Common Water Measurement

1. Temperature 2. pH3. Specific conductance/Total

Dissolved Solids 4. Hardness/Mineral Content 5. Turbidity/Suspended Sediment6. Salinity/Buoyancy7. Dissolved Gasses: Oxygen,

Carbon Dioxide, Nitrogen

8. Plant Nutrients: Oxygen Cycle; Carbon Cycle; Nitrogen Cycle; Phosphorus

9. Bacteria

What components of a water environment can we change to increase or decrease the number of organisms that can exist in it?

CWM Objectives:

• The student should be able to:– Explain what specific conductance is and what

factors influence– Understand what TDS means and why we study it– Compare mineral content to water hardness, and

analyze water hardness effect on detergent performance (lathering)

– Explain how suspended solids relate to turbidity

Term: Specific Conductance1 5

What it means to me:

1. A measure of the ability of water to conduct an electrical current. (Electrical Conductivity = EC)

2. highly dependent on the amount of total dissolved solids (TDS) in the water.

Examples:

1. Pure water, such as distilled water, will have a very low specific conductance, and sea water will have a high specific conductance

2. High TDS = High specific conductance

3. High dissolved-solids concentration can cause deterioration of plumbing fixtures and appliances, scale build-up, and unpleasant taste or odor of drinking water.

My understanding: 1=No 5=Yes

Total Dissolved Solids (TDS)

• TDS is a measure of the combined content of all inorganic and organic substances contained in a liquid • Total dissolved solids are normally discussed only for freshwater

systems, as salinity comprises some of the ions constituting the definition of TDS.

• The principal application of TDS is in the study of water quality for streams, rivers and lakes

• TDS is not generally considered a primary pollutant • it is not deemed to be associated with health effects

• It is used as an indication of aesthetic characteristics of drinking water and as an aggregate indicator of the presence of a broad array of chemical contaminants.

Term: Hardness 1 5

What it means to me:• Hard water is water that has high mineral

content (in contrast with soft water).• Rainwater and distilled water are soft,

because they also contain few ions.[

• Hard water minerals primarily consist of calcium (Ca2+), and magnesium (Mg2+) metal cations, and sometimes other dissolved compounds such as bicarbonates and sulfates.

Examples:

• The simplest way to determine the hardness of water is the lather/froth test: • soap or toothpaste, when

agitated, lathers easily in soft water but not in hard water.

• These ions enter a water supply by leaching from minerals within an aquifer

Soft Water vs Hard Water

The World Health Organization says that "there does not appear to be any convincing evidence that water hardness causes adverse health effects in humans."[

My understanding: 1=No 5=Yes

Hardness can be quantified by instrumental analysis.

• Reported in parts per million (ppm) or mass/volume (mg/L) • Usually measures only the total concentrations of calcium and magnesium, the two most prevalent

divalent metal ions. – iron, aluminium, and manganese can also be present at elevated levels in some locations. – The presence of iron characteristically confers a brownish (rust-like) colour to the calcification, instead of white (the color of most of the other compounds).

• A mixture of minerals dissolved in the water, together with the water's pH and temperature, that determines the behavior of the hardness

• Descriptions of hardness correspond roughly with ranges of mineral concentrations:• Soft:• 0–60 mg/L

• Moderately hard:• 61–120 mg/L

• Hard:• 121–180 mg/L

• Very hard:• ≥181 mg/L

Water hardness varies throughout the United States.

Term: Suspended Sediment1 5

What it means to me:

Solid particles transported in a fluid media or found in deposit after transportation by flowing water, wind, glacier and gravitational action.

Their concentration in a water body is affected by many factors.

Negative Effects of S.S.:

transport adsorbed toxic substances

They block light from reaching submerged vegetation, which in turn slows down photosynthesis

suspended solids absorb heat from sunlight, increasing the water temperature, decreasing the dissolved oxygen level even more.

Examples:

In rivers, the concentration depends on the water’s flow rate, turbidity, soil erosion, urban runoff, and wastewater and septic system effluent

In lakes, the concentration depends on decaying plants and animals, bottom-feeding fish, and wind/wave action play a larger role

Suspended particles can transport heavy metal and other toxic substances into aquatic habitats

This effect causes less dissolved oxygen to be released into the water by the plants and in extreme cases, results in death of the plants.

My understanding: 1=No 5=Yes

Term: Suspended Sediment1 5

What it means to me:

When it rains, soil and debris from the surrounding land are eroded and washed into streams.

Sediment particles from as small as clay to as large as boulders flow along with the water.

Fast-moving water can pick up, suspend, and move larger particles more easily than slow-moving waters.

• This is why rivers are more muddy-looking during storms -- they are carrying a LOT more sediment than they carry during a low-flow period.

• In fact, so much sediment is carried during storms that well over one-half of all the sediment moved during a year might be transported during a single storm period.

My understanding: 1=No 5=Yes

Term: Suspended SedimentSo what does this have to do

with people?1 5

On the plus side, sediment deposited on the banks and flood plains of a river is often mineral-rich and makes excellent farmland.

On the negative side, when rivers flood, they leave behind many tons of wet, sticky, heavy, and smelly mud -- not something you would want in your basement.

Sediments can also harm dams and reservoirs. When a river is dammed and a reservoir is created, the sediments that used to flow along with the relatively fast-moving river water are, instead, deposited in the reservoir.

The Nile in Egypt and the Mississippi River here in the United States are good examples.

This happens because the river water flowing through the reservoir moves too slowly to keep sediment suspended -- the sediment settles to the bottom of the reservoir.

Reservoirs slowly fill up with sediment and mud, eventually making them unusable for their intended purposes.

My understanding: 1=No 5=Yes

Suspended sediments play a key role in shaping the characteristics of a body of water; triggering changes in morphology of an area.

As sedimentation and resuspension occur, particles are moved to different areas, altering the depths of waterbodies.

Term: Turbidity1 5

What it means to me:1. Turbidity measures the scattering effect

that suspended solids have on light: the higher the intensity of scattered light, the higher the turbidity.

2. the cloudiness or haziness of a fluid caused by suspended particles

secchi disk

Examples:

1. Turbidity is measured by shining a light through the water and is reported in nephelometric turbidity units (NTU).

2. Material that causes water to be turbid include:• clay• silt• finely divided organic and inorganic

matter• soluble colored organic compounds• plankton• microscopic organisms

My understanding: 1=No 5=Yes