Skip to main content

Competency Area 7: Non-point source pollution AEM

PO 72. Understand the environmental impacts of various agricultural contaminants on the quality of surface water and groundwater as it relates to their various uses.

Nitrogen - causes eutrophication and hypoxia (low dissolved oxygen and dead zones primarily in bays and estuaries) in surface waters, and nitrate enrichment in groundwater. Elevated concentrations of nitrate or ammonia in surface water also affect aquatic organisms. High nitrate concentrations in drinking water can affect both humans and animals, causing oxygen deficiencies in the blood (methemoglobinemia).

Phosphorus – causes eutrophication (mainly in ponds, lakes and reservoirs) and hypoxia in coastal waters.

BOD - causes depletion of dissolved oxygen in surface water which may kill fish and other aquatic organisims, and can deplete oxygen in soil-water affecting plant growth.

Sediment - causes turbidity of surface waters which affect aquatic habitat, results in sedimentation in ponds, lakes and reservoirs, and increases treatment costs of drinking water supplies.

Pesticides - cause loss of aquatic life and exceedance of drinking water standards. Atrazine, simazine, metolachlor, and alachlor are often present in surface runoff, tile drain discharge, and groundwater.

Pathogens - cause impairment of recreational and drinking water, leading to problems with animal and human health when coming into contact or consuming the contaminated water.

Silage leachate - causes depletion of dissolved oxygen because of high BOD, and ammonia nitrogen and phosphorus enrichment of water. The high BOD and ammonia-nitrogen may kill fish and other aquatic organisms. Suspended organics make it difficult to treat for drinking water.

Process wastewaters - cause turbidity, depletion of oxygen and nutrient enrichment of receiving waters. Milkhouse wastewater contains suspended milk solids and is mostly enriched with dissolved phosphorus. Barnyard runoff is similar to silage leachate, but generally has slightly lower concentrations.