| 摘要 |
There is disclosed, in one aspect, a method for treating the upper layer of a body of water to effect a chemical and/or physical change within this upper layer. This method comprises placing a composition comprising an expanded silicate aggregate, such as a boron-containing silicate aggregate, which is impregnated with at least one treating agent such as a herbicide, onto the surface of a body of water, such as a lake, and allowing the composition to float upon the surface for a sufficient period of time to effect the chemical and/or physical change. In another aspect, there is disclosed a composition useful for treating the upper layer of a body of water to effect a chemical and/or physical change. This composition comprises a mixture of the expanded silicate aggregate and at least one treating agent which, when applied in the appropriate concentration and for the appropriate time period, will effect the desired chemical change within the upper layer of the body of water. Certain of these compositions results in changes in the pH of the water and the control of various plant or other growth within the water. Another composition is useful in the cleaning of oil spills.
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