Eight Plant Species for Phytoremediating Diesel-Contaminated Soils in Japan

Japanese researchers have determined that eight plant species have potential use for phytoremediation of diesel-contaminated soils in the country. These plants are Italian ryegrass, sorghum, maize, alfalfa, Bermuda grass, rice, and the weeds kudzu, and beggar ticks.

Diesel-contaminated soils have become a civic problem in Japan, say Etsuko Kaimi and colleagues. The researchers studied a total of 12 representative plants from known phytoremediators, hydrocarbon-tolerant plants, crops, and weeds. The authors determined the capabilities of the plants in reducing the total petroleum hydrocarbon (TPH) in soils contaminated with 2% (w/w) diesel oil, and they measured the level of soil dehydrogenase activity (DHA), an indicator of degradation activity by microorganisms in the soil.

The observed reduction in TPH was explained by Kaimi and co-authors to be the result of rhizosphere microbial activity. This was supported by the strong correlation between TPH and DHA. The researchers stated that the fibrous root systems of the plants allowed the close interaction between the rhizosphere and the contaminant.

The paper published by the journal Plant Production Science can be downloaded at http://www.jstage.jst.go.jp/article/pps/10/2/211/_pdf.