Heavy Metals

CHEM 3560

Lecturer:        Dr Denise Beckles

Group 7:        Team ARC -

                                Aqilah Mahabir

                                Raeann Chandler

                                Christopher Gilalta

Pollution Micro Project - Heavy Metals

A heavy metal is maybe defined as any one of the several elements that demonstrate metallic properties, furthermore, the term is usually characteristic of elements with an atomic number of 21 or higher for example scandium. Heavy metals became a popular term during discussions of pollutants discharged into the environment via atmospheric, aquatic and terrestrial contaminants and is widely categorised as toxic to both plants and animals. Numerous heavy metals exhibit significantly high levels of toxicity, whereas, others are vital in trace amounts in metabolic functions of organisms as they do not display high toxic characteristics. Heavy metals occur both naturally in the environment and as well as entering it through the influences of man, it is transported through various mediums and carries with it many effects, both minor and major, on both organisms and the surrounding environment.

                According to Managing Environmental Pollution, heavy metals do occur naturally in varying concentrations as a result of rock and soil weathering as well as volcanic activity. In addition, further emissions are the product of human activity such as rapidly expanding industries. Operations such as metal processing, sewage sludge, pesticides and fossil fuel burning are significant sources that emit varying concentrations of heavy metals into its surroundings. A source which is advertised greatly is the lead exhaust from motor vehicle exhaust, as lead is specifically added as an anti-knocking agent. 1 Some common and concerning heavy metals include arsenic, cadmium, cobalt, copper, chromium, iron, lead, manganese, mercury, nickel, silver, tin, titanium, vanadium and zinc.

Although we commonly think of heavy metals as water pollutants, they are for the most part transported from place to place through the atmosphere, either in the gaseous state or as species adsorbed on or in suspended particulate matter such as aerosols. These particles can “fall’ from the atmosphere onto land and water bodies as precipitation (rainfall), which can carry these particles and dissolved gases. Gaseous heavy metals can also dissolve in water body surfaces. In waterbodies, heavy metals can be transported via the erosion of rocks and/or land containing these metals, and also surface runoffs of natural and human formed metal particles. Transportation through groundwater occurs as contamination in soils for example, when contaminated waste dumps and sewage seep through the ground bed into groundwater sources such as aquifers. In the United States, drinking water is monitored for heavy metals to ensure that their concentration falls below the safe limit or maximum contaminant level (MCL) set by the Environmental Protection Agency. 2