PARENT SESSION
Poster Session 30: Invertebrate Ecology
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Hazard Assessment of Organic Waste-Contaminated Soil using Earthworm.
Na, Young Eun*,1, Bang, Hea Son1, Han, Min Su1, Ahn, Young Joon2, 1 National Institute of Agricultural Science and Technology, RDA, Suwon, Rep.of Korea2 School of Agricultural Biotechnology, Seoul National University, Seoul, Rep.of Korea
ABSTRACT- The hazardous effects of organic wastes on soil contamination were assessed by investigating earthworm ecotoxicity in lysimeter. Four types wastes [municipal sewage sludge (MSS), industrial sewage sludge (ISS), leather processing sludge (LPS), and alcohol fermentation processing sludge (AFPS)] along with the standard pig manure compost (PMC) were applied and mixed to 15 cm in depth of soil. The appropriate amounts of waste (12.5 t, 25 t, and 50 t dry matter ha-1 yr-1) were treated every year from 1994 to 2001. Heavy metal contents, residual organic compounds, and earthworm numbers were determined. The residual content of copper was the highest in ISS soil regardless of treatment amount. The copper contents in soil samples treated with 12.5, 25, and 50 tons of test materials were 3.9, 7.3, and 10.9 times higher than the threshold level (50 mg kg-1) respectively. The contents of chromium in ISS and LPS soil were 2 to 7 times higher than threshold level (4 mg kg-1). Amounts of HEM (hexane extractable materials) in the soil treated with MSS, ISS, LPS, and AFPS were 3.2, 15.7, 5.1, and 3.8 times higher than that of PMC (79.4 mg kg-1), respectively. The number of earthworms collected in the plots of ISS and LPS was decreased according to the increase in the treatment level of organic wastes in both fourth and eighth year. Despite increase in the number of earthworms in MSS and AFPS by fourth year, the number was decreased next 4 years. Of the five treatments, plots treated with PMC maintained the highest number of earthworms for eight years. In fourth year, total 115 earthworms collected from 36 plots treated with four organic wastes, MSS, ISS, LPS, and AFPS were classified into 4 species. In 9 plots treated with PMC, a total of 127 earthworms collected was composed of 5 species. However, in eighth year, earthworms were identified to 3 species from 43 individuals collected at 36 plots of four organic wastes. At 9 plots of only PMC 439 individuals of earthworms were catched and identified as 5 species. A relationship between the effects of the total toxic unit of PTEs and the amounts of HEMs on earthworm number was examined. The numbers of earthworms were negatively correlated with the total toxic unit of PTEs (r = -0.63) and HEMs (r = -0.60) for wastes, but were positively correlated with total toxic unit of PTEs (r = 0.99) and HEMs (r = 0.46) for manure compost.
Key words: Earthworm, PTEs(potentially toxic elements), HEMs(hexane extractable materials)