ENV100 Lecture Notes Mar 19, 2012
ENV100 Lecture Notes
Mar 19, 2012
Managing Waste continued Readings: Chapter 18 Several steps precede the disposal of hazardous waste • For many years, hazardous waste was discarded without special treatment o Public did not know it was harmful to human health o It was assumed that substances would disappear or be diluted in the environment o Now cities designate sites or special collection days to gather HHW There are three disposal methods for hazardous waste • Secure landfills o Design and construction standards are similar but stricter than ordinary sanitary landfills o Must have several impervious liners and leachate removal systems o Must be located far from aquifers • Surface impoundments • Deep-well injection Surface impoundments store liquid hazardous waste • Shallow depressions are lined with plastic and clay • Residue of solid hazardous waste is transported elsewhere • The underlying clay layer can crack and leak • Rainstorms cause overflow, contaminating nearby areas In deep-well injection, wastes are stored underground • Well is drilled deep beneath the water table • Waste is injected underground o Long-term disposal o Well is intended to be isolated from humans and groundwater o Wells can become corroded and leak waste into soil Radioactive waste is especially hazardous • Radioactive waste is particularly dangerous and persistent • Geologic isolation = using the absorptive capacity and impermeability of naturally occurring rock to block contaminants • Multiple-barrier approach = engineering the facility to place as many barriers as possible, both physical and chemical, in the pathway of any escaping contaminants
Contaminated sites are being cleaned up, slowly • 11,000 Canadian contaminated sites, including priority sites for cleanup activities: o Faro Mine, Yukon ($14.6 million) o Canadian Forces Base Esquimalt, British Columbia ($4.56 million) o Port Radium Mine, Northwest Territories ($7.1 million) o Belleville Small Craft Harbour, Ontario ($6.8 million) • Brownfields = sites that have been contaminated but have the potential to be cleaned up and remediated Conclusions • Our consumption habits have created more waste than ever before • Finding ways to reduce, reuse and efficiently recycle the materials and goods that we use stands as a key challenge for this century • Modern methods of waste management are far safer for people and gentler on the environment • Recycling and composting are making rapid progress
Environmental Health Readings: Chapter 19 This lecture will help you understand: • Environmental health hazards and the goals of environmental health • Toxins in the environment • Risk assessment and risk management • Philosophical approaches to risk Central Case: The asbestos dilemma • Asbestos has been used widely in buildings in Canada and now its use is regulated • The world’s largest asbestos deposit is in Asbestos, Quebec • Chrysotile asbestos may or may not be as harmful to health o Health Canada says it is safe o World Health Organization and Canadian Cancer Society say it is not • $1 billion export industry for Canada •
Environmental hazards can be physical, chemical, biological, or cultural
Physical and chemical hazards • Physical hazards: natural environmental processes o Earthquakes, volcanoes, fires, floods, droughts o We can’t prevent them, but we can prepare for them and reduce risk o Can be worsened or accelerated by human activity • Chemical hazards: synthetic chemicals such as pesticides, disinfectants, pharmaceuticals o There are 10s of thousands of synthetic chemicals o Harmful natural chemicals also exist Biological and cultural hazards • Biological hazards: interactions with organisms o Viruses, bacteria, and other pathogens o Infectious disease – other species parasitize humans, fulfilling their ecological roles o Vectors = agents that transfer pathogens to hosts • Cultural hazards: from the home, socioeconomic status, occupation, and behavioural choices o “Voluntary” vs. “involuntary” hazards o Smoking, drug use, diet and nutrition, crime, mode of transportation, recreational choices •
Our perception of risk may not match reality
