There is foam accumulating on the lake? Is this indicative of pollution?

Most lake foam is caused when the surface tension of water is decreased and air is mixed into the water. Organic materials from naturally decaying plants and animals can reduce the surface tension of water, and when the wind blows across it, or waves wash against the shore, bubbles are produced.

Most foam observed in lakes or streams is naturally occurring, and not an indicator of pollution.

To determine if foam is natural or not, collect some of the foamy water in a jar. Shake the jar. Detergents will produce more bubbles; natural foam usually dissipates. Detergent foams feel slippery and usually smell of perfumes. Natural foams often smell like fish or soil.