ABSTRACT
As far as the impact of environmental pollution is concerned, heavy metals are known to be the most harmful. Once heavy metals enter the environment, they are very difficult to remove. To develop countermeasures against pollution by heavy metals in soils, studies have also been made on heavy metal elements and rare earth elements. The environmental background values of elements in the major soils of China largely correspond to those in soils of the contiguous United States, Japan, and the United Kingdom, being consistent with them at quantitative levels. In general, to work out the criteria of soil environmental quality, both the background values of the soil and the ecological effect should be taken into account. The heavy metal ions in soil solution form the active fraction, which is very important both for plant trace nutrition and for environmental protection. Metal elements dissolving in soil solutions are an important way of element migration into the water environment.
