4.1 Humans have paid a high price each time when exploitation was excessive, such as the destruction of the selenium ecology in the environment by high levels of sulfur dioxide due to acid rain generated by industrial pollution; the outbreak of “Atypia” caused by greedily eating game; the excessive forcing of birds' productivity (more than 10 methods including increasing illumination time to increase egg output by 3.4 times from 7.95 million tons in 1990 to 27 million tons in 2004 in our country), making birds lose their environmental selenium balance and finally leading to the outbreak of avian influenza. This situation has also endangered humans, and we have to employ a tremendous amount of manpower and material resources to catch and kill a great number of birds. Up to now, about 140 million birds have been killed, resulting in a direct loss of over 3000 (3 million?) US dollars. If human avian influenza breaks out, the cost is estimated to be 800 billion.
China is a large selenium deficiency country. Selenium supplementation of such a large scope can become a widespread practice only based on a macroscopic study. For example, the present selenium distribution map was drawn up in 1980. Since then, 25 years have passed, and our country has witnessed high-speed development, with the selenium level in the food chain having been greatly influenced by serious industrial pollution and the discharge of large amounts of sulfur dioxide. This situation will make selenium availability and utilization decline greatly. For example, the intake of selenium of the English has declined by a full half in 20 years and England is now also becoming a selenium deficiency country.
Our country was originally short of selenium, and with tremendous social changes for 25 years, selenium has been greatly expended. We should now survey our resources and prepare a new selenium distribution map for our country.
4.2 We should adhere to the principle of treating both the principal and secondary aspects of the disease.
On the one hand, we should treat the principal aspect by providing supplemental selenium to the people and birds urgently needing supplementation, and on the other hand, we should dramatically change the selenium composition of the soil by adopting selenium rich fertilizer, letting plants absorb and convert much more organic selenium and increase the selenium content in food for humans and birds to a higher level and eventually up to the standard of 200 mcg selenium daily for each person as proposed by WHO.
A survey of 13 provinces and cities shows that the average intake of selenium for each adult in our country is 26-32 mcg/day, equivalent only to half of 50 mcg/day proposed as a minimum by WHO. It can be thought, therefore, the intake of birds in our country is also very low.
Of course, it will be futile to apply selenium fertilizer if the discharge of sulfur dioxide is not effectively controlled, because it will make the plants unable to absorb the fertilizer. Therefore, it is of great importance to control and reduce industrial pollution.
Finland has been successful in this aspect, That country was seriously short of selenium. When it was found that its incidence and mortality of heart disease were significantly higher than that of high selenium countries and regions, the country promulgated a law to add selenium to soil that produces crop, fodder and grass. The measure has increased the intake of selenium for each Finn up to 90 mcg a day.