- General information and recent history of
cyclodienes (GPA)
- This class of chemical compounds includes such chemicals as aldrin,
dieldrin, chlordane and endrin
- Production of chlordane suspended in 1976
- Aldrin and dieldrin are banned in most developing countries
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- Industrial applications (GPA)
- Cyclodienes are used as insecticides and rodenticides
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- Chemical properties (GPA)
- Aldrin and dieldrin are closely related and are both volatile
- Chlordane is very persistent, surviving in soil for 20 plus years
- Endrin is closely related to both aldrin and dieldrin and it is
the most toxic of the three for the marine environment
- The metabolites of endrin are more toxic than the compound itself
- Endrin is persistent in soils, with a half-life reaching 12 years
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- Cyclodienes and the environment
(GPA)
- In general, cyclodienes get into marine areas from surface
run-off
- Aldrin and dieldrin are easily volatilized from sediment and redistributed
via air currents to areas far from the source
-Chlordane can be transported long distances and is now found in the
Artic food web
- Aldrin bioconcentrates in molluscs and fish
- High levels of dieldrin have been documented in fish, snails and
lake trout
- Endrin has been found responsible for fish kills in areas with high
amounts of agricultural run-off and indirect discharge
- Endrin bioaccumulates in many different species of marine fishes
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- Cyclodienes and marine mammals
- Dieldrin is commonly found in the blubber of marine mammals from
many different geographic areas (O'Shea, 1999)
- Aldrin and endrin are only rarely found in marine mammal blubber
(GPA)
- Higher concentrations of chlordane are found in males than in females
(Lee et al., 1996)
- Age related increase of chlordane concentrations in males (Wells
et al., 1994; Lee et al., 1996)
- Documented placental transfer of chlordane and dieldrin (Duinker
and Hillebrand, 1979; Wells et al., 1994)
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- Potential toxic effects based on other species
- Aldrin and dieldrin: In humans, acute exposure leads
to neurological symptoms and chronic exposure leads to psychological
illness, Parkinson's disease, and abnormal EEG readings; in hamsters
and mice, a single dose while pregnant caused physical deformities
in the fetus GPA
- Chlordane: Acute exposure in humans caused abnormal balance,
slowing of motor speed, and respiratory illnesses; chronic exposure
(low doses) in rats lead to altered hormone function and it is speculated
that chlordane may mimic sex steroids (GPA)
- Endrin: In hamsters, documented developmental abnormalities;
rats dosed with endrin showed an increased mortality of later generations
(GPA)
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