Agriculture Reference
In-Depth Information
Seaboard, nutrients from farms and confined animal feeding operations
flow into estuaries causing algal blooms and outbreaks of
Pfiesteria
piscicida
, a dinoflagellate causing fish lesions and fish kills, and perhaps
posing a threat to human health.
22
Nitrates threaten human health when they contaminate groundwater
drinking supplies because they can affect the blood's ability to carry
oxygen, especially when an infant's digestive tract converts it to nitrite,
causing “blue baby” syndrome. Rural water supplies are susceptible to
nitrate contamination from agriculture, especially shallow wells.
23
For
example, on Washington's Columbia Plateau, nitrate concentrations in
about 20 percent of wells exceed the drinking water standard, and the
highest rates were found where fertilizer use is greatest. Nitrate concen-
trations in shallow wells here are among the highest in the nation.
Agricultural fertilizers are the leading cause of nitrate pollution, followed
by discharges from cattle feedlots and food-processing facilities.
24
Even as
Silent Spring
provoked new environmental policies, US agri-
cultural pesticide use grew dramatically, reaching a billion pounds per
year in 1976 and fluctuating around that level ever since.
25
California's
specialty-crop agriculture has used a disproportionate amount of the
nation's total pesticides, roughly 20-25 percent.
26
After DDT was
banned, many growers compensated by switching to organophosphate
pesticides. These insecticides do not bioaccumulate and threaten top
predators as did DDT, but they are acutely toxic, and increasing reliance
on organophosphates meant greater acute health risks to growers and
farm workers.
27
California's San Joaquin Valley has the maximum con-
centration of many pesticides among all of the US watersheds studied by
the US Geological Survey: pesticides were detected in 69 percent of the
groundwater samples collected from the eastern San Joaquin Valley.
28
A
companion report on the Sacramento River found that watershed to gen-
erally be in better shape, although it did find that agricultural streams
here have some of the nation's highest concentrations of the insecticide
diazanon.
29
Twenty years after the USEPA's creation, attention within the agency
began to focus on agriculture's environmental problems. The USEPA was
initially created with a legislated shotgun marriage of existing media (air,
water) and category (pesticides, solid waste) programs. William Reilly,
USEPA Administrator under President George H. W. Bush, directed his
