Chlordane, or chlordan, is an organochlorine compound that was used as a pesticide. This white solid was sold in the U.S. until 1983 as an insecticide for crops like corn and citrus and on lawns and domestic gardens.[2]
Production and uses
Chlordane is one so-called cyclodiene pesticide, meaning that it is derived from hexachlorocyclopentadiene. Hexachlorocyclopentadiene forms an adduct with cyclopentadiene, and chlorination of this adduct give two isomers, α and β. The mixture is called chlordane. The β isomer is more bioactive.[2] It was sold in the United States from 1948 to 1988 both as a dust and an emulsified solution.
Because of concern about damage to the environment and harm to human health, the United States Environmental Protection Agency (EPA) banned all uses of chlordane in 1983 except termite control. The EPA banned all uses of chlordane in 1988. The EPA recommends that children should not drink water with more than 60 parts of chlordane per billion parts of drinking water (60 ppb) for longer than 1 day. EPA has set a limit in drinking water of 2 ppb.Origin, Pathways of Exposure, Processes of Excretion
Chlordane was a manufactured chemical, commonly used in 1948-1988, on corn and citrus crops as a pesticide, as well as a method of termite control.[3] Pathways of exposure to Chlordane include ingestion of crops grown in Chlordane contaminated soil, ingestion of high fat foods such as meat, fish, and dairy, as Chlordane builds up in fatty tissue, as well as through inhalation of air near Chlordane treated homes and landfills.[4] Chlordane is excreted slowly through feces and urine elimination, as well as through breast milk in nursing mothers and is able to cross placenta and become absorbed by developing fetus’ in pregnant women.[4][5]
Environmental impact
Being hydrophobic, chlordane adheres to soil particles and enters groundwater only slowly owing to its low solubility (0.009 ppm). It degrades only over the course of years.[6] Chlordane bioaccumulates in animals. It is highly toxic to fish, with an LD50 of 0.022–0.095 mg/kg (oral).
Health effects
Exposure to chlordane metabolites may be associated with testicular cancer. The incidence of seminoma in men with the highest blood levels of cis-nonachlor was almost double that of men with the lowest levels.[7] Prostate cancer has been associated with trans-nonachlor levels, a component of chlordane.[8] Japanese workers who used chlordane over a long period of time had minor changes in liver function.[9]
Heptachlor and chlordane are some of the most potent carcinogens tested in animal models. No human epidemiological study has been conducted to determine the relationship between levels of chlordane/heptachlor in indoor air and rates of cancer in inhabitants. However, studies have linked chlordane/heptachlor in human tissues with cancers of the breast, prostate, brain, and cancer of blood cells—leukemia and lymphoma. Breathing chlordane in indoor air is the main route of exposure for these levels in human tissues. Currently, USEPA has defined a concentration of 24 nanogram per cubic meter of air (ng/M3) for chlordane compounds over a 20-year exposure period as the concentration that will increase the probability of cancer by 1 in 1,000,000 persons. This probability of developing cancer increases to 10 in 1,000,000 persons with an exposure of 100 ng/M3 and 100 in 1,000,000 with an exposure of 1000 ng/M3 -.[10]
The non-cancer health effects of chlordane compounds (migraines, respiratory infections, diabetes, anxiety, depression, and activated immune system) may affect more people than cancer. The Agency for Toxic Substances and Disease Registry (ATSDR) has defined a concentration of chlordane compounds of 20 ng/M3 as the Minimal Risk Level (MRLs). ATSDR defines Minimal Risk Level as an estimate of daily human exposure to a dose of a chemical that is likely to be without an appreciable risk of adverse non-cancerous effects over a specific duration of exposure.[11]
From (www.wikipedia.com)
