1. Managing Hazardous Wastes
Environmental Science 20

2. Types of Hazardous Waste
Hazardous Substances and Hazardous Wastes
Hazardous substances can cause harm to organisms and the environment, and they require special methods to reduce or eliminate their potential for harm.
Many common products are hazardous such as: gasoline, pesticides, household cleaners and medicines.
Hazardous Waste is a discarded substance that is or contains a flammable, corrosive, reactive and/or toxic substance.

3. Hazardous wastes are created at many points in the life cycle of a product, from research and development to final disposal.

4. Properties of Hazardous Materials

5. Hazardous Waste from Agriculture
Pesticides are not just deadly to insects and other pests – they are also harmful to humans and other organism.
Pesticides may be used up when applied to crops, but any leftover becomes waste material.
Some pesticides breakdown quickly when they are applied and other do not. These are called persistent pesticides.
One persistent pesticide is called DDT. DDT belongs to a class of hazardous materials called chlorinated hydrocarbons.
DDT has been shown to accumulate in the tissues of humans and other organisms and has been linked to nervous system problems, seizures, premature births and reproductive problems.
The use of DDT was banned in the 1980s.
DDT is still used in some parts of the world to control diseases such as Malaria, which is dominantly spread by mosquitoes.

6. Hazardous Waste from Manufacturing and Industry
The mining, oil and gas, chemical, and pulp and paper industries use and produce high volumes of hazardous substances.
For example: cyanide is used in mining to separate metals from the ore.
Heavy Metals may also be released, such as mercury, arsenic and lead.
The situations is similar in the oil and gas industry. Exploring, drilling well, the refining process, and maintaining machines and vehicles are just a few of the activities that produce hazardous wastes.

7. Many common products produce hazardous wastes.

8. Hazardous Waste from Municipal Sources
Municipal sources of hazardous wastes are closely linked to the use of consumer products, such as: batteries, antifreeze, paint, compact fluorescent light bulbs, and cleaners.
One significant source is electronic products. Unwanted electronic products that enter the waste stream are called e-waste.
Older electronics often contain polychlorinated Biphenyls (PCBs), which are heat resistant, fire resistant, and extremely harmful to organisms and the environment.
Like DDT, PCB’s can accumulate in the tissues of organisms and cause harms in the nervous, immune, reproductive, respiratory and urinary systems.
PCBs were banned in Canada in 1977, but they are still used in developing nations.

9. Effects of Hazardous Substances and Wastes on the Environment
Hazardous materials can have a variety of effects on the environment.
Factors that determine the nature and severity of the health effects include:
Toxicity (how harmful)
Duration of exposure (how long)
Amount of exposure (how much)
Route of exposure (inhaled, ingested, or absorbed)
Over the past few decades, numerous accidents and some deliberate releases of hazardous substances into the environment have occurred. Your textbook explores some of these incidences.

10. Managing Hazardous Waste
Environment Canada promotes a pollution prevention hierarchy. It emphasizes reducing the amount of hazardous waste produced according to the strategy outlined below:
Reduce the amount of waste at its source
Recycle wastes whenever possible
Treat wastes to reduce their hazard or their volume
As a last resort, dispose of wastes on land or incinerate them

11. Pollution Prevention Hierarchy

12. Treating Hazardous Wastes
Treating hazardous waste involves converting it to a less hazardous substance and/or reducing its volume before disposal. There are a variety of technologies used to do this:
Chemical – chemical conversion
Physical – physical devices are used (filter)
Biological – Use of biological organisms to remove contaminants (Bioremediation)
Thermal – treating with extreme heat

13. Disposal of Hazardous Wastes
Despite the best efforts of government, industries, communities and individuals, there will always be some wastes that need to be disposed of. There are 3 methods used in Canada:
Deep Well Injection – Liquid hazardous wastes are injected into Deep wells below the Earth’s surface. The wells are cased with cement to prevent leakage, but leakage from older wells remains a concern.
Non-Retrievable Storage – A special landfill for hazardous substances. This is the most common method and is monitored for leaks.
Retrievable Storage – This is the most expensive option. Hazardous wastes are placed in containers in an accessible, but secure location, such as a building, cave, or abandoned mine. Waste can be monitored easily.

14. Questions
Read sections and answer the questions.