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| | nabarralde.com |
 | | The basins of the rivers Oiartzun, Artibai, Deba, Bidasoa, Urumea, Uroa, Oria, Oka, Barbadun, Butron, Lea, Urola and Nervion are polluted, according to a report of the regional government of Baskongadak's Environment Department released this week. |
 | | The land area drained by rivers and its tributaries, known as a river basin, is the basic unit for understanding the sources and effects of freshwater pollution as well as the ecological relationships between terrestial and aquatic systems. |
 | | Eventually, some of the water may enter tributary streams and rivers, into which a third source of pollution, sewage and industrial wastewater, is discharged directly. |
| www.nabarralde.com /npapers/npapers_riverba.html (1279 words) |
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