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tion; and burying garbage, or land fill tech- niques, raises questions about future soil and water pollution. Water pollution, the most visible of all types of pollution, was the first to attract public con- cern. The green slime, foam along riverbanks, and dead fish called attention to the growing problem of water pollution. Water is considered polluted when it consti- tutes a health hazard or when its usefulness for a particular purpose is impaired. Although no water exists in an absolutely pure state, the danger level varies from case to case according to the purpose for which the water is intended. For example, water that is unfit for human consumption may be suitable for industrial purposes, or vice versa. In the case of electric utilities, most of the minerals required in water for human consumption must be removed to prevent corroding the inside of the large boil- ers they use. The major sources of water pollution are classified as fOIIOWs: municipal, manufactur- ing, mining, steam electric power cooling. and agriculture. Last summer, in August, the Federal De- partment of Health and Welfare conducted a survey on municipal sewage treatment in 19 major Canadian cities. It found that only 9 out of the 19 cities had 100 percent treatment of their sewage and other waste water. In Ontar- io. the only major centers treating 100 percent of their waste water were Toronto. Ottawa. Hamilton, Sudbury and London. A study on pollution in the Great Lakes reâ€" leased in September, 1969, was completed by the International Joint Commission after four years of study. It pinpointed the sources and quantities of pollutants, evaluated their contriâ€" bution to deteriorating water quality and sug- gested remedial measures. One of the key problems is the quantity of phosphorus pumped into the lakes through municipal sysâ€" tems. The report stated that. “50 to 70 percent of the total input of phosphorus from all mu- nicipal and industrial wastes in the lower Great Lakes came from detergents.” This isan area where homemakers Can make a signin- cant contribution to pollution control. Nutrients such as the phosphates found in detergents, and the nitrogen from such prod» ucts as fertilizer, accelerate the aging of lakes by stimulating growth of algae. These algae gradually use up all the oxygen in the water and. as the oxygen disappears, the destrable species of aquatic life die. Finally, when the entire supply of oxygen is taken out of the wt» ter it becomes a dead body of Water. Several major laundry detergents were reâ€" cently analyzed at laboratories at the UanCI'SI- ty of Toronto. The results were released by SUMMER 1970 Pollution Probe. an organization associated with the University of Toronto. to fight pollu- tion, There is an amazing variation in the phosphate content among popular brands of heavy duty laundry detergents. The widely ad- vertised enzyme-active pre-soak products are very high in phosphate content. as are auto- matic dishwasher compounds. However. all liquid dish detergents tested contained less than 1 percent of phosphate. The most common pollutants in domestic sewage are easily handled by well-known and tested techniques â€" sedimentation. oxidation and chlorination. However, industrial wastes are a more complicated problem. since many industrial chemicals are unaffected by ordi- nary sewage treatment. One of the [host diffiâ€" cult to treat is whey. a by-product of the cheese industry. Generally speaking. the nature of air politi- tion. is similar to that of water pollution. The impurities introduced into either air or water are not absorbed adequately or rapidly enough. Polluted air contains substances. gases or radiations which make the air injurious to humans. animals. crops or property. Air pollution‘s major effect on health ap- pears to be respiratory problems. in the opinâ€" ion of many medical experts. air pollution can contribute to the frequency of lung cancer, emphysema. chronic bronchitis and asthma. All chronic respiratory diseases involve stress on the heart since the heart must work harder to compensate for the lack of oxygen absorp- tion. However. an eminent United Kingdom medical specialist. at a recent Toronto confer- ence, pointed out that air pollution‘s ready vic- tims are generally those who already have long. or other physical weaknesses. Air pollution is concentrated in higth in- dustrialized. or highly populated centers. Since you are visiting Toronto, I thought you might be interested in knowing about the air pollu‘ tion situation here. The importance of the fig- ures I am going to mention increases when we realize that each day we breathe about 18.000 lungfuls of air â€" that is between 25 and 50 pounds of air per day. or during a year. from 9,000 to over 18,000 pounds of air. The annual air pollution figures for Toronto were estimated as follows in Probe and GAS? (Group Action to Stop Pollution). The figures are as follows: 0 carbon monoxide. 950,000 tons per year. About 9702- ol' this originates from automo- bile exhaust fumes. o hydrocarbons, about 500.000 tons per year. Of this amount. the transportation industry contributes about 85%. a sulfur dioxide. about 150,000 tons per Year- Power plants contribute 70 to 75% of this. 23