Environmental Engineering Reference
In-Depth Information
Table 3.3
World reserves and production of potash expressed as a thousand tonne.
Country
Production (2008)
Reserves*
Reserve base
†
United States
1,200
90,000
300,000
Belarus
5,100
750,000
1,000,000
Brazil
430
300,000
600,000
Canada
11,000
4,400,000
11,000,000
Chile
580
10,000
50,000
China
2,100
8,000
450,000
Germany
3,600
710,000
850,000
Israel
2,400
40,000
580,000
Jordan
1,200
40,000
580,000
Russia
6,900
1,800,000
2,200,000
Spain
590
20,000
35,000
Ukraine
12
25,000
30,000
United Kingdom
480
22,000
30,000
Other countries
—
50,000
140,000
World total (rounded)
36,000
8,300,000
18,000,000
* That part of the reserve base which could be economically extracted or produced at the time of determination.
†
The reserve base includes those resources that are currently economic (reserves), marginally economic (marginal reserves),
and some of those that are currently subeconomic (subeconomic resources).
Adapted from United States Geological Survey (USGS), 2009b and 2009c.
Impact of pesticides
Pesticides is a generic name for chemicals used in agriculture to control weeds (herbicides),
insects (insecticides), fungi (fungicides), nematodes (nematocides), and rodents (rodenticides)
(Ongley, 1996). Pesticides are an essential component of modern agriculture to control the
development of unwelcomed species that compromise the yield and quality of agricultural
products as well as their protection during transportation and storage.
Pesticides are the result of the modern synthetic chemistry. For their production, petroleum
derivatives used as feedstocks are transformed into pesticides following several steps includ-
ing preparation of intermediates, introduction of functional groups, coupling and esterification,
separation, and purification (World Bank, 1998).
The environmental impact of the production phase of pesticides includes the potential
emission of volatile organic compound and particle matter, the production of liquid effluents
that contain residual pesticides and suspended solids, and the generation of solid waste
consisting primarily of sludge, packaging material, and spent catalysts (World Bank, 1998).
In addition, emission of greenhouse gases from the combustion of fossil fuels for energy
and transportation and the depletion of nonrenewable resources add to the list of impacts at
the production stage.
At the agricultural stage, besides affecting the targeted organism, pesticides impact land
and water by creating disruption of ecosystems, loss of biodiversity, water pollution, and
afflictions of human health. Chronic exposure to pesticides may lead to neurological long-
term problems, birth defects, endocrine disruption, tumor development, teratogenic effects,
and suppression of the immune system (Ongley, 1996). Acute exposure to high doses of pes-
ticides can produce death in humans and wildlife.
Once applied, pesticides have a variable half-life that can oscillate between 1 day for
malathion, an insecticide with low human toxicity, to 1,000 days for paraquat, one of the most
widely used herbicides (Deer, 2004).
