TSS is often associated with toxic contaminants because organic materials and metals tend to bind to particles and stay suspended in the water column. Like TSS, the total dissolved solids measurement refers to the amount of particles in the water. Yet these are the filterable particles of matter. Though the water may appear to be clearer of debris, waters with high dissolved solids generally are of inferior quality. The pollutants have dissolved into smaller particles within the water.
Heavy metals are among the most harmful of the elemental pollutants.
The brake-pads on cars also contain some of these metals. Brake-pad discharges runoff from roads into City streams. At higher concentrations, these heavy metals are toxic to plant and aquatic life in streams. Excessive amounts of nutrients can lead to degradation of water quality by promoting excessive growth, accumulation, and subsequent decay of plants, especially algae. These nutrients result from runoff from fertilizer use, leaching from septic tanks and sewage, and the erosion of natural deposits.