Question

Q. 1. Describe the principal reserves for water. Which areas of the world have adequate supplies and which are facing a chronic shortage? 3 to 5 sentences

Q. 2. Explain the four stages of water treatment. How is it possible for waterborne pathogens such as Cryptosporidium to contaminate water that has been treated in modern treatment plants? 3 to 5 sentences

Q. 3. What are some examples of toxic chemicals that may enter the public water supply? Describe some of the health effects that are attributed to toxic chemicals present in drinking water. 3 to 5 sentences

Answer 1

Oil The prinuple reserves of water are: - & Ground water to I br . Glaciers & ice caps a . Freshwater lakes & rivers . Sea (salt wates) Adequate supply: Amazon basin, Congo river Shartage : Sub-Saharan and north Africa.

Four stages of water treatment are: - h :) Coagulation - filters diet out & adds chemicals to clean. ii) sedimentation - heavy particles fall to bottom; a clear water moves on. ui) Filtration - pass through filters, help remove do even smaller particles. iv) Disinfection - small amount of chlorine is added to kill bacteria * The oocysts of cryptosporidians um is the infective component; .It is resistant to chloine treatment. it can be killed by boiling water: -

3. Tonic chemicals enter the public water supply through natural and anthropogenic soneces. Enamples of tonic chemicals are: o lead arsenic nitrates and nitrites disinfection byproducts pesticides. These chemicals can cause various health effects lead - leads to affects the growth of children. Nitvates & nitrites - can cause blood disorders ush and thyroid dysfunction . Arsenic - can cause Skin conditions & icculatory - system problems.