Particulate Matter and Lead Air Pollution

Water Contaminants

• Chemical contaminants pose health risks and are regulated by Ontario Reg. 170/03, which lists parameters to be monitored, including both organic and inorganic substances.
• Radiological contaminants include naturally occurring elements and products/by-products of nuclear technologies, and drinking systems near nuclear facilities are required to test for radionuclides.
• Microbiological contaminants include pathogens such as viruses, protozoa, and bacteria, as well as algal toxins, which are important due to regulations and public health concerns.

Microbiological Contaminants

• Viruses are small microorganisms capable of reproduction only within living cells, examples include Hepatitis A, norovirus, and Rotavirus.
• Viruses are primarily from sewage contamination and can be inactivated with chlorine, but are not measured directly in drinking water.
• Bacteria are microorganisms, usually one cell, and not all bacteria are pathogens; pathogenic bacteria are used as indicator organisms.
• Protozoa are single-celled microorganisms that lack a cell wall, with two major concerns in drinking water being Cryptosporidum parvum and Giardia lambia.

Waste Reduction and Management

• Source reduction and reuse is waste prevention, including concentrated detergent, light-weight containers, and photocopying both sides of paper.
• Reducing toxicity involves using organic molecules instead of hazardous metals, such as soybean and organic inks in printing, and organic molecules in packing and plastics.
• Food waste can be reduced through composting, and untouched food can be delivered to social services.

Water Treatment

• Conventional surface water treatment plants include:
  • Screen & Intake
  • Coagulation
  • Flocculation
  • Clarification
  • Filters
  • Post Chlorination
  • Clearwell
  • Distribution System
• Coagulation involves rapid dispersion of coagulant in water to destabilize suspended particles and form precipitates.
• Flocculation involves gentle agitation of water to promote contact between particles, increasing settling rate or filterability.
• Sedimentation (clarification) removes suspended solids by gravity settling.

Disinfection and Inactivation

• Inactivation processes depend on raw water characteristics, and must balance the need to inactivate pathogens while minimizing disinfection-by-products.
• Chemical disinfectants include chlorine, chlorine dioxide, chloramines, and ozone.
• Physical disinfectants include UV, filtration, and heat.

Chlorination

• Chlorine is a greenish yellow gas, 2.5 times heavier than air, and is supplied in cylinders or tank cars.
• Chlorine demand is the amount of chlorine used up, and residual is the chlorine left in the water after demand is met.
• Combined and free residuals make up the total residual, and the type of residual depends on pH, temperature, and ammonia left in water.

Air Pollutants

• Particulate matter (PM) comes from both natural and human sources, including volcanoes, dust, and forest fires.
• Lead is a critical air pollutant, doesn't degrade, and is a legacy contaminant from sources like leaded paint, lead in drinking water, and leaded gasoline.
• Volatile organic compounds (VOCs) are organic compounds that easily vaporize, and come from sources like gaseous hydrocarbons, solvents, and trees.
• Hazardous air pollutants include benzene, which is a suspected carcinogen and contributes to sick building syndrome.