WATER

SAFETY

WATER SAFETY

What determines the safety of a water source and how potable it is?

Potable – safe for humans to drink Biological, physical, and chemical variables

BIOLOGICAL VARIABLES Bacteria, viruses, and parasites

can contaminate water Come from sewage and animal

waste

PHYSICAL VARIABLES Temperature Lower temp = water can hold more O2

Higher temp = plants grow faster and produce O2

Water Movement Faster water flow dilutes pollution faster short video clip

PHYSICAL VARIABLES Turbidity How cloudy water is High turbidity can suffocate fish eggs and make it hard for fish to breathe

CHEMICAL VARIABLES Dissolved oxygen microscopic bubbles of gaseous oxygen

(O2) that are dissolved in water Comes from - photosynthesis and the

atmosphere

COMPREHENSION CHECK

CHEMICAL VARIABLES pH Measure of the acidity of a liquid Indicated using a 0 -14 scale (0=acid) (14 =

base) Vinegar = 3 seawater = 8.3

Effects of High pH Water with high pH typically contains large

amounts of dissolved minerals, particularly calcium and magnesium. These represent the principal components of "hard" water. The minerals do not pose a direct health threat, but they cause other problems, such as scale buildup inside water pipes, soap scum, and decreased effectiveness of soaps and detergents.

Effects of Low pH Acid water with a pH less than 6.5 poses no

direct health threat. However, acidic water tends to dissolve metals, including lead, copper, zinc, iron, manganese and other metals commonly found in household water-supply pipes. This process also results in corrosion of the pipes.

CHEMICAL VARIABLES Salinity refers to the amount of salt dissolved in

watero Takes up space oxygen can’t use “a salt is a crime in which one person

attacks and means to harm another person...”

WHAT DEFINES AN OCEAN HABITAT?

Salinity Temperature Dissolved Oxygen pH Light Nutrients Substrate (base layer) Circulation (water movement)

BIOINDICATORS Animals that tell us how healthy an

ecosystem is Provide an early warning of

environmental damage Can’t be too tolerate

BIOINDICATORS Are often insects 3 main types Pollution Intolerant Pollution Semitolerant Pollution Tolerant

I am a dolphin living off the coast of Georgia. I live near a delicious smelling breakfast making factory. One day, the plant workers were throwing a party to celebrate St. Patrick’s day when they left the machines unattended and the large coffee making section of the plant exploded. 250,000 gallons of scalding hot coffee were released into the ocean near my home. This decreased the pH level of the ocean because coffee is acidic. It also increased the water temperature, so the DO levels went down and my family was forced to evacuate from our home. We found out about what happened because my brother likes to play close to the drainage pipe from the factory. The coffee was such a major point pollution source that our home was uninhabitable for weeks and we had to go stay with some cousins who live in Florida. When we got to their house, my mom got sick because she was not used to the bacteria that they have in Florida in the river where my cousins live. Fortunately She did not stay sick for long because the river had a fast current, and would carry the bacteria away as soon as it would grow.

U.S. DRINKING WATER STANDARDS

Pre 1970 Worried about microorganisms in water

causing disease After 1970 Worried about pesticides, industrial sludge,

and chemicals

U.S. DRINKING WATER STANDARDS

Runoff can carry chemicals or oil This can percolate into groundwater Humans dump sewage waste into

rivers This is why U. S. standards were first

introduced in 1914

U.S. DRINKING WATER STANDARDS 1940 – laws were passed to make sure

municipal water was safe 1972 – Clean Water Act For… 1974 – Safe Drinking Act – ensures

quality of drinking water

Studies of perchlorate (a chemical found in explosives) show that it can disrupt the thyroid, a master gland essential for growth and development. That means that fetuses are at the highest risk for perchlorate damage

Industries as well as people need water. It

takes, on average, 39,090 gallons of water to

manufacture a new car and its four tires.