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Environment and Health. The ways in which the environment, and perhaps more significantly, human impacts on the environment hold implications for health. Important to emphasize that we often focus on spectacular environmental disasters
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Environment and Health • The ways in which the environment, and perhaps more significantly, human impacts on the environment hold implications for health. • Important to emphasize that we often focus on spectacular environmental disasters • Yet often everyday actions can also be responsible for serious environmental problems
Overview of environmental health concerns • There is consensus that the earth is under stress • environmental deterioration in many different forms is obvious • Changes in the composition of the atmosphere, water pollution, declining biodiversity • Seems logical that environmental deterioration holds implications for human health
Atmosphere • Air pollution used to be synonymous with soot, smoke and sulfur dioxide given off from domestic heating, power generation and industrial production • More recently though, seen broader understanding of air pollution… • Widespread use of petroleum products added nitrogen oxides, carbon dioxides, hydrocarbons and lead to the atmosphere • Also, range of other chemicals from industry (chlorofluorocarbons among them)
Atmosphere … • Increasing diversity of chemicals, and increasing geographical impact - across borders and continent. • For example, nitrogen and sulphur compounds released in Britain, Czech, Hungary, Germany, for example, produce acid rain in Scandinavia. The same true between US and Canada, and vice versa • Air pollution now a global phenomenon in many respects.
Atmosphere … • Carbon dioxide, methane, nitrous oxide and low level-ozone… contribute to global warming by trapping infrared radiation in the earth’s atmosphere • Air pollution has a significant influence on the prevalence of many chronic diseases • E.G., cardiovascular diseases, respiratory diseases Asthma
Atmosphere … • Asthma is one of the few common chronic diseases in the Western world with an escalating death rate • Increase in deaths from asthma, and increasing incidence of asthma has beenconnected to increase air pollution • Since the 1950s, more than 60,000 new chemicals have been introduced into the commercial market Simply more irritants in the air… • Asthma also reminds us that not just concerned about the outdoor environment… concerned with the indoor environment also.
Atmosphere … • In the workplace and the home… diversity of airborne contaminants has also increased rapidly. • Work settings, in particular, increased concern about “sick building syndrome” where indoor air pollution caused by combustion products, volatile organic compounds, dusts, fibres, particulates and bioaerosols are linked to respiratory irritations, headaches, nausea, fatigue, etc….
Health Effects • Sulphur dioxide and suspended particulate matter • These are traditional atmospheric pollutants, especially in urban areas • These produce low level smog, particularly where had an inversion layer where warm air trapped beneath a layer of denser cooler air… • Happened a lot in cities like London… more recently in cities like Los Angeles…. Smog alerts that people should not engage in strenuous activities
Health Effects – SO2 & Particulate Matter • London… 4 day smog in 1952 produced more than 4,000 deaths… bronchitis and other lung diseases, plus increased heart disease during smog • Also not just extreme events; we also find long-term chronic exposure to SO2 and others also threat to health… pulmonary emphysema and asthma • These same air pollutants also linked to cancers… studies indicating that smokers in urban areas demonstrate significantly higher rates of lung cancer than do smokers in rural areas
Health Effects -Carbon monoxide • Formed by incomplete combustion of carbon containing fuels as well as other industrial and biological processes • CO reacts with hemoglobin in the body … reduces the blood’s ability to carry oxygen and restricts the release of oxygen to the tissues
Health Effects - Metallic pollutants • Metallic air pollutants such as cadmium, manganese, nickel and vanadium… tend to cause health problems near specific sites… industrial sites or waste dumps…. • Lead on the other hand was in much more widespread use until relatively recently. • Now, efforts to deal with consequences. Lead paint, pipes, batteries and gasoline from the 1920s until the mid-1970s in Canada
Health Effects - Metallic pollutants … • Levels of lead in the environment decrease significantly in last two decades because of the removal of lead from gas and growing recognition of health risks… • However, some concern about air-borne lead particles… can be deposited in household dust… important to young children who ingest dirt and dust by putting things in their mouths…