Silent Spring began the public debate over synthetic chemicals • Rachel Carson (1962) o Generated significant social change o Presented the risks of DDT o 1960s: pesticides mostly untested; sprayed over public areas Toxicology is the study of poisonous substances • Toxicology = the study of the effects of poisonous substances on humans and other organisms • Toxicant (toxin) = any toxic agent • Toxicity = degree of harm a toxicant can cause o Toxicity depends on the combined effect of the chemical and its quantity (exposure/dose) o Pathogenicity or virulence = the degree of harm of biological hazards that spread disease Toxins can be difficult to identify • Real samples are complex o Contain many molecular species and interferents • Concentrations are often very small o ppm: 1 part in a million parts (e.g., 1 g per 10^6 g) o ppb: 1 part in a billion parts (e.g., 1 g per 10^9g) o 1 ppt: 1 part in a trillion parts (e.g., 1 g per 10^12g) o Sensitive nose can detect odour of fuel oil at ppb level o Modern analytical techniques can detect and measure concentrations of some chemicals in water and other media at better than ppt level o Equivalent to one barrel of pesticide stirred into all of Lake Ontario There are synthetic toxins all around us in the environment • The environment contains countless natural synthetic chemicals that may pose health risks o Every human carries traces of industrial chemicals o Sources are both indoors and outdoors Environmental toxins exist indoors as well as outdoors • Radon = toxic, radioactive gas o Colourless and undetectable without specialized kits o Causes lung cancer • Lead = heavy metal o From water going through lead pipes, lead-based paint on popular brand-name children’s toys o Damages organs; causes learning problems, behavior abnormalities, and death • PBDEs (polybrominated diphenyl ethers) o Computers, TVs, plastics, furniture
o Endocrine disruptors, brain and nervous system Toxins can act in several different ways • Carcinogens cause cancer • Mutagens cause DNA mutations o Can lead to severe problems, including cancer • Teratogens cause birth defects • Allergens overactivate the immune system • Neurotoxins damage the nervous system • Endocrine disruptors interfere with the endocrine (hormone) system Endocrine disruption is of increasing concern • Chemicals that resemble and are able to mimic hormones • May cause: o Feminization of male animals o Drop in sperm counts o Testicular cancer o Rise in breast cancer rates o Neurological problems Endocrine disruption research has generated debate • Research results uncertain, contradictory o Typical of any new field • Negative findings pose economic threats to chemical manufacturers o Banning a top-selling chemical could cost a company millions of dollars o Bisphenol-A, found in many plastics, can cause birth defects, but the plastics industry protests that the chemical is safe • Studies reporting harm are publicly funded, but those reporting no harm are often industry funded
Mar 19, 2012
Managing Waste continued Readings: Chapter 18 Several steps precede the disposal of hazardous waste • For many years, hazardous waste was discarded without special treatment o Public did not know it was harmful to human health o It was assumed that substances would disappear or be diluted in the environment o Now cities designate sites or special collection days to gather HHW There are three disposal methods for hazardous waste • Secure landfills o Design and construction standards are similar but stricter than ordinary sanitary landfills o Must have several impervious liners and leachate removal systems o Must be located far from aquifers • Surface impoundments • Deep-well injection Surface impoundments store liquid hazardous waste • Shallow depressions are lined with plastic and clay • Residue of solid hazardous waste is transported elsewhere • The underlying clay layer can crack and leak • Rainstorms cause overflow, contaminating nearby areas In deep-well injection, wastes are stored underground • Well is drilled deep beneath the water table • Waste is injected underground o Long-term disposal o Well is intended to be isolated from humans and groundwater o Wells can become corroded and leak waste into soil Radioactive waste is especially hazardous • Radioactive waste is particularly dangerous and persistent • Geologic isolation = using the absorptive capacity and impermeability of naturally occurring rock to block contaminants • Multiple-barrier approach = engineering the facility to place as many barriers as possible, both physical and chemical, in the pathway of any escaping contaminants
Contaminated sites are being cleaned up, slowly • 11,000 Canadian contaminated sites, including priority sites for cleanup activities: o Faro Mine, Yukon ($14.6 million) o Canadian Forces Base Esquimalt, British Columbia ($4.56 million) o Port Radium Mine, Northwest Territories ($7.1 million) o Belleville Small Craft Harbour, Ontario ($6.8 million) • Brownfields = sites that have been contaminated but have the potential to be cleaned up and remediated Conclusions • Our consumption habits have created more waste than ever before • Finding ways to reduce, reuse and efficiently recycle the materials and goods that we use stands as a key challenge for this century • Modern methods of waste management are far safer for people and gentler on the environment • Recycling and composting are making rapid progress
