sitemap | help
Click here to access to our stories featuring images from our collections and related materials ranging from Unusual takes, voices to biographies and more. Click here to find a feature debate and other debates related to some of our subjects and topics found with the READ section, please note, you need to be a registered user to participate in debates Click here to browse or search for images and related materials.  Alternatively use the advanced search for more detailed queries. Click here to create your own web galleries using our image collections or to personalise your experience within Ingenious.  Please note that you need to be a registered user to work with the CREATE tools.  Go to the 'Register' link to utilise Ingenious Create Tools Menu Log in Menu Search
Spacer image
Spacer image
save to my links [ + ]read caption
Topic section: Pesticides
Picture: lovelocks2embed.jpg
James Lovelock in the 1950s when he was at the National Institute for Medical Research at Mill Hill, North London.
Credit: Photograph courtesy of NIMR
The breakdown of civil society in Central Europe at the end of the Second World War produced a major outbreak of typhus, an often fatal disease spread by body lice. This posed a major threat to the Allied armies, as did mosquito-borne malaria on the Pacific front. Both diseases were brought under control by killing the insects that carry them with a powerful new insecticide called DDT.

In the mid-1940s, DDT and several other new insecticides appeared almost miraculous. They killed hosts of harmful insects by simple contact and were harmless to mammals in comparison to earlier insecticides such as arsenic and nicotine. For his development of DDT, Paul Müller of Geigy was awarded the Nobel Prize for Medicine in 1948.

By the late 1950s, however, there was growing concern about DDT entering foods and thereafter climbing up the food chain. Some shipments of fruit and dairy products were impounded by customs on suspicion of being contaminated with insecticides. Alarmingly, DDT was even detected in the body fat of native people in Alaska, thousands of miles away from the main centres of pesticide use. Even more worryingly some marine species appeared to be affected by DDT at levels below one part per million, the existing level of detection by chemical analysis.

Scientists have even discovered pollutants in the Greenland icecap
Combining the new technique of chromatography with very sensitive devices called detectors solved the problem of detecting tiny amounts of pesticides. One of these detectors, the electron-capture detector (ECD), was particularly good for measuring very low levels of DDT. By the end of the 1960s, DDT and similar pesticides could be detected quickly and reliably at a level of parts per trillion, the equivalent of four kilograms of DDT in the entire Mediterranean Sea.

Picture: 10438082s2embed.jpg
An early version of the electron capture detector built by James Lovelock, around 1960.
Credit: Science Museum/Science & Society Picture Library

Did this technological breakthrough make people more confident? Actually, no. Before the rise of DDT and the introduction of the ECD, the situation was simple. Existing techniques could only reliably measure pesticide residues in food down to a level of one part in a million (1 ppm). The authorities could act tough and set a ‘zero tolerance’ level, which in practice meant a level of 1 ppm, and everyone was happy, more or less.

Picture: 10315337s2embed.jpg

 'Monster Soup commonly called Thames Water being a correct representation of that precious stuff doled out to us!',1828.
Credit: Science Museum/Science & Society Picture Library


Once the new techniques made it possible to detect pesticides at a level a million times less than ever before, the concept of zero tolerance vanished. People began to worry more about pesticides as they were discovered in numerous places – including baby food, mother’s milk and schoolyards – even though the concentrations were extremely low. Using yet more sensitive chemical techniques, scientists have even discovered pollutants in the Greenland icecap.

The controversy over Alar, a fruit-ripening agent, illustrates the public disquiet over chemical residues on food. It is an emotional topic that is difficult to debate rationally – particularly for parents. As a society, we are still developing ways of coming to terms with these risks, however small they may be.

Spacer image

Spacer image
Topic section: Radioactivity
Spacer image
Even after Hiroshima, there was little public anxiety about radioactivity. Luminous watch faces and instrument dials did not cause any concern, and even scientists took few precautions. The situation changed after the first H-bomb tests in the mid-1950s, and nuclear fallout became a major political issue.  > more

Spacer image
Topic section: CFCs and the ozone layer
Spacer image
CFCs were the first high-tech gases, used in the 1950s to make domestic fridges and aerosol sprays, the symbols of a new way of life. Considered to be completely harmless chemicals, CFCs were beginning to wreak severe damage to the fragile ozone layer that protects the Earth. And no-one had the faintest inkling that this was happening  > more
Click here to print this page in a printer friendly format  > Printer friendly version > Back to top
© NMSI. All rights reserved. | terms of use | sitemap | contact us | accessibility | privacy | who we are
Spacer image
Spacer image
Read More
Please click here to explore this topic further and to access our our stories featuring images from our collections and related materials ranging from Unusual takes, voices to biographies and more.
If your browser is not javascript enabled then click here to Read More. To learn how to javascript enable your browser click here.
  right arrow Voices - of people involved
  right arrow Unusual Takes - the unexpected angle

See caption
Click here to see images related to this section
Related to: