Water Purity
Around 1900, Seattle began discharging sewage into Lake Washington. During the 1940s and 1950s, eleven sewage treatment plants were sending state-of-the-art treated water into the lake at a rate of 20 million gallons per day. At the same time, phosphate-based detergents came into wide-use. The lake responded to the massive input of nutrients by developing unpleasant blooms of noxious blue-green algae. The water lost its clarity, the desirable fish populations declined, and masses of dead algae accumulated on the shores of the lake. After significant pollution, the October 5, 1963 issue of the Post Intelligencer referred to the lake as "Lake Stinko". Citizen concern led to the creation of a system that diverted the treatment-plant effluents into nearby Puget Sound, where tidal flushing would mix them with open-ocean water. The diversion was complete by 1968, and the lake responded quickly. The algal blooms diminished, the water regained its clarity, and by 1975, recovery was complete. Careful studies by a group of limnologists from the University of Washington showed that phosphate was the culprit. Since then, Lake Washington has undergone major improvements, drastically improving the ecology and water quality, making the water twice as clear as it was in 1950.
Read more about this topic: Lake Washington
Famous quotes containing the words water and/or purity:
“Before the land rose out of the ocean, and became dry land, chaos reigned; and between high and low water mark, where she is partially disrobed and rising, a sort of chaos reigns still, which only anomalous creatures can inhabit.”
—Henry David Thoreau (1817–1862)
“Who knows what sort of life would result if we attained to purity? If I knew so wise a man as could teach me purity I would go to seek him forthwith.”
—Henry David Thoreau (1817–1862)