Contaminants
Research on contaminant transport and control
in soils can improve soil, water, ecosystems,
and human health.
Several classes of contaminants reach the
soil through several means. Excess nitrogen
and phosphorus leaving the soil and entering
water bodies can cause degradation of water
supplies and ecosystems. Both organic and
inorganic fertilizers—when improperly
managed—can contribute to nitrate and
phosphorus contamination through transport
of excess quantities over the soil to surface
waters, and through the soil to ground and
surface waters.
Research has shown that rates and timing
of applications to coincide with plant demand
can reduce the risk of nitrate contamination
of water, as can efficient methods of application
and soil conservation practices to reduce
erosion and runoff. Understanding the processes
that cause retention and transport of excess
nutrients, and development of models to predict
nutrient movement, can improve guidelines
and recommendations for managing these soil
amendments, according to the particular soil,
crop, and season.
Contaminant spills, as well as pesticide
applications and disposal of wastes containing
organic contaminants, can lead to transport
of these contaminants into water bodies.
Transport properties of this kind of contaminant
can be very different from transport properties
of nutrients. These kinds of contaminants
behave differently from nutrients. Models
for predicting transport are needed, based
on understanding of mechanisms of retention
and transformation of these molecules in
the soil.
In some cases, contaminants can be transported
through and over soil via colloids or suspended
particles that contain the contaminants.
NIFA supports research, education, and
extension activities toward a better understanding
of mechanisms, appropriate use of models,
and increased awareness of the practices
that lead to mitigation of contaminant transport
and environmental degradation.
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