ABSTRACT
DEFINITION Generally Contaminated land refers generally to land which contains contaminants in sufficient quantities to harm people, animals, the environment or structures. There is now a statutory definition of ‘contaminated land’ contained within Part IIA of the Environmental Protection Act. Contaminants comprise hazardous substances (solids, liquids or gases) that are not naturally occurring in the site. They arise from previous site usage, although sites can be affected by pollutants arising from adjoining sites through the movement of water and air. A contaminated site can similarly pose a risk to surrounding land by off site migration of contaminants. Contaminated sites can be sold on, although the new owner would take on the responsibility for the contamination and would obviously take this into account in the offered price. The extent of remediation works required to address contamination varies dependent on the intended future use of the site – with industrial uses calling for a lower level of work than if the site were intended to be used for residential or agricultural purposes. In a commercial world, expenditure on decontaminating the land would usually need to be balanced against the release of the latent site value – unless of course the contamination contravened statutory limits. Hazardous contaminants fall into three broad categories: … Chemical contamination of land or water
… Biological contamination of land or water (e.g. samples containing pathological bacteria potentially
harmful to health) … Contamination of a physical nature (e.g. radioactive material, unsuitable fill materials, flammable gas or
combustible material e.g. wood dust) These can also be listed in the following sub-groups: … Gases Toxic, flammable and explosive gases
e.g. hydrogen cyanide
hydrogen sulphide
Flammable and explosive gases
e.g. methane
… Liquids Flammable liquids and solids Fuels, oils and other hydrocarbons
Solvents
… Combustible materials Timber Ash
Coal residue
… Heavy metals Arsenic, lead, mercury, cadmium, chromium … Corrosive substances Acids
Alkalis
… Toxic substances Hydrocarbons Inorganic salts
… Asbestos
DEFINITION - continued Generally - continued … Substituted aromatic compounds PCBs
Dioxins
Furans
… Biological agents Anthrax Tetanus
BSE
Genetically modified organisms
The following is a brief list of some of the main industrial sectors and their potential contaminants. Sector Contaminant type Example
… Gasworks Coal tar Polyaromatic hydrocarbons (PAH’s) Phenol
Cyanide Free / complex
Sulphur Sulphide / sulphate
Metals Lead, cadmium, mercury
Aromatic hydrocarbons Benzene
… Iron + Steel works Metals Copper, nickel, lead Acids Sulphuric, hydrochloric
Mineral oils -
Coking works residues (As for gasworks )
… Metal finishing Metals Cadmium, chromium, copper, nickel, zinc Acids Sulphuric, hydrochloric
Plating salts Cyanide
Aromatic hydrocarbons Benzene
Chlorinated hydrocarbons Trichloroethane
… Non ferrous metal processing Metals Copper, cadmium, lead, zinc Impurity metals Antimony, arsenic
Other wastes Battery cases, acids
… Oil refineries Hydrocarbons Various fractions Acids, alkalis Sulphuric, caustic soda
Lagging, insulation Asbestos
Spent catalysts Lead, nickel, chromium
… Paints Metals Lead, cadmium, barium Alcohols Toluol, xylol
Chlorinated hydrocarbons Methylene chloride
Fillers, extenders Silica, titanium dioxide, talc
… Petrochemical plants Acids, alkalis Sulphuric, caustic soda
Metals Copper, cadmium, mercury
Reactive monomers Styrene, acrylate, VCM
Cyanide Toluene di-isocyanate
Amines Analine
Aromatic hydrocarbons Benzene, toluene
… Petrol stations Metals Copper, cadmium, lead, nickel, zinc Aromatic hydrocarbons Benzene
Octane boosters Lead, MTBE
Mineral oil -
Paint, plastic residues Barium, cadmium, lead
… Rubber processing Metals Zinc, lead Sulphur compounds Sulphur, thiocarbonate
Reactive monomers Isoprene, isobutylene
Acids Sulphuric. hydrochloric
Aromatic hydrocarbons Xylene, toluene
… Semi-conductors Metals Copper, nickel, cadmium Metalloids Arsenic, antimony, zinc
Acids Nitric, hydrofluoric
Chlorinated hydrocarbons Trichloroethylene
Alcohols Methanol
Aromatic hydrocarbons Xylene, toluene
… Tanneries Acids Hydrochloric Metals Trivalent chromium
Salts Chlorides, sulphides
Solvents Kerosene, white spirit
Cyanide Methyl isocyanate
Degreasers Trichloroethylene
Dyestuff residues Cadmium, benzidine
… Textiles Metals Aluminium, tin, titanium, zinc Acids, alkalines Sulphuric, caustic soda
Salts Sodium hypochlorite
Chlorinated hydrocarbons Perchloroethylene
Aromatic hydrocarbons Phenol
Pesticides Dieldrin, aldrin, endrine
Dyestuff residues Cadmium, benzedrine
… Wood processing Coal tar based preservatives Creosote Chlorinated hydrocarbons Pentachlorophenol
Metalloids / metals Arsenic, copper, chromium
… Hat making Mercury