CHEMICAL ANALYSIS OF SOME HEAVY METALS CONTENT OF SWAMP WATER FROM ORON LOCAL GOVERNMENT AREA
CHAPTER ONE
- Introduction
Mangroves colonize protected areas along the coast such as deltas, estuaries, Lagoons and Islands. Topographic and hydrological characteristics within each of these settings define a number of different mangrove ecotypes. A fringe forests borders protected shorelines, canals and Lagoons and is inundated by daily tides. A riverine forest flanks the estuarial reaches of a river channel and is periodically flooded by nutrients rich fresh and brackish water. Behind the fringe, interior areas of mangroves, harbor basin forests, characterized by stagnant or slow-flowing water. Scrub or dwarf forest grow in areas where hydrology is restricted, resulting in conditions of high evaporation, high salinity, low temperature, or low nutrient status. Such stressful environmental conditions stout mangrove growth.
The term “heavy metals” refers to any metallic element that has relatively high density and is toxic or poisonous even at low
concentration (Lenntech, 2004). “Heavy metals” is a general collective term, which applies to the group of metals and metalloids with atomic density greater than 4 g/cm3, or 5 times or more, greater than water (Hutton and Symon, 1986; Battarbee et al., 1988; Nriagu and Pacyna 1988; Nriagu, 1989; Garbarino et al., 1995, Hawkes, 1997).
- Heavy Metal Emission
Heavy metals are emitted both in elemental and compound (organic and inorganic) forms. Anthropogenic sources of emission are the various industrial point sources including former and present mining sites, foundries and smelters, combustion by-products and traffics (UNEP/GPA, 2004). Cadmium is released as a by-product of zinc (and occasionally lead) refining; lead is emitted during its mining and smelting activities, from automobile exhausts (by combustion of petroleum fuels treated with tetracethyl lead antiknock) and from old lead paints, mercury is emitted by the degassing of the earth’s crust. Generally, metals are emitted during their mining and processing activities (Lenntech, 2004).
Heavy metals can be emitted into the environment by both natural and anthropogenic causes. The major causes of emission are the anthropogenic sources specifically mining operations (Hutton and Symon, 1986; Battarbea et al., 1988; Nriagu, 1989). In some cases, even long after mining activities have ceased, the emitted metals continue to persist in the environment. Peplow (1999) reported that hard rock mines operate from 5 – 15 years until the minerals are depleted, but metal contamination that occurs as a consequence of hard rock mining persist of mining operations. Apart from mining operations, mercury is introduced into the environment through cosmetic products as well as manufacturing processes like making of sodium hydroxide.
- Objective of the Study
