Abstract
Recently, soil contamination resulting from marine sediments has been reported to occur in many sites of Japan. Marine sediments containing framboidal pyrite (FeS2) cause the soil to gradually become acidic owing to long-term atmospheric weathering; subsequently, various harmful heavy metals such as lead, cadmium, and arsenic are leached into the environment. In this study, low-cost, environment-friendly countermeasures against the risk of long-term contamination of heavy metals in marine sediments containing natural alkaline materials (pieces of scallop shell) were developed. The shell pieces were effectively suppressed the oxidation of pyrite even in atmosphere, upon adding more than 2.5 wt% shell pieces to the marine sediments. This technique can not only prevent the acidification of the soil caused by the oxidation of pyrite to sulfuric acid but can also retain the chemical forms of arsenic and cadmium in marine sediments in the residual state. Therefore, the risk of arsenic and cadmium leaching into the environment can be greatly reduced.
