Nitrates

Nitrate (NO3) is the primary source of nitrogen for plants, without which they cannot live. When more nitrogen is added to the soil than plants can consume, excess nitrate leaches into groundwater and contaminates wells. High concentrations of nitrate-nitrogen in drinking water can limit the ability of blood to carry oxygen in children. In surface water, nitrogen can be associated with a stratified zone of low oxygen (hypoxia), as observed in the Gulf of Mexico-Mississippi River Delta, where it stimultaes over-growth of aquatic plants and algae. In the SMC Watershed the limiting nutrient in aquatic systems is phosphorus.

Sources: Non-complying septics, agricultural run-off

Phosphates

Phosphorus is an essential nutrient found naturally in rocks, soil, and living creatures. Phosphorus stimulates plant growth, but too much can produce an overabundance of algae in lakes and streams. As algae die and decompose, oxygen levels in the water are lowered, which may kill fish and other aquatic organisms.

Sources: septics, feedlots, erosion of cultivated lands. Phosphorus attaches to soil particles rather than dissolving in water, so erosion is often directly related to phosphate concentration.

Algae bloom at tile discharge into SMC, induced by influx of phosphorus.

Bacteria (Fecal coliform)

The presence of Fecal coliform bacteria in Seven Mile Creek suggests that human and/or animal wastes are entering the water supply. Disease-causing bacteria poses a serious threat to public health when present in drinking water.

Sources: non-complying septics, feedlots and cultivated fields (manure sprayed on fields as fertilizer)

Sediment

Total suspended sediment (TSS) measurement in water refers to the particles of soil and organic matter that are suspended in solution. Excess sediment in a stream or river clouds the water, inhibits the ability of fish to spawn, limits biological diversity, and carries phosphorus.

Sources: Cultivated fields, streambanks