off the equipment on the washrack. It is your responsibility to check with the person in charge of the washrack to be sure this waste water is treated and not discharged into the storm system. Provisions must be made for pretreating or separating oil products and cleaning solvents used at the washrack.

Water Pollution

Pollution results from many activities, both mankind's and nature's. Water becomes polluted when wastes from activities flow into a lake or stream in such quantities that the natural ability of the water to cleanse itself is lessened or completely destroyed.

Wastes are dumped into our waters daily. The following list contains wastes and their sources:

Sewage and other wastes come from cities and industries and from pleasure boats, commercial ships, and marinas.

Nutrients (principally phosphates and nitrates) leach from sewage, industrial waste, and land runoff.

Complex chemicals are found in household detergents, pesticides, herbicides, and wastes from industrial processes.

Oil comes from ships ashore, offshore drilling rigs, and shoreline industrial facilities.

Crankcase oils are improperly disposed of by auto service stations and home auto mechanics.

Silt, sand, and debris come from city streets, urban construction, highway construction, farm surface erosion, and dredging from channel clearings.

Salts flow from winter streets, field irrigation, and industrial processes.

Heater water from power projects, industrial processes, and reservoir impoundments find their way into our waters.

Disease-causing bacteria comes mainly from municipal sewage.

Radioactive wastes come from a variety of sources. These sources include the mining and processing of radioactive ores, materials used in power plants, industrial, medical, and other research, and fallout during nuclear weapons testing.

Mercury and other heavy metals frequently escape from industrial plants.

Drainage waste comes from animal feedlots and meat processing plants.

These wastes have placed a serious strain on our waste treatment systems, as well as on our waterways. Some types of waste are difficult to remove. Other types respond to conventional treatment, but there are not enough treatment facilities to keep them out of our waters. Solving the pollution problem is not easy, but it must be solved if we are to have an adequate supply of safe, clean water for future use.

OIL SPILLS ON WATER. - An oil slick on the surface of the water blocks the flow of oxygen from the atmosphere into the water. This is harmful to fish and other aquatic life. If the fish do not die from the oil coating on their gills or from eating the oil or oil-laden food, their flesh is tainted and they are no longer fit for human consumption. Besides harming aquatic life, drinking water can become contaminated by oil. Drinking water from wells and surface storage facilities is treated with chemicals to rid the water of harmful bacteria. However, no amount of treatment can rid a system of contamination from waste oil products. The system must be abandoned.

Booming of spills has proved to be effective in containing spills of liquids on relatively calm and current-free waters. Because of ecological considerations, booming has become an important means of containing oil spills, even though more effective equipment is now available.

Following confinement of oil spills on water, various methods of removing the confined liquid have been used. One method is the use of absorbents, such as straw, plastics, sawdust, and peat moss. The absorbents are spread on the surface of the spill and then collected and burned on shore. Skimming devices operate on a different principle and must include pumps and separators. Power boats with skimmers on the bow scoop up the oil and water and send them through an oil separator and rollers to which only the oil adheres. The oil is then removed by scraping or compression.

HARMFUL EFFECTS OF POLLUTED WATERS. - Several basic biological, chemical, and physical processes affect the quality of water. Organic wastes (natural products, such as food, paper, and human waste) decompose by bacterial action. Bacteria attack wastes dumped into rivers and lakes, using up oxygen in the process. Fish and other aquatic life need oxygen. If the waste loads are so great that large amounts of oxygen are spent in their decomposition, certain types of fish can no longer live in that body of water. A