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Accession number;03A0178546
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| Title;Herbicide Loadings from Paddy Fields and Purification Effect in Lagoon. Experiments in Ekainuma lagoon basin. |
| Author;
SUDO MIKI
(Univ. Shiga Prefecture, School of Enviromental Sci., JPN)
OKUBO TAKUYA
(Lake Biwa Res. Inst., JPN)
KUNIMATSU TAKAO
(Univ. Shiga Prefecture, School of Enviromental Sci., JPN)
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Journal Title;Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering
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Journal Code:S0345A
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ISSN:0387-2335
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VOL.;NO.223;PAGE.71-77(2003)
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| Figure&Table&Reference;FIG.3, TBL.4, REF.18 |
| Pub. Country;Japan |
| Language;Japanese |
| Abstract;The concentrations and loading rates of herbicide(simetryn and mefenacet) were investigated in Ekainuma lagoon basin at Lake Biwa. The concentrations increased during the application period and during a rainfall event occurring immediately after the application. The herbicides were almost undetectable after two months of the application period. The losses of simetryn and mefenacet from the paddy fields in the lagoon basin were estimated to be 24.9% and 10.2% respectively between April and September in 1998. The purification of herbicide loading(simetryn and molinate) in the lagoon was also estimated between May and August in 2000. The high concentration of herbicide in the inflow water caused by the application or the rainfall event was decreased to a lower level at the lagoon outlet. After the application period the concentration of herbicide in the inflow decreased, and it was often exceeded by that in the outflow. The mass balance of simetryn and molinate during the observation period, when water retention time calculated on an average flow rate at the outlet and pondage of the lagoon was about 65 hours, showed that substantial purification of these herbicides in the lagoon did not occur. (author abst.) |
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