ORGANOCHLORINE INSECTICIDES Chemische Eigenschaften,Einsatz,Produktion Methoden
Chemische Eigenschaften
The organochlorine insecticides are persistent organic pollutants that are highly resistant to biological, photolytic, or chemical degradation due to the stable carbon–chlorine bond. These compounds are characterized by low water solubility, high lipid solubility, and semi-volatility. Large molecular weight compounds with cyclic, aromatic, and cyclodienetype structures include the organochlorine insecticides such as DDT, chlordane, lindane, heptachlor, dieldrin, aldrin, toxaphene, mirex, and chlordecone (IPCS, 1995).
Verwenden
The organochlorine insecticides are important historically as a major class
of synthetic insecticides. During World War 2, European supplies of traditional
botanical insecticides used for crop protection, such as pyrethrum
extract and nicotine, were limited by blockades and shortages. The critical
need to protect crops from insect pests and to protect personnel in tropical
areas from malaria and other insect-borne diseases stimulated the search
for synthetic replacements. The organochlorine insecticides were one of
the first major classes of synthetic chemicals to meet the needs of public
health and agriculture. Despite their great utility and the low costs of
manufacture, the production and use of many organochlorine insecticides
has now been discontinued or restricted because they are not readily biodegradable
and have become ubiquitous environmental contaminants.
They may accumulate or bioconcentrate through the food chain and
directly or indirectly they show potential for adverse effects in man and
the environment.
Environmental Fate
The organochlorines strongly adsorb to soils and do not readily leach into groundwater due to low water solubility. However, the presence of organic solvents at hazardous waste sites may promote leaching. Limited biodegradation by microorganisms may occur in soils and water. Photodegradation and hydrolysis are not important pathways for degradation of these compounds. Volatilization and adsorption to atmospheric particulates results in global transport and deposition. Bioconcentration has been measured throughout the food chain from plants to domestic livestock and fish (IPCS, 1995).
Chemical properties resulting in limited environmental degradation mean these compounds are persistent pollutants. While aldrin is rapidly converted to dieldrin, the half-life of dieldrin on temperate soils is about 5 years. As much as 50% of applied DDT and related compounds can remain on soils for >10 years (IPCS, 1995; ATSDR, 2002a,b).
ORGANOCHLORINE INSECTICIDES Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
