Whether naturally occurring or man made, throughout history we have made many discoveries that have helped us for the better. However, over time it has become apparent that some of these finds and inventions were not as helpful as we initially thought and some have proved fatal. Here we look at four examples of potentially deadly discoveries.
The nausea and vomiting associated with morning sickness can take away the enjoyment of early pregnancy. It seemed that this might be a thing of the past though with the development of thalidomide, which was found to be an effective treatment for morning sickness. However, its use for this purpose was withdrawn in 1962, as it was quickly found to cause birth defects such as shortened limbs. It is still in use though as a treatment for cancer of the bone marrow and for skin lesions as a result of leprosy; research is ongoing for its potential in the management of a number of inflammatory conditions.
Although it is not exactly clear when mercury was discovered, this liquid metal has been found in Egyptian tombs dating back to 1500BC. It is thought that as in ancient Chinese medicine, the Egyptians believed mercury had health giving properties and could prolong life. There is documented use of mercury from past centuries in ointments to treat skin conditions and to heal broken bones, and until the twentieth century it was used as a treatment for syphilis; though whether it actually helped with regard to this is unclear, as a proportion of cases are cured without any intervention. While mercury ores are still used in Chinese medicine and derivatives in dental fillings, vaccine preparations and antiseptics, mercury itself is now known to be toxic, causing damage to the brain, kidney and lungs; if treated early enough the damage is reversible, though the effects are most damaging in young children. The safety of its use in Chinese medicine is questionable and while the link between vaccines containing mercury and autism has not been proven, its use in childhood vaccines has now been discontinued. Its use in thermometers though is perfectly safe.
Asbestos has been in use for over 2000 years. First used by the Greeks in cloths, its popularity declined from the medieval era. However, with the Industrial Revolution asbestos proved very useful owing to its heat resistant and noncorrosive properties, being used to insulate kilns, boilers, pipes and turbines. Then early in the twentieth century, suspicions arose around the safety of asbestos, as it was noted the higher than expected lung problems and premature deaths in those working and living in towns where asbestos was mined. The name asbestosis was coined in 1924 and refers to the inflammation of the lungs due to irritation by asbestos fibres, which is accompanied by a cough and difficulty breathing. In the 1930s laws were introduced for the need for adequate ventilation for those working with asbestos and in the same period the link between asbestos exposure and cancer risk came to light; asbestos is a causative factor of mesothelioma, where the fibres cause changes within the cells lining the lungs and other organs. As a result of mounting evidence for the damaging effects of asbestos on health, the disposal of asbestos is tightly controlled and in 60 countries its use has been fully or partially banned.
Widely grown in the humid tropics, cassava plants are one of the best sources of affordable carbohydrate on the planet and can grow well even in poor quality soils. However, this starchy root vegetable can potentially be deadly if it isn’t correctly prepared. Cassava contains a substance similar to sugar called linamarin, but which has deadly cyanide attached to it; eating just a small amount of poorly prepared cassava root can prove fatal, as the cyanide interferes with respiration, the process required to keep all body cells alive. In smaller doses the toxin can cause damage to the brain, liver and kidneys. To avoid the risk of poisoning the cassava need to be peeled and soaked prior to being well cooked by baking, boiling or roasting.
This is a Guest Post by Jessica.