Related to agricultural runoff
and urban runoff
, suburban runoff
is what you get when everyone in a middle-class neighborhood
decides to coat his or her lawn
s and toxin
s. When it rain
s, these chemical
s wash downstream
into the neighborhood's pretty duck pond
or the nearby lake
-- wherein all biochemical heck breaks loose
Fertilizer is good at making plants grow -- not only your grass, but also algae and miscellaneous even less tasty flora. Some of these are poisonous. Meanwhile, weed killer and insecticide will happily kill not only your crabgrass and Japanese beetles, but all manner of other plants and critters. That's why there are no ducks in the neighborhood duck pond.
Many of your neighbors, however, won't care that they have made the lake too toxic to swim in -- because there's a new health club in town with a big, sparkling blue, chlorinated swimming pool.