Page 171 - Soil Degradation, Conservation and Remediation

160 6 Soil Pollution

6.2.5 Industrial Wastes

Industrial solid wastes are the major sources of soil pollution by toxic organic and
inorganic chemical compounds and heavy metals. Industrial wastes include scrap
metals, trash, oil, solvents, chemicals, cafeteria garbage, dirt and gravel, masonry
and concrete, wood and scrap lumber, and similar wastes. Container wastes with
solid, liquid, or gases are divided into hazardous and nonhazardous waste. Certain

commercial products such as cleaning fluids, paints, or pesticides can also be defi ned
as hazardous waste. Industrial waste may be toxic, ignitable, corrosive, or reactive.
If improperly managed, or disposed, this waste can pose dangerous health and envi-
ronmental consequences. In the USA, the amount of hazardous waste generated by
manufacturing industries increased from an estimated 4.5 million tons annually
after World War II to some 57 million tons by 1975. By 1990, this total had shot up
to approximately 265 million tons. This waste is generated at every stage in the
production process. The introduction of many new products for homes and offi ces –
computers, drugs, textiles, paints and dyes, and plastics – also introduced hazardous
waste, including toxic chemicals, into the environment. The EPA estimated in 1980
that more than 70,000 different chemicals were being manufactured in the USA
with some 1,000 new chemicals being added each year. The human health and
environmental impacts of many of these chemicals are largely unknown. High
levels of toxic contaminants have been found in animals and humans, particularly
those, like farm workers and oil and gas workers, who are continually exposed to such
waste streams. Wastewater from manufacturing or chemical processes in industries
contributes to soil and water pollution. Most major industries have treatment facilities

for industrial effluents but this is not the case with small-scale industries, or in
industries of the undeveloped countries, which cannot afford enormous investments

in pollution control equipment as their profit margin is very slender. Polluted water
is unsuitable for drinking, agriculture, recreation, and industry. Two types of industrial
wastes of particular concern are dry cleaning fluids and embalming fl uids. Dry cleaning

fluids have contaminated groundwater supplies in all areas in the USA. One of

the most common contaminants is PCE (perchloroethylene or tetrachloroethylene
Cl 2 C ═ CCl 2 ). Embalming fluids include carcinogens. The threat of embalming fl uids

contaminating the water supply has prompted some cities to decrease the size of
planned large cemeteries (CEQ 1981 ) (Table 6.2 ).

6.2.6 Agrochemicals

Agrochemicals include various chemical substances used for production and
protection in agriculture. In most cases, it refers to the broad range of pesticides,
including insecticides, herbicides, and fungicides. It may also include synthetic
fertilizers, hormones and other chemical growth agents, and concentrated stores of raw
animal manure. Most agrochemicals are toxic, and their bulk storage may pose sig-
nificant environmental and/or health risks, particularly in the event of accidental spills.