Health Effects - Metallic pollutants … • Problems in older parts of cities, poorer areas with lead-based paints where paint is chipped, producing dust • In US… lead pollution remains problems… estimated that 3-4 million children in the US suffering from lead poisoning • Lead… anemia, and can lead to dysfunction of the brain at higher levels… kidney damage, etc. Some evidence that even low levels can produce altered behavior and learning disabilities in children,
Health Effects - Synthetic chemicals • Upwards of 60,000 new synthetic chemicals introduced since the 1950s and more being introduced each year • They enter the air from number of sources, especially from manufacturing, incinerators and waste disposal plants… • Don’t know enough yet about long-term exposure to low levels of these chemicals… but have seen consequences of acute exposures – e.g., Bhopal
Lithosphere • Earth’s crust - soils and other materials that make up the surface of the earth • In 20th century, scale of human alteration of/impact on lithosphere increased dramatically… large parts of it now altered • Development, terracing, digging, mining, blasting etc… Human actions… produce accelerated soil erosion and sedimentation, subsidence, slope failure… in addition, agricultural fertilizers and pesticides and fungicides… changing the chemical composition of the soils…
Health Effects - Pesticides • In US, pesticide use is about 450 million kg annually …Canada? • Generally… see that about 70-75% of this is used for agriculture, but also see that between 10 and 17% is used to control household and garden pests… so urban problem as well… • Originally… saw that DDT and chlorinated hydrocarbons were the most commonly used pesticides in the 1950s and early 1960s… these were banned in many countries during the 1970s after the publication of Silent Spring which argued that these chemicals were destroying ecosystems…
Health Effects – Pesticides … • They were replaced by organo-phosphorus compounds which actually increased risk of human poisoning • Although cases of acute poisoning from pesticides in developed countries has continued to fall… still not clear about long-term chronic exposures… • Studies suggest long term exposure to some may be associated with reduced immune functioning
Health Effects – Pesticides … • For other impacts… evidence is still being accumulated… studies in Hungary suggest that exposure to one organo-phosphorus insecticide is linked with congenital abnormalities • Organochlorine insecticides also linked to increased incidence of lung cancer… • Again, debates rage about the cancer burden associated with pesticides… difficult to prove
Health Effects -Toxic wastes • Former Communist countries created widespread problems… dumping of toxic wastes… product of the centrally coordinated drive toward industrialization… • In many ways, free market economies have not done that much better… In US, more than 150 million tones of hazardous waste generated each year… • Although now conscious about the problems of dealing with it, traditionally, most of this waste dumped indiscriminately…
Health Effects -Toxic wastes … • Studies in the early 1990s suggested that there were between 32-50,000 uncontrolled waste disposal sites in the US • About 1200 to 2000 were estimated to contain wastes that constituted significant threat to environment and public health • Problems? Corrosion and leakage of waste buried in barrels pollute soil, surface and groundwater. Also, liquid wastes contained in lagoons… could potentially… leak contaminate groundwater…
Health Effects -Toxic wastes … • Industrial liquid waste!
Health Effects - Toxic wastes • 1980, Environmental Response Compensation and Liability Act created the “superfund site” designed to tackle the worst of these sites • Critics have argued that the funds were insufficient… and little has been done… This act motivated in part by the Love Canal incident that you read about in Frank
Hydrosphere • Again, 20th century… seen major increase in magnitude and type of water pollution • Many developed countries, radioactive, chemical and thermal wastes added to more traditional threats to water quality like sewage… outcome… water in rivers, lakes and oceans… quality declined
Health effects - Chemical pollution • Surface and groundwater are becoming increasingly polluted… • Causes include fertilizers and pesticides, acid and heavy metal rains, mine drainage and leaching from landfills and toxic waste sites… • Example - Great lakes… comprise about 1/5 of the world’s fresh surface water…
Hydrosphere - Health effects • Chemical pollution • Source of drinking water for more than 40 million people on both sides of the border…. But they have also been a dumping ground for industrial and domestic waste… • More than 1,000 chemical and metal pollutants found in the lakes by the mid-90s. In the golden triangle region… more than 50 sources of industrial pollution and more than 30 sources of municipal sewage… For many years… untreated industrial and human waste dumped directly into the lakes…
Water Pollution • Water pollution in Mexico City
