11.2 Contaminants in Water • Contaminants areundesirable substances in a solution. • Drinking water that contains contaminants can be hazardous to both plants and animals. • Human activities can result in many different contaminants entering the water. • These include herbicides,pesticides, andfertilizers from agriculture, salt from salting the roads in winter, and other toxic chemicals and heavy metals. • Biological contaminants are organisms that live in the water and can make us sick. • These include micro-organisms (like bacteria), parasites, and organic matter such as animal feces. contaminant fertilizer herbicide pesticide
11.1 Fresh Water and Salt Water • Only 3 % of Earth’s water is fresh water, the rest is salty. • Even so, “fresh water” does not always mean “water suitable for drinking.” • Salinity refers to the amount of salt dissolved in water, and is expressed either as a percentage or as a concentration in g/L.E.g. the Dead Sea is a 30 % salt solution, or 300 g/L • Water that contains salt has a greater density than fresh water. • Salt water can be converted to fresh water. Desalination is any process that removes salt from water, producing pure water and salt. • Some desalination technologies involve using renewable energy sources, such as energy from the Sun, or from underground. salinity concentration desalination
12.6 Water is Life • Over 1 billion people on Earth (one-sixth of the world population) do not have access to safe drinking water, while others waste water daily. • The world’s first “Water Day” was March 22, 2005. This day marked the start of the “Water for Life” decade, when the UN announced a ten-year target to achieve: • To reduce by half the number of people that do not have access to safe drinking water and basic sanitation by the year 2015. • Access to sufficient clean water is a fundamental human right. • Access to clean water is crucial to everyone for health, food production, and economic development. • Then why do the “water-rich” nations treat water as a product they can package and sell?
Group Work • Read the Articles INDIVIDUALLY • Ask for help on the terms or ideas in the article if you need any • As a group discuss what your articles were about • Using the chart paper, write down the main points that you have found in the articles • What is the article about? • What are the article’s main points • Interesting Facts • Solutions to the problem (if given) • As a group: give a 5 min presentation to the class about your articles • Please do not read the articles at the front of the class – use the charts you have made in class!
Homework • Make a Wiki post about your ideas on the topics discussed