is there conceivable that the presence of other element can affect the toxic potential of each of the heavy metal that has been study in isolation.Egborge (1994) reported that Warri River had and unacceptability high cadmium level, 0.3mg/l of H2O, was 60-fold above the maximal allowable level of 0.005mg/l. This report prompted our early studies on the hepato-, nephro- and goladal toxicity of cadmium in rat expose to this high close via water and diet. The diet was formulated with fish expose to 0.3mgCd/water in the ambient water, as protein source and the toxic effects investigated and reported. (Asagba and Obi, 2000; Asagba and Obi, 2001; Obi and Ilori, 2002; Asagba and Obi, 2004a; Asagba and Obi, 2004b; Asagba and Obi, 2005). The studies focus on cadmium without taken into consideration the fact that other metal were also present the river water and as such were co-consumed by the communities using the river water for cooking drinking and other domestic purposes. Hence it is desirable to know if the presence of other metal would enhance or diminish the toxic potential of cadmium or indeed that of any other metal such as lead that was mention above. Therefore the aim of this present studies was to determine the effect of heavy metals on human respiratory system.1.2 STATEMENT OF PROBLEMMetals are natural constituents that exist in the ecosystem. They are substances with high electrical conductivity which voluntarily lose their electrons to form cations. Metals are found all over the earth including the atmosphere, earth crust, water bodies, and can also accumulate in biological organisms including plants and animals. Among the 35 natural existing metals, 23 possess high specific density above 5 g/cm3 with atomic weight greater than 40.04 and are generally termed heavy metals [1, 2]. Theses metals generally termed heavy metals include: antimony, tellurium, bismuth, tin, thallium, gold, arsenic, cerium, gallium, cadmium, chromium, cobalt, copper, iron, lead, mercury, manganese, nickel, platinum, silver, uranium, vanadium, and zinc [1, 2]. This category of metals termed heavy metals have not only been known for their high density but most importantly for their adverse effects to the ecosystem and living organisms . Some of these heavy metals such as cobalt, chromium, copper, magnesium, iron, molybdenum, manganese, selenium, nickel and zinc are essential nutrients that are required for various physiological and biochemical functions in the body and may result to deficiency diseases or syndromes if not in adequate amounts  but in large doses they may cause acute or chronic toxicities.These heavy metals are distributed in the environment through several natural processes such as volcanic eruptions, spring waters, erosion, and bacterial activity, and through anthropogenic activities which include fossil fuel combustion, industrial processes, agricultural activities as well as feeding . These heavy metals do bioaccumulate in living organisms and the human body through various processes causing adverse effects. In the human body, these heavy metals are transported and compartmentalized into body cells and tissues binding to proteins, nucleic acids destroying these macromolecules and disrupting their cellular functions. As such, heavy metal toxicity can have several consequences in the human body. It can affect the central nervous function leading to mental disorder, damage the blood constituents and may damage the lungs, liver, kidneys and other vital organs promoting several disease conditions . Also, long term accumulation of heavy metals in the body may result in slowing the progression of physical, muscular and neurological degenerative processes that mimic certain diseases such as Parkinson’s disease and Alzheimer’s disease . More so, repeated long-term contact with some heavy metals or their compounds may even damage nucleic acids, cause mutation, mimic hormones thereby disrupting the endocrine and reproductive system and eventually lead to cancer .1.3 RESEARCH OBJECTIVESThe main purpose of this study is to determine the effect of heavy metals on human respiratory system. The specific objectives are outlined as follows;1. To determine Sources of heavy metal exposure to humans2. To determine the different heavy metals3. To assess the effect of heavy metals on human respiratiry health.