Waste issues become apparent
when the environmental impact of waste management practices are examined:
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Disposal of waste by landfill, which is the main
waste disposal route, if not properly managed, can cause leaching of contaminants
(heavy metals, ammonia and organic compounds such as PBBs and methane)
into soil, atmosphere and groundwater.
-
Landfill sites occupy considerable space with
significant impact on land use and landscape. These sites are contaminated
by heavy metals, organic chemicals, oils, pesticides, radioactive materials,
asbests and other hazardous minerals. Some countries have started to register
such a contaminated sites and to identify those which require immediate
action.
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Incineration of waste, unless properly regulated,
leads to emissions of toxic substances into atmosphere (metals such as
cadmium, lead, mercury, chromium, tin and zinc and uncombusted residues
of chemical substances present in waste or generated during combustion).
Incinerators also emit large quantities of compounds generally referred
to as acid gases, including HCl, HF, SO2 and NOx, as well as large amounts
of contaminated ashes which contain hazardous metals (eg, cadmium and lead)
and organic compounds (eg, PAHs, PCBs, PCDDs and PCDFs).
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Recycling implies the least load of emissions
and saves materials, but it involves considerable sorting and treatment
during which pollutants present in waste may be transferred to the environment
or incorporated into new products.
-
Waste production implies the use of material
and energy and depletion of the Earth’s renewable and non-renewable resources.
Waste issues and their solutions are linked to production and consumption
throughout all stages of the life-cycle of materials and use of enegy.