Environmental Health Readings: Chapter 19 This lecture will help you understand: • Environmental health hazards and the goals of environmental health • Toxins in the environment • Risk assessment and risk management • Philosophical approaches to risk Central Case: The asbestos dilemma • Asbestos has been used widely in buildings in Canada and now its use is regulated • The world’s largest asbestos deposit is in Asbestos, Quebec • Chrysotile asbestos may or may not be as harmful to health o Health Canada says it is safe o World Health Organization and Canadian Cancer Society say it is not • $1 billion export industry for Canada •
Environmental hazards can be physical, chemical, biological, or cultural
Physical and chemical hazards • Physical hazards: natural environmental processes o Earthquakes, volcanoes, fires, floods, droughts o We can’t prevent them, but we can prepare for them and reduce risk o Can be worsened or accelerated by human activity • Chemical hazards: synthetic chemicals such as pesticides, disinfectants, pharmaceuticals o There are 10s of thousands of synthetic chemicals o Harmful natural chemicals also exist Biological and cultural hazards • Biological hazards: interactions with organisms o Viruses, bacteria, and other pathogens o Infectious disease – other species parasitize humans, fulfilling their ecological roles o Vectors = agents that transfer pathogens to hosts • Cultural hazards: from the home, socioeconomic status, occupation, and behavioural choices o “Voluntary” vs. “involuntary” hazards o Smoking, drug use, diet and nutrition, crime, mode of transportation, recreational choices •
Our perception of risk may not match reality
Silent Spring began the public debate over synthetic chemicals • Rachel Carson (1962) o Generated significant social change o Presented the risks of DDT o 1960s: pesticides mostly untested; sprayed over public areas Toxicology is the study of poisonous substances • Toxicology = the study of the effects of poisonous substances on humans and other organisms • Toxicant (toxin) = any toxic agent • Toxicity = degree of harm a toxicant can cause o Toxicity depends on the combined effect of the chemical and its quantity (exposure/dose) o Pathogenicity or virulence = the degree of harm of biological hazards that spread disease Toxins can be difficult to identify • Real samples are complex o Contain many molecular species and interferents • Concentrations are often very small o ppm: 1 part in a million parts (e.g., 1 g per 10^6 g) o ppb: 1 part in a billion parts (e.g., 1 g per 10^9g) o 1 ppt: 1 part in a trillion parts (e.g., 1 g per 10^12g) o Sensitive nose can detect odour of fuel oil at ppb level o Modern analytical techniques can detect and measure concentrations of some chemicals in water and other media at better than ppt level o Equivalent to one barrel of pesticide stirred into all of Lake Ontario There are synthetic toxins all around us in the environment • The environment contains countless natural synthetic chemicals that may pose health risks o Every human carries traces of industrial chemicals o Sources are both indoors and outdoors Environmental toxins exist indoors as well as outdoors • Radon = toxic, radioactive gas o Colourless and undetectable without specialized kits o Causes lung cancer • Lead = heavy metal o From water going through lead pipes, lead-based paint on popular brand-name children’s toys o Damages organs; causes learning problems, behavior abnormalities, and death • PBDEs (polybrominated diphenyl ethers) o Computers, TVs, plastics, furniture
o Endocrine disruptors, brain and nervous system Toxins can act in several different ways • Carcinogens cause cancer • Mutagens cause DNA mutations o Can lead to severe problems, including cancer • Teratogens cause birth defects • Allergens overactivate the immune system • Neurotoxins damage the nervous system • Endocrine disruptors interfere with the endocrine (hormone) system Endocrine disruption is of increasing concern • Chemicals that resemble and are able to mimic hormones • May cause: o Feminization of male animals o Drop in sperm counts o Testicular cancer o Rise in breast cancer rates o Neurological problems Endocrine disruption research has generated debate • Research results uncertain, contradictory o Typical of any new field • Negative findings pose economic threats to chemical manufacturers o Banning a top-selling chemical could cost a company millions of dollars o Bisphenol-A, found in many plastics, can cause birth defects, but the plastics industry protests that the chemical is safe • Studies reporting harm are publicly funded, but those reporting no harm are often industry funded
