Environmental Contamination

Hazardous waste disposers need to understand the potential toxic effects of these wastes and realize how strictly the wastes must be contained. Dangerous chemicals often migrate from uncontrolled sites, percolating from holding ponds and pits into underlying groundwater, then flowing into lakes, streams, and wetlands. Produce and livestock in turn become contaminated, then enter the food chain. Hazardous chemicals then build up, or bioaccumulate, when plants, animals, and people consume contaminated food and water.

Most groundwater originates as surface water. Great quantities of land-deposited hazardous wastes evaporate into the atmosphere, runoff to surface waters, then percolate to groundwaters (Figure 11.3.1). Atmospheric and surface water waste releases commingle with other releases or are lost to natural processes, but groundwater contamination may remain highly concentrated, relatively lo calized, and persistent for decades or centuries. Although current quantities of waste are being reduced, any additional releases together with previously released materials will continue contaminating aquifers in many areas, and many groundwater supplies are now impaired.

Table 11.3.3 presents EPA guidelines for hazardous handling facilities performance with respect to human health and the environment.

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