Lindane: Pharmaceutical and Environmental Persistance

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gamma structure of Lindane

The gamma structure of Lindane. Image courtesy of the National Library of Medicine 

According to the American Academy of Pediatrics, the pharmaceutical Lindane presents a health hazard to children. Lindane is grouped in same vein as DDT, the infamous insecticide of several generations ago.

The AAP based their pronouncement on the Lindane’s side effects. When used as a scabicide or lice-ridant this chemical has, on occasion, resulted in convulsions, confusion and in rare instances, death.

Unfortunately, Lindane, is still currently registered for use by the U.S. Food and Drug Administration as a lice-ridant and scabicide.

Lindane’s History

Lindane, first synthesized by scientist Michael Faraday in 1825, was formally recognized as an insecticide in 1930. This substance is actually an isomer of eight distinct structures (isomers are structurally distinct molecules). Pharmaceutical-grade Lindane is primarily the gamma-isomer.

Consumers have been using Lindane as a lice-ridant and scabicide since the 1940s. The United States completely banned Lindane’s use in agriculture in 2006.

Lindane Contamination

The most common mode of contact, and most feared, is as a water contaminant. Although it has been more than three decades since peak pesticide usage, Lindane is still a persistent pollutant in the environment.

Each treatment for scabies or lice generates  thousands of gallons of contaminated waste water (from synthesis to consumer use).

Few Significant Bio-pathways of Degradation Mean Lindane is a Bio-accumulating Agent.

When in direct contact with water, there are no known degradation pathways; the molecule does not reportedly change its structure.

However in soil, microbes and fungus partially degrade the pesticide. At that point, the products of degradation can seep into groundwater, or may be evaporated and dispersed into the atmosphere. The current studies characterizing bacterial degradation acknowledge de-chlorination of the cyclohexane ring. This change results in one of two chemicals: chloro-benzene or dichloro-cyclohexene (which are both toxic).

About Lindane

Lindane seemingly has no ‘chemical similarity’ to any naturally occurring bio-cide. In some ways, it is the chemical-equivalent to a ‘bullet.’ As a pharmaceutical, Lindane is currently a second tier scabicide/lice-ridant. This means it’s intended for use only in cases in which other means are ineffective.

As a pesticide, it is highly effective and was a ‘game-changer’ for the agriculture industry – although it is now banned for use in farming. However, since the pesticide was used on a consistent basis for more than 60 years, it turned into a major environmental hazard.

Lindane is not quickly bio-degradable nor completely water soluble.

A quick study of Lindane reveals that its molecular structure is consists of a ‘ring of six carbon atoms’-each carbon atom has a chlorine and hydrogen bonded to it.

One distinguishing feature that makes this molecule fat soluble is carbon-chlorine bonding. The other distinguishing feature is its inertness.  One way to understand this phenomenon is to attempt to cite a familiar case: the case of DDT.

The Case of DDT (dichlorodiphenyltrichloroethane)

The case in point is DDT-although DDT may be described as an extreme case of environmental poison.

DDT was an effective tool in combating mosquitoes and their associated vectors. Unfortunately, however, in the mid-1960s, researchers found that DDT was leaching into the food chain. That discovery led the U.S. to ban the chemical completely.

Lindane and Synthetic Chemicals in the Environment

Lindane makes an unfortunate follow-up case study for the ways in which synthetic chemicals persist in the environment. For example, in the 2005 spill of the stored chemical near an industrial area in Italy, the beta-isomer leached into the water supply. Although the gamma-isomer is the principle ingredient in Lindane, the beta-isomer shows similar toxicity to humans.

beta structure of Lindane

Beta structure of Lindane. Image courtesy of the National Library of Medicine.

The Italian researchers recently published findings that are indicative of blood serum levels that exceeded recommended levels in the U.S. Follow-up studies are nervously awaited.

Lindane Use and Environmental Damage

Although the use of Lindane has diminished greatly from its peak during the 1960s and 1970s, the problem at hand is the damage that has already been done.

We find Lindane throughout the Earth’s biosphere, so much so, that it’s even in the ice in Antarctica.

At the current juncture, studies are questioning the links between Lindane and autism, its role as a carcinogen, and the damage that it does to the human reproductive cycle.

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