i find this rather interesting to read …
http://www.abc.net.au/science/articles/ … 184037.htm
Recently I was browsing in a shop for a perfumed candle. The sales assistant came up and started assuring me that the candle was made entirely from natural ingredients, and contained no chemicals.
In reply, I asked her whether she had ever thought about what those natural ingredients were, and whether they might also be chemical compounds?
This was obviously not a fair question, but the whole conversation made me wonder why, in the view of the general public, substances which are ‘natural’ and those which are ‘chemical’ are seen as two different things. The former seems to stand for something positive, things that are healthy, mild or ‘good for the environment’, whereas the latter (chemicals) are often viewed as the opposite: toxic, dangerous, or unhealthy.
Why is there such a large discrepancy between the daily, ubiquitous use of chemical compounds and their public image?
A common definition of a chemical compound is ‘any substance composed of identical molecules consisting of atoms of two or more chemical elements’.
We are surrounded by chemical compounds, both in and out of the lab. Apples for example, contain sugars (carbohydrates), vitamin C (an antioxidant), malic acid (which contributes to the sourness of green apples), and ethyl 2-methylbutanoate, which creates that delicious apple odour.
All these are naturally occurring chemical compounds made up of carbon ©, hydrogen (H) and oxygen (O). These same elements (and others) are also present in many man-made materials such as synthetic fibres, plastics, rubber, perfumes, fertilisers, preservatives and, not least, pharmaceutical drugs.
Of course, our negative view of chemicals is influenced by the fact that some are used in dangerous man-made materials such as Agent Orange, DDT and napalm. Other manufactured chemicals are responsible for environmental problems, for example air pollution and the ozone hole.
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Nature not always safe
But nature can produce dangerous chemical compounds too! The sea wasp from Northern Australian, for example, is the most lethal jellyfish in the world. The venom from a single animal could kill about 60 adult humans.
The fungus Aspergillus flavus, which contaminate grains, produces aflatoxins which are among the most carcinogenic substances known.
The bacterium Chlostridium botulinum produces the botulinum toxin, the most powerful and dangerous neurotoxin known (and a benign version of which is injected in cosmetic Botox procedures)
But while most of us would agree we want synthetic drugs to treat cancer, HIV, dementia and Parkinson’s disease, we get far more emotional about including chemicals in our daily life, such as in food and beverages, skin care products and cosmetics.
But what is the actual difference between ‘natural’ and ‘chemical’?
In foods, for example, there are several kinds of flavourings. One type is the group known as natural flavours, which are extracted directly from plants or animals. Another are so-called nature-identical flavours. While these compounds are made by chemical synthesis, their molecular structure is identical to natural flavours. This means both have the same taste, colour, odour and feel.
In contrast, artificial flavouring substances (such as the sweeteners aspartame and sorbitol) are not identical to natural flavouring substances. They are derived by chemical modification of naturally occurring compounds, or are even synthesized from raw materials such as crude oil or coal tar.
It has been suggested that these artificial flavours may be safer to consume than natural flavours. This is because natural flavours can contain impurities, whereas synthetic flavours must pass certain standards of purity and consistency, and are also tested before being approved for human consumption.
Perfumes may also contain either natural, nature-identical and artificial fragrances. A synthetic version of the 'real thing is commonly used if natural sources are hard to come by.
Interestingly, synthetic fragrances are often considered less harmful to some people than natural aromatics. This is because synthetic fragrances consist primarily of one chemical compound, whereas a fragrance derived from nature may contain thousands of different chemical compounds at very low concentrations. Such a cocktail of unknown chemicals, which are often not tested, poses the risk of causing allergies.
So next time you’re shopping for a fragrant candle, remember that ‘natural things’ contain chemicals too. I believe we should not demonise synthetically-derived chemical compounds. It would be more useful to classify chemical compounds according to their use, such as fragrances, herbicides, flavourings, paint pigments, etc, and remember that all these can be obtained from both natural and synthetic sources.