Risk Assessment of Abandoned Mine Soils by Physiological Growth Factor In Seedling Growth of Brassica Juncea and Raphanus Sativus.

Over the past 200 years emissions of toxic heavy metals have risen tremendously and significantly exceed those from natural sources for practically all metals. Heavy metal contaminated soil often presents an unacceptable risk to human and ecological health and needs to be evaluated in various toxicity tests. Risk assessment using plant toxicity, 'OECD guideline 208; Terrestrial Plant Test: Seedling Emergence and Seedling Growth Test^’, has been widely employed. Early seedling growth of Brassica juncea (indian mustard) and Raphanus sativus (radish) was monitored over 7 days. Germination Percentage (GP), shoot/root elongation (SE/RE), vegetation index (VI) and water content (WC) were measured as growth factors (GFs) to estimate plant response by heavy metal contaminated soils, and correlations among the GFs were stastically analyzed. 12 soils from abandoned mine sites in South Korea were collected and heavy metal contents were measured by Aqua Regia extraction methods. Soil Pollution Index (SPI) was calculated by measured heavy metal concentrations. Relationship between SPI and GFs were statically analyzed. As a result, As, Pb, and Zn were measured as abundant metals in the soils, and concentrations were 17-40,100 mg/kg, 27-10,047 mg/kg, and 148-3,470 mg/kg respectively. SPI was calculated as 0.13-39.77 in 12 soils. One-way ANOVA test for growth factors, B. juncea were numerously divided to subgroup which indicated more sensitivity. In Pearson correlation analysis, negative relationship between SPI and GFs was observed in B. juncea and R. sativus. GR the GFs, SE and RE were closely correlated in both plants, whereas, poor relationship between GR and RE, and GR and VI were observed in B. juncea, and R. sativus, respectively. It is likely that (i) 7 days monitoring using rapidly germinating plant is considerable as one of ecological risk assessment tools, (ii) More sensitive responses were observed in B. juncea (iii) GR and SE are useful growth factors to assess soil risk in B. juncea and R. sativus respectively. Further efforts are required to estimate bioavailability of heavy metals, and to characterize plant-toxicity symptoms by specific heavy metal.