• Korean Journal of Ecology and Environment
• /
• v.41 no.2
• /
• pp.188-197
• /
• 2008

This research was a preliminary case study to determine the levels of total mercury in the tissues of sentinel species (Zacco platypus) and ecological health in relation to habitat characteristics and chemical conditions. We collected fishes in Gap Stream during June$\sim$October 2007 and analyzed the total mercury from five types of tissues such as liver, kidney, gill, vertebrae and muscle of Zaceo platypus using Direct Mercury Analyzer (DMA-80, US EPA Method 7473). Mean concentrations of total [Hg], based on all tissues, was 67.2 and $20.7\;{\mu}g\;kg^{-1}$, in the upstream and downstream site, respectively, indicating 3 times greater level in the upstream. In other words, the levels were higher in the pristine upstream than the downstream influenced by the wastewater disposal plant. Chemical water quality, based on BOD, COD and nutrients (TN, TP) showed that severe degradation occurred in the downstreams than the upstreams. Index of Biological Integrity (IBI) using fish multi-metric model averaged 32, indicating a "good$\sim$fair" condition and varied from 42 (excellent$\sim$good) at S2 to 22 (fair$\sim$poor) at S5 depending on the sites sampled. Qualitative Habitat Evaluation Index (QHEI) in the all sites averaged 142, which was judged as "good" habitat health, but showed a high variation (181 in Site 2 vs. 67 in Site 5). Overall data suggest that health conditions, based on IBI and QHEI, was better in the upstream sites but the mercury bioaccumulation levels in the fish tissues were opposite. We believe that measurements of various parameters are required for a diagnosis of integrative ecosystem health.

• Korean Journal of Soil Science and Fertilizer
• /
• v.29 no.3
• /
• pp.226-235
• /
• 1996

This pot experiment was conducted to investigate the changes of leaching in percolated water of paddy soil in which rice was cultivated in conditions of 0%, 5%. 30% addition of bituminous and anthracite fly ash respectively in greenhouse. pH in percolated water was higher in non cultivated plot than in cultivated plot. pH of the fly ash treated plot was higher than that of the control plot. pH in the cultivated plot decreased gradually during the cultivation. The contents of $NH_4-N$, $NO_3-N$ and K in percolated water decreased rapidly after mid-July, and was very low in the cultivated plot. Over the cultivation time, P contents in percolated water was very low. $SiO_2$, contents in percolated water decreased rapidly after June. Na contents in percolated water was highest in mid-June and then decreased gradually. In the cultivated plot, Ca contents in percolated water was higher than that in the control plot. During the cultivation, Ca contents in percolated water decreased gradually. But, in later-term of cultivation. Ca contents in percolated water was relatively Mgh. Mg contents in percolated water decreased after mid-July, but decreased continuously till the later-term of cultivation. EC in the percolated water was highest in mid-June. and then decreased gradually. EC of fly ash treated plot was higher than that of the control plot. The soil pH was increased and phosphate content in the soil was accumulated very high by application of fly ashes in paddy field after rice cultivation. Fly ash treatment did not increase the contents of elements in percolated water compared with the control plot. The difference between anthracite and bituminous fly ash was not so clear. Fly ash treatment, inhibited early growth and tillering. But, in later-term of cultivation, the inhibition effects of nonproductive tillering was expected. Fly ash treatment will be good if it was applicated after last year's harvest because leaching would happen over fallowing time. Contents of inorganic elements in percolated water of fly ash treated plot was not so high compared with that in the control plot.