Environmental Issues in Modern Agriculture
Part 3 – 62 | Unit 3.3
vi. Dietary exposure to endocrine-disrupting compounds, known and suspected
carcinogens and nerve toxins
vii. potential synergistic effects of exposure to environmental toxins with similar
mechanisms of toxicity
viii. soil degradation: Reduce biological activity and diversity
ix. Developed resistance and resilience in pest populations
x. Dietary exposure and the safety of existing tolerance levels
xi. pesticides disproportionately affect predaceous “beneficial organisms” over pests,
creating resurgence in populations of pest organisms
f) The “logic” of pesticide use and the externalization of costs
i. For every $1 spent on pesticides there are $3 to $5 in return^3
g) Estimates on financial costs to mitigate environmental damage
i. In the U.s., environmental costs are estimated to be around $10 billion, depending on
assumptions (pimentel 2005). These costs of production are not compensated for by
the farmer or agrochemical company.
h) Legislation restricting the use of biocides (see Benbrook 1996)
i. The Food Quality protection Act of 1996 (see http://www.epa.gov/opppsps1/fqpa/))
ii. shortcomings of the FQpA (see http://www.ecologic-ipm.com))
- synthetically compounded n-p-K fertilizers (see also supplement 4, nitrate Contamination
of Groundwater, in Unit 1.5, Irrigation—principles and practices)
a) What is synthetically compounded fertilizer? synthesizing ammonia from nitrogen and
hydrogen gas involves submitting nitrogen and hydrogen to at least 3,000 pounds per
square inch of pressure, in the presence of osmium as a catalyst. Industrially produced
synthetic ammonia is the principal source of the commercially available, industrially
produced nitrogen and is the principal starting point from which all of the different
kinds of industrially produced, so-called nitrogen “fertilizers” are made.
b) Known and potential agroecological and human health risks (see; U.s. Geological survey
2010 , and Gliessman 2007 )
i. The overapplication of synthetic n, p, and K nutrients are the most extensive form of
“nonpoint source” (runoff ) water pollution in the U.s.
ii Trends in nitrogen concentrations have changed little between 1993 and 2003. In
places where there are changes, they tend to show increases rather than decreases
(U.s. Geological survey 2010).
iii. The overapplication of n-p-K fertilizers has greatly altered the global n and p cycles
with unknown consequences (Gliessman 2007)
iv. surface water contamination: n-p-K contamination leads to growth of algae and
other plants (this process is called eutrophication). The plants utilize available oxygen
and block sunlight penetration, harming fish and other marine organisms. This leads
to “dead zones,” e.g., in the northern Gulf of Mexico (see Carpenter et al. 1998; Miller
2008; U.s. Geological survey 2010).
v. Energy-intensive production: nitrogen fertilizer requires large amounts of natural
gas, both to contribute hydrogen to the nitrogen, but also adding heat manufacture
it. Fertilizer prices tend to be in line with those of natural gas (see Miller 2008; sawyer
et al 2010).
3 United states Environmental protection Agency. 2012. Agricultural pesticides.www.epa.gov/oecaagct/ag101/croppesticideuse.html
Lecture 1: Technological Innovations