Theme 2: Energy and the Environment Background Material

Batteries and the Environment

Overview
The improper disposal of batteries poses serious problems. Their toxic constituents can be released into the environment if they are disposed of in landfills (garbage dumps). Improper incineration of batteries can release hazardous chemicals into the atmosphere.

The sound management of hazardous materials is the first step in health risk reduction. The most powerful management tool for reducing the risks of hazardous materials is reduction of the quantities of hazardous materials used. An increased awareness of the dangers of battery components by the general public can cause increased pressures to find alternatives, and provide increased funding for research and development by private and government agencies.

Batteries
A battery is an electrochemical energy storing technology. They store electricity in the form of a potential chemical reaction between two electrodes through an electrolyte. A battery delivers electric energy produced in a oxidation - reduction (redox) reaction to an external circuit or load. People are using more and more batteries.

Classification of Batteries
Batteries are divided into two main categories: wet cell and dry cell. Wet cell or lead acid batteries are most commonly used to power vehicles. Dry cell or alkaline batteries are commonly used in homes for flashlights, radios, toys, cordless telephones and hearing aids.

Batteries can also classified as primary or secondary. Primary batteries can not be reused. Once discharged, they must be replaced. Primary batteries include alkaline/manganese, carbon-zinc, mercuric-oxide, zinc-air, silver-oxide and other types of "button" batteries. Secondary batteries, or rechargeable batteries include lead-acid, nickel-cadmium, and lithium-ion. They can be recharged and used again.

Environmental Hazards
Batteries may contain hazardous materials such as mercury, cadmium, copper, zinc, lead, manganese, nickel, and lithium metals.

Batteries may also contain strong acids or bases and many are considered corrosive. They may produce the following potential environmental problems or hazards:

• pollute lakes and streams as the metals vaporize into the air when burned in incinerators
• contribute heavy metals, such as lead, mercury and cadmium, that may leach into ground water
• expose the environment to highly corrosive acids and bases

What is being done?
The impact of batteries disposal on the environment can be lessened by:

• reducing the number of batteries in household waste by extending battery life
• reducing the number by introducing rechargeable batteries
• redesigning batteries with less toxic components
• recycling

Reducing the Number of Batteries
To reduce waste, start with prevention. Starting with prevention creates less leftover waste that could become potentially hazardous.

The following are some steps that can be used to reduce the number of batteries used in a household:

• check to see if you already have batteries on hand before buying more
• when suited to the task, buy items that do not require batteries
• read the label and make sure batteries do not have mercury and heavy metals
• consider rechargeable batteries for some needs but remember that they also contain heavy metals such as nickel-cadmium

Rechargeable batteries
Rechargeable batteries result in longer life span which results in less need for as many batteries. Nickel-cadmium (Ni-Cd) batteries, for example, can be recharged hundreds of times. This is accomplished because the chemical reaction that creates the electrical energy can be reversed. Rechargeable batteries usually have a higher initial cost and require a battery charger. However, this initial investment may be recovered. Each rechargeable battery may substitute hundreds of primary batteries and cost much less than the primary batteries it replaces over its life.

Most technologies developed by humans have positive as well as negative impacts. The Ni-Cd battery reduces the number of primary batteries needed because the nickel-cadmium can be recharged over and over again. However, even these batteries must be eventually replaced. When they are thrown out, the environmental release of cadmium poses potential health threats.

Cadmium can accumulate in the environment by leaching from landfills into ground water and surface water. It can also enter the atmosphere if the Ni-Cd battery is burned.

Cadmium is toxic to fish and wildlife and can be passed to humans through the food chain. Cadmium has been associated with numerous human illnesses including lung and kidney damage. Once absorbed into the body, cadmium can remain for decades.

The Ni-Cd industry is addressing this issue by recycling this type of battery. In addition, the battery industry is testing new materials in an attempt to find a cost-effective replacement for cadmium.

Reducing toxicity of batteries
The improper disposal of batteries can result in the leaching of heavy metals into the soil, groundwater or surface water. In the past, the majority of mercury released into the environment was the result of people tossing batteries containing mercury into their household garbage. Within the past decade, the amount of mercury used in household batteries has been reduced to nearly zero. Technological advances have included the replacement of mercuric oxide with less toxic manganese dioxide.

Manufacturers continue to develop new, mercury-free alkaline batteries that can be recharged. At this time, these batteries compete for market share with primary and rechargeable batteries. However, most of these newer batteries can not be recharged as often as the Ni-Cd battery.

Recycling
Recycle batteries if possible. One recycling success story in North America is the lead-acid battery. The battery industry is the largest consumer of lead in the world. Lead is a very toxic metal that enters the human body through ingestion or inhalation. However, over 95 per cent of all battery lead is recycled. When a spent lead-acid battery is collected, it is sent to a recycler where the lead and plastic are reclaimed and sent to a new battery manufacturer.

If recycling batteries is not an option in your community, consider saving batteries for a hazardous waste collection. Storing so-called "dead batteries" in the home however, could create a potential hazard for small children. Personal injury and property damage could occur when old dry cell batteries leak. Stored batteries create a potential risk of fire. Many discarded batteries still have residual voltage. Collected together, these batteries could short and generate sufficient heat to cause a fire. Therefore, great care should be taken when collecting batteries.
MORE:Battery Recycling from Battery Council International.