Lindane or gamma HCH, hexachlorocyclohexane is a chlorinated hydrocarbon insecticide formed by crystallisation from BHC, benzene hexachloride, which in turn is produced by the chlorination of benzene in the presence of ultra-violet light.
The insecticide has contact and some fumigant action. Other ingredients in commercial formulations which are sufficiently poisonous to qualify for Occupational Exposure Standards include ethylene glycol for which limits are set for both the particulate and the vapour. Sodium nitrite is also used.
It persists in soil to such an extent that carrots and potatoes should
not be planted within 18 months of treatment to avoid tainting the
roots and tubers.
Just 1,120 grams (2lbs 7.4oz) of the active ingredient will kill
insects, from beetles to the leatherjacket grubs which eat the plant
roots underground, over an area of 1 hectare (2.471 acres).
It is also used on fruit from apples to strawberries, vegetables, flowers, maize, grassland, cereal crops, sugar beet and oil seeds up to 4 times a year.
Another use has been in wood treatments and in forestry and it has been used in grain stores.
In the UK ,timber treatments proudly carry their "Lindane free" labels and the chemical has been on the PAN "Dirty dozen" list since 1985. It is regarded as toxic or harmful in contact with the skin and by inhalation and is irritating to the eyes and respiratory system. It is dangerous to bees, is described as "Very toxic to fish" and treated areas present a hazard to livestock for at least 14 days.
Lindane has been linked to aplastic anaemia and is suspected as a
causal factor in breast cancer.
In 1994 in the UK a Channel 4 television production by the Dispatches
programme examined the problem under the title "The Lindane Legacy".
They reported that, like all organochlorines, they dissolve in fat
and so have been detected in human fat and in breast milk across the
world.
As with pirimiphos methyl, the OP used in grain, the chemical was formulated and manufactured in the UK by Zeneca who are now prominent in the equally uncertain world of Genetic Modification.
It was reported that Lindane breaks down into even more dangerous
substances which may also be carcinogenic.
Breast cancers are known to be reduced in size by the anti-oestrogen
properties of Tamoxifen and oestrogen is thought to play an important
role in the causation of breast cancer. Hormonal factors are known to
be involved in many cancers and laboratory tests indicate that
chemicals such as Lindane can stimulate the production of a hormone
which damages DNA and can cause cancerous changes in breast cells in
the test tube. It is likely that the Benzene component may be
responsible for such actions since Benzene itself is a known
carcinogen and the "Benzene ring" forms the base from which all
hormones are formed.
The highest areas of breast cancer in the UK appear to coincide with the arable areas where the highest use of Lindane is reported.
Mainstream medical opinion in the UK was reported in 1994 to refute established evidence that the chemical is not only carcinogenic but also is able to effect the gene structure but there have been bans in many countries including Hungary, Israel, Japan, Poland, Finland, Sweden, Holland, Denmark, Portugal and New Zealand.
Recently the UK banned its use as seed dressing and the chemical is now undergoing further restrictions in use.
Sources. Dictionary of Chemistry, Zeneca Product label, Zeneca Product Manual, P is for Pesticides, the Lindane Legacy, the Encyclopaedia Britannica.
Dated 16/9/2000