Abstract: Soil pollution of chromium slag heads has become an important environmental issue, and more and more attention has paid to the topic. In order to have
 a more detailed understanding of this pollution, two basic soil pollution processes, i.e., horizontal and vertical migration of chromium, as well the related a
ffecting factors, including soil organic matter, pH, Eh, water capacity, soil type, composition of soil inorganic colloids, and flowing direction of groundwater
, were analyzed. Meanwhile, the research progress on the identification and screening-out of chromium hyperaccumulators, accumulation mechanisms of chromium hyperaccumulators, and phytoremediation of contaminated soils around chromium slag heads and its mechanisms were summarized. It was considered that the use of chromium hyperaccumulators to remediate the contaminated sites of chromium slag heads would have a wide prospect, though the phytoremediation of chromiumcontaminated soils is still at its initial stage.

Key words: Watermelon, Grafting seedling, Chilling tolerance, Protective system against active oxygen