30. Radiation hormesis and Plutonium.

This “most toxic substance on earth” is one trillion times less toxic than the

botulinum toxins. Low doses of plutonium reduce lung cancer death rates, it should be considered a benign environmental agent. To provide a standard for persons who might be exposed to plutonium in the manufacture of atomic bombs, 17 “terminally ill” patients were intravenously injected with 95 to 400 nCi of 239Pu (some received the +4 citrate and some the +6 nitrate) between April 1945 and July 1947.[23] None who lived longer than nine months died with cancer. Four lived with their plutonium 30- 44 years. Another received 3.5 μCi of 238Pu; his lifetime dose was 64 Sv. He lived with plutonium 21 years before dying of heart disease. This is evidence that low doses of plutonium are not carcinogenic.

31. Radium effects in the theory of hormesis

Early investigators knew that excessive exposures to micrograms of radium caused

erythema and burns. These could eventually become cancers. However, they learned both low doses and high doses were therapeutic. Radium dial painting appeared to increase average life-span. Many physicians used radium extensively in medicine.

32. Radon effects in the theory of hormesis

Radon and lung cancer have usurped the public fear previously held for genetic monsters produced by external radiation. The predicted genetic monsters did not appear and increased chromosomal aberrations were not found in Japanese exposed to low-dose irradiation from atomic bombs. There is good evidence for radiation hormesis in reproducetion and life-span in these survivors. Now

there is strong evidence that indicates radon reduces lung cancer deaths.

33. Human ecology (definition)

Human ecology is the subdiscipline of ecology that focuses on humans. More broadly, it is an interdisciplinary and transdisciplinary study of the relationship between humans and their natural, social, and built environments. Human ecology is the study of the human and its interactions with its surroundings. It recognises that organisms both change their surroundings and are changed by their surrounding. A human ecology approach might highlight the mutual change that has taken place. That we can't create trees or sheep, but that we can alter the breeds of sheep that we farm. We can also selectively breed sheep to produce new breeds. Breeds that have different taste or fat content. Breeds that require special feeds or chemicals to keep down pests. In these ways, sheep change the habits and metabolisms of those humans that farm or eat them

34. The main human impact on the theory of hormesis.

Human impact on the environment or anthropogenic impact on the environment includes impacts on biophysical environments, biodiversity and other resources. The term anthropogenic designates an effect or object resulting from human activity.Natural environment is of crucial importance for social and economic life. We use the living world as

a resource for food supply

an energy source

a source for recreation

a major source of medicines

natural resources for industrial products

Almost all forms of industry have an impact on the natural environment and its sustainability. Transport is perhaps the major contributor to pollution in the world today, particularly global envi- ronmental issues such as the greenhouse effect. The principle environmental impact associated with fisheries activities is the unsustainable har- vesting of fish stocks and shellfish and has consequences for the ecological balance of the aquatic environment.

All energy types have potential impacts on the natural environment to varying degrees at all stages of use, from extraction through processing to end use. Generating energy from any source involves making the choices between impacts and how far those impacts can be tolerated at the local and global scale. This is especially of importance for nuclear power, where there are significant risks of radioactive pollution such as at Chernobyl