Humankind Under Threat of Geochemical Hazards: Scientist

A Chinese scientist has warned that human beings may be threatened by outbreaks of geochemical hazards if they fail to control the amount of harmful materials released into the soil.

Geochemical hazards have been called "chemical time bombs" by some European scientists because they may suddenly burst forth due to the long-term accumulation of harmful materials in the earth, causing massive damage to agricultural production and people's health.

"Unfortunately, the severe aftermath of the 'bomb explosion' is often underestimated," said Prof. Xie Xuejin, a scholar with the Chinese Academy of Sciences (CAS), China's top scientific think tank. "People care more about clean water and sky, thinking that's all there is to a good environment."

Human beings have discarded waste and chemical materials into the earth since the Bronze Age, especially during the European Industrial Revolution that started in the 1760s.

Although modern agricultural technology has helped to dramatically increase the grain output, an enormous amount of pesticides and fertilizer have been left in the soil, Xie said. "Few people have realized that the heavily-polluted earth may take its 'revenge' if human beings put too many hazardous things into it," said the geochemical researcher.

In Europe, which has a long history of industrialization, 15 percent of cultivated land is no longer arable or even cannot be restored with modern technology due to serious pollution, Xie said today at a CAS symposium.

"China could suffer even more severe geochemical hazards than Europe, even though its industrial history is much shorter, because environmental pollution is getting worse quickly," he warned, blaming the country's mushrooming township enterprises with poor pollution-control measures as a major source of pollution.

Environmental monitoring in east China has revealed that the amounts of mercury, phosphorous, lead, sulfur and pesticides such as DDT contained in the soil have risen over the past decades.

The scientist noted that the fight against geochemical hazards would be long-term. Control measures include forming a multi-level monitoring system in big cities, mines, and along major rivers.

Scientists want to imitate the self-cleaning process of nature.

Under the European Union's McSharry Program, 15 percent of cultivated land in EU will be turned into afforestation zones by the year 2010. It is believed that by adding limestone to the soil to prevent soil acidification, 40 percent of the harmful elements in the soil will disappear after 85 years.

And plants can be used to absorb dangerous chemical materials and metals. Plant roots will prevent pollutants on the earth's surface from sinking deeper into the soil and likely polluting underground water.

China's Ministry of Science and Technology has set up a pollution monitoring system targeting the air, the water and the soil in Beijing, aiming to create a model for pollution control in other Chinese cities.

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