Chlordane
Encyclopedia
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.
. 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. 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.
. The incidence of seminoma in men with the highest blood levels of cis-nonachlor was almost double that of men with the lowest levels. Prostate cancer
has been associated with trans-nonachlor levels, a component of chlordane. Japanese workers who used chlordane over a long period of time had minor changes in liver function.
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 -.
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.
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
. This white solid was sold in the U.S. until 1983 as an insecticide for crops like corn
Maize
Maize known in many English-speaking countries as corn or mielie/mealie, is a grain domesticated by indigenous peoples in Mesoamerica in prehistoric times. The leafy stalk produces ears which contain seeds called kernels. Though technically a grain, maize kernels are used in cooking as a vegetable...
and citrus
Citrus
Citrus is a common term and genus of flowering plants in the rue family, Rutaceae. Citrus is believed to have originated in the part of Southeast Asia bordered by Northeastern India, Myanmar and the Yunnan province of China...
and on lawns and domestic gardens.
Production and uses
Chlordane is one so-called cyclodiene pesticide, meaning that it is derived from hexachlorocyclopentadieneHexachlorocyclopentadiene
Hexachlorocyclopentadiene is an organochlorine compound that is a precursor to several pesticides. This colourless liquid is an inexpensive reactive diene. Many of its derivatives proved to be highly controversial, as studies showed them to be persistent organic pollutants. Collectively, the...
. Hexachlorocyclopentadiene forms an adduct
Adduct
An adduct is a product of a direct addition of two or more distinct molecules, resulting in a single reaction product containing all atoms of all components. The resultant is considered a distinct molecular species...
with cyclopentadiene
Cyclopentadiene
Cyclopentadiene is an organic compound with the formula C5H6. This colorless liquid has a strong and unpleasant odor. At room temperature, this cyclic diene dimerizes over the course of hours to give dicyclopentadiene via a Diels–Alder reaction...
, and chlorination of this adduct give two isomers, α and β. The mixture is called chlordane. The β isomer is more bioactive. It was sold in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
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
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
(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. 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. 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.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. Chlordane bioaccumulates in animals. It is highly toxic to fish, with an of 0.022–0.095 mg/kg (oral).Health effects
Exposure to chlordane metabolites may be associated with testicular cancerTesticular cancer
Testicular cancer is cancer that develops in the testicles, a part of the male reproductive system.In the United States, between 7,500 and 8,000 diagnoses of testicular cancer are made each year. In the UK, approximately 2,000 men are diagnosed each year. Over his lifetime, a man's risk of...
. The incidence of seminoma in men with the highest blood levels of cis-nonachlor was almost double that of men with the lowest levels. Prostate cancer
Prostate cancer
Prostate cancer is a form of cancer that develops in the prostate, a gland in the male reproductive system. Most prostate cancers are slow growing; however, there are cases of aggressive prostate cancers. The cancer cells may metastasize from the prostate to other parts of the body, particularly...
has been associated with trans-nonachlor levels, a component of chlordane. Japanese workers who used chlordane over a long period of time had minor changes in liver function.
Heptachlor
Heptachlor
Heptachlor is an organochlorine compound that was used as an insecticide. Usually sold as a white or tan powder, heptachlor is one of the cyclodiene insecticides. In 1962, Rachel Carson's Silent Spring questioned the safety of heptachlor and other chlorinated insecticides. Due to its highly...
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
Leukemia
Leukemia or leukaemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases...
and lymphoma
Lymphoma
Lymphoma is a cancer in the lymphatic cells of the immune system. Typically, lymphomas present as a solid tumor of lymphoid cells. Treatment might involve chemotherapy and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage...
. 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 -.
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
Agency for Toxic Substances and Disease Registry
The Agency for Toxic Substances and Disease Registry is a federal public health agency within the United States Department of Health and Human Services. The agency focuses on minimizing human health risks associated with exposure to hazardous substances...
(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.