The friends thou hast and their attention tried, grapple

1
The friends thou hast and their attention tried,
grapple them to your soul with hoops of
steel. Shakespeare
2
Industrial Pollutants

• Synthetic and organic pollutants - hard to
  generalize
• Organochlorines DDT (pesticide) and PCBs
  (electrical insulation lubricants)
• Are everywhere - observed even in Antarctic snow
  degree of problems relate to solubility in water
  and persistence (so they accumulate)
• Many others 100,000 synthetic chemicals in use
  very poor monitoring in most countries

3

• Newer pesticides degrade more quickly, so dont
  bio-accumulate
• Highest concentrations in surface water near the
  edges of fields
• Rapid increase in pesticides and herbicides
• PAHs - from incomplete combustion (can move long
  distances in air before being deposited)
• Organic solvents lead from landfills
• Links between cancer and organic chemicals?

4
Radionuclides

• Radiation risks in drinking water are negligible,
  with exceptions
• Contamination from Chernobyl
• Nuclear waste from mining and transportation
• May also occur naturally in large concentrations

5
Emerging Trends in Water Quality

• Population growth, industrialization and
  urbanization in developing countries (need
  fertilizer and pesticides trade in toxic waste
  lack of water pollution regulations use of
  outdated technology (ferry accident) lack of
  adequate sanitation ag development (see Chapt 1
  of WWAR)
• Link between urban poverty and water quality
  (water-related disease affects poor and
  children) note about rural-urban migration vs
  natural increase of pop

6

• MDGs
• Changing land use (ag development, e.g., coffee
  and flowers in Kenya)
• Deforestation (releases nutrients from soils)
• Conversion of wetlands (natural pollutant sinks)
• Climate Change??
• Improved water quality management

7
Mexico City, Growth of a Megacity
Title
Body text

• 1973 -Urban growth is concentrated in the center
  of the city

• 2000 -Now expands dramatically into surrounding
  rural areas

8
www.giwa.net or see uneps website
9
Midterm Exam

• Three parts
• Short answer (5 x 4 pts each)
• Medium (pick 3 of 6 x 10 pts each)
• Essay (1 x 50 pts)
• 90 minutes
• Worth 20 of final mark
• Readings
• WWAR Chapters 1 and 5
• Class Notes
• de Villiers to supplement