Water Quality
Periodically the sewerage systems of Paris experience a failure known as sanitary sewer overflow, often in periods of high rainfall. Under these conditions untreated sewage has been discharged into the Seine. The resulting oxygen deficit is principally caused by allochthonous bacteria larger than one micrometre in size. The specific activity of these sewage bacteria is typically three to four times greater than that of the autochthonous (background) bacterial population. Heavy metal concentrations in the Seine are relatively high. The pH level of the Seine at Pont Neuf has been measured to be 8.46. Despite this, the water quality has still improved, with several historians having called it at various times in the past as an "open sewer".
In 2009, it was announced that Atlantic salmon had returned to the Seine.
Read more about this topic: Seine
Famous quotes containing the words water and/or quality:
“When peaceful clouds were reflected in the paddies
and the water buffalo stepped surely along terraces,
maybe fathers told their sons old tales.
When bombs smashed those mirrors
there was time only to scream.”
—Denise Levertov (b. 1923)
“If behind the erratic gunfire of the press the author felt that there was another kind of criticism, the opinion of people reading for the love of reading, slowly and unprofessionally, and judging with great sympathy and yet with great severity, might this not improve the quality of his work? And if by our means books were to become stronger, richer, and more varied, that would be an end worth reaching.”
—Virginia Woolf (1882–1941)