Nannophya pygmaea (commonly known as the scarlet dwarf dragonfly) was designated as an endangered species, level II, by the Ministry of Environment of Korea in 1994; it has been used as a flagship species for the protection and preservation of wetlands. Over 25 sites in Korea have been identified as the habitat of Nannophya pygmaea. However, most of these habitats have proven to be unstable, and there have been subsequent changes in the assemblage structure and organization. Most habitats changed to become grasslands or plain ground, and now only five habitats remain. Although efforts have been made to protect the Nannophya pygmaea as an endangered species, their habitat loss has increased, caused by natural succession and drought. Therefore, we need to make stronger protections in the preservation manual of level II endangered species, particularly Nannophya pygmaea, and its native habitats in Korea.

The removal characteristics of total petroleum hydrocarbons (TPHs) and heavy metals in contaminated soils with ultrasonic washing have been studied. The ultrasonic washing was evaluated on a laboratory scale. In this investigation, the effects of factors such as ultrasonic frequency, power intensity, duration of irradiation, contents of the TPHs and heavy metals and mixing ratios between the contaminated soils and water, were considered. Experimental results suggested that the rates for contaminant extraction of the TPHs and heavy metals in the contaminated soil increased considerably with the ultrasonic washing. Therefore, the ultrasonic washing has previously been to be an effective method to remediate the contaminated soils with the TPHs and heavy metals.