Have them announce what kind of pollutant they are holding before they pass it on. After all the items have reached the final students, discuss the activity. Tell students to reclaim their items. Explain that the items easily identifiable as their own simulate point source pollution. Tell students these represent nonpoint source pollution.
Students can research the regulations governing waterfront property in their communities.
If they believe their waterways are poorly treated, they may want to write letters to local government officials supporting environmentally sound land use legislation. Extensions Instead of a river, have students represent a lake system. One student represents a lake. Other students, standing in lines extending from the lake, can be streams flowing to the lake. Have students adapt the activity to represent a river system that includes tributaries flowing into a main channel.