Adsorption: Process by which an ultrathin layer of one substance forms on the surface of another substance. (Random House Websters College Dictionary, 1997)

Anthropogenic: effects that are caused by human influences.

Arsenicosis: disease in humans caused by chronic arsenic exposure.

Chloride ion: an atom of the element chlorine in another valence state.

Inorganic compound: a chemical compound that contains no carbon. (Bates and Jackson 1980)

Leach: the separation, dissolution or removal in solution of materials such as minerals, pollutants or organic matter from a material with water or other liquid. (Bates and Jackson 1980)

Organic compound: a chemical compound that contains carbon; usually a hydrogen atom is bonded to the carbon atom. (Bates and Jackson 1980)

Oxidation: describes the loss of electrons/hydrogen or gain of oxygen.

Reduction: describes the gain of electrons or hydrogen and the loss of oxygen.

Resin bed: adsorbent designed to trap a specific contaminant. Various beds exist for different contaminants.

Valence: "also known as valency or valency number, is a measure of the number of chemical bonds formed by the atoms of a given element." (Wikipedia 2009)