Health risk assessment for uranium in Korean groundwater

We analyzed the radiological and chemical risks of uranium in groundwater. The total sample number over 4 years was 498. There were several use patterns of groundwater in Korea, but we considered the risk only for drinking water. The geometric mean of uranium concentration in 10 areas in Korea was 0.17 microg x l(-1). The excess cancer risks were in the 10(-7) level in the radiological risk aspect and the hazard quotient was 0.005 in the chemical risk aspect. Therefore, we could conclude that an adverse health risk is unlikely to be posed due to exposure to uranium. However, the concentration of uranium must be monitored periodically and adequate action taken in the few and small areas that contain high uranium levels in groundwater.     

Leaching characteristics of heavy metals from sewage sludge by Acidithiobacillus thiooxidans MET

An acidophilic, sulfur-oxidizing Acidithiobacillus thiooxidans MET bacterium was isolated from anaerobically digested, dewatered sewage sludge. This bacterium showed sulfur-oxidizing ability at both acidic and neutral conditions, and allowed metal leaching even at a high (130 g L(-1)) sludge solids concentration. We found that low metal leaching efficiency at high solids concentration was mainly due to an increase in buffering capacity resulting in retardation of pH reduction. Therefore, metal leaching was mainly influenced not by sludge solids concentration, but by the pH (or sulfate concentration per unit sludge mass) of the sludge solutions. The relationship between the pH of the sludge solution and the efficiency of metal leaching was obtained by quantitatively investigating the effect of pH reduction or the amount of sulfate produced per unit sludge mass on leaching of each metal. Furthermore, the relationship between total metal content in the sludge and metal leached to the solution was obtained for each metal. Such a relationship allowed estimation of leachable metal at various amounts of total metal content in sludge.     

Effects of adding slags on strength and leaching properties of soft soil

Journal of Material Cycles and Waste Management - Dredged soils are typically mixed with additives to improve their mechanical properties and reduce the risks of leaching toxic elements. An...     

Impact of aquaculture on distribution of dissolved organic matter in coastal Jeju Island,Korea, based on absorption and fluorescence spectroscopy

Environmental Science and Pollution Research - In Jeju Island, multiple land-based aquafarms were fully operational along most coastal region. However, the effect of effluent on distribution and...