Guide to Nutrients and Problems
http://www.chesapeakebay.net/stressor1.htm
General thoughts on nutrients, their sources and effects

Nutrients
Background on nitrogen and phosphorus forms, sources, transport

Health Effects of nitrate
Further information on potential nitrogen health effects. Overview of case studies. Read if interested.

Outline
Nitrogen
What is N used for? In what forms?
Nitrogen cycle
Sources of nitrogen in environment, How transported?
Health effects of high nitrogen concentrations

Phosphorus
P cycle
P forms
Transport mechanisms
Sources
Standards
Health Efects

Environmental effects of nutrients

Nutrients

Nutrients are essential elements for life. Two of the most abundant are nitrogen and phosphorus. These two also pose a primary water quality problem. Nutrients cause nuisance overgrowth of algae as well as noxious aquatic plants, which leads to oxygen depletion via plant respiration and microbial decomposition of plant matter.

Nitrogen

Outline
Nitrogen cycle
What is N used for? In what forms?
Sources of nitrogen in environment How transported?
Health effects of high nitrogen concentrations
Occurrence and trends
    SW
    GW

Nitrogen is most widespread environmental contaminant in groundwater and has a very high occurrence in surface water. Nitrogen can occur in many forms and understanding the biogeochemical cycle is important to understanding the movement of any contaminant in the environment.

Distribution of Forms
Atmosphere: N2
Hydrosphere: N2, NH4+, NO2-, NO3-, dissolved and particulate organic matter
Soils: organic forms or clay-fixed NH4+ (plant and animal biomass, litter), soluble inorganic NO3- (in soil water)
Lithosphere: large amount in mantle and core, some in other rocks

What is N used for?
Major component of chlorophyll
Amino acids which form protein
Necessary for carbohydrate utilization
Component of enzymes, vitamins, and hormones
Stimulates root development

Nitrogen Cycle
Fixation
Ammonification
Nitrification
Denitrification
What do you need for denitrification to occur?
What affects it?

In addition to the actual conversion processes, we need to consider the pools that nitrogen moves through.

Mineralization
Immobilization
Ammonia volatilization
Leaching

Standards

Health Effects
Human

Sources:

Nonpoint:
Agriculture
Residential and Urban
Atmospheric nitrogen:

Point source

Phosphorus

Phosphorus (P) is an essential nutrient for all life forms. Phosphorus plays a role in deoxyribonucleic acid (DNA), ribonucleic acid (RNA), adenosine diphosphate (ADP), and adenosine triphosphate (ATP). Phosphorus is required for these necessary components of life to occur.

Phosphorus is the eleventh-most abundant mineral in the earth's crust and does not exist in a gaseous state. Natural inorganic phosphorus deposits occur primarily as phosphate in the mineral apatite.

Cycle
Uptake
Mineralization
Immobilization
Leaching
Erosion

P Forms

Phosphine gas PH3
Soluble inorganic and organic
H3PO4, H2PO4- (acid soils), HPO42-(calcareous soils), PO43-
In soil pH range 5-8, the first and last are negligible
Weakly adsorbed inorganic phosphate
Insoluble phosphates
Ca in calcareous and alkaline soils, Fe and Al in acid soils
Strongly adsorbed phosphates
Fixed phosphates of silicates
Insoluble organic forms
soil biomass, undecomposed plant and animal residue, humus

Phosphorus in aquatic systems
Particulate and dissolved
Effects of bioturbation

Transport mechanisms
Erosion
Runoff

Sources:

Nonpoint:
Agriculture
Residential and Urban
Mining

Point sources
Sewage plants

Standards

Health effects - none

Environmental effects of nutrients