A lot of organic pollutants posing negative impact on the environment and on human health are chlorinated. Well known chlorinated hazardous organic chemicals include the well known DDT, PCBs, HCB, Mirex, Dioxin, etc. All of the 12 persistent organic pollutants (dirty dozens) initially listed in the Stockholm Convention for international regulations are chlorinated compounds. Many of the chlorinated compounds were used as pesticides.
Halogenated organic compounds are seldom found as natural products. Recently, researcher Schulz and colleagues in Germany found one natural chlorinated compounds from the snow flee, a winter-active species of springtail, produces unique polychlorinated octahydroisocoumarins to repel predators. Sigillin A, the active component with five chlorine atoms, showed high repellent activity in a bioassay with predatory ants.
The snow flee is easily ignored as it is only a few millimeter long, just list some pallets of black pepper on the snow. But such tiny flees have their unique strategy to deal with their predators. They can synthesize their own pesticide Sigillin A to repel ants, spiders etc.
Snow flees are quite efficient at synthesizing Sigillin A. despite Sigillin A is such a complicated organic molecules. Sigillin A synthesized by a snow flee can be 0.2% of it tiny body weight. It is still unclear whether Sigillin A is synthesized by snow flees themselves or by microorganisms in the body of a snow flee.
Effort has been make to synthesize this natural chlorinated in the lab. Chemists are looking forward to producing this natural chlorinated compound and use it for termite control.
However, natural generated does not mean it is environmental safe when synthesized and used in large quantity. It's environmental persistence, bioaccumulation potential, and toxicity needs to be carefully evaluated before large quantities is produced and used
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