Hazardous Wastes

STOP - You must read Chapter 7 before doing this lesson

Introduction

In the 1976 Resource Conservation and Recovery Act (RCRA), Congres legally define hazardous waste (HW) as "any discarded material that may pose a substantial threat or potential danger to human health or the environment when improperly handled. Any waste which exhibits one or more of the following characteristics is define as hazardous and subject to regulation:

Toxic - wastes such as arsenic, heavy metals, or certain synthetic pesticides are capable of causing either acute or chronic health problems.

Ignitable - organic solvents, oils, plasticizers, and paint wastes are examples of wastes that are hazardous because they have a flashpoint less than 60°C or because they tend to undergo spontaneous combustion. The resultant fires are dangerous not only becuase of heat and smoke, but also because they can disseminate toxic particles over a wide area.

Corrosive - substances with a pH of 2 or less or 12.5 and above can eat away standard container materials or living tissues through chemical action and are termed corrosive.Such wastes, which include acids, alkaline cleaning agents, and battery manufacturing residues, present a special threat to waste haulers who come into bodily contact with leaking containers.

Reactive - obsolete munitions, wastes from the manufacturing of dynamite or firecrackers, and certain chemical wastes such as picric acid are hazardous because of their tendency to react vigorously with air or water or to explode and generate toxic fumes.

Treats Posed by Careless Disposal of HW

Mismanagement of hazardous wastes can adversely affect huamn health and environmental quality in a number of ways:

Direct contact - direct contact can result in skin irritation, the initiation of serious chronic illness, or acute poisoning.

Fire and/or explosions - accidental fire and explosions are a constant threat when hazardous wastes are in transit, carelessly stored, or roughly handled.

Poison via the foodchain - biomagnification and bioaccumulation of toxic wastes dicharged into the environment can result in the poisoning of animals or humans who consume the toxin indirectly.

Air pollution - when toxic wastes are burned at temperatures insufficiently high to completely destroy them, serious air pollution problems can results. Only specialized types of equipment are licensed for the incineration of hazardous wastes, and even these must be carefully monitored while operating to ensure a complete burn.

Abandoned hazardous waste dump site where hundreds of corroding drums leak their toxic contents onto the ground, endagering drinking water aquifers below the surface.

Surface water contamination - accidental spills or deliberate dumping of hazardous wastes can easily pollute waterways. The extent and duration of environmental damage to surface waters varies widely, depending on the size of the water body in question and the rate of flow, but short-term damage to aquatic ecosystems can be severe. Public drinking water supplies can also be endangered by hazardous waste discharges.

Groundwater contamination - The most common problem associate with poor hazardous waste management is the pollution of aquifers with toxic leachates percoloating downward through the soil from landfills or surface impoundments. This type of pollution is particularly insidious because it is seldom discovered until it is too late to do anything about it.

Methods of Hazardous Waste Disposal

Historically, the largest percentage of hazardous wastes have been disposed of on land, primarily because land disposal, particularly prior to government regulation of hazardous waste management, was by far the cheapest disposal option.

Secure chemical landfill - a specially designed earthen excavation constructed in such a way as to contain dangerous chemiclas and to prevent them from escaping into the environment through leaching or evaporation.

Diagram of a Secure Chemical Landfill. A secure landfil must be located above the 100 year flood plain and away from fault zones; it must contain double liners of clay or synthetic materials to keep leaching to a minimum; a network of pipes must be laid to collect and control polluted rainwater and leachate accumulating in the landfill; and monitoring wells must be installed to check the quality of any groundwater deposits in the area.

Deep Weel Injection -

Diagram of a Deep Well Injection
the process involves pumping liquid wastes through lined wells into porous rock formations deep underground, well below any drinking water aquifers. Some critics point out that cracks in the well casting or undetected faults in the earth which intersect the disposal zone could result in outward migration of waste. A number of industries, most notably petroleum refineries and petrochemical plants, now utilize this disposal method. Commercial deep well injection currently is practiced only in the Midwest and in Texas and neighboring states. Many private firms operated injection wells for the disposal of their own waste.

Controlled Incineration - because burning at very high temperatures actually destroys hazardous wastes most hazardous wastes management experts regard controlled incineration as the best and, in some cases, the only environmnetally acceptable means of disposal. A controlled incinerator burns at temperatures ranging from 750-3000°F, with wastes, air, and fuel being thoroughly mixed to ensure complete combustion.

Waste Exchanges - the ideal way to manage hazardous materials would be to recycle them, thus preventing their entry into the waste stream and eliminating the disposal problem. Waste exchanges establish contact between waste generators and potential waste users. The most common type of waste exchange is basically an information clearinghouse which publishes monthly, bi-monthly, or quarterly coded listings of waste items available or desired.

Hazardous waste management legislation: RCRA

The ABC's of Waste Disposal
NIMBY	Not In My Back Yard
NIMFYE	Not In My Front Yard Either
PIITBY	Put It In Their Back Yard
NIMEY	Not In My Election Year
NIMTOO	Not In My Term Of Office
LULU	Locally Unwanted Land Use
NOPE	Not On Planet Earth
Wall poster seen at the Environmental Protection Agency

The Resource Conservation and Recovery Act (RCRA) mandates the EPA to:

define which waste are hazardous
institute a "manifest system" to track the movement of hazardous wastes from the place they were generated to any offsite storage, treatment, or disposal facility
set performance standards to be met by owners and operators of hazardous waste facilities
issue permits for operation of such facilities only after technical standards have been met
help states to develop hazardous waste management programs of their own which may be more stringent than the federal program, but which cannot be less so.

Household Hazardous Wastes

It is estimated that the average American generates about 20 pounds of household hazardous waste each year.

Typical example of such discarded materials include pesticides, paints and varnishes, brush cleaners, ammonia, toilet bowl cleaners, bleaches and disinfectants, oven cleaners, batteries, motor oil, outdated medicines, and many others. Although these substances may be every bit as toxic, corrosive, flammable,or explosive as the industrial wastes regulated under RCRA, federal and state hazardous waste laws do not apply to the comparatively minor household sources. However, the cumulative environmnetal impact of even small amounts of these materials being carelessly discarded by millions of individuals can be significant.

Household hazardous waste disposal presents a variety of concerns:

Stored inside the home, hazardous chemicals pose poisoning risks, particularly for children; they also pose porblems of indoor air pollution and fire hazards.
The welfare of public employees can be threatened by hazardous household products.
The environment itself can be seriously degraded when householders pour hazardous liquids into drains and flush them down toilets or into septics systems.

In an effort to raise public awareness about these problems and to provide concerned citizens with a safe and responsible way of getting rid of hazardous household wastes, an increasing number of communities and public interest groups have been sponsoring houselhold hazardous waste collection programs in recent years.