Agriculture Reference
In-Depth Information
10
Integration of Air and Water
Quality Issues
C.A. Rotz* and T.L. Veith
USDA-ARS, University Park,
Pennsylvania, USA
Introduction
Water quality effects of animal production
primarily occur during feed production where
nutrients and other compounds are leached
through the soil to groundwater or carried
through runoff to surface waters. Other con-
tamination sources include runoff from feedlots
and accidental leakage of manure into streams
and other water bodies. For agricultural sys-
tems, nitrogen (N) and phosphorus (P) are the
nutrient losses of most concern. Nitrogen,
primarily in the form of nitrate, can leach to
groundwater where levels greater than 10 ppm
of N are a human health concern (EPA, 2009).
Small amounts of nitrate can also drain off field
surfaces into streams, rivers, lakes and large
water bodies such as the Chesapeake Bay and
Gulf of Mexico contributing to eutrophication
and to death or elimination of many natural
organisms (Conley
et al
., 2009). Phosphorus can
also leach to groundwater, but this is typically
not a concern unless that groundwater moves
back to the surface. Surface loss of P through
runoff also contributes to the eutrophication of
water bodies (Sharpley
et al
., 2003).
Managing farms to reduce or control all of
the different nutrient losses affecting air and
water quality is very complex. There are many
interactions among the farm components so
reducing one source or type of emission may
As discussed in more detail in other chapters of
this volume (Chapters 7, 8 and 9), there are many
environmental issues of concern in animal agri-
culture. These include the effects of production
on both air and water quality. There are a num-
ber of gaseous emissions from animal production
with the major sources being the animal, manure
excreted by the animal and feed (primarily
silages) consumed by the animal. Compounds of
concern include ammonia, hydrogen sulfide,
volatile organic compounds and the greenhouse
gases of methane, nitrous oxide and carbon
dioxide. Emissions of ammonia and hydrogen
sulfide can contribute to the formation of fine
particulate matter in the atmosphere, which
contributes to human respiratory problems
(NRC, 2003). Ammonia emission contributes to
regional degradation of terrestrial and aquatic
ecosystems, and both compounds contribute to
the local nuisance of odour (NRC, 2003; Renard
et al
., 2004). Volatile organic compounds include
many different alcohol, acid and aromatic com-
pounds. In addition to their local effect of odour,
they contribute to the formation of ground level
ozone or smog (Howard
et al
., 2010). Greenhouse
gases are a concern due to their role in global cli-
mate change (IPCC, 2007).
