Environmental Engineering Reference
In-Depth Information
battery production, chemicals and the like are the main industrial sources of heavy
metals. Emissions in those sectors increase the zinc and lead content of soil around
factories on average to 3,000 mg/kg. Other main sources of urban heavy metal soil
pollution are motor vehicle exhaust and tire additives.
Furthermore, Chinese aquatic heavy metal pollution is very serious. The heavy
metal pollution ratio in more than 80 % of lakes and rivers is high. A survey shows
that the heavy metal pollutants brought by the Yangtze River, the Pearl River and
the Yellow River total about 341,000 t, which causes enormous damage to oceans.
Samples of near-shore waters show that the over-proof ratio is about 62.9 %, and in
the worst cases, the heavy metal content is roughly 49 times the Level I standard.
The over-proof ratio of copper is 25.9 %, and there is also a high concentration of
mercury and cadmium [
15
].
For these reasons, the Chinese government has set aside money to strengthen the
preventive treatment of heavy metal pollution. In 2010, the special fund for the
preventive treatment of heavy metal pollution totaled about 1 billion yuan, and this
money was mainly used to support the comprehensive cleanup of lead, mercury,
cadmium and chromium in enterprises as well as the development of clean produc-
tion processes and a demonstration and promotion program of new technology.
6.6.2.2 Tighten Control on Pesticide Contamination and Organic
Pollution
At present, pesticide use in our country has reached 1.3 million tons, which is
2.5 times the world average level. The amount of polluted arable soil reached has
1.36 hundred million tons. Film usage has reached 6.3 million tons, which has led
to serious plastic pollution. Animal husbandry in our country has also rapidly
developed, and the number of domestic animals has doubled or tripled every
10 years. In recent years, the excrement of animals has grown to 3.8 times the
amount of industrial solid wastes.
In the main producing areas, the quantity of excrement and waste often exceeds a
safe level several times over, causing serious soil pollution from heavy metals,
antibiotics, hormones or other organic materials.
6.6.3 Problems in Soil Pollution Disposal
The complications involved in the disposal of polluted soil are becoming more
serious. An environmental quality investigation of a typical area will show that
there are varying degrees of declines in soil quality in the areas surrounding the
Pearl River Delta, the Yangtze River Delta and the Bohai Ring.
Soil contamination and high risks exist in heavily polluted areas, areas where
industries are clustered, and industrial mining regions and surrounding areas, which
includes urban and suburban areas. For example, places with a high concentration
of metal mines, smelters or e-waste recycling plants often have correspondingly
high levels of cadmium, mercury, lead and arsenic. The varying types of soil
