A biocide is a chemical substance capable of killing living organisms , usually in a selective way and commonly used in fields such as medicine, agriculture and forestry. Large quantities are also used in industrial applications preventing fouling in water and oil pipelines. The distinction between a biocide and an anti fouling agent or a disinfectant is often vague. As an example, chlorine is used as a short-life biocide in industrial water system, but a a disinfectant in swimming pools.
A biocide can be:
UsesBiocides can also be added to other materials (typically liquids) to protect the material from biological infestation and growth. For example, certain types of quaternary ammonium compounds (quats) can be added to pool water or industrial water systems to act as an algicide, protecting the water from infestation and growth of algae. Chlorine can be added in low concentrations to water as one of the final steps in wastewater treatment as a general biocide to kill micro-organisms, algae, etc. It is often impractical to store and use poisonous chlorine gas for water treatment, so alternative methods of effectively adding chlorine are used. Adding hypochlorite solutions to pools, etc. is one possible solution. Hypochlorite can gradually release chlorine into the water. Even more convenient for some users are compounds such as sodium dichloro-s-triazinetrione (dihydrate or anhydrous), sometimes referred to as dichlor, and trichloro-s-triazinetrione, sometimes referred to as trichlor. These compounds are stable while solid and may be used in powdered, granular, or tablet form. When added in small amounts to pool water or industrial water systems, the chlorine atoms hydrolyze from the rest of the molecule forming hypochlorous acid (HOCl) which acts as a general biocide killing germs, micro-organisms, algae, etc. Halogenated hydantoin compounds are also used as biocides.
Hazards and environmental risksBecause biocides are intended to kill living organisms, many biocidal products pose significant risk to human health and welfare. Great care is required when handling biocides and appropriate protective clothing and equipment should be used. The use of biocides can also have significant adverse impacts on the natural environment. Anti-fouling paints especially those utilising organic tin compounds such as TBT - tri-butyl tin have been shown to have severe and long lasting impacts on marine eco-systems and such materials are now banned in many countries for commercial and recreational vessels but still used for naval vessels.
Disposal of used or unwanted biocides must therefore be done with great care to avoid serious and potentially long lasting damage to the environment.
European Community ClassificationThe Biocidal Products Directive 98/8/EC (BPD), the classification of biocides is broken down into 23 product types (i.e. application categories), with several comprising different subgroups:
MAIN GROUP 1: Disinfectants and general biocidal products
- Product-type 1: Human hygiene biocidal products
- Product-type 2: Private area and public health area disinfectants and other biocidal products
- Product-type 3: Veterinary hygiene biocidal products
- Product-type 4: Food and feed area disinfectants
- Product-type 5: Drinking water disinfectants
MAIN GROUP 2: Preservatives
- Product-type 6: In-can preservatives
- Product-type 7: Film preservatives
- Product-type 8: Wood preservatives
- Product-type 9: Fibre, leather, rubber and polymerised materials preservatives
- Product-type 10: Masonry preservatives
- Product-type 11: Preservatives for liquid-cooling and processing systems
- Product-type 12: Slimicides
- Product-type 13: Metalworking-fluid preservatives
MAIN GROUP 3: Pest control
MAIN GROUP 4: Other biocidal products
- Wilfried Paulus: Directory of Microbicides for the Protection of Materials and Processes. Springer Netherland, Berlin 2006, ISBN 1-4020-4861-0.
- Danish EPA (2001): Inventory of Biocides used in Denmark
- National Pesticide Information Center
- ECB (European Chemicals Bureau) Biocides Website
- US EPA Office of Pesticide Programs Website
- Antimicrobial Center – Why use antimicrobials?
- Towerchlor products
- Pool & Spa Water Testing - © LaMotte Company
biocide in Catalan: Biocida
biocide in Czech: Biocid
biocide in German: Biozid
biocide in Spanish: Biocida
biocide in French: Biocide
biocide in Dutch: Biocide
biocide in Polish: Biocydy
biocide in Romanian: Biocid
biocide in Swedish: Biocid