Environmental Engineering Reference
In-Depth Information
are considered more mobile than those to soils. Therefore, cadmium is
generally found in the environment in the following sequence:(1) Solid waste,
(2) Liquid waste and (3) Gaseous waste. (Figure 1)
2.1. Solid Cadmium Waste
The solid cadmium wastes include municipal incinerator ash, coal fly ash,
hospital incinerator ash, raw sewage sludge, sewage incinerator bottom ash,
and sewage incinerator lagoon ash (which is a combination of bottom and fly
ashes) (Krishnan et al., 1992). Municipal solid waste (Table 1) is generally
disposed off by landfilling which leads to leaching of metals resulting in
contamination of the ground water.
Table 1. Household sources of Cadmium in Municipal Solid Waste
Category
Products
Percent by
Weight
NiCd
Batteries
Rechargeable batteries used in calculators, hand-
held tools, flashlights, handheld vacuums,
electric shavers, alarm systems, lap-top
computers, cellular phones, televisions, camera
lighting and portable hospital equipment
52
Plastics
Stabilizers and pigments in non-food packaging,
misc. durables and nondurables appliances,
furniture and toys
28
Electrical &
Electronic
Devices
Plate television and radio chassis
9
Pigments
Printing inks, textile dyes and paints
4
Glass and
Ceramics
Yellow-orange light bulbs; photochromic glass;
metal sealing solders and microsphere optics,
and glasses for soft drink, beer and cosmetic
bottles
2
Others
Appliances, rubber products, used oil, electric
blankets, & heating pads
5
Source: EPA, 1989.
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