Hazardous Chemical Waste Management

About 70,000 chemicals are currently on the market. Although many of the chemicals have been beneficial to people, approximately 35,000 are classified as definitely or potentially hazardous to public health (Table W). The US currently generates about 250 million metric tons of hazardous chemical waste per year, referred to more commonly as hazardous waste.

Uncontrolled dumping of chemical waste pollutes soil, surface water and groundwater in several ways:

• Chemical waste stored in barrels, either stacked on ground or buried, eventually corrode and leak, polluting surface water, soil, and groundwater;
• Liquid chemical waste dumped in an unlined lagoon, from which contaminated water percolates through soil and rock to the groundwater table; and

Hazardous chemical waste management is one of the most serious environmental problems. Management of hazardous chemical waste involves several options, including recycling, on-site processing to recover by-products with commercial value, microbial breakdown, chemical stabilization, high temperature decomposition, incineration, and disposal by secure landfill or deep-well injection. A number of technological advances have been made in toxic-waste management, and as land disposal becomes more expensive, the recent trend toward on site treatment is likely to continue. However, on-site treatment will not eliminate all hazardous chemical waste; disposal of some waste will remain necessary. However, all available technologies cause some environmental disruption. There is no simple solution for all waste management issues.

Table W: Products and the Potentially Hazardous Waste they Generate  (Q)

Products we Use	Potentially Hazardous Waste
Leather	Heavy metals, organic solvents
Medicines	Organic solvents and residues, heavy metals (e.g., Hg, Zn)
Metals	Heavy metals, fluorides, cyanides, acid and alkaline cleaners, solvents, pigments
Oil, gasoline & other petroleum products	Oil, phenols and other organic compounds, heavy metals, ammonia, salts, acids
Paints	Heavy metals, pigments, solvents, organic residues
Pesticides	Organic chlorine compounds, organic phosphate compounds
Plastics	Organic chlorine compounds
Textiles	Heavy metals, dyes, organic chlorine compounds, solvents

Summary

Direct land disposal of hazardous waste is often not the best initial alternative. Even with extensive safeguards land disposal cannot guarantee that the waste is contained and will not cause environmental disruption in the future. This concern holds true for all land disposal facilities, including landfills, surface impoundments, land application, and injection wells. Pollution of air, land, surface water, and groundwater may result from failure of a land disposal site to contain hazardous waste.  Pollution of groundwater is perhaps the most significant risk, because groundwater provides a convenient route for pollutants to reach humans and other living things.