Environmental Engineering Reference
In-Depth Information
Tomato
Cabbage
Potatoes
Banana
Apple
Bread
Pasta (dry)
Rice
Olives
Cheese
Chicken meat
Butter
Pork
Sheep meat
Beef
Chocolate
0
2000
4000
6000
8000
10,000 12,000 14,000 16,000 18,000 20,000
Amount of water (L/kg of food)
FIGURE 6.2
Amount of water required to produce one kg of food.
drainage basin have not (McCaffrey, 1993). Recently, however, lack of water and increasing
populations have made the other nations more dependent on the Nile. Construction of a
dam on the Ganges River by India has led to riots and protests in Bangladesh, as the water
needed for irrigation is now diverted (Kattlemann, 1990).
6.3.2 Soil and Water Quality Stressors
6.3.2.1 Chemical Soil Nutrients
Agricultural practices can have a signiicant impact on groundwater and receiving waters—
as summarized in Figure 6.3. Chemicals such as nitrogen (N), potassium (K), phosphorus
(P), sulfur (S), and magnesium (Mg), introduced as plant nutrients, can have signiicant
impact on water quality and can affect human health and other biotic receptors—if and
when they become non-point source contaminants for receiving waters and aquifers. Other
sources of nutrients in the farming industry include inorganic fertilizers, animal manure,
biosolids, septic tanks, and municipal sewages. In Canada, in 2011/2012, an average of
2,160,000 tonnes of nitrogen and 733,000 tonnes of phosphorus were purchased for agricul-
tural lands in the form of fertilizers (IFA Short-Term Prospects for World Agriculture and
Fertilizer Demand 2010/11-2012/13: IFA Fertilizer Consumption 2011/12-2016/17 Country
Reports). In 2000/2001, almost 400,000 tonnes of commercial fertilizer were applied to
crops in the province. In 2000 in Quebec, 3850 tonnes of pesticides were sold, which is a
decrease of 3.4% since 1992 (MDDEP, 2013).
The U.S. Environmental Protection Agency (USEPA) has established 10 mg/L of nitrate N
as the maximum contaminant level in groundwater and a goal of 0.05 mg/L. It has also set
a maximum of 0.1 mg/L for phosphate efluents that will enter a lake or reservoirs (USEPA,
1987). Nash (1993) determined that 25% of the U.S. drinking wells had above 3-ppm levels
of nitrate and other wells have nitrate levels that have reached as high as 100 ppm.
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